Tangasaurus

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Extinct genus of reptiles

title: "Tangasaurus" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["diapsids", "prehistoric-reptile-genera", "fossil-taxa-described-in-1924", "lopingian-reptiles-of-africa", "taxa-named-by-sidney-h.-haughton", "changhsingian-life"] description: "Extinct genus of reptiles" topic_path: "general/diapsids" source: "https://en.wikipedia.org/wiki/Tangasaurus" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of reptiles ::

| taxon = Tangasaurus | fossil_range = Late Permian, | display_parents = 2 | authority = Haughton, 1924 | type_species = Tangasaurus mennelli | type_species_authority = Haughton, 1924

Tangasaurus is an extinct genus of aquatic basal tangasaurid neodiapsid known from the Late Permian period (late Changhsingian stage) of Tanga, northeastern Tanzania. It contains a single species, Tangasaurus mennelli.

Etymology

Tangasaurus was first described and named by Sidney H. Haughton in 1924 and the type species is Tangasaurus mennelli. The generic name is derived from the name of the Tanga Region in which the only known specimens were found, and Greek sauros, meaning "lizard". The specific name honors F. P. Mennell, the geologist who reported and collected the specimens of Tangasaurus.

Discovery

Tangasaurus is known only from three syntypes which represent two individuals. The small individual, which is well preserved in two specimens (part and counterpart) and is known from a partial skull and a nearly complete postcranial skeleton, was designated as the lectotype of the genus. The part slab (showing the partial skull and postcranial) is hosted at the Bulawayo Museum, Zimbabwe, while the counterpart slab SAM 6231 (showing the other side of the postcranial) is hosted at the South African Museum, Cape Town. The third syntype, SAM 6232, represents a nearly complete postcranial skeleton from a larger individual, but it is poorly preserved.

All specimens were collected by F. P. Mennell in 1922 at the Mizimbazi River near Tanga City, northeastern Tanzania. They were collected from the Ruhuhu Valley, in the middle part of the Tanga beds, dating to the late Changhsingian stage of the Lopingian series, about 252.5–251 million years ago. Although Mennell reported a presence of eight nearly complete individuals from that site, subsequent work couldn't find any evidence for the missing 6 individuals. Mennell's report, alongside some reptilian fragments that were discovered in 1913 and reported by Janensch (1927), are the only reptilian fossils currently known from the Tanga beds.

Numerous well preserved specimens from various Late Permian localities of Madagascar were initially identified as Tangasaurus by Piveteau (1926). During that time the Mozambique Channel had just started to open. However, a reexamination of these specimens by Carroll (1981) and Currie (1982) has shown that they represent a different genus, Thadeosaurus, known only from Madagascar. Another specimen from Madagascar, MNHN 1908-32-57, was also tentatively referred to Tangasaurus. However, Currie (1980) found it to represent a new and distinct genus which he named Acerosodontosaurus.

Description

Tangasaurus was described and named by Sidney H. Haughton in 1924 who found it to be a probable diapsid reptile that, because of the long, powerful, flattened tail, had become adapted for an aquatic existence. Contrary to Haughton, Piveteau (1926) considered Tangasaurus to be a primarily terrestrial animal. he considered it to be related to the Araeoscelis, Kadaliosaurus, Broomia and the "eosuchians" (a defunct clade that used to unite all diapsids more advanced than Araeoscelis) Saurosternon and Pleurosaurus. Described by Piveteau (1926), Hovasaurus boulei from Madagascar was considered to be related to Mesosaurus. Although not as specialized as Mesosaurus for living in the water, Piveteau noted its short neck, short manus, well developed haemal spines and slight pachyostosis of the ribs. Piveteau (1926) included Broomia, Saurosternon and Tangasaurus in the Tangasaurinae. The known specimens of Tangasaurus were redescribed by Philip J. Currie (1982). He diagnosed the genus on the basis of two autapomorphies: It possesses high and rectangular neural spines of the dorsal vertebrae and the height of neural spine of mid-caudal vertebra about 35% greater than length of associated centrum, and about 75% length of associated haemal arch and spine.

|label1=Diapsida |1={{clade |1=Araeoscelidia |label2=Neodiapsida |2={{clade |1=Lanthanolania |2=Kenyasaurus |3={{clade |label1=Tangasauridae |1={{clade |1=Tangasaurus |2={{clade |1=Acerosodontosaurus |2=Hovasaurus }} }} |2=Youngina |3={{clade |1=Galesphyrus |2=Thadeosaurus }} }} |4={{clade |1=Claudiosaurus |2={{clade |1={{clade |1=Palaeagama |2=Saurosternon }} |2={{clade |1=Coelurosauravus |2=Sauria }} }} }} }} }} }}

More resolved results were obtained by Robert R. Reisz, Sean P. Modesto and Diane M. Scott (2011) in their description of Orovenator. However, those results required the exclusion of the fragmentary taxa Galesphyrus, Kenyasaurus, Palaeagama and Saurosternon from their analysis. The cladogram below shows Tangasaurus phylogenetic position among other neodiapsids following Reisz et al., 2011.

|label1=Diapsida |1={{clade |1=Araeoscelidia |label2=Neodiapsida |2={{clade |1=Orovenator |2={{clade |1=Lanthanolania |2={{clade |label1=Tangasauridae |1={{clade |1=Tangasaurus |2={{clade |1=Acerosodontosaurus |2=Hovasaurus }} }} |2={{clade |label1=Younginidae |1={{clade |1=Thadeosaurus |2=Youngina }} |2={{clade |1=Claudiosaurus |2=Sauria }} }} }} }} }} }} }}

References

References

  1. Sidney H. Haughton. (1924). "On Reptilian Remains from the Karroo Beds of East Africa". Quarterly Journal of the Geological Society.
  2. Philip J. Currie. (1982). "The osteology and relationships of ''Tangasaurus mennelli'' Haughton (Reptilia, Eosuchia)". Annals of the South African Museum.
  3. Jean Piveteau. (1926). "Paleontologie de Madagascar XIII. Amphibiens et reptiles permiens". Annales de Paléontologie.
  4. Franz Nopcsa von Felső-Szilvás. (1924). "On the systematic position of ''Tangasaurus'' and ''Saurosternon''". South African Journal of Science.
  5. J. A. Orlov. (1964). "Osnovy Paleontologii". Nauka.
  6. Jean Piveteau. (1955). "Eosuchia".
  7. Alfred Sherwood Romer. (1956). "Osteology of the reptiles". University of Chicago Press.
  8. Alfred Sherwood Romer. (1966). "Vertebrate paleontology". University of Chicago Press.
  9. Oskar Kuhn. (1969). "Handbuch der palaoherpetologie, Teil 9. Proganosauria, Bolosauria, Placodontia, Araeoscelidia, Trilophosauridae, Weigeltisauria, Millerosauria, Rhynchocephalia, Protosauria". Gustav Fischer Verlag.
  10. (2009). "The enigmatic diapsid ''Acerosodontosaurus piveteaui'' (Reptilia: Neodiapsida) from the Upper Permian of Madagascar and the paraphyly of ''younginiform'' reptiles". Canadian Journal of Earth Sciences.
  11. (2011). "A new Early Permian reptile and its significance in early diapsid evolution". Proceedings of the Royal Society B: Biological Sciences.

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