Anarosaurus pumilio (Dames 1880, Rieppel and Lin 1995, Klein 2009; Middle Triassic, Anisian) Described as a primitive pachypleurosaur, Anarosaurus is basal to the Enaliosauria (placodonts, plesiosaurs, thalattosaurs and ichthyosaurs) in the LRT. Derived from a sister to Claudiosaurus, Anarosaurus was basal to Palatodonta, Pachypleurosaurus and Wumengosaurus.
Distinct from Claudiosaurus, the skull of Anarosaurus is longer with a more dorsal naris. The premaxilla turns up and the anterior dentary turns down. The quadratojugal is retained, but other workers haven't seen it because it this fragile bone has been broken into pieces (see illustration above). The maxilla includes a palatal shelf. Only a few tiny teeth remain on the palate.
Compared to Claudiosaurus, the neck is longer and the skull is relatively larger. The pectoral girdle is much smaller. The hands and feet are not published, but Dactylosaurus is closely related (see above) with gracile digits. The pelvis is deep. |
