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Bemalambdidae

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Bemalambdidae
Temporal range: Early Paleocene–Middle Paleocene
Skeleton of Bemalambda pachyoesteus, exhibited in the National Museum of Nature and Science, Tokyo, Japan.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Pantodonta
Superfamily: Bemalambdoidea
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

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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 is 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

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Notes

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References

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  • Chow, M. M.; Chang, Y.-P.; Wang, B.-Y.; Ting, S.-Y. (1973). "New mammalian genera and species from the Paleocene of Nanhsiung, N. Kwangtung" (PDF). Vertebrata PalAsiatica (in Chinese and English). 11 (1): 31–35. Retrieved 17 July 2013.
  • Li, Qian (2005). "New Material of Bamalamdba from Chijiang Basin in Jiangxi, China" (PDF). Vertebrata PalAsiatica (in Chinese and English). 43 (4): 325–329. Retrieved 17 July 2013.
  • Lucas, Spencer G. (2001). Chinese Fossil Vertebrates. Columbia University Press. ISBN 9780231504614. Retrieved 17 July 2013.
  • Rose, Kenneth David (2006). The beginning of the age of mammals. Baltimore: JHU Press. ISBN 0801884721.
  • Wang, Banyue (1975). "Paleocene mammals of Chaling Basin, Hunan" (PDF). Vertebrata PalAsiatica (in Chinese). 13 (3): 154–62. Retrieved 17 July 2013.