''Rhombopholis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

archosauromorph Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, liza ...

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 ( ...

known from

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. The type species of ''Rhombopholis'' is ''Rhombopholis scutulata''. Specimens of this genus were collected from the Leamington quarry, near

Warwick Warwick ( ) is a market town, civil parish and the county town of Warwickshire in the Warwick District in England, adjacent to the River Avon. It is south of Coventry, and south-east of Birmingham. It is adjoined with Leamington Spa and Whi ...

. This locality belongs to the Bromsgrove Sandstone Formation, which is dated to the

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...

age of the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

, approximately 245 million years ago.

Description

''Rhombopholis'' is known from several different specimens. WARMS Gz10, a sandstone block containing

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 and limb bones from two different individuals, as well as fish scales and vertebrae, has been designated the

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

of the genus. Other specimens include WARMS Gz21 (the

proximal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

part of a left

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

), WARMS Gz4714 (a left ilium), and CAMSM G.343 (a back vertebra). ''Rhombopholis'' lacks distinguishing features, but is believed to be a " prolacertiform" (an outdated term for a basal archosauromorph) due to having low neural spines. The smaller individual present in WARMS Gz10 is represented by three cervical (neck) vertebrae and a partial femur. Although the vertebrae vary significantly in structure, they resemble those of other archosauromorphs such as '' Macrocnemus'' and ''

Malerisaurus ''Malerisaurus'' is an extinct genus of archosauromorph known from Andhra Pradesh of India and Texas of the USA. Description ''Malerisaurus'' was a medium-sized archosauromorph which averaged 1.2 meters in length. ''Malerisaurus'' is known from ...

''. The vertebral centers are broad but constricted in the middle, while the neural spines are long and low. The femur is long and straight, with a bulging front edge at its proximal tip. The larger individual in WARMS Gz10 is represented by an incomplete caudal (tail) vertebra, a rib, the proximal tip of a right femur, and several

metapodial Metapodials are long bones of the hand (metacarpals) and feet (metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes ...

s. The rib is straight but expands into two articulations at its proximal end. The femur possesses a longitudinal ridge and is similar to that of ''

Tanystropheus ''Tanystropheus'' (Greek ~ 'long' + 'hinged') is an extinct archosauromorph reptile from the Middle and Late Triassic epochs. It is recognisable by its extremely elongated neck, which measured long—longer than its body and tail combined. T ...

'' and ''Malerisaurus''. The presumed

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...

has a ridge on its proximal end, a flat shaft, and a wide distal end with a slight depression. The presumed

metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...

is flat and slightly twisted, with a wider proximal end. The other specimens of ''Rhombopholis'' are close to this individual in size. CAMSM G.324 resembles the

lumbar In tetrapod anatomy, lumbar is an adjective that means ''of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum.'' The lumbar region is sometimes referred to as the lower spine, or as an area of the back i ...

vertebrae of ''Macrocnemus''. WARMS Gz21 has a wide posterior expansion and a thin anterior expansion. By comparisons with ''Macrocnemus'', WARMS Gz21 is estimated to have a total length of 134 millimeters while the femur of WARMS Gz10's larger specimen would be 144 millimeters long. Although larger than ''Macrocnemus'', ''Rhombopholis'' would still be smaller than several species of tanystropheid. WARMS Gz4714 has a short anterior process and a broad acetabular region with strongly thickened edges.

References

{{Taxonbar, from=Q48849041 Prehistoric archosauromorphs Prehistoric reptile genera Anisian genera Middle Triassic reptiles of Europe Triassic England Fossils of England Fossil taxa described in 1866 Taxa named by Richard Owen