A new L Agomorph from the L Ate m iocene of ch Ad (centrAL AfricA)

A new species of the genus serengetilagus Dietricht �94�, here named s. tchadensis n. sp., is described from Toros Menalla deposits, Late Miocene of Djurab Erg (North Chad, central Africa). It shows primitive features, such as a simple archaeolagine-type p3, with only two main external folds, and upper cheek teeth strongly widened with wear. Its size and skeletal features resemble s. praecapensis Dietricht �94� from the Middle Pliocene of Laetoli (Tanzania). They differ in several cranial and dental features (choanae width, zygoma, orbits, basicranial-basi- facial angle, lack of hypoflexus in P2, short and asymmetric hypoflexus in P3-M2, lack of lingual folds in p3, etc). Individual variations in s. tchadensis n. sp. approach s. praecapensis , such as an incipient anteroflexid and a forward-curved hypoflexid in some p3. The genus serengetilagus is here assigned to the subfamily Archaeola- ginae Dice �929 and related to Hypolagus Dice �9�7, namely to H. gromovi Gureev �964 from the Late Miocene of Southern Russia. Other related species are serengetilagus orientieuropaeus Topachevsky �987 and primitive species of the genus trischizolagus Radulesco & Samson �967, such as t. maritsae De Bruijn, Dawson & Mein �970 and t. crusafonti (Janvier & Montenat �97�). Pliocene leporids from Spain, Ukraine, Russia, Afghanistan and Mongolia have been questionably attributed to serengetilagus or trischizolagus , which seem synonymous for some authors. Several features are here proposed to distinguish both genera: rounded versus rhombic-shaped p3, weak versus strong lingual anteroconid - anteroflexid, and forward versus backward hypoflexid bend. serengetilagus could have a mixed fossorial-cursorial mode of life, as can be inferred by its ecomorphologi- cal traits (combining features of hare and rabbit) and taphonomical indications. This new African archaeolagine is contemporaneous of the widespread palaeolagine alilepus Dice �93�, recorded in the Late Miocene of Kenya. The independence of these two lineages is favoured after revision of previous hypotheses on the phylogeny of the highly diverse Mio-Pliocene peri-Tethysian leporid species.