Caviramus

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Caviramus
Temporal range: Late Triassic, 205  Ma
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Order: Pterosauria
Clade: Caviramidae
Genus: Caviramus
Fröbisch & Fröbisch, 2006
Species:
C. schesaplanensis
Binomial name
Caviramus schesaplanensis
Fröbisch & Fröbisch, 2006
Synonyms

Caviramus is a genus of caviramid pterosaur from the Late Triassic (early Rhaetian-age) lower Kössen Formation of the Northern Calcareous Alps of Switzerland.

The genus was in 2006 named by Nadia Fröbisch and Jörg Fröbisch. The type species is Caviramus schesaplanensis. The genus name is derived from Latin cavus, "hollow" and ramus, "branch". The specific name refers to Mount Schesaplana.

Description

The genus is based on holotype PIMUZ A/III 1225, three non-contiguous fragments of a ramus (lower jaw) of the mandible with multicuspate teeth. Two teeth are preserved, one with three cusps, and one with four; despite this difference the authors consider them as essentially isodont. The number of teeth is estimated at a minimum of twelve and a maximum of seventeen. A row of large oval foramina runs parallel to the tooth row; foramina in the form of small holes in the anterior part of the lower jaw suggest some sort of soft-tissue structure, or a keratin covering. The jaw is light and hollow. The teeth of this genus resemble those of Eudimorphodon , but the jaw is different. The discovery of this genus is a find of some significance, as there are few pterosaurs known from the Triassic. [1]

A second specimen, sometimes assigned to its own genus and species as Raeticodactylus filisurensis , consists of a single disarticulated partial skeleton including an almost complete skull. The skull shows that it had a tall thin bony crest running along the midline of the front of the upper jaw, and a keel on the lower jaw. The teeth at the front of the upper jaw, in the premaxillae, were fanglike, whereas the teeth in the upper cheeks (the maxillae) had three, four, or five cusps, similar to those of Eudimorphodon. Caviramus had a wingspan of about 135 centimeters (53 in).

Lifestyle

Based on its long limbs, it might have been a terrestrial forager. It bears a dentition atypically suited for mastication, being more specialised to this than other eudimorphodonts, and may have been a generalist or herbivore. Its gracile wings suggested a soaring mode of flight. [2]

Classification

Despite the resemblance to Eudimorphodon the authors classified Caviramus as Pterosauria incertae sedis . A 2009 study by Fabio Dalla Vecchia concluded that Raeticodactylus, which is known from a more complete skeleton including lower jaw, probably belong to the same genus, and possibly the same species, if the differences (such as size and the presence of a crest in the Raeticodactylus specimen) are not due to sex or age. Subsequent studies have supported their synonymy. [3] Dalla Vecchia found the two forms in a sister clade of Carniadactylus , implying that Caviramus was a member of the Campylognathoididae [4] The following phylogenetic analysis follows the topology of Upchurch et al. (2015). [5]

Eopterosauria

In 2020 however, a study upheld by Matthew G. Baron about early pterosaur interrelationships found Caviramus to group with Carniadactylus, Raeticodactylus, and the Austriadraconidae, which in turn were within a clade he called Caviramidae. [6]

See also

Related Research Articles

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<i>Eudimorphodon</i> Genus of eudimorphodontid pterosaur from the Late Triassic

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<i>Peteinosaurus</i> Genus of pterosaur from the Late Triassic

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<i>Raeticodactylus</i> Genus of raeticodactylid pterosaur from the Late Triassic

Raeticodactylus is a genus of non-pterodactyloid pterosaur from the late Norian-early Rhaetian-age Upper Triassic lower Kössen Formation of the central Austroalpine of Grisons, Switzerland. It is known from holotype BNM 14524, a single disarticulated partial skeleton including an almost complete skull, found in August 2005. This genus was named and described in 2008 by its discoverer Rico Stecher; the type species is Raeticodactylus filisurensis. The specific name refers to Filisur.

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<span class="mw-page-title-main">Eopterosauria</span> Clade of basal pterosaurs

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<span class="mw-page-title-main">Eudimorphodontidae</span> Family of eopterosaurs from the Late Triassic

Eudimorphodontidae is an extinct family of early pterosaurs from the Late Triassic of Europe. It was named by Peter Wellnhofer in 1978 to include Eudimorphodon ranzii. Some phylogenetic analyses suggested that Eudimorphodontidae is a junior synonym of Campylognathoididae, however more comprehensive analyses found Eudimorphodontidae to be basal to Macronychoptera that includes Campylognathoididae and more derived pterosaurs (Breviquartossa). Wang et al. (2009) found Eudimorphodontidae to include six species, but they didn't defined the clade. Brian Andres define Eudimorphodontidae and found Peteinosaurus to be most closely related to it. Furthermore, he found monophyletic Eudimorphodon clade, and defined two subfamilies within Eudimorphodontidae. The Eudimorphodontinae includes all taxa more closely related to Eudimorphodon ranzii than to Raeticodactylus filisurensis while the Raeticodactylinae includes all taxa more closely related to Raeticodactylus filisurensis than to Eudimorphodon ranzii. More recently, Raeticodactylus and Caviramus were moved into their own family, Raeticodactylidae. The below cladogram follows that analysis.

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References

  1. Fröbisch, N.B.; Fröbisch, J. (2006). "A new basal pterosaur genus from the upper Triassic of the Northern Calcareous Alps of Switzerland". Palaeontology. 49 (5): 1081–1090. doi: 10.1111/j.1475-4983.2006.00581.x .
  2. Wilton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. ISBN   0691150613.
  3. Ősi, Attila (2011). "Feeding-related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet". Lethaia. 44 (2): 136–152. doi:10.1111/j.1502-3931.2010.00230.x. hdl: 10831/74599 .
  4. Dalla Vecchia, F.M. (2009). "Anatomy and systematics of the pterosaur Carniadactylus (gen. n.) rosenfeldi (Dalla Vecchia, 1995)". Rivista Italiana de Paleontologia e Stratigrafia. 115 (2): 159–188.
  5. Upchurch, P.; Andres, B.B.; Butler, R.J.; Barrett, P.M. (2015). "An analysis of pterosaurian biogeography: implications for the evolutionary history and fossil record quality of the first flying vertebrates". Historical Biology. 27 (6): 697–717. doi:10.1080/08912963.2014.939077. PMC   4536946 . PMID   26339122.
  6. Matthew G. Baron (2020). "Testing pterosaur ingroup relationships through broader sampling of avemetatarsalian taxa and characters and a range of phylogenetic analysis techniques". PeerJ. 8: e9604. doi:10.7717/peerj.9604. PMC 7512134. PMID   33005485.