Familia Bataguridae

Gray, 1869a
Batagurid turtles

The semi-aquatic to semi-terrestrial Old World pond turtles and their tropical American relatives in the genus Rhinoclemmys comprise the most diverse family of turtles with 23 genera and 63 species. The fossil record for the family dates from the Eocene (Ocadia) of Europe and Asia (Geoclemys, and several species of the Geoemydinae). Today members of the family are found from Mexico to northern South America, and southern Europe and northern Africa eastward to southeast Asia, Indonesia, the Philippines and Japan.
The Bataguridae skull resembles both those of the families Emydidae and Testudinidae. The temporal region is widely emarginated posteriorly preventing squamosal-parietal contact. The frontal bone enters the orbit, and the postorbital bone is wider than that found in the Testudinidae. The maxilla and quadratojugal are separated, and the quadrate is exposed posteriorly. The premaxillae usually do not meet to form a hooklike process except in some species of Cuora. The triturating surface of the upper jaw varies in width and may lack a ridge. In some species there is a tendency toward a secondary palate. A vestigial splenial bone may be present. The lower jaw has the angular bone completely or nearly separated from Meckel's cartilage by the prearticular. The basioccipital is broad, in contact with the paracapsular sac and pterygoid, and contributes a lateral tuberosity to form the floor of the tympanic cavity. Only a single articulation exists between the centra of the 5th and 6th cervical vertebrae. The carapace varies from low arched to considerably domed. Dorsal rib heads are well-developed, and the supporting buttresses may be very strong. A vertebral keel is usually present, but may be poorly developed or absent in some species, and some species have a pair of lateral keels. The seam between the supracaudals and the last vertebral lies over the suprapygal bone, but not over the pygal. Carapaceandplastron are usually united to a broad bridge. The plastron is well-developed, and in several Asian genera may bear a movable hinge between or near the seam separating the pectoral and abdominal scutes. Mesoplastral bones are absent, as also are intergular and inframarginal scutes. Limbs are developed for both swimming and terrestrial life, but have at least remnants of toe webbing. Usually more than two phalanges occur in the second and third digits, and the femoral trochanteric fossa is reduced. In the pelvic girdle, the pubis normally touches the ischium of the same side; however, cartilage along the ventral midline of the girdle prevents the pubis and ischium from touching those from the other side.

Formerly, the Bataguridae was considered a subfamily of the family Emydidae, but Gaffney and Meylan (1988) elevated the batagurid turtles to family status, Bataguridae, recognizing two subfamilies: Batagurinae (including the Batagur, Hardella and Orlitia complexes of McDowell, 1964) and Geoemydinae (the Geoemyda complex of McDowell, 1964). This arrangement has been adopted by Das (1991) and David (1994).
Bramble (1974), Hirayama (1984), Sites et al. (1984), Carr and Bickham (1986), and Gaffney and Meylan (1988) have all revealed weaknesses in the arrangement of McDowell's complexes. Hirayama and Gaffney and Meylan performed cladistic analyses based principally on cranial characters, Sites et al. reconstructed the batagurid phylogenies on the basis of biochemical characters, Carr and Bickham presented a phylogeny of the Bataguridae based on karyological data, and Bramble concentrated on hinge structure and kineses found in some species of McDowell's Geoemyda complex. The "complexes" were more variable than McDowell had envisioned, and several seem to have multiple origins. Hirayama (1984), Sites et al. (1984), and Gaffney and Meylan (1988) concluded that the Bataguridae is probably polyphyletic with regard to the Testudinidae. Therefore, the batagurids are treated in alphabetical rather than phylogenetical order.