(\ AN EVALUATION OF THE SUPPOSED ANHINGA OF MAURITIUS STOEBS L. OLSON Made in United States of America Reprinted from THE AUK Vol. 92, No. 2, April 30, 197S pp. 374-376 An evaluation of the supposed anhinga of Mauritius.?From the Quaternary deposits of the Mare aux Songes on the island of Mauritius in the Indian Ocean, Newton and Gadow (1893) described a species of small anhinga as Flotus nanus, based on a left hum?rus, a left tibiotarsus, and a fragmentary pelvis, now in the Zoology Museum of Cambridge University. A left hum?rus lacking the distal end, from superficial black earth near Sirab? (= Antsirabe of modern usage), central Madagascar, was referred to this species by Andrews (1897). Both of these records appear in Brodborb (1963) under the name Anhinga nana. While I have not re- examined the specimens themselves, the illustrations accompanying the descriptions of these bones are more than adequate to establish that all of them are from a small cormorant {Phalacrocorax, sensu lato) and not from an anhinga. Some of the differences between the humeri of anhingas and cormorants were noted by Miller (1966), who, in a similar instance, found a small hum?rus from April 1975] General Notes 37S Australia described by De Vis (1888) as Plotus (= Anhinga) parvus to be referable to the modern cormorant Pkalacrocorax melanoleucos. In anconal view the type hum?rus of "Anhinga nana" agrees with that of cormorants in having the pneumatic fossa deep and extending well under the median crest and internal tuberosity; the olecranal fossa is deep and the entepicondyle distinctly set off from it. In anhingas the pneumatic fossa is shallow and not overhung by the median crest, the olecranal fossa is shallower and merges imperceptibly into the entepicondyle. In palmar view both the type hum?rus of "A. nana" and the referred specimen from Madagascar agree with cormorants in that the ligamental furrow is "longer and deeper and ex- tends transversely to, but is narrowly separated from, the bicipital furrow . . . whereas the ligamental furrow is shorter and deep only medially in anhingas" (Miller 1966). The tibiotarsus of Pkalacrocorax differs from that of Anhinga as follows: the internal condyle extends much farther distally than the external condyle; the an- terior intercondylar fossa is narrow, with the tendinal groove opening in the middle and occupying most of the space between the condyles; the bulge for the groove of M. peroneus profundus is larger and extends farther up the shaft; and the fibular crest is longer. In Anhinga the internal condyle extends only slightly past the ex- ternal condyle, the anterior intercondylar fossa is much wider and the tendinal groove opens much more medially, occupying only two-thirds of the space between the con- dyles; the bulge for the groove of M. peroneus profundus is smaller, and the fibular crest is shorter. In all these respects the type tibiotarsus of "A, nana" agrees per- fectly with Pkalacrocorax. The pelvis of Anhinga has distinct crests extending anteromedially from the anti- trochanter to the median dorsal ridge. These are lacliing in Pkalacrocorax and in the fragmentary type pelvis of "A. nana." In Table 1 the measurements of the syntypes of "Anhinga nana" are compared with three specimens of nominate Pkalacrocorax africanus, a small species of cormorant found in Africa and Madagascar. There is complete agreement except in the second pelvis measurement. Breaking or warping in the fossil fragment might account for this discrepancy, Or perhaps I have not taken the measurement in the same manner as Newton and Gadow. There is no doubt that "Anhinga nana" is a cormorant and, with the possible ex- ception noted above, that it is identical in size with Pkalacrocorax a. africanus. The TABLE 1 MEASUREMENTS (MM) OF SYNTYPES OF "ANHINGA NANA"^ COMPARED WITH THREE SPECIMENS OF PHALACROCORAX A. AFRICANUS Pkalacrc icorax a. africanus 9 USNM ? USNM ? USNM "Anhinga nana" 291775 291776 431490 Length hum?rus 89 85.9 89.2 93.9 Length tibiotarsus 61 60.0 60,8 65.4 "Distance from acetabular axis to anterior end of sacrum" 30 30.1 34.5 33.5 "Distance between ventral inner margins of the acetabula" 14.5 11.8 11.3 10.0 1 From Newton and Gadow (1893: 289). 376 General Notes [Auk, Vol. 92 Malagasy race P. a. pictilis is reported to be larger than the nominate African race (Bangs 1918). It is, of course, possible that the Mauritian bird represents an endemic race, in which case the name nanus would apply. Until this can be either demon- strated or disproved, Plottis nanus Newton and Gadow should be regarded as an undetermined form of Phaiacrocorax africanus. I thank John Farrand, Jr., and A. D. Forbes-Watson for comments on the manu- script. LITERATURE CITED ANDREWS, C. W. 1897. On some fossil remains of car?nate birds from central Mada- gascar. Ibis 3, 7th Ser.: 343-359, BANCS, O. 1918. Aves. Pp. 489-511 in Vert?brala from Madagascar. Bull. Mus. C?mp. Zool. 61: 475-516. BEODKORB, P. 1963. Catalogue of fossil birds, part I (Archaeopterygiformes through Ardeiformes). Bull. Florida State Mus., Biol. Sei. 7: 179-293. DE VIS, C. W, 1888. A glimpse of the post-Tertiary avifauna of Queensland. Proc. Linnaean Soc. New South Wales 3: 1275-1292. MILLER, A. H. 1966. An evaluation of the fossil anhingas of Australia. Condor 68: 315-320. NEWTON, E., AND H. GADOW. 1893. On additional bones of the Dodo and other ex- tinct birds of Mauritius obtained by Mr. Th?odore Sauzier. Trans, Zool. Soc. London 8: 281-302. STORES L. OLSON, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. Accepted 1 Mar. 74.