The phylogenetic relationships of soft-shelled turtles (family Trionychidae). Bulletin of the AMNH ; v. 186, article 1

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[New York] : American Museum of Natural History
"Phylogenetic analysis of 113 characters of the osteology of the 22 living species of trionychid turtles and representatives of all other living turtle families, provides abundant evidence on the relationships of soft-shelled turtles to other turtles and on the interrelationships within the family. These data suggest that the family Trionychidae shares a unique common ancestor with the Dermatemydidae, Kinosternidae, and Carettochelyidae, and that the Kinosternidae share a unique common ancestor with the Trionychidae and Carettochelyidae. Furthermore, it appears that the staurotypine kinosternids are most closely related to the Trionychidae and Carettochelyidae. Carettochelyids and trionychids share numerous unique features and clearly constitute a monophyletic group. Within the Trionychidae, the subfamilies Cyclanorbinae and Trionychinae are recognized as monophyletic clades. Recognition of three cyclanorbine genera, Cycloderma, Cyclanorbis, and Lissemys, is warranted. Within the Trionychinae, four distinct clades are recognized. The Trionyx cartilagineus group includes Chitra indica and Pelochelys bibroni, on the basis of the unique location of the foramen posterior canalis carotici interni, and features of the trigeminal region. The North American group includes T. triunguis, T. euphraticus, T. swinhoei, T. ferox, T. spiniferus, and T. muticus, and can be recognized by the presence of eight or fewer neurals (first and second are fused), deeply emarginate prefrontals, and a large contribution by the parietal to the processus trochlearis oticum. The Indian group includes four species: T. gangeticus, T. hurum, T. leithii, and T. nigricans; all exhibit a free first neural, five plastral callosities, and intermediately extended epiplastra. Lastly, the T. steindachneri group, which includes T. steindachneri, T. sinensis, and T. subplanus, is diagnosed by a descending spine of the opisthotic that divides the fenestra postotica in most specimens. Two equally parsimonious arrangements of the Trionychinae differ in the placement of the North American clade. In one, this clade is the sister group of the T. cartilagineus clade; in the other, it is the sister group of the T. steindachneri clade. In both, the Indian group is paraphyletic and gives rise to the T. steindachneri clade. A revised classification of the family Trionychidae is provided. The use of 2 subfamilies, 6 tribes, and 14 genera is recommended. This expanded taxonomy will more completely reflect the hierarchical relationships that reflect recency of common ancestry as determined by the cladistic analyses"--P. 4.
101 p. : ill. ; 26 cm.
Includes bibliographical references (p. 96-101).