''Wannia'' 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 ...

of basal

phytosaur Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent ...

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 the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

(late

Carnian The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by t ...

or early

Norian The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic defi ...

stage) of

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, southern United States. It contains a single species, ''Wannia scurriensis'', which is known from a single specimen. This species was originally named as a species referred to ''

Paleorhinus ''Paleorhinus'' (Greek: ''"Old Nose"'') is an extinct genus of widespread basal (phylogenetics), basal phytosaur known from the Late Triassic (late Carnian stage). The genus was named in 1904 based on the type species ''Paleorhinus bransoni'', wh ...

'' and later was considered as a possible

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of ''

Paleorhinus bransoni ''Paleorhinus'' (Greek: ''"Old Nose"'') is an extinct genus of widespread basal phytosaur known from the Late Triassic (late Carnian stage). The genus was named in 1904 based on the type species ''Paleorhinus bransoni'', which is known from Wyo ...

''. However its re-description revealed five

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 t ...

, and a phylogenetic position as the most basal known phytosaur, justifying the erection of a new generic name for the species.

Discovery and naming

''Wannia'' was first described and named by the late Dr. Wann Langston Jr. in

1949 Events January * January 1 – A United Nations-sponsored ceasefire brings an end to the Indo-Pakistani War of 1947. The war results in a stalemate and the division of Kashmir, which still continues as of 2022. * January 2 – Luis ...

as a species referable to ''

'', ''P. scurriensis''. An alternative generic name, ''Wannia'', was proposed by Michelle R. Stocker in

2013 File:2013 Events Collage V2.png, From left, clockwise: Edward Snowden becomes internationally famous for leaking classified NSA wiretapping information; Typhoon Haiyan kills over 6,000 in the Philippines and Southeast Asia; The Dhaka garment fact ...

creating the

new combination ''Combinatio nova'', abbreviated ''comb. nov.'' (sometimes ''n. comb.''), is Latin for "new combination". It is used in taxonomic biology literature when a new name is introduced based on a pre-existing name. The term should not to be confused wi ...

''Wannia scurriensis''. The generic name honors Langston for his extensive work on

archosaur Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian d ...

palaeontology, and the specific name refers to the

Scurry County Scurry County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 16,932. Its county seat is Snyder, which is the home for Western Texas College. Scurry County is named for Confederate General William ...

where the holotype was found. ''Wannia'' is known solely from 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 ...

TTU P-00539, a partial

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 ...

preserved in two parts housed at

Texas Tech University Texas Tech University (Texas Tech, Tech, or TTU) is a public research university in Lubbock, Texas. Established on , and called Texas Technological College until 1969, it is the main institution of the five-institution Texas Tech University Sys ...

. TTU P-11422, a partial juvenile skull, had also been referred to ''"P." scurriensis'', however Stocker (2013) found no basis for this referral as the specimens do not share any

synapomorphies 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 have ...

. The holotype was collected near

Lake Alan Henry Lake Alan Henry is a reservoir situated in the upper Brazos River Basin in the United States. Created by the construction of the John T. Montford Dam in 1993, it is operated and used as a future tertiary water supply by the city of Lubbock, Texas ...

, 4 km northeast of the town of Camp Springs, from the

Camp Springs Formation The Camp Springs Formation is a geologic formation in Texas. It preserves fossils dating back to the Triassic period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleo ...

of the

Dockum Group The Dockum is a Late Triassic (approximately late Carnian through Rhaetian, or 223–200 Ma) geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Color ...

. Previously known as the Camp Springs Conglomerate, this unit probably correlates with the lower member of the

Santa Rosa Sandstone The Santa Rosa Formation is a geologic formation exposed in New Mexico that was deposited in the Carnian Age of the late Triassic Period. Description The formation consists mostly of white to brown sandstone and mudstone with some interbedded ...

in Texas and the Tecololito Member of the Santa Rosa Formation in New Mexico. The age of this unit is not precisely known, it was originally considered to be late

based on correlations with the Opponitzer Limestone of Austria, using the presence of ''

Dolerosaurus ''Dolerosaurus'' is an extinct genus of diapsid known from the early Late Triassic (late Carnian stage) upper Lunz Formation of Austria. ''Dolerosaurus'' was first named by Richard J. Butler in 2013 and the type species is ''Francosuchus traut ...

'', which was previously considered to be a member of ''Paleorhinus''. However, recent

zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the r ...

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

suggests that the Santa Rosa Sandstone is equivalent to the

-aged Shinarump Member. Furthermore, the Post Quarry which is within the stratigraphically higher

Cooper Canyon Formation The Cooper Canyon Formation is a geological formation of Norian age in Texas and New Mexico.Weishampel, David B; et al. (2004).Dinosaur distribution (Late Triassic, North America)" In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (e ...

of the Dockum Group was recently demonstrated to be mid Norian (220–215 Ma). Thus the most probable age for the Camp Springs Formation and the lower member of the Santa Rosa Sandstone is latest Carnian or early Norian.

Description

Stocker (2013) diagnosed ''Wannia scurriensis'' using five unambiguous

(unique traits) and additionally by a unique combination of characters. Unlike all other phytosaurs, the basitubera, areas at the base of the skull in front of its attachment point with the neck, are widely separated mediolaterally. A distinctive ridge is present on the lateral surface of the

jugal bone 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 ...

. A thickened shelf is present along the posteroventral edge of an expanded "wing" formed by 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 () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the th ...

and the

quadrate bone The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids (reptiles, birds), and early synapsids. In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper ...

. A swelling on 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 ...

is present behind the posterior borders of the nares. Finally, the "septomaxillae", probably not homologous to the septomaxillae of

squamate Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...

s and

synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptil ...

s, do not contact one another and do not form part of the internarial septum. Eight characters are shared by ''Wannia'' and all other phytosaurs (

), including nares that are directed dorsally and the presence of separate ossification, the septomaxilla, anterior to the nasals and surrounded by 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 mammal has b ...

. Although a

synonymy A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

between ''Wannia scurriensis'' and ''

'' was previously suggested, ''Wannia scurriensis'' differs from ''Paleorhinus bransoni'' in lacking a contact between the premaxilla and

palatine bone In anatomy, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ''pa ...

, as seen in '' Paleorhinus angustifrons'' and '' Ebrachosuchus neukami''. Additionally, ''W. scurriensis'' differs from both species of ''Paleorhinus'' in the presence of a ridge, rather than a row of nodes, on the lateral surface of the jugal. The small partial skull previously catalogued as referable to this species, TTU P-11422, does not share any diagnostic characters with the holotype. The specimens can be compared only in the area surrounding the right antorbital fenestra. Although TTU P-11422 does have a large antorbital fossa with a slightly posterodorsally inclined antorbital fenestra as in ''W. scurriensis'', the nasals just posterior to the nares are not swollen in contrast to the autapomorphic condition seen in the latter. However, a further preparation of TTU P-11422 may reveal additional morphological traits.

References

{{Taxonbar, from=Q16760255 Phytosaurs Prehistoric reptile genera Late Triassic reptiles of North America Paleontology in Texas Fossil taxa described in 2013 Taxa named by Michelle R. Stocker