Origin and evolution of Heterocephalus from East Africa (Rodentia: Heterocephalidae)

Abstract

Known today by a single species only in the Horn of Africa, rodents of the Heterocephalus genus displayed through Neogene times a larger geographical distribution and a higher diversity. Here we present the state of art of the knowledge of the described fossil Heterocephalus species and follow the different described lineages through time and space. We also present some morphological and classical morphometric analyses upon the skulls and teeth of the modern representative of the genus compared with the fossil ones. This allowed to find some cranio-dental criteria allowing to validate the probable presence of two to three modern species in the horn of Africa and define and discuss some dental trends of evolution of the fossil lineages through time and space. Finally, by gathering the paleoclimatic conditions and collecting environmental parameters of each site were Heterocephalus remains were collected we propose a scenario of evolution of the genus.