Sansanosmilus

S. palmidens and Necromanis

Sansanosmilus is a member of the family Barbourofelidae, a group of feliform carnivorans related to either felids[2] or nimravids.[3] It had short legs, was very muscular and had a long tail. Sansanosmilus was 1.5 metres (4 ft 11 in) long and probably weighed around 80 kilograms (180 lb). In 1961, paleontologist L. Ginsburg concluded that Sansanosmilus was possessed of a plantigrade walking stance, after studying its foot bones and comparing it with those of the true felid Pseudaelurus from the same site. This is different from later barbourofelids, which are believed to have had semi-plantigrade or semi-digitigrade stances.[4]

The type species, Sansanosmilus palmidens, is known from fossils from the Orleanian and Astaracian stages in France. Although Albanosmilus was seen as a junior synonym of Sansanosmilus from the 1970s onwards, Robles et al. (2013) demonstrated that the type species of Albanosmilus, S. jourdani (which they considered to be a senior synonym of S. vallesiensis), is more closely related to Barbourofelis than to the type species of Sansanosmilus and thus generically distinct.[5] Wang et al. (2020) agreed with Robles et al. (2013) in recovering Albanosmilus as closer to Barbourofelis than to Sansanosmilus.[3]

A further two species of Sansanosmilus (S. rhomboidalis and S. serratus) were described by G.E. Pilgrim in 1932 based on fragmentary fossils from the Siwaliks.[6] Sansanosmilus rhomboidalis was described further, with new material assigned, in 2022.[7]