Earliest-known arboreal and subterranean ancestral mammals discovered
The Fossil of Agilodocodon scansorius. The specimen is preserved in two rock slabs. The main part (BMNH-PM001138A, left) and counter part (BMNH-PM001138B, right) of Agilodocodon scansorius type specimen of Beijing Museum of Natural History (BMNH). Found in lake sediments of the 165 million years old Daohugou Fossil Site of Inner Mongolia of China, Agilodocodon scansorius is preserved with a halo of dense, carbonized furs and hair impressions. The horny claws on hands and feet are also preserved (Photo by Zhe-Xi Luo, the University of Chicago).
攀援灵巧柱齿兽－北京自然博物馆馆藏正型标本（BMNH－PM00138A-正化石板）照片。9KB, 150px X 120px
28KB, 288px X 231px
401KB, 1200px X 962px
Skeletal and life style reconstructions of Agilodocodon scansorius, a docodont mammaliaform. Agilodocodon has a skull length of 2.7 cm and body length about 13 cm (about 5 inches) and likely weighed between 27 grams and 40 grams (1 to 1.4 ounces). The skeletal features suggest that it was an agile and active animal living on the tree. Its incisors were specialized to feed on tree sap (exudate feeding) and its molars suggest omnivorous feeding (Illustration by April I. Neander, the University of Chicago).
攀援灵巧柱齿兽（Agilodocodon scansorius）骨骼复原和生活方式重建 （美国芝加哥大学April I. Neander）9KB, 150px X 150px
21KB, 288px X 288px
168KB, 1200px X 1200px
Photos of the type specimen of Docofossor brachydactylus Beijing Museum of Natural History BMNH-PM131735A (main part, left) and BMNH-PM131735B (counter part, right), as preserved in split rock slabs in part and counter-part. Docofossor was found in lake sediments of the Jurassic Ganggou fossil site in Hebei Province of China. The fossil of Docofossor is preserved with dense and carbonized furs around its skeleton (Photo by Zhe-Xi Luo, the University of Chicago).
短指挖掘柱齿兽－北京自然博物馆馆藏正型标本（BMNH－PM131735A正化石板和BMNH-PM131735B对化石板）照片。1.1MB, 105px X 106px
17KB, 288px X 204px
220KB, 1200px X 849px
Skeletal and life style reconstructions of Docofossor brachydactylus. Docofossor has a mandible length of 1.7 cm and an estimated skull-to-rump length of 7 cm (about 2.8 inches), and the animal weighed up to 16 grams (about half of an ounce). Docofossor has robust and short finger bones, but greatly enlarged terminal phalanges (claw-bones) and massive limb bones for its tiny body size, all for digging. Docofossor lived in burrows on the lakeshore and fed on the worms and insects in the soil. Docofossor is also unique in that it has one segment fewer of finger bone segments, than most other mammals, suggesting that it had a unique embryonic development of its hands and feet (Illustration by April I. Neander of the University of Chicago).
短指挖掘柱齿兽（Docofossor brachydactylus）骨骼复原和生活方式重建 （美国芝加哥大学April I. Neander9KB, 150px X 150px
23KB, 288px X 288px
207KB, 1200px X 1200px
Map of Fossil Sites
Geographical locations of the new fossil discoveries. The specimen of Agilodocodon scansorius is from the Middle Jurassic Daohugou fossil site in Ningcheng County of Inner Mongolia Region of China。 The Daohugou Site is directly dated to be 165 million years. The specimen of Docofossor brachydactylus is from the Late Jurassic Ganggou Fossil Site in Qinglong County of Hebei Province of China. Although not directly dated, the Ganggou Site is estimated to be 160 million years old by geological correlation (Illustration by April I. Neander of the University of Chicago).
柱齿兽类新化石的野外化石地点。攀援灵巧柱齿兽发现于内蒙古宁城的中侏罗系道虎沟化石产地。短指挖掘柱齿兽发现于河北省青龙县晚侏罗系干沟村化石产地。5KB, 150px X 118px
11KB, 288px X 226
70KB, 1200px X 940px
Evolutionary History of Stem and Extant Mammals
Stem mammaliaforms (also known as “stem mammals”) are long-extinct relatives to the extant mammals (crown Mammalia). Docodonts are such a lineage of stem mammaliaforms. Their morphologies provide evidence for the ancestral mammalian condition. Their functional adaptations provide new insight on the ecological diversification of the earliest mammals. The newly discovered arboreal specialization and fossorial and subterranean specialization of fossil docodonts indicate that the stem mammaliaforms had very diverse feeding and locomotor functions, and a much wider ecological divergence as a whole, despite the dominance of dinosaurs in the Mesozoic (Illustration by April I. Neander of the University of Chicago).
柱齿兽哺乳型动物与现代哺乳动物的演化历史。哺乳型动物是现生哺乳动物的已绝灭的近亲支系。柱齿兽类是哺乳型动物多个支系中的一个广泛分布的支系。柱齿兽哺乳型动物的形态特征代表了哺乳动物起源演化过程中原始的形态。新发现的前所未知的柱齿兽动物的树栖和挖掘穴居生态适应类型，表明最早的原始哺乳动物更为多样，分异范围更宽 。它们多元的生态适应为哺乳动物最早期生态分异的演化机制提供了新证据和新认识。7KB, 50px X 133px
37KB, 500px X 443px
129KB, 1200px X 1062px
Docodont Reconstruction Movie
Image reconstruction from CT scanning of the jaws of the docodont mammaliaforms Agilodocodon and Docofossor (visuals available from April I. Neander of the University of Chicago: email@example.com).