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 ...
of
procolophonian
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) 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, ...
of
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-eig ...
and
North America. They are sometimes classified as a sister group to
pareiasaurids (but see ''Classification)''. The group includes the genera ''
Macroleter'', ''
Bashkyroleter'', ''"Bashkyroleter" mesensis'', ''
Nycteroleter'', ''
Emeroleter'', and probably ''
Rhipaeosaurus''. They were
carnivorous, and occasionally ate insects.
The group was most common in
European Russia, with only a few fossils in
North America. 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.
Classification
Nycteroleteridae is sometimes considered a sister group to the
Pareiasauridae, but
Bayesian inference suggests that it was in fact
paraphyletic, with ''
Rhipaeosaurus'' 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, t ...
- 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
** †''
Nycteroleter''
** †''
Emeroleter''
* Unassigned subfamily
** †''
Bashkyroleter''
*** † ''Bashykroleter'' ''mesensis''
** †''
Macroleter''
** †''
Rhipaeosaurus''
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 otic notch, 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.
Examination of the nycteroleterids'
middle ear bones and comparison with living
amniotes 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, but ''Rhipaeosaurus'' may have been an omnivore.
References
{{paleo-reptile-stub