1. National Geological Museum of China , Beijing 100034, China
2. China University of Geosciences, Beijing 100083, China
3. Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213-4080, USA

Correspondence to: Luo Zhexi³ Correspondence and requests for materials should be addressed to: Z. Luo (e-mail: Email: luoz@clpgh.org).

Abstract

Here we describe a new triconodont mammal from the Late Jurassic/Early Cretaceous period of Liaoning, China. This new mammal is represented by the best-preserved skeleton known so far for triconodonts which form one of the earliest Mesozoic mammalian groups with high diversity. The postcranial skeleton of this new triconodont shows a mosaic of characters, including a primitive pelvic girdle and hindlimb but a very derived pectoral girdle that is closely comparable to those of derived therians. Given the basal position of this taxon in mammalian phylogeny, its derived pectoral girdle indicates that homoplasies (similarities resulting from independent evolution among unrelated lineages) are as common in the postcranial skeleton as they are in the skull and dentition in the evolution of Mesozoic mammals. Limb structures of the new triconodont indicate that it was probably a ground-dwelling animal.

1. National Geological Museum of China , Beijing 100034, China
2. China University of Geosciences, Beijing 100083, China
3. Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213-4080, USA

Correspondence to: Luo Zhexi³ Correspondence and requests for materials should be addressed to: Z. Luo (e-mail: Email: luoz@clpgh.org).