| Bemalambdidae Temporal range: | |
|---|---|
 | |
| Skeleton of Bemalambda pachyoesteus, exhibited in the National Museum of Nature and Science, Tokyo, Japan. | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | † Cimolesta |
| Suborder: | † 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.
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]
Andrewsarchus is an extinct genus of mammal that lived during the Middle Eocene in China. It contains two species, A. mongoliensis and A. crassum. It was formerly placed in the families Mesonychidae or Arctocyonidae, but is now the sole member of a distinct family, Andrewsarchidae. It is most notable for being estimated as the largest terrestrial, carnivorous mammal, but that status has been disputed.
Miacis is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from early to middle Eocene.
Sinosaurus is an extinct genus of theropod dinosaur which lived during the Early Jurassic Period. It was a bipedal carnivore approximately 5.5 metres (18 ft) in length and 300 kilograms (660 lb) in body mass. Fossils of the animal were found at the Lufeng Formation, in the Yunnan Province of China.
Mesonyx is a genus of extinct mesonychid mesonychian mammal: fossils of the various species are found in Early to Late Eocene-age strata in the United States and Early Eocene-aged strata in China, 51.8—51.7 Ma (AEO).
Pantolambda is an extinct genus of Paleocene pantodont mammal. Pantolambda lived during the middle Paleocene, and has been found both in Asia and North America.
Pantodonta is an extinct suborder of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve after the end of the Cretaceous. The last pantodonts died out at the end of the Eocene.
Kubanochoerus is an extinct genus of large, long-legged suid artiodactyl mammal from the Miocene of Eurasia and Africa.
Mesonychidae is an extinct family of small to large-sized omnivorous-carnivorous mammals. They were endemic to North America and Eurasia during the Early Paleocene to the Early Oligocene, and were the earliest group of large carnivorous mammals in Asia. They are not closely related to any living mammals. Mesonychid taxonomy has long been disputed and they have captured popular imagination as "wolves on hooves," animals that combine features of both ungulates and carnivores. Skulls and teeth have similar features to early whales, and the family was long thought to be the ancestors of cetaceans. Recent fossil discoveries have overturned this idea; the consensus is that whales are highly derived artiodactyls. Some researchers now consider the family a sister group either to whales or to artiodactyls, close relatives rather than direct ancestors. Other studies define Mesonychia as basal to all ungulates, occupying a position between Perissodactyla and Ferae. In this case, the resemblances to early whales would be due to convergent evolution among ungulate-like herbivores that developed adaptations related to hunting or eating meat.
Hapalodectidae is an extinct family of relatively small-bodied mesonychian placental mammals from the Paleocene and Eocene of North America and Asia. Hapalodectids differ from the larger and better-known mesonychids by having teeth specialized for cutting, while the teeth of other mesonychids, such as Mesonyx or Sinonyx, are more specialized for crushing bones. Hapalodectids were once considered a subfamily of the Mesonychidae, but the discovery of a skull of Hapalodectes hetangensis showed additional differences justifying placement in a distinct family. In particular, H. hetangensis has a postorbital bar closing the back of the orbit, a feature lacking in mesonychids. The skeleton of hapalodectids is poorly known, and of the postcranial elements, only the humerus has been described. The morphology of this bone indicates less specialization for terrestrial locomotion than in mesonychids.
Arctocyonidae has been defined as an extinct family of unspecialized, primitive mammals with more than 20 genera. Animals assigned to this family were most abundant during the Paleocene, but extant from the late Cretaceous to the early Eocene . Like most early mammals, their actual relationships are very difficult to resolve. No Paleocene fossil has been unambiguously assigned to any living order of placental mammals, and many genera resemble each other: generalized robust, not very agile animals with long tails and all-purpose chewing teeth, living in warm closed-canopy forests with many niches left vacant by the K-T extinction.
The Subashi Formation is a Late Cretaceous formation from the Xinjiang Autonomous Region of western China. Initially described by Dong Zhiming in 1977, the formation contains remains of Tarbosaurus which were initially described as a separate taxon Shanshanosaurus huoyanshanensis. Remains of a sauropod, likely Nemegtosaurus, and a hadrosaurid, likely Jaxartosaurus, have also been found.
Peipehsuchus is an extinct genus of metriorhynchoid crocodyliform from the Early Jurassic (Toarcian). The type species, P. teleorhinus, is known from China and fragmentary remains were found in the Callovian of Kyrgyzstan. The type specimen is known only by a fragmentary rostrum and teeth, and was originally believed to be a teleosaurid. A complete teleosaurid skull was referred to Peipehsuchus, however, the type specimen of Peipehsuchus has since been determined to be a metriorhynchoid and so the skull cannot belong to it.
Tillodontia is an extinct suborder of eutherian mammals known from the Early Paleocene to Late Eocene of China, the Late Paleocene to Middle Eocene of North America where they display their maximum species diversity, the Middle Eocene of Pakistan, and the Early Eocene of Europe. Leaving no descendants, they are most closely related to the pantodonts, another extinct group. The tillodonts were medium- to large-sized animals that probably feed on roots and tubers in temperate to subtropical habitats.
Ovaloolithus is an oogenus of dinosaur egg. Eggs of the genus have been found in China, Mongolia and Utah.
Ordosiodon is an extinct genus of therocephalian therapsids from the Early Triassic of China. It includes two species, O. lincheyuensis and O. youngi.
Coryphodontidae is an extinct family of pantodont mammals known from the Late Paleocene to the Middle Eocene of Eurasia and North America.
Plethorodon is an extinct genus of tillodont that lived during Early to Late Paleocene. The type species is P. qianshanensis. which known from partial skull and upper teeth that had been discovered by Huang and Zheng at 1987 at Qianshan, Anhui Province, China.
Meiostylodon is an extinct genus of tillodont that lived during Paleocene. The lone type species, M. zaoshiensis, is known only from three isolated teeth found at Zaoshi, Chaling County, Hunan Province in the People's Republic of China. These isolated fossil teeth are stored at the Paleozoological Museum of China.
Liaoningvenator is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, L. curriei, named after paleontologist Phillip J. Currie in 2017 by Shen Cai-Zhi and colleagues from an articulated, nearly complete skeleton, one of the most complete troodontid specimens known. Shen and colleagues found indicative traits that placed Liaoningvenator within the Troodontidae. These traits included its numerous, small, and closely packed teeth, as well as the vertebrae towards the end of its tail having shallow grooves in place of neural spines on their top surfaces.
Bemalambda is an extinct mammal, belonging to the pantodonts. It lived in the lower-middle Paleocene and the fossil remains have been found in China.
