Polemon barthi Jan 1858 and P. bocourti Mocquard 1897, two West African snakes which are allopatric, not sympatric

Abstract

Two species of Polemon ‐ P. barthi and P. bocourti, are morphologically very similar and are currently supposed to both occur within the rain forest of West Africa (Guinea to Nigeria) and Central Africa (Cameroon eastward). Reliance on postocular number to distinguish the species is shown to be unreliable and when specimens are sexed, there is found to be a correlation between ventral counts and geographic distribution such that P. barthi is restricted to West Africa, P. bocourti to Central Africa.