Augustasaurus

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Augustasaurus
Temporal range: Middle Triassic
Skull of Augustasaurus hagdorni in the Field Museum of Natural History, Chicago
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: †Sauropterygia
Clade: †Eosauropterygia
Clade: †Pistosauroidea
Clade: †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[edit]

The first part of Augustasaurus' name comes from the Augusta Mountains of northwestern Nevada,[4] USA, 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[edit]

Life restoration of Augustasaurus hagdorni.

Augustasaurus measured 2.5–3 m (8.2–9.8 ft) long and weighed 100 kg (220 lb).[5][6] Its 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.[7] Its coracoids are large plates similar to those in other plesiosaurs.[8] However, the coracoid foramen are missing from Agustasaurus, in a way similar to those in the pistosauroid Corosaurus.[8] Its cervical ribs have anterior process,[9] and like most plesiosaurs, Augustasaurus' vertebrae have "thickened transverse processes".[9]

Distribution[edit]

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.[10]

See also[edit]

References[edit]

  1. ^ a b c d e 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" (PDF). Journal of Vertebrate Paleontology. 26 (2): 501–503. doi:10.1671/0272-4634(2006)26[501:fcpftt]2.0.co;2. S2CID 85634946. Archived from the original (PDF) on 2011-09-28. Retrieved 2011-11-02.
  3. ^ Hilary F. Ketchum & 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.
  4. ^ a b c "Plesiosaur.com entry on Augustasaurus". Archived from the original on 2007-12-10. Retrieved 2008-07-16.
  5. ^ Sander, P. Martin; Rieppel, Olivier C.; Bucher, Hugo (1997). "A new pistosaurid (Reptilia: Sauropterygia) from the Middle Triassic of Nevada and its implications for the origin of the plesiosaurs". Journal of Vertebrate Paleontology. 17 (3): 526–533. Bibcode:1997JVPal..17..526S. doi:10.1080/02724634.1997.10010999.
  6. ^ Sander, P.M.; Griebeler, E.M.; Klein, N.; Juarbe, J.V.; Wintrich, T.; Revell, L.J.; Schmitz, L. (2021). "Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans". Science. 374 (6575): eabf5787. doi:10.1126/science.abf5787. PMID 34941418. S2CID 245444783.
  7. ^ O’Keefe. Pg.52
  8. ^ a b O'Keefe Pg. 5
  9. ^ a b O'Keefe. Pg. 51
  10. ^ O'Keefe Pg.9

External links[edit]

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