Palatodonta
| Palatodonta | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Middle Triassic ( Anisium ) | ||||||||||||
| approx. 243 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Palatodonta | ||||||||||||
| Neenan et al., 2013 | ||||||||||||
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Palatodonta ("palatal tooth") is a genus of the fin lizard (Sauropterygia), the representatives ofwhichinhabitedthe western Tethys in the Middle Triassic . They were characterized by two rows of pointed teeth in the upper jaw and a short, small-snouted skull. The genus palatodonta and their only way , palatodonta bleekeri were in 2013 by James Neenan , Nicole Klein and Torsten Scheyer using a fossil skull from the shell of the Netherlands set up . The authors classified palatodonta as the sister taxon of the placodonts with which it forms the placodontiformes . Both lines separated in the early Triassic and differ among other things in their dentition, which is rounder, flatter and more massive in the placodonts.
features
The Palatodonta fossil material comes from a young animal. As with placodons, however, it probably already shows typical characteristics of adult individuals. The skull was short and had a sloping, small snout. Palatodonta had three rows of pointed teeth: One in the lower jaw and one each on the palatine bone and the maxilla (including the premaxilla ). Both rows of teeth interlocked, with the premaxilla teeth being pin-shaped, all the others rather pointed. Similar to the original Placodus , the maxilla does not border the eye socket and the zygomatic bone touches the scaly bone .
Fossil Material, Distribution, and Stratigraphy
The Palatodonta fossil material includes a largely preserved fossil skull and some fragments of the postcranial skeleton. It was found in 2010 in a Dutch limestone quarry near Winterswijk and comes from rock layers that belong to the Vossenveld Formation . The find layer is dated to the lower shell limestone or the early anisium (about 243 mya ). Palatodonta lived in a western shelf sea of the Tethys , which was bordered by Pangea .
Systematics and taxonomy
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| Systematic position of the palatodonta according to Neenan et al. (2013). The genus forms the sister taxon of the placodonts in the real sense, which are characterized by rounded, flattened and massive teeth in both jaws. |
The holotype ( inventory number TW 480000470) of Palatodonta was first described in 2013 by the paleontologists James Neenan , Nicole Klein and Torsten Scheyer . The generic name (German "Gaumenzahn") is based on the individual row of teeth on the palatine bone, the palatodonta - unlike more original fin lizards and placodonts - had. The authors chose the specific epithet bleekeri in honor of the finder of the holotype, Remco Bleeker. An analysis of the osteological features of the skull of Palatodonta and other diapsids revealed that the genus is at the base of the Placodontia. Given the age of the earliest Placodonten parted palatodonta well in Olenekian from the common ancestor of Placodonten. The genus is very similar to original placodons such as Placodus . Compared to primitive fin lizards, both have reduced palatal teeth and interlocking rows of teeth. While the massive, flattened teeth of the placodonts were used to crack hard-shelled food, the palatodonta probably ate rather soft food that it dug up from the seabed. Since palatodonta differed significantly from placodons in both morphology and lifestyle, Neenan and colleagues set up the taxon Placodontiformes , which unites both lines of development, instead of classifying the genus under the placodons.
swell
literature
- James M. Neenan, Nicole Klein, Torsten M. Scheyer: European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia. In: Nature Communications. Vol. 4, Article 1621, 2013, doi : 10.1038 / ncomms2633 .