Filling a gap in the proboscidean fossil record: a new genus from the Lutetian of Senegal

A long hiatus encompassing most of the Eocene (end of the Ypresian to the early Priabonian) breaks up the proboscidean evolutionary history, which is otherwise documented by a rich fossil record. Only two post Ypresian localities from West Africa (Mali and Senegal) yielded scarce Moeritherium-like dental remains. Here, we study one of these remains from Senegal and name a new genus, Saloumia. This taxon, confidently mid-Lutetian in age, evokes Moeritherium and elephantifoms in view of its wrinkled enamel, the lack of centrocrista, and its strong lingual cingulum. However, due to its pronounced bunodonty, which departs from the bunolophodonty of both Moeritherium and elephantifoms, we cannot exclude that Saloumia documents an early experiment in dental diversity among Paleocene-Eocene proboscideans, without direct relationships with later proboscideans.

一段覆盖绝大多数始新世（伊普雷斯阶末期至普里亚邦阶早期）的长期沉积间断，中断了长鼻类的演化历史——而长鼻类的演化原本拥有丰富的化石记录作为佐证。西非仅在两个伊普雷斯阶之后的化石点（马里与塞内加尔）出土了少量类始祖象的牙齿化石。本文对其中一件来自塞内加尔的化石标本展开研究，并建立新属Saloumia。该分类单元的时代被确定为卢台特阶中期，其具有褶皱釉质、缺少中央脊以及发育强壮的舌侧齿带，这些特征与始祖象和象形类相似。然而，由于其具有显著的丘形齿特征，与始祖象和象形类的丘脊形齿型截然不同，因此我们无法排除Saloumia代表古新世-始新世长鼻类中一次早期的牙齿形态多样性尝试，且与后续的长鼻类类群无直接演化关系。