Adriosaurus

Adriosaurus
Temporal range: Late Cretaceous, 95 Ma
↓
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
Clade: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 & 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. 1 2 Michael W. Caldwell & 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 & 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.


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