Bemalambdidae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Bemalambdidae
Temporal range: Early Paleocene–Middle Paleocene
Skeleton of Bemalambda pachyoesteus.jpg
Skeleton of Bemalambda pachyoesteus, exhibited in the National Museum of Nature and Science, Tokyo, Japan.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Infraclass: Eutheria
Order: Cimolesta
Suborder: Pantodonta
Cope, 1873
Family: Bemalambdidae
Chow et al. 1973
Genera and species[1]

Bemalambdidae is an extinct family of pantodont mammals known from Early and Middle Paleocene of China.

Description[edit]

The bemalambdids are, along with Harpyodus and Alcidedorbignya, the most primitive pantodonts. Hypsilolambda is known only from a skull and teeth, but Bemalambda is known from complete cranial and postcranial specimens and the best preserved mammal from Shanghuan. It was dog-sized (a large animal for its era) and omnivorous.[2]

Both genera have dilambdodont upper premolars (W-shaped crests on the crowns), one of the characteristics of pantodonts, but their upper molars, unlike in later pantodonts, are almost zalambdodont (V-shaped crests) and transversely elongated with the paracone and metacone (cusp) appressed or connated. On p3-M3, there is a large buccal platform on the crowns, the stylar shelf. An exterior indentation on the buccal side, the ectoflexus, is very deep. The lower cheek teeth are easily recognizable as pantodont.[3]

The bemalambdids had a low and short skull with a very small braincase; a prominent sagittal crest and deep temporal fossae, a broad snout; and flaring zygomatic processes. The high coronoid process on the mandible suggest the chewing musculatures was more developed than in later pantodonts. The postcranium was robust, and, judging from a single massive humerus, adapted for digging.[3]

Fossil localities[edit]

Notes[edit]

References[edit]