The Current And Historic Distribution Of Tomistoma Schlegelii (The False Gharial) (Muller, 1838) (Crocodylia, Reptilia)

Tomistoma schlegelii the "False Gharial" (Muller, 1838) is one of the largest yet least-known of the world's 23 crocodilian species, restricted to Indonesia and Malaysia. We compiled and mapped 210 records and overlaid these against geological river systems and current vegetation, in order to assess historic and current distribution, relationship to key habitats and potential centres of current abundance. The current distribution of T. schlegelii extends over lowland regions of eastern Sumatra, Kalimantan and western Java (Indonesia), Sarawak and Peninsular Malaysia, Vietnam and Thailand, within 5 degrees north and south of the equator. Additional records from Sabah (Borneo) and Thailand are unconfirmed, and early records from Thailand may have originated from regions currently within Peninsular Malaysia. The Pliocene to early Pleistocene distribution of T. schlegelii was apparently much broader than its historical range, and extended over lowland river systems of Indonesia, Malaysia and into southern China. Since the discovery of the species in 1838, a significant decline in the density of populations throughout range states has occurred, more markedly since the 1940s. Ironically, the broad outlines of the original distribution seem to have remained. A large portion of the records appear to be associated with peat swamp forest, a highly threatened category of tropical forest, suggesting that a decline in abundance is related to habitat loss. Current areas in which the species appears to still maintain reasonable levels of abundance are in southern Sumatra, west Kalimantan and south-central Kalimantan, although some smaller protected populations occur in central Sarawak. Current T. schlegelii breeding habitats are under threat throughout range states as a result of the progressive draining, logging, burning and clearing of swamp forests.