Adriosaurus

Adriosaurus Temporal range: Late Cretaceous, 95 Ma PreЄ Є O S D C P T J K Pg N ↓
London specimen of A. suessi above, with interpretative drawing of its skull on the left. Vienna holotype specimen of A. suessi below.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Infraorder:	Anguimorpha
(unranked):	Pythonomorpha
Genus:	Adriosaurus Seeley, 1881
Species
A. microbrachis Palci & Caldwell, 2007[1] A. skrbinensis Caldwell & Palci, 2010[2] A. suessi Seeley, 1881 (type)

Adriosaurus is an extinct genus of aquatic lizard that lived about 95 million years ago. It was snake-like and grew 10 to 12 inches. This is the first fossil record of vestigial limbs in lizards, and gives scientists a glimpse back to the time when terrestrial lizards evolved to be limbless and returned to their watery origins.^[3][4]

Cladogram based on Palci and Caldwell (2010a), Caldwell and Palci (2010b)^[5][2]: 

Anguimorpha	Anguidae Xenosaurus Shinisaurus Heloderma Lanthanotus Varanus Pythonomorpha Aigialosauridae Mosasauridae Ophidiomorpha Dolichosauridae Coniasaurus Dolichosaurus Pontosaurus lesinensis Pontosaurus kornhuberi Aphanizocnemus Adriosaurus skrbinensis Adriosaurus suessi Acteosaurus Ophidia

References

1. Alessandro Palci and Michael W. Caldwell (2007). "Vestigial forelimbs and axial elongation in a 95-million-year-old non-snake squamate". Journal of Vertebrate Paleontology 27 (1): 1–7. doi:10.1671/0272-4634(2007)27[1:VFAAEI]2.0.CO;2.
2. Michael W. Caldwell and Alessandro Palci (2010b). "A new species of marine ophidiomorph lizard, Adriosaurus skrbinensis, from the Upper Cretaceous of Slovenia". Journal of Vertebrate Paleontology 30 (3): 747–755. doi:10.1080/02724631003762963.
3. Ancient lizard missing front limbs - LiveScience - MSNBC.com
4. Aquatic Lizard Was Losing Its Front Limbs
5. Alessandro Palci and Michael W. Caldwell (2010a). "Redescription of Acteosaurus tommasinii von Meyer, 1860, and a discussion of evolutionary trends within the clade Ophidiomorpha". Journal of Vertebrate Paleontology 30 (1): 94–108. doi:10.1080/02724630903409139.