Sillae

Sillae is a genus of extinct early Cretaceous mammals that lived during the Aptian age. This genus is classified within the family Sillae and is primarily known from dental and postcranial remains. The fossil record of Sillae is primarily restricted to North America, although there are also records of related species found in Europe and Asia.

Phylogenetic analysis suggests that Sillae is a part of the larger group of Mesonychia, a clade of mammals that also includes the extinct herbivore Andrewsarchus and the carnivorous genus Repenomamus. The relationship between Sillae and other Mesonychia remains somewhat uncertain and continues to be the subject of ongoing research.

The dentition of Sillae indicates that these early mammals possessed a combination of primitive and advanced dental features. Some of the notable characteristics include the presence of multiple cuspids and a postcanine dental formula that is generally arranged in a 3:3 format. Sillae also exhibits characteristics of advanced dental morphology such as an elongated buccal cleft and carinated molar form.

Specimens of Sillae have been found in various geological formations of North America, most notably in the Clovis Formation in New Mexico. These specimens are often preserved as impressions or compressions, which have yielded valuable information about the internal structure and organization of the Sillae dentition. Continued study of Sillae fossils will contribute to our understanding of mammalian evolution during the Cretaceous period.