''Bemalambda'' is an extinct mammal, belonging to the

pantodonts 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 l ...

. It lived in the lower-middle

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

(about 63–58 million years ago) and the fossil remains have been found in China.

Description

It was a medium-size animal, and could reach the size of a large

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...

. The body was strong, the tail was short and the legs were strong and muscular. The skull was short and low, with a broad muzzle, swollen zygomatic processes, and a very small skull. The temporal fossae were deep, the sagittal crest prominent, and the coronoid process on the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

was very high; these characteristics indicate a more developed temporal musculature (useful for chewing) than that of the subsequent pantodonts. Like all pantodonts, ''Bemalambda'' had upper

premolars The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...

with V-shaped ectolofi; the upper

molars 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 to ...

, however, had a transverse structure, almost zalambdodonte, with closely paired paracone and metaconus, and did not possess the dilambdodont W-shaped structure like the typical pantodonts. The stylar platform of the teeth from the third premolar to the third molar was very broad, and the ``ectoflexus'' (an additional external indentation of the molars) was deeply incised.

Classification

The genus ''Bemalambda'' was established in

1973 Events January * January 1 - The United Kingdom, the Republic of Ireland and Denmark 1973 enlargement of the European Communities, enter the European Economic Community, which later becomes the European Union. * January 15 – Vietnam War: ...

on the basis of some fossils found in the area of

Nanxiong Nanxiong (), historically Namyung, Namhung, and Nanhsiung, is a county-level city of northern Guangdong province, People's Republic of China, bordering Jiangxi to the north, east and southeast. It is under the administration of Guangdong Gua ...

in the Lofochai formation (

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), dating back to the lower/middle Paleocene. The study by Chow and colleagues established various species: ''Bemalambda crassa, Bemalambda nanhsiungensis'' (the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

), ''Bemalambda pachyoesteus'', distinguished on the basis of some dental characteristics. Subsequently, in

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 ...

, fossils of a slightly more recent species (Middle Paleocene) were found, ''B. dingae''. ''Bemalambda'' is a rather atypical representative of the pantodonts, a group of archaic mammals with the characteristic ambdodon teeth. In particular, ''Bemalambda'' and other related forms such as '' Hypsilolambda'' would seem to be part of a radiation of primitive pantodonts of relatively modest size, developed in the Asian Paleocene, the ''Bemalambdidae'' . Probably close to this group were other small animals, such as '' 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 ...

''.

Paleoecology

The representatives of the ''Bemalambda'' genus were animals with a strong and robust build, with a herbivorous or perhaps omnivorous diet. The strong legs, in particular the humerus, indicate a propensity for digging.

Bibliography

*M. M. Chow, Y.-P. Chang, B.-Y. Wang and S.-Y. Ting. 1973. New mammalian genera and species from the Paleocene of Nanhsiung, N. Kwangtung. Vertebrata PalAsiatica 11(1):31-35 *Zhou, M., Y. Zhang, B. Wang, and S. Ding. 1977. Mammalian fauna from the Paleocene of Nanxiong Basin, Guangdong. Palaeontologia Sinica, new series C 20:1–100. *C. de Muizon and L. G. Marshall. 1992. Alcidedorbignya inopinata (Mammalia: Pantodonta) from the Early Paleocene of Bolivia: Phylogenetic and Paleobiogeographic Implications. Journal of Paleontology 66(3):499-520 *Q. Li. 2005. New material of Bemalambda from Chijiang Basin in Jiangxi, China. Vertebrata PalAsiatica 43(4):325-329 Pantodonts Prehistoric mammal genera Paleocene first appearances Paleocene extinctions Paleocene mammals of Asia {{paleo-mammal-stub