THE MIXOSAURID ICHTHYOSAUR PHALARODON CF. P. FRAASI FROM THE MIDDLE TRIASSIC OF GUIZHOU PROVINCE, CHINA

作者：D. Jiang, Lars Schmitz, Ryosuke Motani, Wei-Cheng Hao, Yuanlin Sun · 发表于：Journal of Paleontology · 年份：2007 · DOI：10.1666/05092.1 · 被引用次数：23 · 研究领域：Paleontology and Evolutionary Biology、Ichthyology and Marine Biology、Evolution and Paleontology Studies

The family Mixosauridae Baur, 1887 is a dominant group of Middle Triassic ichthyosaurs. Its generic composition has been controversial, but recent findings from southern China enabled Jiang et al. (2006) to recognize two monophyletic taxa within the clade, suggesting the presence of two genera within the family, namely Mixosaurus Baur, 1887 and Phalarodon Merriam, 1910. The latter genus, which was invalidated at one point (Nicholls et al., 1999; McGowan and Motani, 2003), was recently resurrected by Schmitz (2005) by validating its type species. Mixosaurus is Tethyan in distribution, whereas Phalarodon had been known mostly from North America and Spitsbergen, apart from a possible juvenile from Switzerland (Brinkmann, 1997, 1998). More recently, Jiang et al. (2003) reported a largely complete, yet poorly preserved skeleton as the first record of the genus Phalarodon from Asia and referred it to Phalarodon sp. However, important synapomorphies were not clearly identified, and evidence has since emerged that the specimen had been tampered with by farmers after it was collected. In the light of the cladistic analysis by Jiang et al. (2006), the referral of the specimen to the genus Phalarodon is questionable. A new specimen was excavated in Panxian County, near the western border of Guizhou Province, by the Geological Museum and Department of Geology of Peking University. The new material, the authenticity of which is unquestionable, is from the same stratigraphic horizon as th...