Euryaspis

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Euryaspis
Temporal range: Tithonian
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Thalassochelydia
Genus: Euryaspis
Wagner, 1861
Species:
E. radians
Binomial name
Euryaspis radians
Meyer, 1843

Euryaspis is a dubious genus of extinct thalassochelydian turtle from the Late Jurassic of Germany. The type and only species is Euryaspis radians, originally proposed by Wagner in 1859 before being validly described and illustrated in 1861. The only specimen was a partial carapace probably from the Tithonian, although the original locality is unknown. The genus is referred to Thalassochelydia and has been considered a synonym of Eurysternum or Acichelys before, but casts that remain of the lost holotype show that it bears no features that can clarify its validity making it a nomen dubium . [1]

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Solnhofia is a genus of extinct thalassochelydian turtle from the Late Jurassic of Germany. The type species is Solnhofia parsoni, named by Gaffney in 1975 for a partial skull and jaw from the early Tithonian of the Solnhofen Formation in Bavaria. Additional material including a complete skeleton is known from the late Kimmeridgian of Switzerland and the Kimmeridgian/Tithonian of other deposits within Bavaria, and potentially also unprepared material from the Late Jurassic of France. The genus was referred to the family Eurysternidae by Anquetin and colleagues in 2017, which may represent an artificial clade of early thalassochelydians. In 2020 a new species Solnhofia brachyrhyncha was described from the Kimmeridigan aged Reuchenette Formation of Switzerland.

Aplax is a dubious genus of extinct thalassochelydian turtle from the Late Jurassic of Germany. The type and only species is Aplax oberndorferi, named by Hermann von Meyer in 1843 for a complete juvenile skeleton from the early Tithonian of the Solnhofen Formation in Bavaria. Despite being aware that shell morphology changes during growth, Meyer named Aplax due to his consideration it represented a relative of Dermochelys, where the adults lack distinction of shell regions as in Aplax. However the taxon was later referred to Thalassochelydia by Anquetin and colleagues in 2017, and due to the loss of the original holotype it cannot be identified as a distinct taxon of a juvenile of existing Solnhofen turtles and is therefore a nomen dubium.

Pelobatochelys is a genus of extinct thalassochelydian turtle from the Late Jurassic of the United Kingdom. The type and only species is Pelobatochelys blakii, named by Harry Govier Seeley in 1875 for a central carapace fragment along with five additional specimens from the remainder of the shell from the early Kimmeridgian of the Kimmeridge Clay in Dorset, and additional material from the Kimmeridge Clay has also been referred to the taxon. The material was considered to be related to various turtles throughout time, including being reassigned to Tropidemys as T. blakii based on limited evidence. A large shell also from Weymouth, Dorset may represent further material of Pelobatochelys, but could also be from Tropidemys langii which was also present in the deposits.

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Sandownidae is a family of extinct marine turtles from the Cretaceous and Paleogene. The family is defined as all taxa closer to the type genus Sandownia than to Pelomedusa, Testudo, Solnhofia, Eurysternum, Plesiochelys, Thalassemys or Protostega, a definition that encompasses the previous concept of the clade while also excluding it from being synonymous with other clades of modern or extinct marine turtles. Sandownidae may be within the larger clade Angolachelonia, defined as inclusive of Angolachelys and Solnhofia, sister to the entirely Late Jurassic marine group Thalassochelydia, although the concepts of the clades may shift with further phylogenetic analysis.

References

  1. Anquetin, J.; Püntener, C.; Joyce, W.G. (2017). "A Review of the Fossil Record of Turtles of the Clade Thalassochelydia" (PDF). Bulletin of the Peabody Museum of Natural History. 58 (2): 317–369. doi:10.3374/014.058.0205. S2CID   31091127.