Gray, 1852
Indochinese tortoises
Recognition
The Asian tortoises of this genus lack hinges on either the carapace or plastron. The oval carapace may be either domed or flattened dorsally, and has a cervical indentation (concave anterior rim). Both the anterior and posterior marginals may be serrated. Usually 11 marginals lie on each side, and the supracaudal is divided into two scutes. The cervical scute is broad and triangular, and no submarginal scutes are present. Neurals are hexagonal, and there are usually two suprapygals. The plastron is well-developed and has a deep anal notch. The entoplastron lies anterior to the humero-pectoral seam. Axillary and inguinal buttresses are short, and barely touch the costals. The skull is moderate to long with only a slightly hooked upper jaw. The triturating surface of the maxilla is strongly ridged, but the premaxilla lacks a ridge. The maxillae do not contribute to the roof of the palate, and the anterior orbito-nasal foramina are small, but the lateral caroticum foramen, containing the palatine artery, is large. The prootic bone is well-exposed dorsally and anteriorly, and the quadrate bone usually encloses the stapes. There is no supraangular process. Limbs are club shaped with five claws on each forefoot.
Remark
The two living species are the least derived of extant tortoises. Their primitive characters include hexagonal (6-sided) anterior neurals; divided, non-enlarged supracaudals; a non-enlarged pygal bone; and mental glands (which they share with the Bataguridae; Winokur and Legler, 1975). See Obst (1983) and Hoogmoed and Crumly (1984) for a review of the taxonomic history and a discussion on the validity of the name Manouria.
Species identification
Jump to the key: Page 137: Genus Manouria