Gobiconodontidae

Life image of Gobiconodon

• Eurasia, North America

The Gobiconodontidae are a group of extinct mammals ( Mammalia), who lived in the Lower Cretaceous. These carnivorous animals include the largest known mammals of the Mesozoic, including Repenomamus.

Features

The Gobicodontidae were built stocky animals with short, powerful limbs, from their construction can be probably close to a life on land. The body size within this group varied considerably, besides some mice to hare - large representatives Repenomamus reached a body length of about 50 centimeters and an estimated weight of 12-14 kg. The skull length varied accordingly and was 2.7 to 16 centimeters.

The incisors were large and pointed, the molars ( back teeth ) of these animals had three consecutively arranged hump on, a feature which ( Eutriconodonta ) of the Mesozoic is also found in other mammals. The central protuberance was significantly greater than the other two, it is also slightly offset to the center, so that the triangular arrangement, it is anticipated that occurs during subsequent groups of mammals. The dental formula (if known) should have I 2/2-3 C 1/ 1 P M 4/4-5 3-4/2-3 gelautet. The sharp teeth was applied for a total of carnal nutrition; at least from Repenomamus is known that he was eating other mammals and small dinosaurs ( Psittacosaurus ).

History of development and external system

The Gobiconodontidae are so far only a comparatively short section of Lower Cretaceous known, the fossils come from Asia and North America, and thus from the former North continent Laurasia.

There are a number of Mesozoic mammals which are characterized by three molar successively arranged protuberances. Together, they are classified in the group of Eutriconodonta. Whether it really is, however, closely related animals or just to convergent developments, is controversial. Their position in the scheme of mammals is unclear, it is likely, however, have been a relatively early, specialized side branch. They are therefore more closely related to any modern group of mammals.

Inside systematics

There have been described several classes of Gobiconodontidae, the genus Repenomamus is sometimes performed in a separate family, Repenomamidae. This separation is justified by differences in construction and number of teeth, it is common ground that it is closely related to the other genera listed here.

• From the genus Gobiconodon several species have been described, which differ significantly in terms of size, its skull length varies between three and four inches. Findings are occupied from the U.S., Russia, Mongolia and China ( from the Yixian Formation, which is also known for their feathered dinosaurs).
• From Hangjinia only parts of the lower jaw are known so far.
• Meemannodon was a comparatively large representative, who is also known from the Yixian Formation.
• Repenomamus was the greatest representative of this group and the largest previously known Mesozoic mammal ever. Two different-sized species, R. and R. robustus giganticus have been described, both of which are also known from the Yixian Formation.