Abstract
Unresolved taxonomy poses a significant challenge for conservation and recovery efforts of freshwater fishes in Indonesia. Asian knifefishes or featherbacks of the genus Chitala are found in the Indonesian Islands of Java, Sumatra and Borneo and the genus is currently thought to be composed of three species: Chitala lopis, Chitala hypselonotus, and Chitala borneensis. According to the IUCN, Chitala species are of least concern in Indonesia, except for C. lopis, which is considered Extinct. However, the taxonomy of Chitala species is unclear with three nominal species historically synonymized under a single name (C. lopis), but more recently tentatively considered as valid species. The recent rediscovery of C. lopis in its type locality (Java) since last recorded in 1851, enabled a comprehensive genetic and morphological study of the three nominal species to clarify their status. We examined 151 mitochondrial sequences from all known species of Chitala, includ-ing sequences from the type localities of the three taxa in question. We identified three well supported clades corresponding to C. lopis, C. hypselonotus, and C. borneensis. The analyses of 22 measurements identified several diagnostic characters between C. lopis and C. borneensis. We provide evidence that C. lopis is not extinct and is widespread across Java, Sumatra and Borneo. In contrast, C. hypselonotus has a more restricted distribution to Central Sumatra and may be at risk of extinction given it was not collected from the Musi River since 2015. We argue for an urgent revision of the IUCN conservation status of the three species and quickly expand molecular basedinventories to all freshwater fishes in Indonesia.