''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 "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 ( ...
."[ 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 ...
ry 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 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 (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]
See also
* Timeline of plesiosaur research
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished duri ...
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