Phytosaurus

Phytosaurus (meaning "plant lizard") is a dubious genus of extinct parasuchid phytosaur[1] found in an outcrop of the Keuper (likely the Exter Formation)[2] in Germany. Phytosaurus was the first phytosaur to be described, being done so by Georg Friedrich von Jaeger in 1828.[3] The type species is P. cylindricodon and a second species, P. cubicodon, is also known.[3]

Phytosaurus
Temporal range: Late Triassic,
Holotype jaw of P. cylindricodon
Holotype of P. cubicodon
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: †Phytosauria
Family: †Parasuchidae
Genus: †Phytosaurus
von Jaeger, 1828
Type species
†Phytosaurus cylindricodon
von Jaeger, 1828
Other species
  • †P. cubicodon von Jaeger, 1828

Discovery and naming
Associated elements from the holotype of P. cylindricodon

In 1826, the holotypes of both species were discovered in Wurttemburg, Germany at the "Neckar" site at the base of the hill which Wildenau Castle stands upon.[3] The holotype of P. cylindricodon consists of parts of the skull and jaws, with natural casts of the teeth which, however, did not preserve their conical form but were flattened which led to the misunderstanding they were specialised in eating plant material,[3] and the holotype of P. cubicodon consists of fragments of the jaw.[3] Both species were named and described by von Jaeger (1828)[3] and were first commented on by von Meyer (1837).[4]

Many later authors, beginning with Owen (1841), have classified both species of Phytosaurus as nomen dubia due to the lack of known diagnostic material.[1] Owen (1841) had Phytosaurus classified as a synonym of Mastodonsaurus, an unrelated amphibian, and later Labyrinthodon, a now obsolete taxon.[5]

A partial phytosaur specimen found at the "UCMP V6333" locality of the Dockum Formation in Texas was initially referred to Phytosaurus sp.,[6] but has since been reclassified as an indeterminate mystriosuchine phytosaur.[7]

Description

P. cylindricodon appeared to have cylindrical teeth, while P. cubicodon appeared to have teeth that were square in shape.[3][4] The conical teeth of the P. cylindricodon holotype appear to show evidence of grinding.[4]

Phytosaurus likely grew up to 3 metres (9.8 ft) long and the skull of P. cylindricodon likely reached up to 1 metre (3.3 ft) when complete.[7]

Classification

Phytosaurus likely belonged to the Parasuchidae, a family of phytosaurs.[8]

References
  1. Lydekker, Richard (1899-01-01). Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History). Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. Elibron.com. p. 124. ISBN 978-0-543-95654-5.
  2. H. v. Meyer and T. Plieninger. (1844). Beiträge zur Paläontologie Württemberg’s, enthaltend die Fossilen Wirbelthierreste aus den Triasgebilden mit Besonderer Rücksicht auf die Labyrinthodonten des Keupers [Contributions to the Paleontology of Württemberg, Including the Fossil Vertebrate Remains from the Triassic Formations with Special Regard to the Labyrinthodonts of the Keupers] 1-132
  3. G. F. Jaeger. (1828). Über die Fossile Reptilien, Welche in Württemberg Aufgefunden Sind [On the Fossil Reptiles That Are Found in Württemberg]. Verlag der Metzler'schen Buchhandlung, Stuttgart 1-48
  4. von Meyer, H. (1837) “On the Structure of Fossil Saurians.”
  5. In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods by Nicholas C. Fraser and Hans-Dieter Sues
  6. U.C.M.P. Database. (2005). UCMP collections database. University of California Museum of Paleontology
  7. Stocker, Michelle R.; Butler, Richard J. (2013). "Phytosauria". Geological Society, London, Special Publications. 379 (1): 91–117. Bibcode:2013GSLSP.379...91S. doi:10.1144/sp379.5. ISSN 0305-8719. S2CID 219192243.
  8. Kammerer, Christian F.; Butler, Richard J.; Bandyopadhyay, Saswati; Stocker, Michelle R. (2016). Angielczyk, Kenneth (ed.). "Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885". Papers in Palaeontology. 2 (1): 1–23. doi:10.1002/spp2.1022. S2CID 83780331.
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