<Tr> <Th_colspan="2"> Trinomial name </Th> </Tr> <Tr> <Td_colspan="2"> Diceros bicornis longipes Zukowsky, 1949 </Td> </Tr> <P> The western black rhinoceros (Diceros bicornis longipes) or West African black rhinoceros was a subspecies of the black rhinoceros, declared extinct by the IUCN in 2011 . The western black rhinoceros was believed to have been genetically different from other rhino subspecies . It was once widespread in the savanna of sub-Saharan Africa, but its numbers declined due to poaching . The western black rhinoceros resided primarily in Cameroon, but surveys since 2006 have failed to locate any individuals . </P> <P> This subspecies was named Diceros bicornis longipes by Ludwig Zukowsky in 1949 . The word "longipes" is of Latin origin, combining longus ("far, long") and pēs ("foot"). This refers to the species' long distal limb segment, one of many special characteristics of the species . Other distinct features of the western black rhino included the square based horn, first mandibular premolar retained in the adults, simple formed crochet of the maxillary premolar, and premolars commonly possessed crista . </P>

When did the western black rhino become extinct