Turfanosuchus
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''Turfanosuchus'' is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
archosauriform Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemming from the last common anc ...
reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...
, likely a
gracilisuchid Gracilisuchidae is an extinct family of suchian archosaurs known from the early Middle Triassic to the early Late Triassic (Anisian – early Carnian) of China, Argentina, and Brazil. Distribution Currently, the oldest known gracilisuchid is '' ...
archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...
, which lived during the Middle
Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
(
Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...
) of northwestern
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
. The
type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
, ''T. dabanensis'', was described by C.C. Young in 1973, based on a partially complete but disarticulated fossil skeleton (IVPP V.32237) found in the
Kelamayi Formation Karamay (also spelled Karamai) is a prefecture-level city in the north of the Xinjiang Uyghur Autonomous Region, People's Republic of China. It is surrounded on all sides by Tacheng Prefecture. The name of the city comes from the Uyghur language ...
of the Turfan Basin.''Turfanosuchus''
at
Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...
.org
''Turfanosuchus'' had a peculiar combination of features which has made it difficult to classify in the past. It possessed teeth on the
palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...
, and
internal carotid arteries The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation. In human anatomy, the internal and external carotid arise from the common carotid artery, where it bifurcates at cervical verteb ...
which entered the braincase from below. These two traits were rare among Archosauria (true,
crown-group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...
s) and are more similar to non-archosaurian archosauriforms like ''
Euparkeria ''Euparkeria'' (; meaning "Parker's good animal", named in honor of W. K. Parker) is an Extinction, extinct genus of archosauriform reptile from the Triassic of South Africa. ''Euparkeria'' is close to the ancestry of Archosauria, the reptile gro ...
''. On the other hand, the ankle was much more advanced than that of animals like ''Euparkeria'', and some features of the skull have only been observed in true archosaurs, particularly early
suchia Suchia (from Ancient Greek σούχος (''soúkhos''), meaning "crocodile") is a clade of archosaurs containing the majority of pseudosuchians (crocodilians and their extinct relatives). It was defined as the least inclusive clade containing ''A ...
ns (distant ancestors of modern
crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...
ns). Out of this group, ''Turfanosuchus'' shares the most similarities with ''
Gracilisuchus ''Gracilisuchus'' (meaning "slender crocodile") is an extinct genus of tiny pseudosuchian (a group which includes the ancestors of crocodilians) from the Late Triassic of Argentina. It contains a single species, ''G. stipanicicorum'', which is pl ...
'' and '' Yonghesuchus'', and a 2014 study grouped these three genera in the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Gracilisuchidae. Gracilisuchidae lies within
Pseudosuchia Pseudosuchia, from Ancient Greek ψεύδος (''pseúdos)'', meaning "false", and σούχος (''soúkhos''), meaning "crocodile" is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely relat ...
, which contains all archosaurs more closely related to crocodilians than to birds. Some skull features previously considered unique to ''Turfanosuchus'' are now considered to characterize Gracilisuchidae, but ''Turfanosuchus'' retains a few unique features of the jaw and cheek region.


Description


Skull

The skull of ''Turfanosuchus'' was proportionally similar to that of other small generalized archosauriforms such as ''Euparkeria'' and ''Gracilisuchus''. The
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 mammals h ...
(a toothed bone at the tip of the snout) projects a small prong behind the nares (nostril holes). This prong, known as a posterodorsal process, bisects a corresponding branch of the
nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Eac ...
s (which formed the upper surface of the snout). As with other archosaurs and their relatives, the side of the snout has a hole (known as an
antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with Archosauriformes, archosauriforms, first appearing during the Triassic Period. Among Extant ...
) surrounded by a lowered basin of bone (known as an antorbital fossa). The
maxilla In vertebrates, the maxilla (: maxillae ) 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 two maxil ...
(the main toothed bone of the snout) also had a posterodorsal process, a much more rare trait compared to the posterodorsal process of the premaxilla (which was present in most
archosauromorphs Archosauromorpha (Greek language, 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) than to Lepidosauria, lepidosaurs ( ...
). The maxilla's posterodorsal process was a small, triangular peak of bone which formed the lower rear corner of the antorbital fossa and connected to the
lacrimal bone The lacrimal bones are two small and fragile bones of the facial skeleton; they are roughly the size of the little fingernail and situated at the front part of the medial wall of the orbit. They each have two surfaces and four borders. Several bon ...
(which lies between the antorbital fossa and the eye socket). These posterodorsal processes are very characteristic, either by bisecting the nasal (in the case of the premaxilla's) or existing in the first place (in the case of the maxilla's). As such, they were considered by Wu & Russell (2001) to be
autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...
(unique distinguishing traits) of ''Turfanosuchus.'' However, they are now both known to be present in '' Yonghesuchus'' and (to a lesser extent) ''Gracilisuchus'', so they likely diagnose the entire family Gracilisuchidae, or possibly even larger subsets of Archosauria. For example, the premaxillary posterodorsal process of ''
Revueltosaurus ''Revueltosaurus'' ("Revuelto lizard") is an extinct genus of suchian pseudosuchian from Late Triassic (late Carnian to middle Norian stage) deposits of New Mexico, Arizona and North Carolina, United States. Many specimens, mostly teeth, have bee ...
'' also bisects its nasal, and a posterodorsal process of the maxilla is present in some
aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order (biology), order Aetosauria (; from Ancient Greek, Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized Omnivore, omnivorous or Herbivore, herbivor ...
s and
poposauroids Poposauroidea is a clade of advanced pseudosuchians. It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as '' Qianosuchus'' and ''Lotosaurus''. It excludes most large predatory quadrupedal " rauisuchia ...
. The premaxilla probably had five teeth, while the maxilla had at least 13. Preserved teeth were curved and finely serrated. The nasal bones project over the side of the snout and form the upper border of the antorbital fossa. The
frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...
s (which form the portion of the skull above the eye sockets) wedge into the nasals as a large, V-shaped suture. Both of these traits are also present in ''Gracilisuchus''. The shape of the
jugal The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy ...
(cheek bone), on the other hand, is truly unique to ''Turfanosuchus''. The portion of the jugal which rises behind the eye socket has a very wide base, and its surface is set inwards relative to the portion below the eye socket. As with other diapsids, ''Turfanosuchus'' had a pair of openings at the rear portion of the skull known as temporal fenestra. The bone separating the two holes, 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 bones form the cheek series of the skull. The bone forms an ancestra ...
, had a lower branch which curved forwards to contact the jugal and divide the lower temporal fenestra into two separate holes, leaving three holes at the back of the skull in total. This trait is also known is
rauisuchids Rauisuchidae is a group of large (up to ) predatory Triassic archosaurs. Some disagreement exists over which genera should be included in the Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed whether thes ...
such as ''
Postosuchus ''Postosuchus'', meaning "Crocodile from Post", is an extinct genus of rauisuchid reptiles comprising two species, ''P. kirkpatricki'' and ''P. alisonae'', that lived in what is now North America during the Late Triassic. ''Postosuchus'' is a ...
''. A similar situation is visible in other gracilisuchids, which have a broad contact between the jugal and the lower branch of the squamosal. However, they did not retain the upper portion of the lower temporal fenestra, leaving only a small, triangular remnant of the lower temporal fenestra under the squamosal-jugal contact. Preserved portions of the
palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...
(roof of the mouth) were generally similar to ''Euparkeria''. One particular similarity is the presence of teeth on the
pterygoid bone The pterygoid is a paired bone forming part of the palate of many vertebrates, behind the palatine bone In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal specie ...
. Traditionally, pterygoid teeth are considered to be absent in
crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...
-
archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...
s. Wu & Russell (2001) used this to justify classifying ''Turfanosuchus'' as a non-archosaur
archosauriform Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemming from the last common anc ...
. However, more recently pterygoid teeth have been reported in crown-archosaurs such as ''
Eoraptor ''Eoraptor'' () is a genus of small, lightly built, Basal (phylogenetics), basal sauropodomorpha, sauropodomorph dinosaur. One of the earliest-known dinosaurs and one of the earliest sauropodomorphs, it lived approximately 231 to 228 million yea ...
,
Eudimorphodon ''Eudimorphodon'' is an extinct genus of pterosaur that was discovered in 1973 by Mario Pandolfi in the town of Cene, Lombardy, Cene, Italy and described the same year by Rocco Zambelli. The nearly complete skeleton was retrieved from shale depos ...
,
Lewisuchus ''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tru ...
,'' ''
Eodromaeus ''Eodromaeus'' (meaning "dawn runner") is an extinct genus of probable basal (phylogenetics), basal theropod dinosaurs from the Late Triassic of Argentina. Like many other of the earliest-known dinosaurs, it hails from the Carnian-age (~230 Ma) I ...
'', and ''Yonghesuchus''. Therefore, their presence in ''Turfanosuchus'' does not preclude its classification as a crown-archosaur. Another seemingly non-archosaurian trait reported in ''Turfanosuchus'' is the fact that its
internal carotid arteries The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation. In human anatomy, the internal and external carotid arise from the common carotid artery, where it bifurcates at cervical verteb ...
enter the braincase from below, rather than from the sides as in almost all other archosaurs (including ''Gracilisuchus'' and ''Yonghesuchus''). However, this trait is also known to occur in other crown-archosaurs like ''
Arizonasaurus ''Arizonasaurus'' (meaning "Arizona reptile") was a ctenosauriscid archosaur from the Middle Triassic (243 million years ago) Moenkopi Formation of what is now Arizona. The taxon is known for having a large back sail formed by elongated neural sp ...
'', '' Qianosuchus'', and ''
Silesaurus ''Silesaurus'' is a genus of silesaurid dinosauriform from the Late Triassic, of what is now Poland. Discovery and naming The Krasiejów claypit near Opole, Poland, was first discovered as a fossil locality in the 1980s after quarrying for ...
.'' Otherwise, the braincase is generally similar to other archosaurs. The lower jaw was slender, with an elliptical hole known as a mandibular fenestra. The toothed dentary bone had two rear prongs surrounding the mandibular fenestra. Unique to ''Turfanosuchus'' among gracilisuchids, the lower prong was much longer than the upper prong. This had the added effect of excluding the
angular bone The angular is a large bone in the lower jaw (mandible) of amphibians and reptiles (birds included), which is connected to all other lower jaw bones: the dentary (which is the entire lower jaw in mammals), the splenial, the suprangular, and the ...
(which formed the rear lower edge of the jaw) from forming the lower border of the mandibular fenestra. The
surangular The surangular or suprangular is a jaw bone found in most land vertebrates, except mammals. Usually in the back of the jaw, on the upper edge, it is connected to all other jaw bones: dentary, angular bone, angular, splenial and articular. It is o ...
, which forms the upper rear portion of the jaw (and the upper border of the mandibular fenestra), was large. Another autapomorphy of ''Turfanosuchus'' is how the outer surface of the surangular was highly concave. There were at least 16 teeth in the lower jaw, and they were similar in shape to those of the upper jaw.


Postcranial skeleton

The
vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...
e of ''Turfanosuchus'' were similar to those of ''
Euparkeria ''Euparkeria'' (; meaning "Parker's good animal", named in honor of W. K. Parker) is an Extinction, extinct genus of archosauriform reptile from the Triassic of South Africa. ''Euparkeria'' is close to the ancestry of Archosauria, the reptile gro ...
'' and
pseudosuchia Pseudosuchia, from Ancient Greek ψεύδος (''pseúdos)'', meaning "false", and σούχος (''soúkhos''), meaning "crocodile" is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely relat ...
ns, with concavities on their sides and neural spines with expanded tops. There were two sacral (hip) vertebrae, which connected to the ilium (upper plate of the hip) with large, fan-shaped sacral ribs. No intercentra were preserved, and the vertebrae lacked bevelled edges, but since the vertebrae were disarticulated and some euparkeriids retain intercentra while lacking bevelled edges, their absence in ''Turfanosuchus'' cannot be proven. The ilium was similar to that of ''
Ticinosuchus ''Ticinosuchus'' is an extinct genus of suchian archosaur from the Middle Triassic (Anisian– Ladinian) of Switzerland and Italy. Description One of only a handful of fossil reptiles that have been found in Switzerland, ''Ticinosuchus'' (mea ...
'', with a short forward projection, a much larger rear projection, and a large bony
acetabulum The acetabulum (; : acetabula), also called the cotyloid cavity, is a wikt:concave, concave surface of the pelvis. The femur head, head of the femur meets with the pelvis at the acetabulum, forming the Hip#Articulation, hip joint. Structure The ...
(hip socket). The pubis (lower front plate of the hip) was moderate in length and also similar to that of ''Ticinosuchus''.
Osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amph ...
s (bony plates) were initially reported as being absent, but later preparation revealed one. This osteoderm was broad, with a ridge on its upper surface culminating in a pointed front prong. A corresponding groove-like depression was present on the lower surface. The
humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
(upper arm bone) had a deltopectoral crest which was poorly differentiated from the
humeral head The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of ...
. The
femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...
(thigh bone) was similar to that of ''Euparkeria'' and most pseudosuchians, but it lacked the offset
femoral head The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the ...
and raised
fourth trochanter The fourth trochanter is a shared characteristic common to archosaurs. It is a protrusion on the posterior-medial side of the middle of the femur shaft that serves as a muscle attachment, mainly for the '' musculus caudofemoralis longus'', the m ...
of
avemetatarsalia Avemetatarsalia (meaning "bird metatarsals") is a clade of diapsid Reptile, reptiles containing all archosaurs more closely related to birds than to crocodilians. The two most successful groups of avemetatarsalians were the dinosaurs and pterosau ...
ns or early
crocodylomorphs Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ...
. The
calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel; : calcanei or calcanea) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is t ...
(heel bone) had many similarities with that of "
crurotarsan Crurotarsi is a clade of archosauriformes, archosauriform reptiles that includes crocodilians and stem-crocodilians and possibly bird-line Archosaur, archosaurs too if the extinct, crocodile-like phytosaurs are more distantly related to crocodile ...
" archosauriforms (i.e. ones with a
crurotarsal A crurotarsal joint is one that's situated between the bones of '' crus'', i.e. shin (tibia and fibula) and the proximal tarsal bones, i.e. astragalus and calcaneum. The ankle joint of therian mammals ( marsupials and placentals) is a crurotarsa ...
ankle like
phytosaur Phytosaurs (Φυτόσαυροι in Greek, meaning 'plant lizard') are an extinct group of large, mostly semiaquatic Late Triassic archosauriform or basal archosaurian reptiles. Phytosaurs belong to the order Phytosauria and are sometimes ref ...
s and suchians). These include a hemicylindrical (barrel-shaped)
condyle A condyle (;Entry "condyle"
in
for the
fibula The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...
(outer shin bone), a continuous facet between this condyle and the facet for the fourth distal tarsal (a minor ankle bone), and a rear projection known as a calcaneal tuber which was wider than tall and had flared edges. Some of these characteristics were not considered to be present until a re-evalutation of the specimen in 2011.


Classification

The classification of ''Turfanosuchus'' has gone through much revision in the past due to its combination of features from both suchian archosaurs and earlier archosaur relatives such as ''Euparkeria''. Young originally believed that the fossils came from an animal similar to ''
Euparkeria ''Euparkeria'' (; meaning "Parker's good animal", named in honor of W. K. Parker) is an Extinction, extinct genus of archosauriform reptile from the Triassic of South Africa. ''Euparkeria'' is close to the ancestry of Archosauria, the reptile gro ...
'', and assigned it to the family
Euparkeriidae Euparkeriidae is an extinct family of small carnivorous archosauriforms which lived from the Early Triassic to the Middle Triassic (Anisian). While most other early archosauriforms walked on four limbs, euparkeriids were probably facultative bi ...
. The fossil, however, was not fully prepared. Subsequent analysis by Parrish in 1993 indicated that the fossils represented a
suchia Suchia (from Ancient Greek σούχος (''soúkhos''), meaning "crocodile") is a clade of archosaurs containing the majority of pseudosuchians (crocodilians and their extinct relatives). It was defined as the least inclusive clade containing ''A ...
n. A putative second species, ''"Turfanosuchus" shageduensis'', was described in 1982. However, due to its large intercentra, this species is not considered to be a close relative of ''Turfanosuchus'', and was likely an indeterminate euparkeriid related to ''
Halazhaisuchus ''Halazhaisuchus'' is an extinct genus of archosauriform from the Early Triassic of China. It is known from a single species, ''Halazhaisuchus qiaoensis'', which was named in 1982 from the lower Ermaying Formation in Shaanxi. It was assigned to ...
''. In 2001, Xiao-Chun Wu (of the
Institute of Vertebrate Paleontology and Paleoanthropology The Institute of Vertebrate Paleontology and Paleoanthropology (IVPP; ) of People's Republic of China, China is a research institution and collections repository for fossils, including many dinosaur and pterosaur specimens (many from the Yixian For ...
in Beijing) and Anthony Russell (of the
University of Calgary {{Infobox university , name = University of Calgary , image = University of Calgary coat of arms without motto scroll.svg , image_size = 150px , caption = Coat of arms , former ...
) redescribed the fossil. Wu and Russell prepared the fossil, and noted the limb bones (femur and humerus) resembled those of ''
Ticinosuchus ''Ticinosuchus'' is an extinct genus of suchian archosaur from the Middle Triassic (Anisian– Ladinian) of Switzerland and Italy. Description One of only a handful of fossil reptiles that have been found in Switzerland, ''Ticinosuchus'' (mea ...
'' and ''Euparkeria'', though the
calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel; : calcanei or calcanea) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is t ...
did not. Further preparation revealed a partial
osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amph ...
. Wu and Russell concluded that ''Turfanosuchus'' was not a suchian nor even a member of the
Pseudosuchia Pseudosuchia, from Ancient Greek ψεύδος (''pseúdos)'', meaning "false", and σούχος (''soúkhos''), meaning "crocodile" is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely relat ...
(archosaurs closer to crocodilians than to dinosaurs, also known as
Crurotarsi Crurotarsi is a clade of archosauriform reptiles that includes crocodilians and stem-crocodilians and possibly bird-line archosaurs too if the extinct, crocodile-like phytosaurs are more distantly related to crocodiles than traditionally though ...
in publications which include
phytosaur Phytosaurs (Φυτόσαυροι in Greek, meaning 'plant lizard') are an extinct group of large, mostly semiaquatic Late Triassic archosauriform or basal archosaurian reptiles. Phytosaurs belong to the order Phytosauria and are sometimes ref ...
s in the group). This conclusion was supported by features such as teeth on the
palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...
and
internal carotid arteries The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation. In human anatomy, the internal and external carotid arise from the common carotid artery, where it bifurcates at cervical verteb ...
which entered the braincase from below, rather than from the side. However, they also ruled out the possibility of a close relationship with ''Euparkeria'', noting several
apomorphic In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...
("advanced") features, such as a calcaneal tuber directed further backwards. In 2010, paleontologists Martín Ezcurra, Agustina Lecuona, and Augustín Martinelli found ''Turfanosuchus'' to be a pseudosuchian once again during the study of the recently discovered archosauriform ''
Koilamasuchus ''Koilamasuchus'' is an extinct genus of indeterminate archosauriform from the Triassic of Argentina. It is based on an external mold of a partial postcranial skeleton from the Quebrada de los Fósiles Formation. Due to its incomplete nature, t ...
''. This reassignment was based on the structure of the calcaneum (heel bone), which is similar to that of other early pseudosuchians, especially
aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order (biology), order Aetosauria (; from Ancient Greek, Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized Omnivore, omnivorous or Herbivore, herbivor ...
s. This conclusion was also supported in 2011 by
Sterling Nesbitt Sterling Nesbitt (born March 25, 1982, in Mesa, Arizona) is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Departme ...
's comprehensive analysis on archosaurs and archosauriforms. This analysis noted that some archosaurs (such as ''
Eoraptor ''Eoraptor'' () is a genus of small, lightly built, Basal (phylogenetics), basal sauropodomorpha, sauropodomorph dinosaur. One of the earliest-known dinosaurs and one of the earliest sauropodomorphs, it lived approximately 231 to 228 million yea ...
'') also had palatal teeth, and other (such as ''
Silesaurus ''Silesaurus'' is a genus of silesaurid dinosauriform from the Late Triassic, of what is now Poland. Discovery and naming The Krasiejów claypit near Opole, Poland, was first discovered as a fossil locality in the 1980s after quarrying for ...
'' and early
poposauroids Poposauroidea is a clade of advanced pseudosuchians. It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as '' Qianosuchus'' and ''Lotosaurus''. It excludes most large predatory quadrupedal " rauisuchia ...
) had internal carotid arteries which entered the braincase from below. In addition, the calcaneum was re-evaluated and Parrish's observations of the ankle were reconfirmed. In 2014, ''Turfanosuchus'' was found to be closely related to the small suchians ''
Gracilisuchus ''Gracilisuchus'' (meaning "slender crocodile") is an extinct genus of tiny pseudosuchian (a group which includes the ancestors of crocodilians) from the Late Triassic of Argentina. It contains a single species, ''G. stipanicicorum'', which is pl ...
'' and '' Yonghesuchus'', in the newly created family Gracilisuchidae. Most of the similarities justifying this classification were present in the skull, and some were originally considered unique to ''Turfanosuchus''.


References

{{Taxonbar, from=Q1838372 Gracilisuchidae Middle Triassic pseudosuchians Middle Triassic reptiles of Asia Anisian life Triassic China Fossils of China Fossil taxa described in 1973 Taxa named by Yang Zhongjian Prehistoric pseudosuchian genera