Cryptolacerta

• Hesse ( Messel )

Cryptolacerta is a small, extinct lizard from the Eocene, whose discovery gave important information on the systematics of Squamata. The holotype of Cryptolacerta hassiaca, the only known species, was found in the Messel Pit in Hesse and is preserved in the Senckenberg Museum. The selected genus name refers to the grave border, hidden life of the animals ( Gr. " crypto" = hidden, Lat: . " Lacerta " = lizard ), the type - hassiaca epithet refers to the locality in Hesse.

The exact investigation, including by means of computed tomography in the Helmholtz Centre Berlin for Materials and Energy, was the basis for a detailed morphological description of the fossil.

Features

Cryptolacerta had a head -body length of seven inches, came to the tail, which is missing in the only known fossil to a large extent. Your anatomical characteristics are a mosaic of features lizards and amphisbaenians features. With the amphisbaenians Cryptolacerta in common especially the capsule-like, heavily ossified skull. The snout is blunt and rounded. The jaws are heterodont dentate with 14 teeth on the dentary, 7 on the premaxilla and 12 on the maxilla. The external nares are small. Overall, the skull of Cryptolacerta how the skull of amphisbaenians - which has the function of a drill head and the animals will allow the ditch - has evolved from a lizard-like skull.

Front and hind feet of Cryptolacerta are greatly reduced in comparison with the other bones of the front and hind legs. The Phalangenformel is 2-3-4-4 / 5? -3 And shows that no toe was reduced.

System

Cryptolacerta is most closely related to the genuine lizards ( Lacertidae ) and the amphisbaenians ( amphisbaenians ), but closer to the latter, which can be occupied by 19 common characteristics. Thus the argument is refuted that snakes ( Serpentes ) and amphisbaenians have emerged from a common ancestor grave end. The common taxon of Lacertidae and Amphisbaenia is called Lacertibaenia and has already been set up in 2005 by Vidal and Hedges, after molecular studies had hinted at a relationship between the two groups. The separation of the core group of lizards and amphisbaenians - determined using the method of molecular clock - took place in the Late Cretaceous period 20 million years before the appearance of Cryptolacerta. Due to the island geography of the European continent in the Paleogene was Europe at that time into a refuge for archaic Mesozoic Squamata.

The following diagram shows the position of Cryptolacerta as a sister group to amphisbaenians in a common clade with the lizards.

Rail lizards ( Teiidae ) and Zwergtejus ( Gymnophthalmidae )

Lizards ( Lacertidae )

Cryptolacerta

Amphisbaenians ( amphisbaenians )

Swell

• Johannes Müller, Christy A. Hipsley, Jason J. Head, Nikolay Kardjilov, André Hilger, Michael Wuttke & Robert R. Reisz (2011): Eocene lizard from Germany Reveals amphisbaenian origins. Nature, Volume 473, page 364-367, doi: 10.1038/nature09919