Augustasaurus

Augustasaurus
Temporal range: Middle Triassic
Skull of Augustasaurus hagdorni in the Field Museum of Natural History, Chicago
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: †Sauropterygia
(unranked): †Eosauropterygia
Branch: †Pistosauroidea
Node: †Pistosauria
Genus: †Augustasaurus
Sander et al., 1997
Type species
†Augustasaurus hagdorni
Sander et al., 1997

Augustasaurus is a genus of aquatic sauropterygian reptile belonging to the Pistosauria, a clade containing plesiosaurs and their close relatives. Pistosaurus and Augustasaurus were thought to be the only known members of the family Pistosauridae.[1] However, some recent cladistic analyses found Augustasaurus to be a more advanced pistosaur, as a sister group of the order Plesiosauria.[2][3] The only known species of Augustasaurus is Augustasaurus hagdorni , which was first described in 1997.

Etymology

The first part of Augustasaurus' name comes from the Augusta Mountains of northwestern Nevada,[4] where its fossil bones were first discovered.[1] The second part of the name is the Greek word sauros (σαυρος), which means "lizard" or "reptile."[4] The type species, Augustasaurus hagdorni, was named in honor of the paleontologist Hans Hagdorn.[4]

Description

Life restoration of Augustasaurus hagdorni

Augustasaurus' skull shares many general characteristics with its relative, Pistosaurus, such as tall, blade-like upper temporal arches.[1] The skull's elongated rostrum tapers to a dull point, the anterior premaxillary and maxillary teeth have been described as "fang-like",[1] and the squamosal makes a box-like suspensorium.[1]

The dorsal neural spines of Augustasaurus are low with rugose tops.[5] Its coracoids are large plates similar to those in other plesiosaurs.[6] However, the coracoid foramen are missing from Agustasaurus, in a way similar to those in the plesiosaur Corosaurus.[6] Its cervical ribs have anterior process,[7] and like most plesiosaurs, Augustasaurus' vertebrae have "thickened transverse processes".[7]

Distribution

Augustasaurus is known from the Augusta Mountains of northwestern Nevada (United States). The holotype specimen was found in the Favret Formation, which dates from the mid-Triassic period, of Pershing County, Nevada.[8]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Journal of Vertebrate Paleontology. Article: pp. 577–592. THE SKULL OF THE PISTOSAUR AUGUSTASAURUS FROM THE MIDDLE TRIASSIC OF NORTHWESTERN NEVADA. OLIVIER RIEPPEL, P. MARTIN SANDER, and GLENN W. STORRS. 1997
  2. ↑ Cheng, Y.-N.; Sato, T.; Wu, X.-C.; Li, C. (2006). "First complete pistosauroid from the Triassic of China". Journal of Vertebrate Paleontology 26 (2): 501–503. doi:10.1671/0272-4634(2006)26[501:fcpftt]2.0.co;2.
  3. ↑ Hilary F. Ketchum and Roger B. J. Benson (2011). "A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids". Special Papers in Palaeontology 86: 109–129. doi:10.1111/j.1475-4983.2011.01083.x.
  4. ↑ 4.0 4.1 4.2 "Plesiosaur.com entry on Augustasaurus". Retrieved 2008-07-16.
  5. ↑ O’Keefe. Pg.52
  6. ↑ 6.0 6.1 O'Keefe Pg. 5
  7. ↑ 7.0 7.1 O'Keefe. Pg. 51
  8. ↑ O'Keefe Pg.9

External links