Remains of Leatherback turtles,
Dermochelys coriacea, at Mid-Late
Holocene archaeological sites in
coastal Oman: clues of past worlds
John G. Frazier1, Valentina Azzarà2,3, Olivia Munoz3,
Lapo Gianni Marcucci4, Emilie Badel3, Francesco Genchi4,
Maurizio Cattani4, Maurizio Tosi4,† and Massimo Delfino5,6
1 National Museum of Natural History, Smithsonian Institution, Department of
Vertebrate Zoology–Amphibians & Reptiles, Washington, D.C., USA
2 Faculty of Archaeology, Leiden University, Leiden, Netherlands
3 UMR 7041 Archéologie et Sciences de l’Antiquité, Equipe “du Village à l’Etat au Proche
et Moyen Orient”, Maison de l’Archéologie et de l’Ethnologie, Nanterre, France
4 Department of History and Cultures, University of Bologna, Bologna, Italy
5 Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
6 Institut Català de Paleontologia Miquel Crusafont, Universitat Autónoma de Barcelona,
Cerdanyola del Valles, Barcelona, Spain
† Deceased author.
ABSTRACT
Small, irregular isolated bones identified as remains of leatherback turtles
(Dermochelys coriacea) were recovered from Mid to Late Holocene sites at Ra’s
al-Hamra and Ra’s al-Hadd, coastal Oman. These provide the third instance of this
animal being documented from any prehistoric site anywhere, and the
records provide one of the oldest, if not the oldest, dates for this distinctive
chelonian—even though they do not refer to fossils. Decades of research in this
region has yielded vast amounts of archeological information, including abundant
evidence of intense exploitation and utilization of marine turtles from about
6,500 to 4,000 BP. During part of this period, turtle remains in human burials have
been extraordinary; the turtle involved, Chelonia mydas, has been abundant in
the region during modern times. Yet despite intense and varied forms of prehistoric
marine resource exploitation, and major, long-term archeological work, no other
turtle species has been previously authenticated from these, or other coastal sites.
The documentation of remains of the largest and most distinctive of living marine
turtles, D. coriacea, at Ra’s al-Hamra and Ra’s al-Hadd, presented herein, provide
detailed information that serves as the basis for future interpretations and
discussions regarding incomplete, disarticulated remains from the Mid to Late
Holocene, particularly in reference to taphonomic questions and diverse
environmental conditions.
Subjects Anthropology, Conservation Biology, Marine Biology, Zoology
Keywords Bronze Age, Ra’s al-Hamra, Neolithic, Zooarcheology, Ossicles, Taphonomy,
Marine turtles, Ra’s al-Hadd
How to cite this article Frazier JG, Azzarà V, Munoz O, Marcucci LG, Badel E, Genchi F, Cattani M, Tosi M, Delfino M. 2018. Remains of
Leatherback turtles, Dermochelys coriacea, at Mid-Late Holocene archaeological sites in coastal Oman: clues of past worlds. PeerJ 6:e6123
DOI 10.7717/peerj.6123
Submitted 29 March 2018
Accepted 17 November 2018
Published 17 December 2018
Corresponding author
Massimo Delfino,
massimo.delfino@unito.it
Academic editor
James Reimer
Additional Information and
Declarations can be found on
page 27
DOI 10.7717/peerj.6123
Copyright
2018 Frazier et al.
Distributed under
Creative Commons CC-BY 4.0
INTRODUCTION
Dermochelys coriacea (Vandelli, 1761) is the largest living turtle, and the only extant
member of the family Dermochelyidae, presently considered to include nine genera with a
total of 17 species, the oldest of which dates back to at least the Early/Lower Campanian
(Late Cretaceous), nearly 84 Ma (Supplemental Information 1). At most, the fossil
record ofD. coriaceamay include one, or two, small isolated bones, from the Plio-Pleistocene
Lee Creek Mine, North Carolina, USA. These irregular ossicles (alternately called
“dermal ossicles,” “osteoderms,” or “platelets”) were reported in an unpublished thesis
(Köhler, 1996) which was briefly mentioned in two recent paleontological publications
(Karl, Gröning & Brauckmann, 2012a: 166; Karl, Lindow & Tütken, 2012b: 214), and
only tentatively confirmed recently (Supplemental Information 2). However,
consistently D. coriacea is regarded to have no fossil record (Wood et al., 1996, 2009;
F. de Lapparent de Broin in litt. to JF August 22, 2017; J. Parham in litt. to JF
September 20, 2017; R. Hirayama in litt. to JF September 11, 2018; R. Weems in litt.
to JF September 12, 2018).
Similarly, despite its circumglobal distribution, distinctive morphology, and large
body size, growing to over 1.5 m in length and up to a tonne in body weight (Frazier,
Gramentz & Fritz, 2005: 249–251, 271 ff; Eckert et al., 2012: 6–8, 53), this animal has been
reported only twice from prehistoric archeological sites, both later than 200 AD and
from the Caribbean (Frazier, 2005). The fact that hundreds of coastal sites, around the
world, have been studied by archeologists and zooarcheologists emphasizes the rarity of
these archeological specimens.
The Sultanate of Oman, in the south-eastern corner of the Arabian Peninsula,
hosts hundreds of prehistoric sites, some estimated to be more than 10,000 years old
(Charpentier, 2008; Charpentier & Crassard, 2013, Charpentier et al., 2016; Rose et al.,
2018); Paleolithic, Neolithic, Bronze Age, Iron Age, and Islamic sites are well represented
(Uerpmann & Uerpmann, 2003; Cleuziou & Tosi, 2007). Lagoonal and marine
environments are regarded to have been major sources of food and materials for all
prehistoric coastal populations—even after the development of agricultural and pastoral
economies, and these resources continue to be important today (El Mahi, 2000; Uerpmann
& Uerpmann, 2003; Cleuziou & Tosi, 2007; Azzarà, 2012; Berger et al., 2013; Zazzo,
Munoz & Saliège, 2014; Munoz, 2017). Two coastal headlands are central to the present
study: Ra’s al-Hamra, on the eastern limit of the sandy coast of Batinah, and Ra’s al-Hadd,
at the easternmost extreme of the Ja’alan region (Fig. 1).
Archeological research at Neolithic sites along coastal Oman began in 1973 at
Ra’s al-Hamra, with the first excavations in 1977 (Tosi, 1989;Marcucci, 2014); research on
this limestone platform has continued to the present (Durante & Tosi, 1977; Salvatori,
Coppa & Cucina, 2007; Marcucci et al., 2011, 2014; Zazzo et al., 2016). This headland is
within the urban area of Muscat, the nation’s capital. A total of 12 different archeological
sites have been enumerated at Ra’s al-Hamra (Fig. 2; Supplemental Information 3),
but primarily because of coastal development, nine sites were destroyed before systematic
work by trained archeologists could begin (Durante & Tosi, 1977: 141–142; Salvatori, 1996;
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 2/34
Figure 1 Two coastal headlands are central to the present study: Ra’s al-Hamra, on the eastern limit
of the sandy coast of Batinah, and Ra’s al-Hadd, at the easternmost extreme of the Ja’alan region.
(A) The localities mentioned in the text, mainly the archeological sites: As-Sabiyah (Kuwait), Dalma,
Umm an-Nar, Akab, Umm al-Qawain, Jebel al-Buhais, and Kalba (United Arab Emirates);
Ra’s al-Hamra, on the Batinah coast, Ra’s al-Hadd, Ra’s al-Jinz, Ra’s al-Khabbah, and As-Suwayh, all on
the coast of Ja’alan (Oman), as well as the offshore Daymaniyat Islands, Masirah Island, and Al Halaniyath
Islands of Oman; Neolithic and Early Bronze Age sites are distinguished (figure by V. Azzarà, based on a
base map of H. David). (B) The most easterly extension of the Arabian Peninsula, and Oman, showing
the geographic relationship between Ra’s al-Hamra, with RH-6, and Ra’s al-Hadd, with HD-6 (figure by
L.G. Marcucci, based on a base map of H. David). Full-size DOI: 10.7717/peerj.6123/fig-1
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 3/34
Figure 2 The archeological sites and sandy beaches at Ra’s al-Hamra. (A) The Ra’s al-Hamra and
Qurum area, showing locations of archeological sites mentioned in the text, as well as present-day sand
beaches in the area: seaward and west of RH-6, Sifat al-Ghar, Marsa al-Abyad, Marsa al-Murjan,
Ra’s al-Hamra bay, and Mina al-Fahal (figure by L.G. Marcucci, based on a base map of H. David;
note: RH-9 is not an ancient site, see Supplemental Information 3). (B) General excavation plan
of Ra’s al-Hamra 6, showing Sector A, Sector B, Sector C, TT-Z, and Trench North (modified by
L.G. Marucci; Google, 2013 DigitalGlobe). Full-size DOI: 10.7717/peerj.6123/fig-2
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 4/34
Uerpmann & Uerpmann, 2003; Munoz, 2014). Radiocarbon dating from Ra’s al-Hamra
sites indicates a maximum span from 5608 BC to 55 AD (Biagi, 1994; Uerpmann &
Uerpmann, 2003; Zazzo, Munoz & Saliège, 2014; Zazzo et al., 2016; Munoz, 2014),
although the shell middens and the period of intense habitation are estimated to date
between 6,000 and 3,000 BC (Cleuziou & Tosi, 2007; Munoz, 2014: 134, fig. A4).
Voluminous evidence is available on Neolithic subsistence, settlement, and funerary
practices; skeletal remains of marine animals have been abundantly documented;
the dominance of tuna bones in middens is notable (Uerpmann & Uerpmann, 2003, 2007;
Uerpmann, 2003). Site RH-5, estimated to have been occupied from before 4,000
until about 3,000 BC, includes a large human cemetery, where at least 149 graves have been
excavated (Salvatori, 2007; Salvatori, Coppa & Cucina, 2007). Recent microstratigraphic
excavations in RH-5 graves yielded repeated evidence of nets, some evidently of large
size (Munoz, 2014: 169). Although there is no physical evidence of boats or other types of
vessel, evidence of the “material culture”—particularly artifacts interpreted to have been
fishing implements—and zooarcheological evidence—including remains of large
pelagic fishes as well as sharks—have prompted trained archeologists to propose that some
kind of watercraft was used at RH-5 (Uerpmann & Uerpmann, 2003; Uerpmann, 2003;
Salvatori, Coppa & Cucina, 2007; Marcucci et al., 2011). Some of the most remarkable
grave goods at RH-5 are skeletal remains of green turtles, Chelonia mydas (Linnæus,
1758), whose bones have been recovered from 80 graves. Turtle crania, or parts of
crania, are remarkably common, appearing in nearly 13% of excavated graves: as many as
29 skulls have been recovered from a single grave, and as many as 34 lower jaws were
found in another grave: hence, the conclusion that Chelonia mydas was an important
resource for nutritional as well as cultural needs (Uerpmann & Uerpmann, 2003;
Salvatori, 2007; Salvatori, Coppa & Cucina, 2007; Munoz, 2014). Although marine turtle
remains are well documented from human graves around the world, their predominance
in RH-5 burials is unique (Frazier, 2003, 2005); and some authors have called the
RH-5 people “seasonal turtle worshipers” (Tosi, 1989: 152; Cleuziou & Tosi, 2007: 76,
fig. 58 ff).
The older RH-6 site at Ra’s al-Hamra is nowadays located on the eastern edge of a
mangrove within the Qurum Nature Reserve, presently about 600 m inland from the sea,
and about 700 m south of RH-5 (Fig. 2). RH-6 is dominated by a massive midden,
nearly two m high in some places, associated with settlement areas and a graveyard.
This midden was first identified in 1975 (Tosi, 1975; Durante & Tosi, 1977), and then more
thoroughly investigated during several excavation seasons in the 1980s and late 1990s
and early 2000s (Biagi, 1999; Marcucci, 2015). Most recently, RH-6 was studied in 2012
and 2013 in response to pending construction of an archeological park planned at
Ra’s al-Hamra (Marcucci, 2017: 6). Several studies (Marcucci et al., 2014: fig. 2; Marcucci,
2015: 350–353) have concluded that the thick, well-packed layers of marine shells and
fish bones that constitute the RH-6 midden are the result of intense prehistoric, year-round
exploitation of lagoon and marine animals; the evidence supporting this proposition
includes: remains interpreted as ancient features (e.g., post holes, hearths, refuse pits)
and human burials, as well as hard objects, interpreted to have been made or modified by
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 5/34
human agency (“artifacts”) (e.g., widely found net sinkers, fish hooks, and gorges), and also
remains of living organisms, interpreted to have been impacted in diverse ways by human
agency (“ecofacts”) (e.g., numerous hearths with concentrated remains of molluscs
and fishes—signs of food preparation) As in the case of RH-5, there are abundant remains
of fish bones, with trevallies (Carangidae) and tunas predominating; hence, archeologists
have argued that some kind of watercraft was used at RH-6 (Uerpmann & Uerpmann,
2003; 198–199; Marcucci, 2015: 390, 391, 450 fn 1361). Based on radiocarbon dating, the
RH-6 settlement is estimated to have been occupied from about 5,603 to 4,473, 2s cal BC
(Zazzo et al., 2016); and it is one of the earliest known human occupations, both for
Ra’s al-Hamra and coastal Oman. However, the radiocarbon dates also indicate that the
RH-6 graveyard was in use later, after a 500- to 700-year hiatus, around 3,996–3,830,
2s cal BC (Zazzo et al., 2016).
“Interestingly, turtles and sea mammals were rare or nonexistent at RH-6 as compared
to the later sites” [viz RH-4, RH-5, and RH-10] (Uerpmann & Uerpmann, 2003: 247).
The only published information on turtle remains recovered from RH-6 seems to be an
enigmatic comment in Biagi (1999: 66, fig. 19–44) that reported and illustrated
“a turtle bone with a double, diverging perforation,” and a brief comment inMarcucci et al.
(2014: 245) that “a few turtle bones were found inside” Pit 8 (of Sector C, attributed to
Period II).1 In addition, Marcucci’s unpublished PhD dissertation (2015: 392–398)
gave a brief, preliminary description of marine turtle remains at RH-6, including
D. coriacea ossicles reported in detail in the present article.
Ra’s al-Hadd, the second area of importance for the present study, lies about 300 km SE
of Ra’s al-Hamra; it is the eastern-most extension of Oman and the Arabian Peninsula,
forming the limit between the Gulf of Oman to the north and the Arabian Sea to the
south (Figs. 1 and 3). Archeological research began in 1987, with increased activity after
1995 (Azzarà, 2015: 113–114). More than 13 archeological sites have been identified at
Ra’s al-Hadd, which range from Neolithic to Islamic; nearly all of these are regarded to be
younger than the Ra’s al-Hamra sites.
Although at least three different sites at Ra’s al-Hadd are interpreted to have been
occupied after about 2,500 BC; site HD-6, central to this study, is the only settlement
thought to have been occupied earlier (∼3,100–2,700/2,600 BC). HD-6 stands on a sand
bar at the edge of a paleo-lagoon, about 200 m from the Arabian Sea and about 300 m
south of the present-day village of Ra’s al-Hadd. HD-6 was excavated from 1996 to
2015 (Tosi & Cattani, 1997; Cattani & Cavulli, 2004; Azzarà, 2009, 2012, 2013). The first
occupation (Phase I-1), was followed by three subsequent phases (I-2, I-3, and I-4),
each with adobe and stone structures, and further divided into several subphases (i.e., I-2a
to I-2e, I-3a to I-3e, and I-4a to I-4b) based on stratigraphic-structural sequences
(Azzarà, 2013, 2015). The timings of these phases/subphases is supported by recent C14
analysis of charcoal from the first to nearly the last occupational phase which gave
radiocarbon estimates from 3,090–2,870 to 2,620–2,330, 2s cal BC (Azzarà, 2012: fn 3,
2013: fn 1, fig. 3, 2015: 126–133).
The settlement at HD-6 was larger and more complex than those at Ra’s al-Hamra.
Remains of buildings (Fig. 4), with apparent workshops and storage facilities, indicate
1 From what can be seen in a photo of a
wall of Pit 8 (Marcucci, 2015: fig. 6), one
of these turtle bones is at least 13 cm long
and up to one cm thick, and appears to
be from a “hard-shelled” (cheloniid)
turtle (J. G. Frazier, 2018, personal
observation).
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 6/34
Figure 3 The Ra’s al-Hadd area, showing locations of archeological sites mentioned in the text, as
well as present-day turtle nesting beaches. EBA, Early Bronze Age; Hafit Period refers to about 3,200
to 2,600 BC; Umm an-Nar Period refers to about 2,600 to 2,000 BC (figure by V. Azzarà).
Full-size DOI: 10.7717/peerj.6123/fig-3
Figure 4 Plan of the Early Bronze Age occupation at Ra’s al-Hadd HD-6, Oman. Locations of key
areas mentioned in the text: Room 33, Room 54, Courtyard F/G, and T.T.2/97 (figure based on
Azzarà, 2015). Full-size DOI: 10.7717/peerj.6123/fig-4
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 7/34
activities such as production of domestic supplies and jewelry, mainly stone- and
shell-beads and rings (Azzarà, 2009, 2012; Hilbert & Azzarà, 2012: 18–24). Abundant
faunal evidence indicates that intense fishing occurred during all occupational phases at
HD-6, and included a wide variety of animals, invertebrates and vertebrates, pelagic and
benthic. Artifacts interpreted as net sinkers, vestiges of large nets, and fish hooks are
common; and abundant evidence supports the interpretation of prehistoric preparation of
marine animals, particularly fishes and marine turtles. The material culture as well as the
faunal remains (e.g., sharks, tuna, and other large pelagic fishes) indicate that some
sort of watercraft was used (Tosi et al., 2002; Cleuziou & Tosi, 2007: 58; Azzarà, 2012; 255).
Oil from dolphins (Delphinidae) and marine turtles (evidently Chelonia mydas) is thought to
have been extracted in large quantities for both storage and trade (Mosseri-Marlio, 1998a,
1998b, 2000, 2002). During modern times the beach seaward of Ra’s al-Hadd has been
of major importance for nesting Chelonia mydas, with up to 10,000 females estimated to nest
each year (Salm & Salm, 1991; Gasperetti et al., 1993; Salm, Jensen & Papastavrou, 1993).
HD-6 has yielded numerous signs of trade. The scale of production of shell- and
stone-beads indicates that they were produced, at least partially, for trade, evidently to
obtain different goods from other communities, a hypothesis supported by copper objects
(including fishing hooks) recovered from HD-6, made from copper that apparently
came from the interior of the country. Notably, later sites at Ra’s al-Hadd show
clear material evidence of trade with overseas regions, such as Mesopotamia and the
Indus Valley; indeed, Ra’s al-Hadd has been called the “main [prehistoric] port for
international trade” (Cleuziou & Tosi, 2007: 235).
HD-6 is the most complex coastal settlement from Oman known from before 2,500 BC
(Azzarà, 2013). Within one km of HD-6 there are numerous “cairn,” or “turret,”
graves, from the same period, located in sepulchral areas, including sites HD-10
(Salvatori, 2001), and HD-7, where fish remains were recovered from all tombs that have
been studied; although other animal remains (including turtle bones) have been found,
it is unclear if these were part of the burial ritual, or simply included with infill
(Munoz, 2014: 231–232).
During modern times the coasts and waters of Oman have hosted all five of the
circumglobal species of marine turtles, and the numbers of three of the species that nest
in Oman are globally important. Most abundant, and widely distributed, is the green turtle,
Chelonia mydas, which is recorded to nest on at least 275 beaches along approximately
2,000 km of coast. An estimated 90% of nesting occurs along the Arabian Sea; and the 45 km
stretch of beach from Ra’s al-Hadd south to Ra’s al-Khabbah (Fig. 1) is of particular
importance. There are an estimated 20,000 nesters per year in Oman, of which half nest
in the Ra’s al-Hadd area; nesting is year round in Oman. During present times there
has been little nesting on the Batinah coast, but this may be a result of modern-day
human disturbances. The mainland coasts of southern Oman provide important feeding
areas for Chelonia mydas (Salm & Salm, 1991; Gasperetti et al., 1993; Salm, Jensen &
Papastavrou, 1993; Baldwin & Al Kiyumi, 1999).
The island of Masirah, off the south-eastern coast of Oman (Fig. 1), hosts one of the
largest nesting populations in the world of loggerhead sea turtles, Caretta caretta
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 8/34
(Linnæus, 1758). They also nest on other islands, primarily the Al Halaniyat Islands, and
on nearly 200 mainland beaches of the Arabian Sea, particularly in the south-western
extreme of Oman. The southwest of the country also seems to provide important
feeding areas. There are occasional records of Caretta caretta from the Muscat area
(Ross & Barwani, 1982; Salm & Salm, 1991; Salm, Jensen & Papastavrou, 1993; Baldwin,
Hughes & Prince, 2003; Conant et al., 2009).
While the numbers are nowhere near as large as for Chelonia mydas or Caretta caretta,
there are abundant records of the hawksbill, Eretmochelys imbricata (Linnæus, 1766)
nesting in Oman, especially on the Daymaniyat islands (in the Muscat area, Fig. 1), and less
so on Masirah Island. With nearly 1,000 nesters per year, the number of E. imbricata
nesting in Oman is of regional and global significance. Known feeding areas of importance
for this turtle are around Masirah Island and in the far west of Oman (Salm & Salm,
1991; Gasperetti et al., 1993; Salm, Jensen & Papastavrou, 1993; Rees & Baker, 2006;
Pilcher et al., 2014).
The fourth species known to nest in Oman is the olive ridley, Lepidochelys olivacea
(Eschscholtz, 1829). There is scattered nesting on the mainland coast of the Arabian sea,
but most known nesting, estimated to be more than 100 females per year, is on Masirah
Island. The waters around this island seem to be important feeding areas; and there
are accounts of unexplained large die-offs of these turtles that have stranded along the
coasts of the Gulf of Masirah (Salm & Salm, 1991; Gasperetti et al., 1993; Salm, Jensen &
Papastavrou, 1993; Rees & Baker, 2006; Rees et al., 2012).
The leatherback, D. coriacea, occurs in Oman, but there are no accounts, contemporary
or historical, of nesting. There may be some feeding in Omani waters, particularly in the
western extreme. There are occasional reports of these turtles washing up dead on the
Arabian Sea coast of the country. Oman is not considered to be an important area for
this species, and some authors regard this turtle as a vagrant in Oman (Salm & Salm, 1991;
Gasperetti et al., 1993; Salm, Jensen & Papastavrou, 1993; Baldwin & Al Kiyumi, 1999;
Hamann et al., 2006).
During modern times local fishermen have caught marine turtles on beaches and in the
sea with harpoons, gaffs, and nets; the fat is reputed to be a preferred part. At least
four species of turtles are known to have been hunted during recent times, but Chelonia
mydas comprises more than 95% of the catch. Eggs are also consumed (Salm, Jensen &
Papastavrou, 1993; Baldwin & Al Kiyumi, 1999). To date, only Chelonia mydas
has been documented from archeological sites in Oman, including RH-6 and HD-6
(Frazier, 2003, 2005; Uerpmann & Uerpmann, 2003).
MATERIALS AND METHODS
The zooarcheological specimens discussed herein derive from two localities of
coastal Oman: Ra’s al-Hamra and Ra’s al-Hadd (Fig. 1); work at sites RH-6 and HD-6, has
been carried out under two different frameworks. Although the research objectives and
conditions at the two sites have not been identical, investigations at both sites have
employed similar sampling and excavation procedures, such as spatial matrix sampling
and stratigraphic sequencing as described by Harris (1997). These widely recognized
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 9/34
standard protocols in the field of archeology have thus providing common ground for data
extrapolation and comparison between the two Omani sites. The zooarcheological
specimens described in this paper were compared with known reference specimens of both
recent D. coriacea and fossil Psephophorus polygonus Meyer, 1847. The RH-6 and HD-6
specimens were examined macroscopically; no detailed microscopic analyses were
undertaken.
Ra’s al-Hamra
Although the RH-6 midden was first identified in 1975, with subsequent excavations over
nearly four decades, the specimens reported herein were only retrieved during the
2012 and 2013 seasons; four loci were investigated: Sectors A, B, and C, as well as Trench
North (Fig. 2A). All but the last-named were worked during earlier excavations
(Marcucci et al., 2014; Marcucci, 2015). Extensive excavation of Sector A, at the eastern
edge of the anthropogenic deposit, revealed two occupational periods, the first of which is
the earliest known period of occupation at RH-6 (Marcucci et al., 2014; Zazzo et al., 2016).
At Sector B (a graveyard area), which is toward the center and top of the mound,
only the upper-most layers of the stratigraphic sequence were investigated. Six funerary
structures, part of a larger cluster of graves, were excavated. Sector C, near the western
extreme of the site, showed six periods of occupation, the longest occupational sequence
for RH-6. Test trench TT-Z complemented main Sector C. Trench North, despite
exhibiting different occupational evidence, resembled Sector C, although the stratigraphy
showed only four occupational periods (Marcucci et al., 2014).
The same excavation, sampling, and retrieval procedures were employed in each of
the settlement areas (Sectors A and C, and Trench North); a grid of 2 
 2 m excavation
units was used for all excavations. Sediments were sieved with one to five mm
mesh sizes. When stratigraphic units presented concentrations of dark colored
anthropogenic deposits, a ca. eight litre basket of sediment was processed for flotation
with 0.5–3 mm sieves. For the graveyard area (Sector B), sediments from all graves were
sampled from the surface to the bottom of the pit with one mm sieves. In summary,
all osteological remains were recovered in situ (directly from the excavation) or
from sieves.
Ra’s al-Hadd
Specimens retrieved fromHD-6 discussed in this paper were collected during the 1997, 2000,
2002, 2007, and 2008 seasons. Excavations and sample retrieval at Ra’s al-Hadd followed
standardized procedures, adapted to the contexts being investigated. Deposits from
F/G Courtyard and Room 54 (Fig. 4) were excavated using 2 
 2 m excavation units;
Room 33 was excavated using 50 
 50 cm units in order to analyze the distribution of
small objects which were remarkably common in this space: beads and other evidence of
bead and ring production, as well as D. coriacea ossicles, Anthropogenic deposits removed
from excavations from within these enclosed spaces were collected in their entirety
and dry-sieved using one to three mm mesh; artifacts were collected both in situ and by
sieving. Samples retrieved from test trench T.T. 2/97 were collected in situ, and there was
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 10/34
no systematic sieving. Likewise, sampling from outside dwelling areas was carried out
in situ; nonanthropogenic deposits from these areas were only partially sieved (see Fig. 4
for a general plan of HD-6, which shows general locations and dimensions of discrete
spaces relevant to this study).
Data concerning D. coriacea ossicles from both RH-6 and HD-6 discussed herein are
original contributions to this paper, as is information concerning most of the retrieval
contexts for HD-6 (i.e., Room 54, F/G Courtyard, T.T.2/97, and outside of buildings).
The assemblage of artifacts from Room 33 at HD-6 has been addressed in a previous article
(Azzarà, 2009: 7, figs. 5, 6.1, 6.4–5. 6.8).
The archeological materials described in this paper are stored permanently in the
collections of the Department of Excavations and Archeological Studies of the Ministry of
Heritage and Culture of the Sultanate of Oman in Muscat.
RESULTS
Identification of Dermochelys coriacea
Irregularly shaped bony ossicles were recovered from both sites: a total of 184 from
RH-6, and a total of 149 from HD-6. These laminar structures are approximately round,
elliptical, or polygonal, with borders covered by very fine, needle-like projections
(Fig. 5). The maximum dimension across the lamina varies considerably, from a few
millimetres to a few centimetres. One of the largest ossicles, from RH-6, Sector C, TT-Z,
is 30 mm in the greatest dimension and 21 mm perpendicular to that; its dorsoventral
thickness varies from three to four mm (Fig. 5A); one of the largest ossicles from
Ra’s al-Hadd, Room 54, is shown in Fig. 5F. Two of the smallest ossicles, from RH-6,
Sector A, are 9 
 7 
 3 mm and 9 
 5 
 3 mm. The surface of the ossicles that
was toward the exterior of the animal is generally smooth or uniformly porous, whereas
the visceral surface is irregular with sparse vascular foramina. The vast majority of
ossicles, 99% from RH-6 and 89% from HD-6, are essentially flat (Figs. 5A–5D), while a
small proportion of the ossicles are tectiform with a convex external surface topped by a
more or less central ridge (Figs. 5E and 5F). Most of the ossicles were solitary, but
in HD-6 Room 33 at least 14 were retrieved while still articulated with other ossicles,
held together by the deeply interdigitating needle-like projections, and a fine mineralized
concretion (Fig. 6).
The size and shape of the ossicles, along with their interdigitating sutures that interlock
tightly with neighboring ossicles, as well as the tectiform structure of some ossicles,
are diagnostic features of the carapace, and plastron, of most post-Eocene marine turtles of
the family Dermochelyidae (Supplemental Information 1). The relative thinness of the
333 Omani ossicles and the deeply convex exterior surface of those ossicles that are
tectiform, with a more or less central ridge and deeply concave visceral surface, and the
abundant, fine needle-like projections covering the sides of the ossicles, are characters
consistent with D. coriacea that contrast from the morphology of the extinct dermochelyid
P. polygonus, whose ossicles are much thicker (very rarely less than five mm), virtually
flat on the visceral surface, and lack the dense cover of fine needle-like projections
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 11/34
Figure 5 Examples of 6 ossicles of Dermochelys coriacea (Vandelli, 1761), recovered from the
Sultanate of Oman, during the present study. (A) One of the largest ossicles encountered from
Ra’s al-Hamra-6, from Sector C, test pit TT-Z, showing the flat (nonridged) external surface, the internal
(or visceral) surface, and a side view. (B) A flat, nonridged, ossicle from Ra’s al-Hamra-6, Sector C, test pit
TT-Z, showing: the flat (nonridged) external surface, the internal (or visceral) surface, and a side view.
(C) A flat, nonridged, ossicle from Ra’s al-Hadd-6, Room 33, showing the external surface. (D) A flat,
nonridged, ossicle from Ra’s al-Hadd-6, Room 33, showing the external surface. (E) A ridged ossicle from
Ra’s al-Hamra-5, Sector C, test pit TT-Z, showing: the ridged external surface, the internal (or visceral)
surface, and a side (anterior or posterior) view. (F) Two tightly articulated ossicles, the largest of which is
one of the largest ossicles encountered from Ra’s al-Hadd-6, Room 54, showing the ridged external
surface, the internal (or visceral) surface, a lateral view, and a side (anterior or posterior) view. Thin lines
connect different views of the same ossicle. All scale bars equal 10 mm. Photos: M. Delfino.
Full-size DOI: 10.7717/peerj.6123/fig-5
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 12/34
on the sides (Delfino et al., 2013). The tectiform, ridged ossicles documented herein
correspond to somewhere from one of the seven anteroposterior ridges of the carapace
(less probably to one of the six longitudinal ridges of the plastron); the flat ossicles
correspond to the broad areas between longitudinal ridges (Wood et al., 1996; Frazier,
Gramentz & Fritz, 2005; Delfino et al., 2013; see also Fig. 7).
There are no obvious differences between ossicles retrieved from RH-6 and those from
HD-6. No cut marks, signs of burning, or other indications of postmortem modification
were observed on any of the ossicles. The interlocking ossicles of this turtle form the
majority of the carapace, or dorsal shell (Fig. 7), and part of the plastron, or ventral shell.
No other bones (i.e., no cranial, axial, appendicular, or thecal elements from the carapace
Figure 6 Remains of Dermochelys coriacea (Vandelli, 1761), recovered from the Sultanate of
Oman, during the present study, excavated from Room 33 of the Bronze Age archeological site at
Ra’s al-Hadd-6. This carapace fragment shows 14 ossicles articulated and covered with mineralized
concretions. (A) Dorsal, exterior view. (B) Interior view. The scale bar equals 10 mm. Photos: M. Delfino.
Full-size DOI: 10.7717/peerj.6123/fig-6
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 13/34
or plastron) were identified as, or suspected to be from, D. coriacea from either RH-6,
HD-6, or any other site in Oman.
Ra’s al-Hamra-6
The majority of the 184 ossicles recovered from RH-6 (Table 1) came from settlement
areas (91%), showing that all the sectors excavated, and nearly the entire occupational
sequence that has been sampled, yielded remains of Dermochelys: 71 ossicles from Sector
A; 72 from Sector C; and 25 from Trench North. Of the six funerary structures that
were excavated during 2012 and 2013 in Sector B, only Grave 7 (without any human
Figure 7 Desiccated carapace ofDermochelys coriacea (Vandelli, 1761).American Museum of Natural
History (AMNH) specimen no. R 57749, received from aquarium in 1936, no further collection data are
available; at the anterior end of the specimen the ruler with alternating black and white squares is 10 cm
long, which shows that the specimen is approximately half the length of an adult. (A) Dorsal view
showing the mosaic of thousands of small, irregular, interlocking ossicles that make up the dorsal shell.
(B) Ventral view of the same specimen, showing the dried tissue that supports the ventral surface of the
mosaic, and the nuchal element, at the extreme anterior (left side). Photos: L. Vonnahme.
Full-size DOI: 10.7717/peerj.6123/fig-7
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 14/34
skeleton and thought to be a symbolic burial structure) produced ossicles, of which 16 were
recovered. Out of the 184 D. coriacea ossicles recovered from RH-6 only two (1%) were
ridged, both from Sector C, Period V (Table 1: collection 26).
The 71 ossicles found in Sector A (Table 1: collections 1–5) are all from Period II of this
sector, the locus with the oldest known signs of human presence at RH-6. These ossicles
were primarily associated with anthropogenic deposits and structural features
located a few centimeters above the bedrock, in a very restricted area between traces of
two habitational structures. The 72 D. coriacea ossicles unearthed in Sector C are
from later occupations, Periods C-V and C-VI; the artifacts and ecofacts from these
Table 1 Ossicles of Dermochelys coriacea (Vandelli, 1761), from Ra’s al-Hamra-6.
Collection no. Number of ossicles Sector Stratigraphic
unit(s)
Period Figure 5
Total Ridged only
1 11 A SU109 A-II
2 1 A SU19 A-II
3 32 A SU11 A-II
4 25 A SU3 A-II
5 2 A SU2 A-II
6 3 C SU118 C-V
7 1 C SU103 C-V
8 3 C SU98 C-V
9 14 2 C SU97 C-V E
10 1 C SU91 C-V
11 8 C SU90 C-V
12 4 C SU89 C-V A
13 6 C SU75 C-V
14 5 C SU73 C-VI B
15 26 C SU57 C-VI
16 1 C SU3 C-VI
17 1 Tr N SU55 TN-I
18 6 Tr N SU49 TN-I
19 9 Tr N SU31 TN-I
20 2 Tr N SU25 TN-I
21 1 Tr N SU24 TN-I
22 5 Tr N SU22 TN-II
23 1 Tr N Surface TN-IV
24 16 B SUs 12 and 13 Grave 7
Total 184 2
Note:
Collection no. = the arbitrary serial number that corresponds to the collection of ossicles that were recovered from
specific stratigraphic units in a certain locus; Number of ossicles = the number of ossicles recovered from a collection;
Total = number of ridged + nonridged ossicles recovered from a collection; Ridged only = number of ridged ossicles
recovered from a collection; Sector = the sector in RH-6 (see Marcucci et al., 2014 for details).
All collections were from settlement contexts, with the exception of collection 24 from Grave 7; Stratigraphic unit(s) = the
stratigraphic unit(s) designated during the excavation from which ossicles from this collection were recovered: SU98 of
Sector C corresponds to Pit 5; SUs 12 and 13 of Sector B correspond to Grave 7; Period = the occupational period to
which the stratigraphic unit(s) in this sector have been designated: Sector A has II Periods; Sector C has VI periods;
Trench North has IV Periods; Figure 5 = the image in Fig. 5 which illustrates an ossicle from this collection.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 15/34
periods indicate a larger human settlement and diversification of subsistence activities at
the site. The ossicles, often associated with traces of food-processing and a diversity of
artifacts (including worked shells, shell fish hooks, shell-beads, gorges, bone tools,
and stone tools), were discovered in a variety of depositional contexts: sandy sediments
containing well-preserved fish bones in situ (Table 1: collections 10 and 13), over “living”
floors (Table 1: collections 6, 7, and 15), and from a large pit (Table 1: collection 8).
All but six of the 25 ossicles recovered from Trench North came from the lowest
stratigraphic levels of this trench. These ossicles laid on tabular gravelly surfaces (Table 1:
collections 19 and 22) and within compacted deposits of fish bones or seashells (Table 1:
collection 17), bearing traces of ephemeral settlement structures (pits and post holes;
Table 1: collections 18, 20, and 21). Grave 7 (probably a cenotaph) produced 16 ossicles
from the filling of the pit (Table 1: collection 24). These were mixed with many fragmented
mollusc shells that were commonly found in the general surroundings outside the
grave, and whose presence in the grave is therefore probably incidental to the action
of filling.
Ra’s al-Hadd-6
Of the 149 ossicles recovered from HD-6, 130 (87%) were found in contexts ascribed to
Phase I-3; another 13 (9%) were from contexts attributed to Phase I-4, and just six ossicles
were found in a context attributed to Period II (Table 2). A total of 16 (11%) of the
149 ossicles from HD-6 were ridged. Most of the D. coriacea remains from HD-6 were
Table 2 Ossicles of Dermochelys coriacea (Vandelli, 1761), from Ra’s al-Hadd-6.
Collection
no.
Number of ossicles Locus Stratigraphic
unit(s)
Phase Figure 5
Total Ridged
only
1 94 Room 33 SUs 791, 794,
and 797
I-3b C and D
2 34 8 F/G Courtyard SU2049 I-3c
3 1 F/G Courtyard SU2050 I-3c
4 1 Outside of buildings SU2071 I-3c
5 1 1 Outside of buildings SU2097 I-4a
6 2 2 Room 54 SU2057 I-4a F
7 3 F/G Courtyard SU2189 I-4a
8 7 3 Outside of buildings SU2190 I-4b
9 6 2 T.T.2/97 SU19 II
Total 149 16
Note:
Collection no. = the arbitrary serial number that corresponds to the collection of ossicles that were recovered from
specific stratigraphic units in a certain locus; Number of ossicles = the number of ossicles recovered from a collection;
Total = number of ridged + nonridged ossicles recovered from a collection; Ridged only = number of ridged ossicles
recovered from a collection; Locus = the location at HD-6: see Azzarà (2009) for details regarding “Room 33”; for
“F/G Courtyard” see Azzarà & Cattani (2007: 5–7, figs. 5 and 7) ; for “Outside of buildings” see Azzarà & Cattani (2007:
2–3) for “Room 54” see Azzarà (2015: 180); for “T.T.2/97” see Tosi & Cattani (1997: 1); Stratigraphic unit(s) = the
stratigraphic unit(s) designated during the excavation from which ossicles from this collection were recovered;
Phase = the occupational phase (or subphase) to which the stratigraphic unit(s) in this locus have been designated.
Phase I-3c has been dated to 2,880–2,570, 2s cal BC (Azzarà, 2013: fig. 3); Figure 5 = the image in Fig. 5 which illustrates
an ossicle from this collection.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 16/34
collected from occupational deposits. A total of 94 ossicles (63%) was retrieved from
an indoor space, 2.3 
 1.5 m, Room 33 (Fig. 4), from deposits ascribed to Phase I-3b
(Table 2: collection1); none of these were ridged. This room showed evidence of
workshop activities related to the production of shell and stone jewelry. Two ossicles,
both ridged, came from a similar context, Room 54, but assigned to Phase I-4a (Table 2:
collection 6). In addition, 35 ossicles (23% of the Ra’s al-Hadd total), were collected
in the F/G Courtyard, Phase I-3c; eight of these were ridged. This was the second largest
number of specimens from a single locus, and the largest proportion of ridged ossicles
(23%) from any single recovery location. These ossicles from F/G Courtyard were together
with mixed plant and animal remains related to food-preparation activities (Table 2:
collections 2 and 3). An additional three ossicles were recovered from the same locus, but a
later occupation, Phase I-4a (Table 2: collection 7); none were ridged. A total of eight
ossicles were from mixed sediments indicative of the abandonment of the settlement
(or a part of it) that occurred between occupational phases, namely at the end of Phase I-3c
and beginning of Phase I-4b (Table 2: collections 4 and 8); three of these were ridged.
One ridged ossicle was recovered from outside of buildings, Phase I-4a (Table 2: collection
5). Six more ossicles came from the late occupation of the area, T.T.2/97, of which two were
ridged (Table 2: collection 9).
DISCUSSION
This paper is the third ever published account of D. coriacea remains from archeological
sites, from any locality, from any period, but since very little has been explained about
the stratigraphic and archeological contexts of the previous two records, there are
few points of comparison to make or precedents that can be followed. The two previously
published records are from the Caribbean (Frazier, 2005), and much later dates:
Cerro Brujo, Bocas del Toro, Panama (600–900 AD) (Wing, 1980: table 1) and St. Thomas,
US Virgin Islands (300–700 AD) (Wing, DeFrance & Kozuch, 2002); other than
documentation of this species, these earlier records provide next to no information on
the remains of D. coriacea that were recovered. Nonetheless, several questions about, or
stemming from, the Omani D. coriacea ossicles warrant exploration, several of which
must be addressed in a subsequent study:
1) Are the ossicles reported herein of archeological relevance, or simply beach debris
mixed in with archeological materials?
2) How many individual D. coriacea were involved in the RH-6 and HD-6 records?
3) Why are there not more prehistoric records of D. coriacea from SE Arabia or anywhere
else in the world?
4) Why were only ossicles recovered, with no other bones (e.g., skull, vertebral
column, larger thecal bones from the carapace or plastron, or axial skeleton)
reported?
5) Were environmental conditions off the coast of Oman during the Mid-to Late Holocene
more favorable to D. coriacea than they are today?
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 17/34
Are the ossicles reported herein of archeological relevance, or simply
beach debris mixed in with archeological materials?
One interpretation of the ossicles reported herein (as proposed by a reviewer) could be that
they were simply the remains of D. coriacea that had washed up on beaches, decomposed,
and became miscellaneous components of beach debris. This explanation requires
these animal remains to then be incorporated into diverse inland stratigraphic sequences,
from different time periods, after which they would be found in close spatial and temporal
association with other materials identified as cultural artifacts (e.g., worked shells,
fish hooks, gorges, net weights, shell and stone beads, bone and stone tools, post holes,
walls, etc.) as well as associating with ecofacts (e.g., dense accumulations of fish bones and
mollusc shells, including concentrations of marine animal remains that had been modified
by burning, boiling, and/or other forms of cooking and modification by human
agency). In this regard it is essential to understand the details of the strategic and temporal
contexts in which the ossicles were found, as summarized above in the Results section.
These details show that at both RH-6 and HD-6 the vast majority of ossicles were
distant from beaches where miscellaneous debris would have been deposited. Moreover,
at least 90% of the ossicles were clearly in archeological contexts, including close spatial
association with both diverse cultural artifacts and diverse ecofacts, as well as the
occurrence on occupational floors (i.e., primary evidence related to actual human action),
and presence in relatively small closed spaces, enclosed by solid walls, which were evidently
still in use at the time of the deposit. Finally, there were no significant macroscopic
signs of abrasion or tooth marks on any ossicles that would have resulted from wind, tidal,
or scavenger transport.
Animal remains found in archeological contexts, which show no macroscopically visible
signs of carnivore damage, are regularly considered to be evidence of past human
predation, if not capture, of the species in question (Henshilwood et al., 2001). Nonetheless,
empirical evidence that shows human modifications of prey remains is clearly preferable
(Thompson & Henshilwood, 2014). In this light, although 333 ossicles of D. coriacea
were found in different archeological contexts at RH-6 and HD-6, it has been noted no
macroscopic signs of human modification were found on these specimens (i.e., no signs of
cut marks and no signs of burning/charring).
The usual, commonly recognized signs, and evaluation protocols, for mammalian bones
can be of little relevance for chelonian remains, a point amply explained by Thompson &
Henshilwood (2014). Furthermore, various signs of modification by human agency
may be missed unless detailed microscopic analyses are carried out; yet, even with
comprehensive microscopic analysis of animal food remains, clear signs of modification by
human agency may be rare (Thompson, 2010). For example, Thompson & Henshilwood
(2014) did an exhaustive analysis of 4,343 bones, primarily of the small angulated
tortoise, Chersina angulata (Schweigger, 1812), which is commonly prepared by roasting
entire on the fire. Although they reported charring on over 66% of the sample, the
incidence of cut marks was only 1%, percussion marks were recorded on less than 2%
of the sample, and “tooth marks” (not necessarily all attributable to humans) were
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 18/34
observed on 5% of the sample. Because no microscopic analyses of the RH-6 or HD-6
ossicles were undertaken, we cannot assert that there are no signs of modification by
human agency on these remains.
Moreover, evidence of human modification to faunal remains is not a requisite to
establish an archeological context, but rather it is an additional, compelling source of
evidence. In the specific case of the present study, the production of conspicuous cut marks
on relatively small bones that form a large mosaic on the shell of an enormous animal,
such as D. coriacea ossicles, seems highly unlikely. Hence, it is concluded that the
vast majority of the Omani ossicles clearly pertain to archeological contexts
(see Supplemental Information 4 for more details).
How many individual Dermochelys coriacea were involved in the RH-6
and HD-6 records?
The ossicles of D. coriacea do not provide a means to distinguish among age classes or
sexes, much less individuals; hence, the usual method of calculating minimum number
of individuals (MNI) (Grayson, 1979: 205 ff), dependent on morphological characteristics,
is not feasible. Therefore, to comply with this standard procedure for estimating MNI, that
has been practiced in zooarcheological research for decades, the “maximum distinction
method” (Grayson, 1973: 433) was used to establish spatial-temporal boundaries, by which
aggregates of ossicles could be distinguished. This yielded estimates of between six
and 24 individual D. coriacea from RH-6, and between four and nine individuals from
HD-6 (see Supplemental Information 5 for details).
Radiocarbon investigations indicate that the Omani ossicles were deposited between
about 5,600 and 2,600 BC, a span of about 3,000 years. The ossicles from just RH-6
would have been deposited between about 5,600 and 3,080 BC, yielding a rough average
minimum deposition rate (RAMDR) of no less than oneD. coriacea every 300 years, and as
many as one every 75 years.
Ossicles from just HD-6 would have been deposited between about 3,100 and 2,600 BC,
indicating a RAMDR of no less than one D. coriacea every 125 years, and as many as
one every 55 years. However, such comparisons of deposition rates between sites are based
on the assumption that volumes of substrate sampled at the sites under study are
comparable, but this information is not available.
Finally, numbers used for estimating theMNI—however, theymay be obtained—represent
only the estimated MNI recovered from the sampling under study. They cannot pretend
to estimate the actual number of individuals deposited at the site.
Why are there not more prehistoric records of D. coriacea from
SE Arabia or anywhere else in the world?
For a vertebrate animal with a circumglobal distribution, distinctive morphology, and
large body size, it is remarkable that there is so little archeological and paleontological
information on D. coriacea: just three published archeological records (including this one),
and the general belief that there are no fossils (see Introduction). A lack of adequate
prehistoric technologies, and/or cultural aspects (e.g., taboos) that reduced the chances
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 19/34
of capturing and depositing even parts of these turtles in middens or habitational
areas could explain the lack of archeological records, but it is unlikely that these
factors could explain the scarcity of records for more than seven millennia. And, these
considerations do not explain the lack of fossils. A central question appears to be
taphonomic.
A possible explanation for the lack of reported remains could be that the relatively small,
irregularly shaped ossicles have been missed, and simply discarded in the overburden.
However, since sieving with meshes no larger than five mm has been standard practice for
archeological sites in this area, it is close to impossible that these obvious, although
perhaps unusual, bones would not be noticed, for even the smallest ossicles would not pass
through a five mm mesh. Moreover, much smaller, more delicate, fish bones have been
regularly collected in very large numbers from these same sites. The challenges of
collecting and identifying small irregular bones, such as ossicles of D. coriacea, are not
trivial; these apparently worthless specimens can easily be unknown, overlooked, and
undervalued. For example, it is notable that D. coriacea ossicles at RH-6 have been
documented only during the most recent 2012 and 2013 campaigns, when ossicles were
widely distributed horizontally and stratigraphically. Remarkably, this was the first time
this distinctive species had been documented at RH-6, even though work began there
in 1975 and was continued for almost 40 years before the species was reported.
Indeed, even other nearby sites at Ra’s al-Hamra, RH-5 in particular, but also RH-4
and RH-10, which has been extensively worked starting in 1981, have produced no known
D. coriacea material. Possibly, detailed re-evaluations by faunal specialists of remains
recovered from earlier excavations could detect ossicles where they were previously
overlooked, undervalued and/or unknown, for even very experienced and
thorough zooarcheologists would not have expected a species that is virtually unknown
from archeological sites (M. Uerpmann in litt. to JF November 12, 2017; see also
Hoch, 1979: 596).
The enigma is further emphasized by the fact that hundreds of archeological sites
are known along coastal Oman, and farther north, and in some sites excavations
have been conducted for years—if not decades (Frifelt, 1995; Cleuziou & Tosi, 2000;
Charpentier, Marquis & Pellé, 2003; Beech, 2004; Charpentier, 2008: fig. 1; Cavulli & Scaruffi,
2012; Berger et al., 2013: 3091; Charpentier et al., 2013). There are no explicit records, but the
amount of sediment that has been examined from just a single site may be several
tonnes, and considering all coastal sites that have been worked, many tonnes of sediment
will have been sieved since the 1970s. Yet, the only recorded D. coriacea remains are
those reported herein.
Nonetheless, even if a site has been investigated for years, this is no guarantee that the
faunal remains have been adequately studied; the fact that D. coriacea ossicles were
reported at RH-6 for first time nearly four decades after excavations began, is a case in
point. Few sites in the region, known for long-term archeological research, have benefited
from systematic, thorough faunal studies. Even sites that have been extensively worked
and included faunal analysis (such as RH-4, RH-5, and RH-10) could ultimately
yield D. coriacea remains after more thorough investigations of faunal materials; for
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 20/34
example, in their detailed study of numerous sites at and near Ra’s al-Hamra, Uerpmann &
Uerpmann (2003: 200; M. Uerpmann in litt. to JF November 12, 2017) explained that
they did not have access to all the faunal remains that had been recovered. Hence, the
paucity of records could be explained, at least in part, by the lack of systematic
zooarcheological analysis; and even when faunal analyses have been carried out, there may
have been instances when the researcher was unfamiliar with the irregularly shaped
and seemingly unusual ossicles, that are in fact ready identifiers of D. coriacea.
Another way of considering the lack of archeological records of D. coriacea is to ask the
opposite question: what was it about RH-6 and HD-6 that makes these sites so unusual that
they yielded remains of animals almost never reported? Cleuziou & Tosi (2007: 57)
provide a clue: “ : : : by the beginning of the fourth millennium BC the settlements of the
Arabian Sea coast displayed all the evidence of a new and revolutionary adaptation that
took place in very few areas across the globe: deep sea fishing.” In other words, the
environmental conditions in which RH-6 and HD-6 existed made possible unique
opportunities for interactions with deep sea marine animals—which include D. coriacea.
Hence, where human settlements were not close to the deep sea there was less
probability that such sites would yield remains of this pelagic animal. Nonetheless, this
proposition alone does not explain the absence of records from other sites along the coast
of the Arabian sea, such as as-Suwayh, al-Khabbah, and Ra’s al Jinz (Fig. 1). It will be
necessary to wait until systematic zooarcheological investigations at these sites produce
more robust data about their respective faunal records.
As regards fossils, some vertebrate palaeontologists have observed that “Pelagic taxa
with thin fragile shells (e.g., D coriacea) don’t make for good fossils” (J. Parham in litt. to
JF September 20, 2017; also R. Hirayama in litt. to JF September 11, 2018). It does
seem that taphonomic aspects are central to this enigma. As Wood et al. (1996: 266)
explained: “when a beached leatherback dies, its shell does not long retain the rotund
profile characteristic of live individuals. The carapace first sags and then quickly
collapses into a jumble of disarticulated ossicles—a true paleontologist’s nightmare.”
Although this description is certainly accurate, even a “jumble,” and haphazard
scattering, of small bones is nothing unusual for the experienced zooarcheologist or
palaeontologist. Nonetheless, there is no simple explanation for the remarkable rarity of
archeological and fossil records of D. coriacea.
Why were only ossicles, and no other bones, recovered from RH-6
and HD-6?
The present study documents 184 ossicles from Ra’s al-Hamra site 6, and 149 ossicles from
Ra’s al-Hadd site 6: a grand total of 383 ossicles. Remarkably, no other bone from
D. coriacea has been reported from either of the two sites where ossicles were recovered,
bones which evidently derived from, at least, between 10 and 33 individual turtles.
The only other published records of this turtle from archeological sites are Cerro Brujo,
Bocas del Toro, Panama (Wing, 1980: Table 1) and Tutu Main Street, St. Thomas,
US Virgin Islands (Wing, DeFrance & Kozuch, 2002), which are based on limb bones from
3, or 4, individual turtles from Panama, and a single carpal, or tarsal, bone from St. Thomas
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 21/34
(unpublished species cards and reports on file at Florida Museum of Natural History,
Environmental Archaeology Program, FLMNH-EA accession numbers Cerro Brujo
Acc# 0152, Tutu Acc# 0489).
The conditions in which bony remains were deposited in many coastal sites in Arabia
indicate that preservation conditions were very good. As Beech, Charpentier & Méry
(2004: 331) explained: “[d]ue to the presence of large quantities of marine shells at these
sites, the relatively high calcium carbonate content ensures that animal bones are
much better preserved within these ‘shell-middens’” (see also Hoch, 1979: 595; Marcucci,
2014: 506). The general appearance of many bony remains (particularly marine turtle,
most likely Chelonia mydas) from RH-6 and HD-6 do not indicate serious problems of
deterioration, although in some cases there is evidence of some deterioration, from
unknown causes. However, even if there were widespread deterioration of turtle bones, this
alone would not explain why the only remains of D. coriacea that have been recovered
from Oman are ossicles.
Ossicles of D. coriacea may be more compact and resistant to deterioration than other
bones of this animal, and therefore more likely to endure, especially for millennia.
Studies of bone morphology of this turtle—particularly osteochondral development—
show that the limb bones are highly vascularized with large cartilaginous portions
remaining throughout life, and not composed of dense periosteal bone, as occurs in other
marine turtles (Rhodin, Ogden & Conlogue, 1981; Rhodin, 1985; Snover & Rhodin, 2008).
Although these larger bones appear to be hefty and solid, their structure would lend
them more susceptible to environmental deterioration than bones that have thick layers of
dense periosteal bone. In contrast: “ : : : ossicles are epidermal ossifications of much denser,
less vascularized bone, than the appendicular, cranial, or spinal elements, which are
more porous with less sclerotic compact bone, and the ossicles would therefore survive
more easily in middens.” (A. Rhodin in litt. to JF October 2, 2017) (for details of ossicle
microstructure see Delfino et al., 2013: 774). This indicates that the bones that
one might normally expect to find—limb, axial, and cranial bones—are more highly
subject to taphonomic degradation than are ossicles, particularly over periods of centuries
and millennia. One way or the other, J. Parham notes (in litt. to JF September 20, 2017)
that the majority of Dermochelyid fossils are ossicles, with no other bones. Hence,
both zooarcheologists and paleontologists need to be aware of the limitations of finding
skeletal remains of these turtles, a sentiment reinforced by Hirayama (in litt. to JF
September 24, 2018).
Were environmental conditions off the coast of Oman during the
Mid- to Late Holocene more favorable to Dermochelys coriacea than
they are today?
Present-day patterns of abundance and distribution of D. coriacea most likely do not
reflect the biogeographic situations when RH-6 and HD-6 were inhabited. This point has
been made by various authors: “marine transgressions or regressions in the relatively
shallow waters of the Gulf must have influenced the life cycles of migrating fishes
[and other marine organisms], so in this case we perhaps cannot transfer present day
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 22/34
observations back into a fourth-third millennia context.” (Biagi et al., 1984: 50). Indeed,
over the past 20,000 years the Gulf area has experienced enormous changes, evolving
from a virtually dry area to a flooded sea by about 6,000 BP; at present times it is almost an
inland sea with an average depth of about 35 m (Lambeck, 1996).
However, the specific accounts of past conditions vary—sometimes considerably—between
different studies. “At 6,000 year BP the predicted sea levels [in the Gulf of Oman]
lie above the present level by about two to three m.” (Lambeck, 1996: 47), and “ : : : levels
along this section of the coast [the northern Gulf] having been one to three m above
the present levels between about 3,500 and 6,000 year BP.” (Lambeck, 1996: 48; see also
details in his Table 1). In contrast, Zarins (1992: 57) reported that “[b]y 5,000 BC
sea-level was at -10 m of present-day m.s.l. : : : and the sea-coast was approximately
100–150 km from it present-day position : : :with the modern shoreline returning in
stages between 2,000 and 1,000 BC”; and “[b]etween 5,000 and 2,000 BC sea level may
have risen as much as three m above [present-day] m.s.l. : : : ” There are numerous
challenges to interpreting evidence relating to past conditions (Lambeck, 1996), so it is
not surprising that accounts of different scenarios have been proposed.
Nevertheless, there is clear evidence of a significant marine transgression from Kuwait
to Oman, and on to the Red Sea, with different phases of expansion and contraction
of the Gulf between 5,000 and 2,000 BC. Because of different environmental conditions
between 5,000 and 3,000 BC, the summer Southwest Monsoon, whose latitudinal position
is determined by the Inner Tropical Convergence Zone, is thought to have been as far
north as central Arabia and present-day southern Iraq, “ : : : during which the entire Gulf
was a dry plain filled with river runoff from Mesopotamia, Arabia and Iran. Gradual
marine infilling began by 4,000 BC which culminated in a higher sea-stand by 3,000 BC”
(Zarins, 2008: 218).
Along the Oman coast, from 6,000 to 3,000 cal BC, five cycles of sea level rise and fall
are recognized, associated with other environmental changes including mangrove
development and salt flat expansion. When RH-6 was occupied, about 5,600–4,500 BC, sea
level and landscapes are thought to have been similar to the present, although at the
end of the RH-6 occupation period, beginning about 4,800 BC, “the maximum postglacial
sea transgression (+2/3 m)” was reported (Berger et al., 2013: 3096). Later, at the time
when the RH-6 cemetery was in use, around 4,000–3,800 BC, sea level and mangrove
development were decreasing. By the time HD-6 was occupied, around 3,000 BC, sea level
was again falling and extensive salt flats (“sabkhas”) were developing (Berger et al., 2013).
Obviously, these major differences between past and present in sea level, marine
shorelines, as well as the surface area and depth of the Gulf would be intimately related to
the distributions and abundance of marine turtles during these periods.
In this respect, Dutton et al. (1999) reported singularly low genetic diversity (mt DNA)
in their global sample from 10 different nesting grounds of D. coriacea, which they
hypothesized was due to a global reduction in the population, caused by global cooling
during the Plio-Pleistocene. They further suggested that later, during the Holocene,
global warming enabled relatively recent population expansion and global population
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 23/34
radiation. This scenario suggests that Mid-Holocene populations of D. coriacea, likely
occurring off the coasts of Oman, were expanding relatively rapidly.
There are two major aspects of past environments for RH-6 and HD-6 that are
especially relevant: beaches where D. coriacea may have nested, and coastal areas,
particularly deep waters, where these turtles could have occurred during seasonal feeding
migrations. Both beach and marine aspects are interrelated, but it is simplest to treat
them separately.
It is not known if steeply sloping sand beaches–characteristic of D. coriacea nesting
beaches (Frazier, Gramentz & Fritz, 2005: 285; Eckert et al., 2012: 28–29)–were more, or
less, available during any of the four periods discussed above (i.e., main RH-6 occupation,
end of RH-6 occupation, RH-6 graveyard in use, and HD-6 occupation). Nonetheless,
changes in sea level would have direct effects on coastal and beach physiognomy. Where
steep cliffs characterize present-day coasts, such as at Ra’s al-Hamra on the Batinah coast
(Durante & Tosi, 1977: 141), sea level fall could have resulted in greater availability of
potential D. coriacea nesting beaches. Hence, at the end of the RH-6 occupation and when
the RH-6 graveyard was in use, there could have been increased D. coriacea nesting within
the vicinity of the site; the same could have been true when HD-6 was occupied.
Durante & Tosi (1977: 141) reported that until the late 1960s turtles (species not
identified, but most likely Chelonia mydas) nested on “the long Ra’s al-Hamra beach”;
Uerpmann & Uerpmann (2003: 179, 204) pointed out that this long “flat sandy” beach is
nearly three km west of the archeological site, and there are other small (“pocket”) beaches
that are to the east, between cliffs of the actual headland (Fig. 2). They (2003: 204)
suggested that the long beach to the west “probably did not exist during the time of
occupation of RH 5, when there was a lagoon where the mangrove area is now.” The lack of
evidence for steeply sloping beaches in the Ra’s al-Hamra area indicates that few, if any,
D. coriacea nested there. With regard to Ra’s al-Hadd, there is a major nesting beach
for Chelonia mydas, but, once again, these beaches do not seem to have the steep sloping
profile characteristic of D. coriacea nesting beaches. Nonetheless, environmental—
particularly sea level—changes during certain periods between 5,600 and 2,500 BC could
have resulted in more nesting beaches for D. coriacea than are now known for this area,
and hence increased the chances of remains of this turtle being deposited in these sites.
An understanding of past availability of D. coriacea nesting beaches requires specific,
detailed paleogeomorphological studies along the Batinah and Ja’alan coasts.
In addition to the question regarding possible past D. coriacea nesting on the coast of
Oman, it is necessary to understand past abundance and distribution of these turtles in
coastal waters. Although this reptile is generally regarded as a pelagic, open-ocean
species, at least during modern times it is well known to occur in coastal waters in many
parts of the world (Frazier, Gramentz & Fritz, 2005: 269–271, 286 ff; Eckert et al., 2012:
63–64, 71, 73, 81). This exception to an open ocean existence is tied to seasonal
feeding migrations into certain coastal areas, particularly where upwelling results in fertile
feeding grounds. As mentioned above, during modern times, the headlands of specific
relevance to the present study—Ra’s al-Hamra and Ra’s al-Hadd—are well known
for their seasonal upwellings, and thus, their rich fishing areas not far off shore.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 24/34
Schott & McCreary (2001) and Schott, Xie & McCreary (2009) have provided abundant
oceanographic documentation for this phenomenon; indeed, the “Ras al Hadd Jet” figures
prominently in their figures and discussions about oceanic currents.
Hence, during Mid- to Late Holocene the abundance and availability of these turtles in
Omani waters, particularly off the Ja’alan and Batinah coasts, may well have been very
different—perhaps more common—than during modern times. This raises the possibility
that during certain periods within this span of three millennia remains of these turtles
were more likely to be deposited at Neolithic and Bronze Age sites than they are today in
Oman. If the amount of sediment sampled at RH-6 was comparable to the amount
sampled at HD-6, the RAMDR of D. coriacea was evidently higher at HD-6 than at
RH-6. This would indicate that conditions around 3,000 BC off the Ja’alan coast may have
been more favorable for these turtles than they were around 5,000 BC off the Batinah.
If there were significant environmental and/or socio-cultural differences between
the two sites this would also have profound implications on differences in marine fishing,
settlement characteristics, trade, and other activities between RH-6 and HD-6, much
of which should be discernible from archeological evidence. As Lambeck (1996: 555–556)
explained, the key to understanding a multitude of questions about how past societies in
this region developed, functioned and survived—their economies, technologies, and
relationships with their surroundings—is understanding past environmental conditions
and their changes through time.
CONCLUSIONS
The results of the present study reveal far more than a new record of a species rarely
documented from archeological sites. They provide clues about the past, and raise questions
about both pending and new issues related to the geographic area, sites, communities, turtles,
and environments under study, as well as to much broader applications of data that are
required to illuminate these issues. Several major topics, developed in the preceding
Discussion section, warrant emphasis.
A total of 383 ossicles of D. coriacea were recovered from two coastal sites in Oman,
with dates that span from approximately 5,600 to 2,500 BC. At Ra’s al-Hamra 6 a total of
184 ossicles was recovered. All of these were found at least 600 m inland from the
present shoreline, and at least seven m above the present highest level reached by the tide.
At least 91% of the RH-6 ossicles were closely associated with either cultural artifacts and/or
ecofacts resultant from the past occupation of the site. At Ra’s al-Hadd 6 a total of
149 ossicles were recovered; all of these were at least 200m inland from the present shoreline.
Of the HD-6 ossicles, 90% were recovered from closed spaces, as well as in association
with cultural artifacts and/or ecofacts having been left from past human activities. Hence,
nearly all, if not all, of the ossicles reported herein are interpreted to be archeological in
origin, and not simply miscellaneous beach debris. Beyond that, however, there is no
incontrovertible proof of how prehistoric humans interacted with the species; for example,
no sign of modification through human agency was detected for any of the 383 ossicles.
Considering details of locus and stratigraphy from where ossicles were recovered
indicates that the remains were deposited in multiple spatial-temporal events.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 25/34
Although there is no known way to distinguish ossicles between individuals of this species,
or even between different sexes, a judicious use of excavation data to establish
spatial-temporal groupings (“aggregations”) of the animal remains permits defensible
estimates of MNI: between six and 24 turtles from RH-6 and from four to nine at HD-6.
This approach warrants further application in other studies of zooarcheological specimens,
for which there is little opportunity to make morphological comparisons between
retrieved bones, but adequate archeological details from excavations are available.
The present study is only the third case of archeological documentation of this globally
distributed, large, distinctive animal. Similarly, there are no known fossils, with the
possible exception of one or two ossicles. Hence, taphonomic issues, likely the reason for
this lack of remains, need to be further elucidated. Nonetheless, a plausible explanation for
the paucity of records is that certain skeletal elements (i.e., ossicles) of this animal are
subject to being overlooked, undervalued, and/or unknown. Hence, there is a pressing
need for more systematic, detailed studies of faunal remains in this region.
It is also remarkable that the skeletal elements that are reported in both
zooarcheological and paleontological research are, with very few exceptions, ossicles,
despite the fact that the skeleton of this turtle includes scores bones other than ossicles,
most of which are larger than ossicles. A possible explanation for this apparent anomaly
is that ossicles are much more compact and resistant to environmental degradation
than other bones, some of which include large proportions of cartilage and relatively little
hard, resistant periosteal bone—even in adults. If that explanation holds widely throughout
the family Dermochelyidae, it may help to illuminate topics that are often obscure to
paleontology, particularly osteochondral development and bone composition in extinct
species. With a similar focus, comparisons between the ossicles of the extinct Mid-Miocene
turtle P. polygonus, and ossicles of the living D. coriacea (Delfino et al., 2013: 778),
supported inferences about the diving habits of the long extinct animal. The detailed
chondro-osseous work on appendicular elements (Snover & Rhodin, 2008) needs to be
extended to the epithecal ossicles of this unique living turtle.
Beyond issues about methods for estimating MNI, taphonomic concerns, and skeletal
characteristics of the animals under consideration, the documentation of a few hundred
bony ossicles raises basic questions about past environments and how they may have
impacted both the human communities and turtles that are central to this study.
During modern times in Omani waters, D. coriacea has been rare, and often regarded as a
vagrant, yet during past millennia remains of this turtle were repeatedly deposited in
different strata of two distant sites. The study of past climates, sea levels, and
oceanographic current systems, and how these major drivers may have affected beach
physiognomy and upwelling areas along the Omani coast, have a particular relevance for
an understanding of the relationship between prehistoric populations and marine turtles,
as well as the human populations that survived and developed during those periods.
ACKNOWLEDGEMENTS
We thank the Ministry of Heritage and Culture of Oman, Mr. Sultan Saif al-Bakri,
Assistant-Director General for Archaeology and Museums, Mr. Khamis al-Asmi and
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 26/34
Ms. Byubwa Ali Al-Sabri, Director and former Director of the Department of Excavations
and Archaeological Studies. Richard Gemel and Peter Pritchard assisted M.D.
while studying comparative osteological material, respectively, at the Naturhistorisches
Museums Wien (Vienna, Austria) and Chelonian Research Institute (Oviedo, Florida).
David Bohaska, France de Lapparent de Broin, Ken Dodd, Jim Gardner, Ren Hirayama,
Walter Joyce, Hans-Volker Karl, Jim Knight, Richard Köhler, Julian McCreary Jr,
James Parham, Anders Rhodin, Juliana Sterli, Peter Stahl, Mark Uhen, Evangelos Vlachos,
Robert Weems, and George Zug provided valuable information on fossil dermochelyids,
oceanographic, osteochondral, paleontological, and zooarcheological issues; Kitty
Emery patiently helped with obtaining and deciphering records from the Florida Museum
of Natural History; Rob Baldwin and Jeff Miller provided publications about Omani
marine turtles; Polly Lasker consistently and patiently helped find and provide many other
publications. Lucio Calcagnile and his team at Centro di datazione e diagnostic (CEDAD),
University of Salento, provided the radiocarbon determinations of charcoal samples
from HD-6. Philippe Béarez, Márton Rabi, Wim Van Neer, Hans-Peter Uerpmann,
Margarethe Uerpmann, and two anonymous reviewers made helpful comments on earlier
versions of this paper.
ADDITIONAL INFORMATION AND DECLARATIONS
Funding
Massimo Delfino was supported by Università di Torino (Fondi ex-60%, 2016–2017),
Generalitat de Catalunya/CERCA Programme, Agencia Estatal de Investigación (AEI) from
Spain/European Regional Development Fund of the European Union (CGL2016-76431-P,
and Synthesys Programme (AT TAF-1281). The funders had no role in study design,
data collection and analysis, decision to publish, or preparation of the manuscript.
Grant Disclosures
The following grant information was disclosed by the authors:
Università di Torino (Fondi ex-60%, 2016–2017), Generalitat de Catalunya/CERCA
Programme, Agencia Estatal de Investigación (AEI) from Spain/European Regional
Development Fund of the European Union (CGL2016-76431-P, and Synthesys
Programme (AT TAF-1281).
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
 John G. Frazier conceived and designed the experiments, performed the experiments,
analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the
paper, approved the final draft.
 Valentina Azzarà performed the experiments, analyzed the data, contributed
reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed
drafts of the paper, approved the final draft.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 27/34
 Olivia Munoz performed the experiments, analyzed the data, contributed
reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed
drafts of the paper, approved the final draft.
 Lapo Gianni Marcucci performed the experiments, analyzed the data, contributed
reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed
drafts of the paper, approved the final draft.
 Emilie Badel performed the experiments, analyzed the data, contributed reagents/materials/
analysis tools, authored or reviewed drafts of the paper, approved the final draft.
 Francesco Genchi contributed reagents/materials/analysis tools, approved the final draft.
 Maurizio Cattani contributed reagents/materials/analysis tools, approved the final draft,
organised field work.
 Maurizio Tosi contributed reagents/materials/analysis tools, organised field work.
 Massimo Delfino conceived and designed the experiments, performed the experiments,
analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the
paper, approved the final draft.
Data Availability
The following information was supplied regarding data availability:
The raw data are provided in the Tables.
Supplemental Information
Supplemental information for this article can be found online at http://dx.doi.org/10.7717/
peerj.6123#supplemental-information.
REFERENCES
Azzarà VM. 2009. Domestic architecture at the Early Bronze Age sites HD–6 and RJ–2
(Ja’alān, Sultanate of Oman). Proceedings of the Seminar for Arabian Studies 39:1–16.
Azzarà VM. 2012. The organization of food processing at HD-6 (Sultanate of Oman).
In: Matthews R, Curtis J, eds. The Archaeology of Consumption & Disposa. Proceedings of the
7th International Congress on the Archaeology of the Ancient Near East. London: Harrassowitz,
251–268.
Azzarà VM. 2013. Architecture and building techniques at the Early Bronze Age site of HD-6,
Ra’s al-Hadd, Sultanate of Oman. Proceedings of the Seminar for Arabian Studies 43:11–26.
Azzarà VM. 2015. L’architecture domestique et l’organisation de la maisonnée dans la
péninsule d’Oman à l’âge du Bronze ancien. D. Phil. thesis, University of Paris 1
Panthéon-Sorbonne, Vol. 1: 1–664; vol II–III: 1–548; abstract and exerpt. Available at
https://www.academia.edu/33704035/Larchitecture_domestique_et_lorganisation_de_la_
maisonn%C3%A9e_dans_la_p%C3%A9ninsule_dOman_%C3%A0_l%C3%A2ge_du_Bronze_
ancien_3%C3%A8me_mill%C3%A9naire_av.N.E._._2015._Th%C3%A8se_de_Doctorat_
Universit%C3%A9_Paris_1_Panth%C3%A9on-Sorbonne_in%C3%A9dit_.
Azzarà VM, Cattani M. 2007. Excavation season at the Early Bronze Age Site of HD-6
(January–March 2007). In: Azzarà V, De Rorre A, Cattani M, eds. The Joint Hadd Project.
Summary Report on 2007 Excavation Season at HD-6 and RJ-2, January-March 2007.
Unpublished circulated report, available in Library of University of Bologna, Department of
History and Cultures.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 28/34
Baldwin RM, Al Kiyumi ABA. 1999. The ecology and conservation status of the sea turtles of
Oman. In: Fisher M, Ghazanfar SA, Spalton JA, eds. The natural history of oman: a festschrift for
michael gallagher. Leiden: Backhuys Publishers, 89–98.
Baldwin RM, Hughes G, Prince RIT. 2003. Loggerhead turtles in the Indian Ocean. In: Bolten AB,
Witherington BE, eds. Loggerhead sea turtles. Washington, D.C.: Smithsonian Institution Press,
218–232.
Beech MJ. 2004. In the land of the Ichthyophagi. Modelling fish exploitation in the Arabian Gulf and
Gulf of Oman from the 5th millennium BC to the late Islamic period. Oxford: Archaeopress,
xix, 293.
Beech MJ, Charpentier V, Méry S. 2004. Evidence for deep-sea fishing and cultural identity during
the Neolithic period at Akab Island, Umm al-Qaiwain, United Arab Emirates. In: Mashkour M,
Beech MJ, eds. Proceedings of the Archaeozoology of the Near East 9 Proceedings of the 2008
Al Ain-Abu Dhabi Conference. Oxford: Oxbow Books, 331–338.
Berger JF, Charpentier V, Crassard R, Martin C, Davtian G, López-Sáez JA. 2013. The dynamics
of mangrove ecosystems, changes in sea level and the strategies of Neolithic settlements along
the coast of Oman (6000–3000 cal. BC). Journal of Archaeological Science 40(7):3087–3104
DOI 10.1016/j.jas.2013.03.004.
Biagi P. 1994. A radiocarbon chronology for the aceramic shell-middens of coastal Oman.
Arabian Archaeology and Epigraphy 5(1):17–31 DOI 10.1111/j.1600-0471.1994.tb00053.x.
Biagi P. 1999. Excavations at the shell-midden of RH6 1986-1988 (Muscat, Sultanate of Oman).
Al-Rāfidān 20:57–84.
Biagi P, Torke W, Tosi M, Uerpmann HP. 1984. Qurum: a case study of coastal archaeology in
Northern Oman. World Archaeology 16(1):43–61 DOI 10.1080/00438243.1984.9979915.
Cattani M, Cavulli F. 2004. La Missione Archeologica Italiana in Oman. In: Guaitoli MT,
Marchetti N, Scagliarini D, eds. Scoprire. Scavi del dipartimento di archeologia. Catalogo della
Mostra, Bologna, S. Giovanni in Monte, 18 maggio-18 giugno 2004. Bolongna: Università degli
studi di Bologna, Dipartimento di archeologia, 225–232.
Cavulli F, Scaruffi S. 2012. The Holocene Settlement of KHB-1 (Ra’s Al Khabbah, Sultanate of
Oman): an overview. In: Giraud J, Gernez G, De Castéja V, eds. Aux marges de l’archéologie.
Hommage à Serge Cleuziou. Paris: Maison de René-Ginouvès, Archéologie et Ethnologie:
De Boccard, 405–429.
Charpentier V. 2008. Hunter-gatherers of the “empty quarter of the early Holocene” to the last
Neolithic societies: chronology of the late prehistory of south-eastern Arabia (8000–3100 BC).
Proceedings of the Seminar for Arabian Studies 38:93–116.
Charpentier V, Berger JF, Crassard R, Borgi F, Béarez P. 2016. Les premiers chasseurs-collecteurs
maritimes d’Arabie (IXe-IVe millénaires avant notre ère). In: Dupont C, Marchand G, eds.
Archéologie des chasseurs-cueilleurs maritimes. De la fonction des habitats à l’organisations de
l’espace littoral. Paris: Société préhistorique française, 345–365.
Charpentier V, Berger JF, Crassard R, Borgi F, Davtian G, Méry S, Phillips CS. 2013.
Conquering new territories: when the first black boats sailed to Masirah Island.
Proceedings of the Seminar for Arabian Studies 43:85–98.
Charpentier V, Crassard R. 2013. Back to Fasad : : : and the PPNB controversy. Questioning a
Levantine origin for Arabian Early Holocene projectile points technology. Arabian Archaeology
and Epigraphy 24(1):28–36 DOI 10.1111/aae.12011.
Charpentier V, Marquis P, Pellé E. 2003. La nécropole et les derniers horizons Ve millénaire
du site de Gorbat al-Mahar (Suwayh, SWY–1, Sultanat d’Oman): premiers résultats.
Proceedings of the Seminar for Arabian Studies 33:11–19.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 29/34
Cleuziou S, Tosi M. 2000. Ra’s al-Jinz and the Prehistoric coastal cultures of the Ja’alan.
Journal of Oman Studies 11:19–73.
Cleuziou S, Tosi M. 2007. In the shadow of the ancestors. the prehistoric foundations of the
early arabian civilization in oman. Muscat: Ministry of Heritage and Culture, xii, 334.
Conant T, Dutton PH, Eguchi T, Epperly SP, Fahy CC, Godfrey MH, Macpherson SL,
Possardt EE, Schroeder BA, Seminoff JA, Snover ML, Upite CM, Witherington BE. 2009.
Loggerhead sea turtle (Caretta caretta) 2009 status review under the U.S. Endangered Species Act.
Report of the Loggerhead Biological Review Team to the National Marine Fisheries Service.
Washington, D.C., viii, 222.
Delfino M, Scheyer TM, Chesi F, Fletcher T, Gemel R, MacDonald S, Rabi M, Salisbury SW.
2013. Gross morphology and microstructure of type locality ossicles of Psephophorus
polygonus Meyer, 1847 (Testudines, Dermochelyidae). Geological Magazine 150(5):767–782
DOI 10.1017/S001675681200091X.
Durante S, Tosi M. 1977. The aceratnic shell middens of Ra’s al-Hamra: a preliminary note.
Journal of Oman Studies 3:137–162.
Dutton PH, Bowen BW, Owens DW, Barragan A, Davis SK. 1999. Global phylogeography of
the leatherback turtle (Dermochelys coriacea). Journal of Zoology 248(3):397–409
DOI 10.1111/j.1469-7998.1999.tb01038.x.
Eckert KL, Wallace BP, Frazier JG, Eckert SA, Pritchard PCH. 2012. Synopsis of the biological
data on the leatherback sea turtle (Dermochelys coriacea). Washington, D.C.: Department of
Interior, Fish and Wildlife Service, xii, 158.
El Mahi AT. 2000. Traditional fish preservation in Oman: the seasonality of a subsistence strategy.
Proceedings of the Seminar for Arabian Studies 30:99–114.
Eschscholtz F. 1829. Zoologischer Atlas, enthaltend Abbildungen und Beschreibungen neuer
Thierarten, während des Flottcapitains von Kotzebue zweiter Reise um die Welt, auf der Russisch-
Kaiserlichen Kriegsschlupp Predpriaetië in den Jahren 1823–1826. Heft 1. Berlin: G. Reimer, 19.
Frazier JG. 2003. Prehistoric and ancient historic interactions between humans and marine
turtles. In: Lutz PL, Musick JL, Wyneken J, eds. The biology of sea turtles. Boca Raton:
CRC Press, 1–38.
Frazier JG. 2005.Marine turtles—the ultimate tool kit: a review of worked bones of marine turtles.
In: Luik H, Choyke AM, Batey CE, Lõugas L, eds. From Hooves to Horns, from Mollusc
to Mammoth, Manufacture and Use of Bone Artefacts from Prehistoric Times to the Present,
Proceedings of the 4th Meeting of the ICAZ Worked Bone Research Group at tallin, 26–31
August 2003. Tallin: Muinasaja Teadus, 359–382.
Frazier JG, Gramentz D, Fritz U. 2005. Dermochelys Blainville, 1815—Lederschildkröten.
In: Fritz U, ed. Handbuch der Reptilien und Amphibien Europas. Schildkröten (Testudines).
Wiebelsheim: AULA Verlag, 249–328.
Frifelt K. 1995. The island of Umm an-Nar, Vol. 2, The third millennium settlement. Vol. 26.
Aaraus: Jutland Archaeological Society Publication, 1–259.
Gasperetti J, Stimson AF, Miller JD, Ross JP, Gasperetti PR. 1993. Turtles of Arabia.
In: Buttiker W, Krupp F, eds. Fauna of saudi arabia. national commission for wildlife
conservation and development, riyadh, saudi arabia and pro entomolgia. Vol. 13. Basle:
Natural History Museum, 170–367.
Grayson DK. 1973. On the methodology of faunal analysis. American Antiquity 38(4):432–439
DOI 10.2307/279149.
Grayson DK. 1979. On the quantification of vertebrate archaeofaunas. Advances in Archaeological
Method and Theory 2:199–237.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 30/34
Hamann M, Limpus C, Hughes G, Mortimer J, Pilcher N. 2006. Assessment of the conservation
status of the leatherback turtle in the Indian Ocean and South-East Asia including consideration
of the impacts of the December 8 2004 tsunami on turtles and turtle habitats. Bangkok:
IOSEA Marine Turtle MoU Secretariat, vii, 166.
Harris EC. 1997. Principles of archaeological stratigraphy. London: Academic Press, xiv, 170.
Henshilwood CS, Sealy JC, Yates R, Cruz-Uribe K, Goldberg P, Grine FE, Klein RG,
Poggenpoel C, Van Niekerk K, Watts I. 2001. Blombos Cave, Southern Cape, South Africa:
preliminary report on the 1992–1999 excavations of the middle stone age levels.
Journal of Archaeological Science 28(4):421–448 DOI 10.1006/jasc.2000.0638.
Hilbert YH, Azzarà VM. 2012. Lithic technology and spatial distribution of artefacts at the
Early Bronze Age site HD-6 (Sharqiyya Region, Sultanate of Oman). Arabian Archaeology
and Epigraphy 23(1):7–25 DOI 10.1111/j.1600-0471.2011.00348.x.
Hoch E. 1979. Reflections on prehistoric life at Umm an-Nar (Trucial Oman) based on faunal
remains from the third millennium BC. In: Taddei M, ed. South Asian archaeology 1977. Vol. 6.
Naples: Seminario di Studi Asiatici, Series Minor, 590–638.
Karl H-V, Gröning E, Brauckmann C. 2012a. New materials of the giant sea turtle Allopleuron
(Testudines: Chelonioidea) from the marine Late Cretaceous of Central Europe and the
Palaeogene of Kazakhstan. Studia Palaeocheloniologica 4:153–173.
Karl H-V, Lindow BE, Tütken T. 2012b. Miocene leatherback turtle material of the genus
Psephophorus (Testudines: Dermochelyoidea) from the Gram Formation (Denmark).
Studia Palaeocheloniologica 4:205–216.
Köhler R. 1996. Eocene whales and turtles from New Zealand. PhD thesis. Dunedin:
Department of Geology, University of Otago, xv, 359. Available at
http://theses.otagogeology.org.nz/items/show/324.
Lambeck K. 1996. Shoreline reconstructions for the Persian Gulf since the last glacial
maximum. Earth and Planetary Science Letters 142(1–2):43–57
DOI 10.1016/0012-821x(96)00069-6.
Linnæus C. 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera,
species, cum characteribus, differentiis, synonymis, locis. In: Tomus I. Editio decima, reformata.
Stockholm: Laurentius Salvius, 824.
Linnæus C. 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera,
species, cum characteribus, differentiis, synonymis, locis. In: Tomus I. Editio duodecima,
reformata. Stockholm: Laurentius Salvius, 532.
Marcucci LG. 2014. The Site of Ra’s al-Hamra 5 (Muscat, Sultanate of Oman)—Brief Chronicle of
the Excavations (1973–2010). (With the contribution of al-Taie Hatim). In: Lamberg-
Karlovsky CC, Genito B, Cerasetti B, eds. “My Life is Like the Summer Rose,” Maurizio Tosi e
l’Archeologia Come modo di vivere. Papers in Honour of Maurizio Tosi for his 70th Birthday.
Oxford: Archaeopress, 505–515.
Marcucci LG. 2015. I siti preistorici di RH-5 e RH-6 a Ra’s al-Hamra (Muscat, Sultanate d’Oman):
analisi comparativa della stratigrafia, delle strutture di abitato e della cultura materiale.
Continuità e sviluppo di due villaggi di pescatori-raccoglitori. D. Phil. thesis, University of Paris
1 Panthéon-Sorbonne and Università di Bologna, Vol. 1: 1–570 and Vol. 2: 1–417. Available at
https://www.academia.edu/14325767/I_siti_preistorici_di_RH-5_e_RH-6_a_Ra_s_al-Hamra_
Muscat_Sultanato_d_Oman_analisi_comparativa_della_stratigrafia_delle_strutture_di_
abitato_e_della_cultura_materiale._Continuit%C3%A0_e_sviluppo_di_due_villaggi_di_
pescatori-raccoglitori_Italian-French-English_versions_Summaries_and_abstracts.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 31/34
Marcucci LG. 2017. In Memoriam—Maurizio Tosi (1944–2017). A great explorer with an
eclectic mind. Paléorient 43(1):5–7.
Marcucci LG, Badel É, Genchi F, Munoz O, Todero A, Tosi M. 2014. New investigations at the
prehistoric shell midden of Ra’s al-Hamra 6 (Sultanate of Oman): results of the 2012 and 2013
excavation seasons. Proceedings of the Seminar for Arabian Studies 44:235–256.
Marcucci LG, Genchi F, Badel É, Tosi M. 2011. Recent investigations at the prehistoric site
RH-5 (Ra’s al-Hamrā’, Muscat, Sultanate of Oman). Proceedings of the Seminar for Arabian
Studies 41:201–222.
Meyer HV. 1847. Mittheilungen an Professor Bronn gerichtet. Neues Jahrbuch für Mineralogie,
Geognosie, Geologie und Petrefaktenkunde 1847:572–581.
Mosseri-Marlio CE. 1998a. Marine animal resources at Ra’s al-Hadd during the Bronze Age.
Bulletin of the Society for Arabian Studies 3:12–15.
Mosseri-Marlio CE. 1998b. Marine turtle exploitation in Bronze Age Oman. Marine Turtle
Newsletter 81:7–9.
Mosseri-Marlio CE. 2000. Sea turtle and Dolphin remains from Ra’s al-Hadd, Oman.
In: Mashkour M, Choyke AM, Buitenhuis H, Poplin F, eds. Proceedings of the Fourth International
Symposium on the Archaeozoology of Southwestern Asia and Adjacent Areas. Archaeozoology
of the Near East IV B. Vol. 32. Groningen: ARC—Publicatie, 94–103.
Mosseri-Marlio CE. 2002. Sea turtles and dolphins: aspects of marine animal exploitation
from Bronze Age Ra’s al-Hadd. Journal of Oman Studies 12:197–210.
Munoz O. 2014. Pratiques funéraires et paramètres biologiques dans la Péninsule d’Oman
du Néolithique à la fin de l’âge du Bronze ancien (V-IIIe millénaires av. n.e.). D. Phil. thesis,
University of Paris, Panthéon-Sorbonne; Vol. 1: 522, Vol. 2: 333, abstract. Available at
https://www.academia.edu/5944507/Pratiques_fun%C3%A9raires_et_param%C3%A8tres_
biologiques_dans_la_p%C3%A9ninsule_d_Oman_du_N%C3%A9olithique_%C3%A0_la_fin_
de_l_%C3%A2ge_du_Bronze_ancien_Ve-IIIe_mill%C3%A9naires_av._N.E._.
Munoz O. 2017. Transition to agriculture in South-Eastern Arabia: insights from oral conditions.
American Journal of Physical Anthropology 164(4):702–719 DOI 10.1002/ajpa.23307.
Pilcher NJ, Antonopoulou M, Perry L, Abdel-Moati MA, Al Abdessalaam TZ, Albeldawi M,
Al Ansi M, Al-Mohannadi SF, Al Zahlawi N, Baldwin R, Chikhi A, Das HS, Hamza S,
Kerr OJ, Al-Kiyumi A, Mobaraki A, Al Suwaidi HS, Al Suweidi AS, Sawaf M, Tourenq C,
Williams J, Willson A. 2014. Identification of important sea turtle areas (ITAs) for hawksbill
turtles in the Arabian region. Journal of Experimental Marine Biology and Ecology 460:89–99
DOI 10.1016/j.jembe.2014.06.009.
Rees AF, Al-Kiyumi A, Broderick AC, Papathanasopoulou N, Godley BJ. 2012. Conservation
related insights into the behaviour of the olive ridley sea turtle Lepidochelys olivacea nesting
in Oman. Marine Ecology Progress Series 450:195–205 DOI 10.3354/meps09527.
Rees AF, Baker SL. 2006. Hawksbill and olive ridley nesting on Masirah Island, sultanate of
Oman: an update. Marine Turtle Newsletter 113:2–5.
Rhodin AGJ. 1985. Comparative chondro-osseous development and growth of marine turtles.
Copeia 1985(3):752–771 DOI 10.2307/1444768.
Rhodin AGJ, Ogden JA, Conlogue GJ. 1981. Chondro-osseous morphology of Dermochelys
coriacea, a marine reptile with mammalian skeletal features. Nature 290(5803):244–246
DOI 10.1038/290244a0.
Rose JI, Hilbert YH, Marks AE, Usik VI. 2018. The first peoples of Oman—Palaeolithic
archaeology of the Nejd plateau. Muscat: Ministry of Heritage and Culture, xvii, 196.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 32/34
Ross JP, Barwani MA. 1982. Review of sea turtles in the Arabian area. In: Bjorndal KA, ed.
The biology and conservation of sea turtles. Washington, D.C.: Smithsonian Institution Press,
373–383.
Salm RV, Jensen RAC, Papastavrou VA. 1993. Marine fauna of Oman: Cetaceans, turtles,
seabirds and shallow water corals. A marine conservation and development report. Gland: IUCN,
vi, 66.
Salm R, Salm S. 1991. Sea turtles in the Sultanate of Oman. Ruwi: The Historical Association
of Oman, 1–37.
Salvatori S. 1996. Death and Ritual in a population of coastal food foragers in Oman.
In: Afanas’ev G, Cleuziou S, Lukacs JR, Tosi M, eds. Colloquium XXXII: Trade as a Subsistence
Strategy. Post Pleistocene Adaptations in Arabia and Early Maritime Trade in the Indian Ocean.
In: Tosi M, (Secretary) The prehistory of Asia and Oceanea XIII International Congress of
Prehistoric and Protohistori. Forli: ABACO Edizioni, 205–222.
Salvatori S. 2001. Excavations at the funerary structures HD 10-3.1, 3.2, 4.1, 4.2 and 2.1 at
Ra’s al-Hadd (Sultanate of Oman). Rivista di Archeologia 25:67–83.
Salvatori S. 2007. The prehistoric graveyard of Ra’s al-Hamra 5, Muscat, Sultanate of Oman.
Part I. 1981–1985 excavations report. Journal of Oman Studies 14:5–57.
Salvatori S, Coppa A, Cucina A. 2007. The prehistoric graveyard of Ra’s al-Hamra 5, Muscat,
Sultanate of Oman. Part II. Inventory of graves. Journal of Oman Studies 14:59–206.
Schott FA, McCreary JP Jr. 2001. The monsoon circulation of the Indian Ocean.
Progress in Oceanography 51(1):1–123 DOI 10.1016/S0079-6611(01)00083-0.
Schott FA, Xie SP, McCreary JP Jr. 2009. Indian Ocean circulation and climate variability.
Reviews of Geophysics 47(1):1–46 DOI 10.1029/2007RG000245.
Schweigger AF. 1812. Prodromus monographia cheloniorum. Königsberger Archiv für
Naturwissenschaft und Mathematik 1:271–368, 406–458.
Snover ML, Rhodin AGJ. 2008. Comparative ontogenetic and phylogenetic aspects of Chelonian
chondro-osseous growth and skeletochronology. In: Wyneken J, Godfrey MH, Bels V, eds.
The biology of turtles. New York: CRC Press, 17–43.
Thompson JC. 2010. Taphonomic analysis of the middle stone age faunal assemblage from
Pinnacle Point Cave 13B, Western Cape, South Africa. Journal of Human Evolution
59(3–4):321–339 DOI 10.1016/j.jhevol.2010.07.004.
Thompson JC, Henshilwood CS. 2014. Tortoise taphonomy and tortoise butchery patterns at
Blombos Cave, South Africa. Journal of Archaeological Science 41:214–229
DOI 10.1016/j.jas.2013.08.017.
Tosi M. 1975. Notes on the distribution and exploitation of natural resources in ancient Oman.
Journal of Oman Studies 1:187–206.
Tosi M. 1989. Protohistoric archaeology in Oman: the first 30 years (1956–1985). In: Costa P,
Tosi M, eds. Oman Studies. Papers on the archaeology and history of Oman. Serie Orientale
Roma 63. Rome: ISMEO, 135–161.
Tosi M, Cattani M. 1997. Missione arhceologica Italiana nel Sultanato d’Oman. Ocnus,
Quaderni della Scuola di Specializzazione in Archeologia 5:249–254.
Tosi M, Cattani M, Curci A, Marcucci LG, Usai D. 2002. Missione archeologica nel Sultanato di
Oman “Joint Hadd Project” Campagna di ricerca 2000–2001. Ocnus, Quaderni della Scuola
di Specializzazione in Archeologia 9–10:357–366. Note: This article by M. Tosi and colleagues,
which appears in Ocnus, Quaderni della Scuola di Specializzazione in Archeologia, volume 9/10,
pages 357–366, has frequently been cited as “Tosi et al. 2001”. However, volume 9/10 is a
double issue which was published in 2002, so the correct citation must be “Tosi et al. 2002,”
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 33/34
confirmed by Ms. Alessandra Citti, Responsabile gestionale di biblioteca, Alma Mater
Studiorum–Università di Bologna, where the journal is published (A. Citti in litt to JF 17
October 2017).
Uerpmann M. 2003. The dark millennium—remarks on the final stone age in the emirates and
Oman. In: Potts DT, Al Nabooda H, Hellyer P, eds. Archaeology of the United Arab Emirates,
Proceedings of the First International Conference on the Archaeology of the U.A.E.
London: Trident Press, 73–81.
Uerpmann HP, Uerpmann M. 2003. Stone age sites and their natural environment.
The capital area of Northern Oman, Part III. Wiesbaden: Ludwig Reichert, xiii, 265.
Uerpmann M, Uerpmann HP. 2007. Shell midden economy in the 4th millennium BC.
In: Cleuziou S, Tosi M, eds. In the shadow of the ancestors. the prehistoric foundations of the early
arabian civilization in oman. Muscat: Ministry of Heritage and Culture, 103–104.
Vandelli D. 1761. Epistola de holothurio, et testudine coriacea ad celeberrimum Carolum
Linnaeum equitem naturae curiosum Dioscoridem II. Padua: Conzatti, 12.
Wing ES. 1980. Aquatic fauna and reptiles from the Atlantic and Pacific sites. In: Linares OF,
Ranere AJ, eds. Adaptive radiations in prehistoric panama. peabody museum monographs, 5.
Cambridge: Harvard University Press, 194–215.
Wing ES, DeFrance SD, Kozuch I. 2002. Faunal remains from the Tutu site. In: Righter E, ed.
The Tutu Archaeological Village Site: A Multidisciplinary Case Study in Human Adaptation.
New York: Routledge Taylor & Francis Group, 141–165.
Wood RC, Johnson-Grove J, Gaffney ES, Maley KF. 1996. Evolution and phylogeny of
leatherback turtles (Dermochelyidae), with descriptions of new fossil taxa. Chelonian
Conservation and Biology 2(2):266–286.
Wood RC, Knight JL, Cicimuri D, Sanders A. 2009. Fossil leatherback turtles (Dermochelyidae)
from the Paleogene of South Carolina. In: Braman DR, compiler. Turtle Symposium,
October 17–18, 2009. Abstracts and Program. Alberta: Special Publication of the Royal
Tyrrell Museum, 195–198.
Zarins J. 1992. The early settlement of Southern Mesopotamia: a review of recent historical,
geological, and archaeological research. Journal of the American Oriental Society 112(1):55–77
DOI 10.2307/604585.
Zarins J. 2008. Magan Shipbuilders at the Ur III Lagash State Dockyards (2062-2025 B.C.).
In: Olijdam E, Spoor RH, eds. Intercultural Relations Between South and Southwest Asia. Studies
in Commemoration of E.C.L. During Caspers (1934–1996). Oxford: BAR International Series
1826, 209–229.
Zazzo A, Munoz O, Badel E, Béguier I, Genchi F, Marcucci LG. 2016. A revised radiocarbon
chronology of the aceramic shell midden of Ra’s Al-Hamra 6 (Muscat, Sultanate of Oman):
implication for occupational sequence, marine reservoir age, and human mobility.
Radiocarbon 58(2):383–395 DOI 10.1017/RDC.2016.3.
Zazzo A, Munoz O, Saliège J-F. 2014. Diet and mobility in a late neolithic population of coastal
Oman inferred from radiocarbon dating and stable isotope analysis. American Journal of
Physical Anthropology 153(3):353–364 DOI 10.1002/ajpa.22434.
Frazier et al. (2018), PeerJ, DOI 10.7717/peerj.6123 34/34