Bemalambdidae

Bemalambdidae Temporal range: Early Paleocene–Middle Paleocene PreꞒ Ꞓ O S D C P T J K Pg N
Skeleton of Bemalambda pachyoesteus, exhibited in the National Museum of Nature and Science, Tokyo, Japan.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Cimolesta
Suborder:	†Pantodonta Cope, 1873
Family:	†Bemalambdidae Chow et al. 1973
Genera and species[1]
† (type) Chow et al. 1973 †B. nanhsiungensis (type) Chow et al. 1973 †B. pachyoesteus Chow et al. 1973 †B. dingae Li 2005 †B. crassa Chow et al. 1973 † Wang 1975 †H. chalingensis Wang 1975

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

Description[]

The bemalambdids are, along with 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[]

• the Early Paleocene (65.5 to 58.7 Ma) of Guangdong, China (type) (25°06′N 114°18′E / 25.1°N 114.3°E / 25.1; 114.3, paleocoordinates 26°00′N 109°24′E / 26.0°N 109.4°E / 26.0; 109.4)^[4]
• the Early Paleocene (65.5 - 58.7 Ma) of Shaanxi, China^[5]
• the Middle Paleocene (61.7 - 58.7 Ma) of Jiangxi, China^[6]

Notes[]

References[]