Bemalambdidae
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Bemalambdidae is an extinct family of
pantodont Pantodonta is an extinct suborder (or, according to some, an order) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve (around 66 million years ago) after the end of the Cretaceous. The last ...
mammals known from Early and Middle Paleocene of China.


Description

The bemalambdids are, along with '' Harpyodus'' and ''
Alcidedorbignya ''Alcidedorbignya'' is an extinct pantodont mammal known from the Early Paleocene ( Tiupampan SALMA, ) Santa Lucia Formation (, paleocoordinates ) at Tiupampa near Mizque, Cochabamba, Bolivia. Following a naming convention established by p ...
'', 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. 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 The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone ...
(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. 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.


Fossil localities

* the Early Paleocene () of
Guangdong Guangdong (, ), alternatively romanized as Canton or Kwangtung, is a coastal province in South China on the north shore of the South China Sea. The capital of the province is Guangzhou. With a population of 126.01 million (as of 2020) ...
, China ( type) (, paleocoordinates ) * the Early Paleocene (65.5 - 58.7 Ma) of
Shaanxi Shaanxi (alternatively Shensi, see ยง Name) is a landlocked province of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E), Henan (E), Hubei (SE), Chongqing (S), Sichuan (SW), Gansu (W), N ...
, China * the Middle Paleocene (61.7 - 58.7 Ma) of
Jiangxi Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north int ...
, China. Retrieved July 2013.


Notes


References

* * * * * {{Taxonbar, from=Q15839257 Pantodonts Paleocene first appearances Paleocene extinctions Prehistoric mammal families