''Feeserpeton'' is an extinct

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 ...

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 ...

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 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

of Richard's Spur,

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

. It is known from a single species, ''Feeserpeton oklahomensis'', which was named in 2012 on the basis of a nearly complete skull. ''Feeserpeton'' is a member of the clade

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 ...

and is one of the earliest parareptiles.

Description

The only known skull of ''Feeserpeton'' is small, but well-fused bones, deep pitting, and worn teeth indicate that the individual was close to maturity when it died. Large eye sockets may indicate that ''Feeserpeton'' was

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

. The skull is nearly complete, missing parts of 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 bone at the tip of the snout) and 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 ...

(a bone making up the "cheek" region). A combination of features distinguish ''Feeserpeton'' from other related parareptiles, including a triangular skull, large caniniform teeth in the upper and lower jaws, and

postorbital bone 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 ...

s behind the eye sockets that are much larger than the nearby

squamosal bone 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 ancestral ...

s. Part 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 ...

is exposed on the right side of the skull, revealing many worn palatal teeth. The teeth in the

mandible 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 ...

or lower jaw are hidden beneath the bones of the upper jaw, but

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

ning has revealed that there is a single tooth row on each side with mostly small teeth. Two teeth are much larger than the rest, similar in size to the enlarged caniniforms of the upper jaw. The braincase is preserved at the back of the skull and includes the

stapes The ''stapes'' or stirrup is a bone in the middle ear of humans and other tetrapods which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the f ...

, a bone rarely preserved in parareptile fossils. ''Feeserpeton'' has a large opisthotic bone in its braincase, similar in size to that of another Early Permian parareptile called '' Acleistorhinus''.

Discovery

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 ...

skull of ''Feeserpeton'', cataloged as OMNH 73541, was found in the Dolese Brothers Limestone Quarry near the town of Richard's Spur, Oklahoma. Several other parareptiles have also been found from Richard's Spur, including ''

Bolosaurus ''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 ...

'', '' Colobomycter'', ''

Delorhynchus ''Delorhynchus'' is an extinct genus of lanthanosuchoid parareptile known from the late Early Permian (Artinskian age) Garber Formation of Comanche County, Oklahoma. It contains three species: the type species ''D. priscus'' is based on a series ...

'', ''

Microleter ''Microleter'' is an extinct genus of basal (phylogenetics), basal Procolophonomorpha, procolophonomorph parareptiles which lived in Oklahoma during the Early Permian period. The type species, type and only known species is ''Microleter mckinzieo ...

'', and an acleistorhinid. OMNH 73541 was preserved in a

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

-rich nodule of

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

which was removed during preparation. CT scans of the skull revealed many internal details. The specimen was described as a new genus and species in 2012. The genus name ''Feeserpeton'' honors Mike Feese, a manager of the Dolese Brothers quarry who was also a fossil collector, and the species name ''oklahomensis'' refers to Oklahoma, the state in which it was found.

Phylogeny

''Feeserpeton'' was included in a

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 ...

analysis when it was first named in 2012. It nested within 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 ...

, a poorly known group that includes the parareptiles ''Acleistorhinus'' and '' Lanthanosuchus''. ''Feeserpeton'' was found to be a basal member of this group, the

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 ...

of a clade including ''Acleistorhinus'' and ''Lanthanosuchus''. Features that place ''Feeserpeton'' within Lanthanosuchoidea include a ridge on 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 ...

above the eye socket, a plate-like

supraoccipital The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone lies over the occipital lobes of the cere ...

bone with a

sagittal crest A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are excepti ...

on the braincase, and a notch midway along the margin of the back of the skull. ''Feeserpeton'' is the oldest member of the clade. Below is a

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 ...

from the analysis showing the position of ''Feeserpeton'':

References

{{Taxonbar, from=Q5441460 Permian vertebrates of North America Acleistorhinidae Prehistoric reptile genera