Torvoneustes
Encyclopedia
Torvoneustes is a genus
of extinct metriorhynchid mesoeucrocodylia
n. It is known from a partial skull and some postcranial remains that have been found from the Kimmeridge Clay
of Wiltshire
, England
. The skull was first to be found, and was first assigned to the species Metriorhynchus superciliosus
. Postcranial remains were later discovered, and the material was then recognized as belonging to a new species of Dakosaurus
, D. carpenteri. D. carpenteri was later reassigned to the genus Geosaurus
in 2008. More recently, it was assigned to its own genus, Torvoneustes.
When T. carpenteri was considered a species of Dakosaurus, its relatively long snout and smaller, more numerous teeth were thought to be features retained from more basal metriorhynchids. Because of this, the species was seen as a transitional form between long-snouted, piscivorous metriorhynchids and hypercarnivorous, short-snouted species of Dakosaurus.
While Dakosaurus and Geosaurus have ziphodont dentitions with teeth that are laterally compressed, Torvoneustes is unique in having a false-ziphodont dentition. The common ancestor of Dakosaurus and Geosaurus may also have had a ziphodont dentition, and as Torvoneustes is also a descendant of this common ancestor, it is possible that a ziphodont dentition was secondarily lost in the genus. However, it is also possible that Dakosaurus and Geosaurus acquired similar dentitions independently, and that Torvoneustes is not descended from a ziphodont ancestor.
The species was named to honour Simon Carpenter, an amateur geologist
from Frome
in Somerset
, who provided access to the fossil material.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of extinct metriorhynchid mesoeucrocodylia
Mesoeucrocodylia
Mesoeucrocodylia is the name of the clade that includes Eusuchia and the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day....
n. It is known from a partial skull and some postcranial remains that have been found from the Kimmeridge Clay
Kimmeridge Clay
The Kimmeridge Clay Formation is a sedimentary deposit of fossiliferous marine clay which is of Jurassic age. It occurs in Europe.Kimmeridge Clay is arguably the most economically important unit of rocks in the whole of Europe, being the major source rock for oil fields in the North Sea hydrocarbon...
of Wiltshire
Wiltshire
Wiltshire is a ceremonial county in South West England. It is landlocked and borders the counties of Dorset, Somerset, Hampshire, Gloucestershire, Oxfordshire and Berkshire. It contains the unitary authority of Swindon and covers...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. The skull was first to be found, and was first assigned to the species Metriorhynchus superciliosus
Metriorhynchus
Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Metriorhynchus was named by the German palaeontologist Christian von Meyer in 1830. Metriorhynchus was a carnivore that spent much, if not all, its life out at sea...
. Postcranial remains were later discovered, and the material was then recognized as belonging to a new species of Dakosaurus
Dakosaurus
Dakosaurus is an extinct genus within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially . The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named...
, D. carpenteri. D. carpenteri was later reassigned to the genus Geosaurus
Geosaurus
Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae that lived during the Late Jurassic to the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea...
in 2008. More recently, it was assigned to its own genus, Torvoneustes.
When T. carpenteri was considered a species of Dakosaurus, its relatively long snout and smaller, more numerous teeth were thought to be features retained from more basal metriorhynchids. Because of this, the species was seen as a transitional form between long-snouted, piscivorous metriorhynchids and hypercarnivorous, short-snouted species of Dakosaurus.
While Dakosaurus and Geosaurus have ziphodont dentitions with teeth that are laterally compressed, Torvoneustes is unique in having a false-ziphodont dentition. The common ancestor of Dakosaurus and Geosaurus may also have had a ziphodont dentition, and as Torvoneustes is also a descendant of this common ancestor, it is possible that a ziphodont dentition was secondarily lost in the genus. However, it is also possible that Dakosaurus and Geosaurus acquired similar dentitions independently, and that Torvoneustes is not descended from a ziphodont ancestor.
The species was named to honour Simon Carpenter, an amateur geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
from Frome
Frome
Frome is a town and civil parish in northeast Somerset, England. Located at the eastern end of the Mendip Hills, the town is built on uneven high ground, and centres around the River Frome. The town is approximately south of Bath, east of the county town, Taunton and west of London. In the 2001...
in Somerset
Somerset
The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...
, who provided access to the fossil material.