Adriosaurus
Adriosaurus is an extinct genus of squamate which lived in what is now Slovenia and other parts of Europe during the Late Cretaceous. It was small, snake-like reptile, with type species measuring up to 30 cm (12 in) in length. This is the first fossil record of vestigial limbs in lizards. It lost its manus and forearm completely in order to elongate its axial skeleton. These unique anatomical features led to discussions of the evolutionary patterns of limb reduction in Squamata.
| Adriosaurus Temporal range: Late Cretaceous, | |
|---|---|
| London specimen of A. suessi above, with interpretative drawing of its skull on the left. Vienna holotype specimen of A. suessi below. | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Clade: | Pythonomorpha |
| Genus: | Adriosaurus Seeley, 1881 |
| Species | |
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Adriosaurus includes three species: A. microbrachis (“micro”, meaning small, and “brachis”, meaning arm, referring to the vestigial forelimb composed of only the humerus), A skrbinensis (named after the location where they found the fossil, Skrbina, northwest of Komen, Slovenia) and A. suessi. However, A. microbrachis lacks many crucial characters to be qualified for cladistic analysis, thus it's not included in the list of terminal taxa.