Pan-Amphisbaenia M. Kearney and K. de Queiroz, new clade name 
Registration Number: 115 taxon Cryptolacerta hassiaca from the Eocene of 
Germany to be a stem amphisbaenian; however, 
De!nition: !e total clade of the crown clade a more recent analysis places Cryptolacerta closer 
Amphisbaenia. !is is a crown-based total-clade to Lacertidae than to Amphisbaenia (Longrich 
de"nition. Abbreviated de"nition: total ∇ of et al., 2015). As noted in the Composition 
Amphisbaenia. section for Amphisbaenia (this volume), some 
North American fossil amphisbaenians possess 
Etymology: Derived by adding the pre"x seemingly ancestral characters (e.g., a complete 
Pan- (for Pan-Monophylum = total clade) to postorbital bar) not seen in any living amphis-
Amphisbaenia (see entry for Amphisbaenia, this baenians (see e.g., Berman, 1972, 1973, 1976); 
volume, for the etymology of that name). however, current phylogenetic inferences (e.g., 
Kearney, 2003a; Hembree, 2007; Gauthier et 
Reference Phylogeny: Figure 2b of Longrich et al., 2012) place those fossils as crown rather 
al. (2015) is the primary reference phylogeny. On than stem amphisbaenians. 
that tree, Pan-Amphisbaenia applies to the clade 
that includes Rhineuridae, Chthonophidae†,  Diagnostic Apomorphies: As a maximum 
Oligodontosauridae†, Bipedidae, Blanidae, (and total) clade, Pan-Amphisbaenia may not 
Cadeidae, Trogonophidae, and Amphisbaenidae, have any apomorphies (de Queiroz, 2007); how-
as well as all extinct taxa (of which there are ever, possession of any of the apomorphies of 
none on that tree) that are more closely related Amphisbaenia (see Kearney, 2003b) constitutes 
to them than to Teius, Tachydromus, and evidence for inclusion of a species or specimen 
Lacerta. However, the de"nition stipulates that within Pan-Amphisbaenia. !ose apomorphies 
the name is to be applied to the total clade of of Amphisbaenia that are most likely to be pre-
Amphisbaenia regardless of which extant taxa served in fossils include: enlarged median pre-
are inferred to be its closest relatives. maxillary tooth, elongated postorbital region of 
skull, braincase enclosed anteriorly by enlarged 
Composition: Amphisbaenia (applied to a orbitosphenoid(s), absence of suborbital fenes-
crown clade in this volume) and the members tra, absence of epipterygoid, reduction of hind 
of its stem group. See entry for Amphisbaenia (in limbs (and possibly fore limbs), short tail with 
this volume) for the composition of the crown caudal autotomy septa con"ned to a single ver-
clade. Wu et al. (1993, 1996) considered the fos- tebra. In the absence of well-supported assign-
sil taxon Sineoamphisbaena hexatabularis from ments of fossils to the amphisbaenian stem 
the Upper Cretaceous of China to belong to group, the order of evolution of these apomor-
the amphisbaenian stem group and thus part of phies is currently unknown. Müller et al. (2011) 
the clade that is here named Pan-Amphisbaenia; inferred 19 characters to be synapomorphies of 
however, subsequent analyses by Kearney Cryptolacerta and Amphisbaenia, including a 
(2003a), Lee (2005), and Gauthier et al. (2012) tongue and-groove articulation of the frontals, 
indicated that Sineoamphisbaena is not part of transversely widened frontal downgrowths, 
that clade. Müller et al. (2011) inferred the fossil thickened frontals and maxillae, the absence 
Pan-Amphisbaenia 
of a tympanic crest on the quadrate, very low clade and the crown. For example, the name 
vertebral neural spines, and a sutural prefron- Annulata could be applied to the clade originat-
tal-postorbitofrontal contact. If Cryptolacerta ing in the "rst ancestor of Amphisbaena fuliginosa 
is a stem amphisbaenian, then this list likely Linnaeus 1758 that possessed the apomorphy of 
includes some of the earliest characters to evolve having the body scales arranged in rings. 
along the amphisbaenian stem lineage. 
Literature Cited 
Synonyms: Most, if not all, of the names 
listed as approximate (and partial) synonyms Berman, D. S. 1972. Hyporhina tertia, new spe-
of Amphisbaenia (see entry in this volume) are cies (Reptilia: Amphisbaenia) from the early 
also approximate (and partial) synonyms of Oligocene (Chadronian) White River 
Pan-Amphisbaenia, given that authors who Formation of Wyoming. Ann. Carnegie Mus. 
used those names rarely, if ever, clearly distin- 44:1–10. Berman, D. S. 1973. Spathorhynchus fossorium, a 
guished between the total clade and the crown. middle Eocene amphisbaenian (Reptilia) from 
Wu et al. (1993) clearly applied both the names Wyoming. Copeia 1973(4):704–721. 
Amphisbaenia (see also Wu et al., 1996) and Berman, D. S. 1976. A new amphisbaenian 
Annulata (treating them as synonyms) to a clade (Reptilia: Amphisbaenia) from the Oligocene-
more inclusive than the crown, but it is not clear Miocene John Day Formation, Oregon. J. 
if they applied those names to the total clade. Vertebr. Paleontol. 50:165–174. 
Gauthier, J. A., and K. de Queiroz. 2001. Feathered 
Comments: See the Comments in the entry dinosaurs, #ying dinosaurs, crown dino-saurs, and the name “Aves.” Pp. 7–41 in New 
for Amphisbaenia (this volume) for histori- Perspectives on the Origin and Early Evolution 
cal information concerning recognition of the of Birds: Proceedings of the International 
named group and support for its status as a clade Symposium in Honor of John H. Ostrom (J. 
(given that earlier authors rarely distinguished Gauthier and L. F. Gall, eds.). Peabody 
between the crown and total clades). !e names Museum of Natural History, Yale University, 
Amphisbaenia and Pan-Amphisbaenia were New Haven, CT. 
selected for the crown and total clades, respec- Gauthier, J. A., M. Kearney, J. A. Maisano, 
tively, in the interest of developing an inte- O. Rieppel, and A. D. B. Behlke. 2012. Assembling the squamate tree of life: perspec-
grated system of names for those categories of tives from the phenotype and the fossil record. 
clades (e.g., Meier and Richter, 1992; Gauthier Bull. Peabody Mus. Nat. Hist. 53:3–308. 
and de Queiroz, 2001; de Queiroz, 2007). In Hembree, D. I. 2007. Phylogenetic revi-
this context, Amphisbaenia was selected for the sion of Rhineuridae (Reptilia: Squamata: 
crown clade because it appears to be the most Amphisbaenia) from the Eocene to Miocene 
widely used name (see Comments in the entry of North America. Univ. Kansas Paleontol. 
for Amphisbaenia, this volume), and the name Contrib. 15:1–20. 
of the total clade was then formed by adding Kearney, M. 2003a. !e phylogenetic position of 
the pre"x Pan- to the name of the crown clade Sineoamphisbaena hexatabularis reexamined. J. Vertebr. Paleontol. 23:394–403. 
(Amphisbaenia). Moreover, none of the syn- Kearney, M. 2003b. Systematics and evolution of 
onyms appear to have been used unambiguously the Amphisbaenia: a phylogenetic hypothesis 
for the total clade, and they remain available for based on morphological evidence from fossil 
application to nested clades between the total and recent forms. Herpetol. Monogr. 17:1–75. 
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sampling, and data congruence. Org. Divers. comments on the phylogenetic relationships of 
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worm lizards (Amphisbaenia) driven by end- Authors 
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ambiguities related to the stem lineage con- Email: mkearney@aaas.org. 
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A. Hilger, M. Wuttke, and R. R. Reisz. 2011. 
Eocene lizard from Germany reveals amphis-
baenian origins. Nature 473:364–367. Date Accepted: 1 November 2013; updated 3 
Wu, X.-C., D. B. Brinkman, and A. P. Russell. 1996. November 2017 
Sineoamphisbaena hexatabularis, an amphis-
baenian (Diapsida: Squamata) from the Upper Primary Editor: Philip Cantino 
Cretaceous redbeds at Bayan Mandahu (Inner 
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