''Agilodocodon'' was a genus of

shrew Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to diffe ...

-sized

docodont Docodonta is an order of extinct mammaliaforms that lived during the Mesozoic, from the Middle Jurassic to Early Cretaceous. They are distinguished from other early mammaliaforms by their relatively complex molar teeth, from which the order ge ...

from the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations ...

, believed to be the earliest known tree-climbing

mammaliaform Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts. It is defined as the clade originating from the most recent ...

. It contains one species, ''A. scansorius''.

Appearance

''Agilodocodon'' measured approximately from head to tail, weighing about 27 grams. Its appearance was similar to a squirrel, with a long snout, curved, horny claws and flexible ankle and wrist joints typical of modern arboreal mammals. The front teeth were spade-like, indicating that ''Agilodocodon'' could gnaw tree bark and consume gum or sap. Evolutionary biologist Frietson Galis, however, questioned whether ''Agilodocodon'' gnawed bark and ate tree sap, saying its teeth "are quite different" from the modern sap-eating primates, and the long, thin lower jaw seems too weak for chomping on tree bark.

Discovery

The fossil of ''Agilodocodon scansorius'',

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

BMNH 001138, along with that of ''

Docofossor ''Docofossor'' is an extinct mammaliaform (a docodont) from the Jurassic period. Its remains have been recovered in China from 160 million years old rocks. It appears to have been the earliest-known subterranean mammaliaform, with adaptations rem ...

brachydactylus'', was originally found by farmers in the Chinese

Tiaojishan Formation The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period (Bathonian- Oxfordian stages). It is known for its exceptionally preserved fossils, including those of ...

and acquired by the

Beijing Museum of Natural History The Beijing Museum of Natural History (BMNH; ) is located at 126 Tian Qiao Nan Street, Dongcheng District, Beijing, 100050, and is the most popular natural history museum in China.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 specimen( ...

''Agilodocodon scansorius'' was named and described in the journal ''

Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...

'' in 2015. The generic name refers to the membership of the Docodonta and the agility. The specific name refers to the

scansorial Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...

lifestyle.

References

Docodonts Middle Jurassic synapsids of Asia Jurassic China Fossils of China Fossil taxa described in 2015 Taxa named by Qing-Jin Meng Taxa named by Ji Qiang Taxa named by Yu-Guang Zhang Taxa named by Di Liu Taxa named by David M. Grossnickle Taxa named by Zhe-Xi Luo Prehistoric cynodont genera {{paleo-therapsid-stub