A well-preserved skull of Qianichthyosaurus zhoui LI, 1999 (Reptilia: Ichthyosauria) from the Upper Triassic of China and the phylogenetic position of the Toretocnemidae
Maisch, Michael W.; Jiang, Da-Yong Hao
published: Jun 1, 2008
ArtNo. ESP155024803001, Price: 29.00 €
A well-preserved skull and mandible of the toretocnemid ichthyosaur Qianichthyosaurus zhoui LI, 1999 is described from the Upper Triassic Wayao Member of the Falang Formation (Carnian) of Guanling County, Guizhou Province, southwestern China. It allows substantial additions to the knowledge of the cranial osteology of this taxon and the rectification of previous misinterpretations, particularly of the temporal region. Qianichthyosaurus shows numerous similarities to the mixosaurids in its cranial skeleton, particularly with regard to the temporal region, skull proportions and dentition, although it lacks some key features of the family, such as continuous supranarial and supraorbital crests or a high saggital crest on nasal, frontal and parietal. Nevertheless, there is some evidence that the jaw muscles were arranged similarly to the mixosaurids. The similarities in cranial osteology, together with some remarkably plesiomorphic features of the postcranial skeleton, suggest, that the Toretocnemide may not be the sister-group of the Longipinnati, as previously proposed, but may be closely related to the Mixosauridae instead, developing the basically tridactylous fin pattern independently of other longipinnate ichthyosaurs.