''Delorhynchus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 ...

lanthanosuchoid Lanthanosuchoidea is an extinct superfamily of ankyramorph parareptiles from the middle Pennsylvanian to the middle Guadalupian epoch (Moscovian - Wordian stages) of Europe, North America and Asia. It was named by the Russian paleontologist Iva ...

parareptile Parareptilia ("near-reptiles") is an extinct group of Basal (phylogenetics), basal Sauropsida, sauropsids ("Reptile, reptiles"), traditionally considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds ...

known from the late

Early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

(

Artinskian In the geologic timescale, the Artinskian is an age (geology), age or stage (stratigraphy), stage of the Permian. It is a subdivision of the Cisuralian Epoch (geology), Epoch or series (stratigraphy), Series. The Artinskian likely lasted between ...

age)

Garber Formation The Garber Sandstone is a geologic formation from the Permian Period in Oklahoma. It serves as an important aquifer, the Garber-Wellington Aquifer, in Logan, Oklahoma, and Cleveland counties of central Oklahoma. The upper portion of the Garber i ...

Comanche County, Oklahoma Comanche County is a County (United States), county located in the U.S. state of Oklahoma. As of the 2020 United States census, 2020 census, the population was 121,125, making it the fifth-most populous county in Oklahoma. Its county seat is L ...

. It contains three

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

: 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 ...

''D. priscus'' is based on a series of

maxillae 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 maxillar ...

. The second species to be described, ''D. cifellii'', is known from a larger number of well-preserved skulls and skeletal material. The third species, ''D. multidentatus'', is based on a fragmentary skull with several rows of teeth on its jaw.

Discovery

The

, ''D. priscus,'' was first described and named by Richard C. Fox in

1962 The year saw the Cuban Missile Crisis, which is often considered the closest the world came to a Nuclear warfare, nuclear confrontation during the Cold War. Events January * January 1 – Samoa, Western Samoa becomes independent from Ne ...

. The generic name "''Delorhynchus''" is derived from

Greek Greek may refer to: 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 of all kno ...

''rhynchos''/''ρυγχος'', meaning "beak" (a common suffix for extinct reptile genera names). The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

of the type species ''D. priscus'' is derived from Greek ''πρίσκος'', meaning "ancient" or "venerable" in reference to the fragmentary nature of the known remains. ''D. priscus'' is known from the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

KU 11117, a fragmentary left

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 ...

bearing 4 teeth, and from the fragmentary referred specimens KU 11118 and KU 11119, a right and a left maxillae respectively, each bearing 4 teeth. All known specimens of ''D. priscus'' are housed at the

University of Kansas Natural History Museum The University of Kansas Natural History Museum is part of the University of Kansas Biodiversity Institute, a KU designated research center dedicated to the study of the life of the planet. The museum's galleries are in Dyche Hall on the uni ...

Lawrence, Kansas Lawrence is a city in and the county seat of Douglas County, Kansas, United States, and the sixth-largest city in the state. It is in the northeastern sector of the state, astride Interstate 70 in Kansas, Interstate 70, between the Kansas River ...

. ''D. cifellii'' was first described and named by Robert R. Reisz, Mark J. Macdougall and Sean P. Modesto in

2014 The year 2014 was marked by the surge of the Western African Ebola epidemic, West African Ebola epidemic, which began in 2013, becoming the List of Ebola outbreaks, most widespread outbreak of the Ebola, Ebola virus in human history, resul ...

. Its specific name honors Dr. Richard L. Cifelli, a paleontologist at the

Sam Noble Oklahoma Museum of Natural History The Sam Noble Oklahoma Museum of Natural History is the officially designated natural history museum for the State of Oklahoma, located on the campus of the University of Oklahoma. The museum was founded in 1899 by an act of the Oklahoma Terri ...

(OMNH), for his contributions to the paleontology of Oklahoma and support in studying ''D. cifellii''. Unlike the type species, ''D. cifellii'' is known from a well-preserved partial subadult

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

, an isolated adult

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

, and other disarticulated elements, all housed at the OMNH. The subadult individual preserves both the partial skull and the postcranial remains in articulation, and thus was chosen as the holotype, represented by OMNH 73515. OMNH 73362 represents the complete skull of the large, adult, individual. Other remains referred to ''D. cifellii'' include OMNH 73363, a complete right

mandibular ramus In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

of an individual equal in size to OMNH 73362, as well as the right maxilla OMNH 73524. ''D. multidentatus'' was described by Dylan C.T. Rowe, Diane M. Scott, Joseph J. Bevitt, and Robert Reisz in

2021 Like the year 2020, 2021 was also heavily defined by the COVID-19 pandemic, due to the emergence of multiple Variants of SARS-CoV-2, COVID-19 variants. The major global rollout of COVID-19 vaccines, which began at the end of 2020, continued ...

. It is based on ROMVP 87042, a fragmentary skull housed in the

Royal Ontario Museum The Royal Ontario Museum (ROM) is a museum of art, world culture and natural history in Toronto, Ontario, Canada. It is one of the largest museums in North America and the largest in Canada. It attracts more than one million visitors every year ...

Toronto Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...

. It was named in reference to the multiple rows of teeth on the lower jaw of the skull, a unique feature which distinguished it from other ''Delorhynchus'' species. ''Delorhynchus'' is only found in the fissure fill

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

and conglomerate of OMNH Locality V51. This locality, also known as

Richards Spur Richards Spur is a Permian fossil locality located at the Dolese Brothers Limestone Quarry north of Lawton, Oklahoma. The locality preserves clay and mudstone fissure fills of a karst system eroded out of Ordovician limestone and dolomite, with t ...

, is found at the Dolese Brothers limestone quarry near

Fort Sill Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (137 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark a ...

. The fissure fill deposits of Richards Spur are probably equivalent to the

of Oklahoma and the

Arroyo Formation The Arroyo Formation, sometimes termed the Lower Clear Fork Formation, is a geologic formation in Texas.Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. Uranium-Lead dating of speleotherms in the cave deposits suggest that the fossils of Richards Spur were deposited in the

stage of the

Cisuralian The Cisuralian, also known as the Early Permian, is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mou ...

(Early Permian).

Classification

Until recently, the

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

position of ''Delorhynchus'' within

Procolophonomorpha Procolophonomorpha is an order containing most parareptiles. Many papers have applied various definitions to the name, though most of these definitions have since been considered synonymous with modern parareptile clades such as Ankyramorpha and ...

was uncertain, due to the fragmentary nature of the remains of ''D. priscus''. However, with the description of ''D. cifellii'' by Reisz ''et al.'' (2014), ''Delorhynchus'' could be added for the first time into a

phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

to resolve its position. Reisz ''et al.'' (2014) recovered ''Delorhynchus'' in a

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

position to the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

formed by ''

Acleistorhinus ''Acleistorhinus'' (ah-kles-toe-RYE-nuss) is an extinct genus of parareptile known from the Early Permian (middle Kungurian stage) of Oklahoma. It is notable for being the earliest known anapsid reptile yet discovered. The morphology of the lower ...

'' and ''

Lanthanosuchus ''Lanthanosuchus'' is an extinct genus of parareptile from the Late Permian. It was found at Isheevo in Tatarstan Tatarstan, officially the Republic of Tatarstan, sometimes also called Tataria, is a Republics of Russia, republic of Russia ...

''. Thus ''Delorhynchus'' was either considered to be the

Lanthanosuchoidea Lanthanosuchoidea is an extinct superfamily of ankyramorph parareptiles from the middle Pennsylvanian to the middle Guadalupian epoch ( Moscovian - Wordian stages) of Europe, North America and Asia. It was named by the Russian paleontologist ...

, or a basal lanthanosuchoid, depending on the definition of Lanthanosuchoidea used. The following

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

is simplified after the phylogenetic analysis of MacDougall and Reisz (2014), an updated version of Reisz ''et al.'' (2014), and shows the placement of ''D. cifellii'' within

Parareptilia Parareptilia ("near-reptiles") is an extinct group of basal sauropsids (" reptiles"), traditionally considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near the en ...

. Relationships within bolded clades are not shown.

Paleoecology

The Richards Spur locality presents a very rich Early Permian

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

paleofauna, including species of

chondrichthyes Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...

lepospondyls Lepospondyli is a diverse clade of early tetrapods. With the exception of one late-surviving lepospondyl from the Late Permian of Morocco ('' Diplocaulus minimus''), lepospondyls lived from the Visean stage of the Early Carboniferous to the Earl ...

seymouriamorph Seymouriamorpha were a small but widespread group of limbed vertebrates (tetrapods). They have long been considered stem-amniotes (reptiliomorphs), and most paleontologists still accept this point of view, but some analyses suggest that seymouria ...

s, basal

synapsid Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant rept ...

s, and basal

eureptile Sauropsida (Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the class Reptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern reptiles and birds (which, as theropod dinosaur ...

s. At least six species of

s have been described apart from the three ''Delorhynchus'' species. They include the basal parareptile '' Microleter mckinzieorum'', the

bolosaurid Bolosauridae is an extinct family of parareptiles known from the latest Carboniferous ( Gzhelian) or earliest Permian ( Asselian) to the early Guadalupian epoch (latest Roadian stage) of North America, China, Germany, Russia and France. The bolo ...

Bolosaurus grandis ''Bolosaurus'' (from Ancient Greek ''bolos'', "lump" + ''sauros'': lizard]) is an extinct genus of bolosaurid reptile from the Cisuralian Epoch (geology), epoch (middle Sakmarian to early Kungurian stages) of North Asia and North America (Red Be ...

'', the

nyctiphruretid Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States. Nyctiphruretidae was named by Efremov in 1938. The type genus is '' N ...

'' Abyssomedon williamsi'', and three other

s: ''

Colobomycter pholeter ''Colobomycter'' is an extinct genus of acleistorhinid parareptile known from the Early Permian of Oklahoma. Discovery The type species, ''Colobomycter pholeter'', was first described from fossil remains in 1958, at which time it was believed ...

'', ''Colobomycter vaughni'', and ''

Feeserpeton oklahomensis ''Feeserpeton'' is an extinct genus of parareptile from the Early Permian of Richard's Spur, Oklahoma. It is known from a single species, ''Feeserpeton oklahomensis'', which was named in 2012 on the basis of a nearly complete skull. ''Feeserpeton ...

''.

References

{{Taxonbar, from=Q252747 Acleistorhinidae Cisuralian reptiles of North America Fossil taxa described in 1962 Fossil taxa described in 2014 Extinct animals of the United States Paleontology in Oklahoma Prehistoric reptile genera