An unusual archosaurian from the marine Triassic of China.

A new Triassic archosaurian from China shows a number of aquatic specializations, of which the most striking is the extreme lateral compression of the long tail. Others that may also reflect aquatic adaptations include plate like scapula and coracoid, elongate neck with extremely long and slender ribs, and reduction of osteoderms. In contrast, its pelvic girdle and hind limb have no aquatic modifications. Anatomic features, taphonomy, and local geological data suggest that it may have lived in a coastal-island environment. This lifestyle, convergent with some Jurassic marine crocodyli-forms that lived at least 40 million years later and the saltwater species of extant Crocodylus, contradicts with the prevailing view that Triassic archosaurians were restricted to non-marine ecosystems. Its mosaic anatomy represents a previously unknown ecomorph within primitive archosaurians.