Protostegidae
| Protostegidae | ||||||||||||
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Live reconstruction of Protostega gigas , a protostegid from the Upper Cretaceous of Kansas up to 3 meters long |
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| Temporal occurrence | ||||||||||||
| chalk | ||||||||||||
| 140.2 to 65.5 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Protostegidae | ||||||||||||
| Cope , 1872 | ||||||||||||
The Protostegidae are an extinct family of turtles (Testudines), which together with the still existing sea turtles (Cheloniidae) and leatherback turtles (Dermochelyidae) form the sea turtle relatives (Chelonioidea).
So far, fossils from representatives of five different genera are known. These include the species of the genera Santanachelys , Notochelone , Desmatochelys , Chelosphargis and the eponymous Protostega . The oldest fossil of this group found so far is Santanachelys gaffneyi from the Santana Formation in eastern Brazil . It dates from the Early Cretaceous Period and is around 110 million years old. The largest representative of this group is the up to 4.5 m long Archelon from the Upper Cretaceous ( Campan ) of North America.
Systematics
On the basis of a comparison of a total of 104 characteristics of the skeletons of various extinct and still living sea turtle relatives and some species outside this taxon (outgroup comparison ), the first person to describe the species Santanachelys gaffneyi carried out a cladistic family tree analysis in order to classify it within the sea turtle system. The analysis was carried out with the help of the software known as PAUP (phylogenetic analysis using parsimony) and came to the following result (simplified), according to which the relationships within the Protostegidae are clarified:
| Sea turtle relatives (Chelonioidea) |
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literature
- Ren Hirayama: Oldest known sea turtle. In: Nature . Vol. 392, No. 6677, 1998, pp. 705-708, doi : 10.1038 / 33669 .
