''Augustasaurus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of aquatic

sauropterygian Sauropterygia (" lizard flippers") is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria bec ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

belonging to the

Pistosauria Pistosauroidea is a group of marine reptiles within the superorder Sauropterygia that first appeared in the latter part of the Early Triassic and were the ancestors of plesiosaurs. Pistosauroids are rare in Triassic marine assemblages, and are ...

, a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

containing plesiosaurs and their close relatives. ''

Pistosaurus ''Pistosaurus'' (''pistos'' in Greek meaning 'credible' and ''sauros'' 'lizard') is an extinct genus of aquatic sauropterygian reptile closely related to plesiosaurs. Fossils have been found in France and Germany, and date to the Middle Triassi ...

'' and ''Augustasaurus'' were thought to be the only known members of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Pistosauridae.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 However, some recent

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analyses found ''Augustasaurus'' to be a more advanced pistosaur, as a sister group of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Plesiosauria The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeare ...

. The only known species of ''Augustasaurus'' is ''Augustasaurus hagdorni'', which was first described in

1997 File:1997 Events Collage.png, From left, clockwise: The movie set of ''Titanic'', the highest-grossing movie in history at the time; ''Harry Potter and the Philosopher's Stone'', is published; Comet Hale-Bopp passes by Earth and becomes one of t ...

Etymology

The first part of ''Augustasaurus name comes from the

Augusta Mountains The Augusta Mountains are a small mountain range in Pershing, Churchill and Lander counties of Nevada.''Nevada Atlas and Gazetteer,'' DeLorme, 8th ed., 2012, p. 37. To the northeast the range merges with the Fish Creek Range. To the north acros ...

of northwestern

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

, USA, where its

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

bones were first discovered. The second part of the name is the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word ' (), which means "

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

" or "

." The type species, ''Augustasaurus hagdorni'', was named in honor of the

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Hans Hagdorn.

Description

''Augustasaurus'' measured long and weighed . Its

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

shares many general characteristics with its relative, ''Pistosaurus'', such as tall, blade-like upper

temporal arches Temporal may refer to: Entertainment * Temporal (band), an Australian metal band * ''Temporal'' (Radio Tarifa album), 1997 * ''Temporal'' (Love Spirals Downwards album), 2000 * ''Temporal'' (Isis album), 2012 * ''Temporal'' (video game), a 200 ...

. The skull's elongated

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

tapers to a dull point, the anterior

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

ry and

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

have been described as "

fang A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fang ...

-like", and the

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal The quadratojugal is a skull bone present in many vertebrates, including ...

makes a box-like suspensorium. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

neural spines The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

of ''Augustasaurus'' are low with

rugose Rugose means "wrinkled". It may refer to: * Rugosa, an extinct order of coral, whose rugose shape earned it the name * Rugose, adjectival form of rugae Species with "rugose" in their names * '' Idiosoma nigrum'', more commonly, a black rugose tr ...

tops. Its coracoids are large plates similar to those in other

plesiosaurs The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared ...

.O'Keefe Pg. 5 However, the coracoid foramen are missing from ''Agustasaurus'', in a way similar to those in the

pistosauroid Pistosauroidea is a group of marine reptiles within the superorder Sauropterygia that first appeared in the latter part of the Early Triassic and were the ancestors of plesiosaurs. Pistosauroids are rare in Triassic marine assemblages, and are ...

Corosaurus ''Corosaurus'' is an extinct genus of pistosauroid known from Wyoming of the United States. The holotype measured about long, while larger specimens would have belonged to individuals measuring more than long. History of discovery ''Corosaur ...

''. Its cervical ribs have anterior process,O'Keefe. Pg. 51 and like most plesiosaurs, ''Augustasaurus

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

e have "thickened transverse processes".

Distribution

''Augustasaurus'' is known from the

of northwestern Nevada (

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

). The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen was found in the Favret Formation, which dates from the mid-Triassic period, of

Pershing County, Nevada Pershing County is a county in the U.S. state of Nevada. As of the 2020 census, the population was 6,650. Its county seat is Lovelock. The county was named after army general John J. Pershing (1860–1948). It was formed from Humboldt County ...

.O'Keefe Pg.9

References

External links

*https://web.archive.org/web/20081120014242/http://www.vertpaleo.org/publications/jvp/22-577-592.cfm *https://web.archive.org/web/20071210085257/http://www.plesiosaur.com/database/genusIndividual.php?i=32 *https://web.archive.org/web/20081005203917/http://www.palaeos.com/Vertebrates/Units/220Lepidosauromorpha/220.400.html {{Taxonbar, from=Q3629564 Triassic sauropterygians Fossil taxa described in 1997 Middle Triassic reptiles of North America Pistosaurs Aquatic reptiles Sauropterygian genera

Etymology

Description

Distribution

See also

References

External links