Nycteroleteridae is a

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

procolophonia The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria (later renamed Captorhinida Carroll 1988) but are n ...

parareptilia Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near th ...

ns (extinct early

reptiles 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 rhynchoceph ...

) from the Middle to

Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

. They are sometimes classified as a sister group to

pareiasaur Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permi ...

ids (but see ''Classification)''. The group includes the genera ''

Macroleter ''Macroleter'' is an extinct genus of nycteroleterid parareptile which existed in Oklahoma and Russia during the upper Permian period. It was a quite generalized primitive reptile, in many ways resembling their amphibian ancestors. It was first ...

'', '' Bashkyroleter'', ''"Bashkyroleter" mesensis'', ''

Nycteroleter ''Nycteroleter'' is an extinct genus of nycteroleterid parareptile known from the Middle Permian of European Russia. Fossils were first found in the Mezen River, near to Arkhangelsk. Within the Nycteroleteridae, it is considered most closely rel ...

'', ''

Emeroleter ''Emeroleter'' is an extinct genus of nycteroleterid parareptile known from the early Late Permian of European Russia. It was a long-legged lizard Lizards are a widespread group of Squamata, squamate reptiles, with over 7,000 species, rangin ...

'', and probably ''

Rhipaeosaurus ''Rhipaeosaurus'' is an extinct genus of nycteroleterid parareptile known from an articulated skeleton from the mid Middle Permian of European Russia. It contained a single species, ''Rhipaeosaurus tricuspidens''. A bayesian analysis suggests tha ...

''. They were

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...

, and occasionally ate insects. The group was most common in

European Russia European Russia (russian: Европейская Россия, russian: европейская часть России, label=none) is the western and most populated part of Russia. It is geographically situated in Europe, as opposed to the cou ...

, with only a few fossils in

. One fossil has also been found in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, but this is the only one from

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

Classification

Nycteroleteridae is sometimes considered a sister group to the

Pareiasaur Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permi ...

idae, but

Bayesian inference Bayesian inference is a method of statistical inference in which Bayes' theorem is used to update the probability for a hypothesis as more evidence or information becomes available. Bayesian inference is an important technique in statistics, and ...

suggests that it was in fact

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

, with ''

'' a basal member of the Pareiasauridae and other members of the Nycteroleteridae as outgroups. This is supported by the appearance of ''Rhipaeosaurus

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, th ...

and

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, ...

- it had tricuspid teeth and multiple horns on the skull, resembling a pareiasaur but smaller and with a longer tail. For this reason it is often seen as intermediate between more primitive nycteroleterids and more advanced pareiasaurids such as '' Scutosaurus.''

Subdivisions

* Subfamily † Nycteroleterinae ** †''

'' ** †''

'' * Unassigned subfamily ** †'' Bashkyroleter'' *** † ''Bashykroleter'' ''mesensis'' ** †''

'' ** †''

Features

As discussed above, Nycteroleteridae technically includes all pareiasaurs as well as the five given genera. Within the five genera mentioned, there seems to be a smooth gradient of form from ''Macroleter'' to ''Rhipaeosaurus.'' Where ''Macroleter'' has no horns, ''Emeroleter'' has a few small horns, and ''Rhipaeosaurus horns are quite large. However, there are some characteristic features of the Nycteroleteridae. They have a deeply

incised Incision may refer to: * Cutting, the separation of an object, into two or more portions, through the application of an acutely directed force * A type of open wound caused by a clean, sharp-edged object such as a knife, razor, or glass splinter * ...

otic notch Otic notches are invaginations in the posterior margin of the skull roof, one behind each orbit. Otic notches are one of the features lost in the evolution of amniotes from their tetrapod ancestors. The notches have been interpreted as part of an ...

, post parietal bones that enter the

pineal The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycl ...

opening, regular circular pits in the skull, and a row of palatal teeth from the interpterygoid vacuity to the edge of the

choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodili ...

. Examination of the nycteroleterids' middle ear bones and comparison with living

amniote Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are dis ...

s showed that they probably had efficient impedance-matching hearing. This suggests that they may have been active at night or in dim-light environments. They are thought to have been carnivorous or

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were ...

, but ''Rhipaeosaurus'' may have been an omnivore.

References

Prehistoric reptile families Extinct reptiles Permian reptiles of North America Reptiles of Russia Guadalupian first appearances Lopingian extinctions Pareiasauromorphs {{paleo-reptile-stub