''Slaugenhopia'' 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 ...

dvinosauria Dvinosaurs are one of several new clades of Temnospondyl amphibians named in the phylogenetic review of the group by Yates and Warren 2000. They represent a group of primitive semi-aquatic to completely aquatic amphibians, and are known from t ...

temnospondyl Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order (biology), order of small to giant tetrapods—often considered Labyrinthodontia, primitive amphi ...

within the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Tupilakosauridae Tupilakosauridae is an extinct family of dvinosaurian temnospondyls. It contains the genera ''Slaugenhopia'', '' Thabanchuia'', ''Tupilakosaurus'', and possibly ''Kourerpeton''. Tupilakosaurs are known from Texas, Greenland, Russia, and France. ...

. Fossils have been found from the

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 (Son of Dave album), ''01'' (Son of Dave album), 2000 * 01 (Urban ...

San Angelo Formation The San Angelo Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian period. It is one of the geologically youngest formations to preserve fossils of pelycosaurs. Stratigraphy and age The San Angelo Formati ...

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 ...

. The type and only species, ''S. texensis'', was named in 1962. It may be closely related to the dvinosaur ''

Kourerpeton ''Kourerpeton'' is an extinct genus of dvinosaurian temnospondyl. Fossils of ''Kourerpeton'' were discovered in a window of a barber's shop in either Bisbee or Mesa, Arizona. ''Kourerpeton'' was named in 1976, with the type and only species be ...

''. ''Slaugenhopia'' was once classified as a trimerorhachid but is now classified as a tupilakosaurid.

Description and history

''Slaugenhopia'' was found from the San Angelo Formation within the Kahn Quarry of Driver Ranch in

Knox County, Texas Knox County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 3,353. Its county seat is Benjamin. The county was created in 1858 and later organized in 1886. It is named for Henry Knox, an American Revolu ...

. Although it was known only from fragments, paleontologist

Everett C. Olson Everett Claire Olson (November 6, 1910 – November 27, 1993) was an American zoologist, paleontologist, and geologist noted for his seminal research of origin and evolution of vertebrate animals. Through his research studying terrestrial verte ...

reconstructed the entire skull when he named the genus in 1962. He placed the genus in the dvinosaur family Trimerorhachidae and thought that it was intermediate between the dvinosaurs ''

Trimerorhachis ''Trimerorhachis'' is an extinct genus of dvinosaurian temnospondyl within the family Trimerorhachidae. It is known from the Early Permian of the southwestern United States, with most fossil specimens having been found in the Texas Red Beds. Th ...

'' and ''

Dvinosaurus ''Dvinosaurus'' is an extinct genus of amphibious temnospondyls localized to regions of western and central Russia during the middle and late Permian, approximately 265-254 million years ago. Its discovery was first noted in 1921 by Russian pal ...

'' based on the shape of the skull. A mandible that was found earlier in Little Croton Creek was also referred to ''Slaugenhopia''. ''Slaugenhopia'' continued to be classified as a trimerorhachid until 1999 when a new dvinosaur called ''

Thabanchuia ''Thabanchuia'' is an extinct genus of dvinosaurian temnospondyl within the family Tupilakosauridae. It is known from the Lystrosaurus Assemblage Zone in Thaba N'chu, Free State, South Africa. The genus contains just one species, ''Thabanchuia ...

'' was named from

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. ''Thabanchuia'' is a member of the family Tupilakosauridae and shares many similarities with ''Slaugenhopia''. Because of these similarities, ''Slaugenhopia'' is now considered a tupilakosaurid. Defining characteristics of ''Slaugenhopia'' include a notch in the pterygoid bone 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 sepa ...

called the pterygoid incisure; the wideness of a projection of bone in the palate called the cultriform process, a wide contact between the

parasphenoid The parasphenoid is a bone which can be found in the cranium of many vertebrates. It is an unpaired dermal bone which lies at the midline of the roof of the mouth. In many reptiles (including birds), it fuses to the endochondral (cartilage-derived) ...

and basisphenoid bones on the underside of the skull, and uniquely "L"-shaped

postparietal Postparietals are cranial bones present in fish and many tetrapods. Although initially a pair of bones, many lineages possess postparietals which were fused into a single bone. The postparietals were dermal bones situated along the midline of the ...

bones at the back of the skull. Another Early Permian dvinosaur called ''Kourerpeton'' is also known from Texas and may be related to ''Slaugenhopia''. Both dvinosaurs have an enlarged

postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ve ...

bone and a small

postfrontal 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 ...

bone near the eye sockets. They also have similar vertebrae, with ring-like intercentra and small, crescent-shaped pleurocentra. While the posterior margin of the skull is relatively straight in ''Slaugenhopia'', the same margin is curved and irregular in ''Kourerpeton''. ''Kourerpeton'' also lacks the pterygoid incisure of ''Slaugenhopia'', which is characteristic of other tupilakosaurids as well. Based on these differences, ''Kourerpeton'' is probably a basal relative of tupilakosaurids, including ''Slaugenhopia''.

References

{{Taxonbar, from=Q7539002 Dvinosaurs Cisuralian temnospondyls of North America Taxa named by Everett C. Olson Fossil taxa described in 1962