''Moschorhinus'' 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 of therocephalian in the family

Akidnognathidae Akidnognathidae is an extinct family of therocephalian therapsids from the Late Permian and Early Triassic of South Africa, Russia and China. The family includes many large-bodied therocephalians that were probably carnivorous, including ''Mosch ...

with only one species: ''M. kitchingi''. It was a carnivorous synapsid which has been found in the Late Permian to Early Triassic of the South African

Karoo Supergroup The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a perio ...

. It was a large carnivore, reaching in total body length with the largest skull comparable to that of a lion in size. It had a broad, blunt snout which bore long, straight canines. It appears to have replaced the

gorgonopsid Gorgonopsia (from the Greek Gorgon, a mythological beast, and 'aspect') is an extinct clade of sabre-toothed therapsids from the Middle to Upper Permian roughly 265 to 252 million years ago. They are characterised by a long and narrow skull ...

s ecologically, and hunted much like a big cat. While most abundant in the Late Permian, it survived a little after the

Permian Extinction The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozo ...

, though these Triassic individuals had stunted growth.

Taxonomy

The genus name ''Moschorhinus'' is derived from the Ancient Greek words μόσχος (mos'-khos) ''moschos'' for calf or young animal, and ''rhin/rhino-'' for nose or snout, in reference to its short, broad snout. The species name, ''kitchingi'', refers to Mr. James Kitching, who originally found (but did not describe) the specimen. Kitching discovered the holotype specimen, a skull (best preserved, the palate), in the

in South Africa, near the village of

Nieu-Bethesda Nieu-Bethesda (Afrikaans for ''New Bethesda'') is a village in the Eastern Cape at the foot of the Sneeuberge, approximately north of Graaff Reinet. It was founded in 1875 as a church town, like many other Karoo villages, and attained municipa ...

. It was first described by paleontologist Robert Broom in 1920. It is now one of the best known and most recognizable therapsids of the supergroup. Geology of Karoo Supergroup

''Moschorhinus'' remains have been found most prominently in the

Upper Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

Lower Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...

Beaufort Group The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper Tarkastad Subgroup. It follows conformably after the Ecca Group and unconformably underlie ...

Classification

''Moschorhinus'' is a therocephalian, a member of the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Eutheriodontia and the sister taxon to

cynodont The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...

s and modern mammals. ''Moschorhinus'' is classified into the family

, along with other large, carnivorous theraspids with strong skulls and large upper canines. ''Moschorhinus'' took over the

niche Niche may refer to: Science *Developmental niche, a concept for understanding the cultural context of child development *Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ecology, the ...

once controlled by

s. Both groups were built much like big cats. Following the extinction of ''Moschorhinus'' by the Triassic,

s took over a similar niche.

Description

left, Side view of the head, showing the sabers and range of motion for the jaw ''Moschorhinus'' was a large carnivore, reaching in total body length. The skull is similar to that of the Gorgonopsids, with large temporal fenestrae (three in total as a synapsid) and a convexly bowed palate. The skull ranged in size to comparable to a

monitor lizard Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recogn ...

, to those of a lion. They possess a characteristically short, broad snout. They possess a pair of prominently long incisors, similar to the canines of

saber toothed cat Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae (true cats). They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million ...

s. Lateral view of ''Moschorhinus'' jaw, showing range of motion necessary for such large incisors, and upper palatal fenestrae of snout. (From van Valkenburgh and Jenkins, 2002).

Snout

The snout of ''Moschorhinus'' is characteristically short and broad. The blunt tip of the snout features a ridge running down the midline to the frontal bone. The lower jaw is much broader than that of any other therocephalian. The upper snout projects a bit beyond the incisors in juveniles. The nostrils were large and positioned towards the tip of the snout.

Teeth

''Moschorhinus'' is thought to have had a dental formula of I6.C1.M3, with 6 incisors, 1

canine Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** '' Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the ...

, and 3

postcanine Cheek teeth or post-canines comprise the molar and premolar teeth in mammals. Cheek teeth are multicuspidate (having many folds or tubercles). Mammals have multicuspidate molars (three in placentals, four in marsupials, in each jaw quadrant) and p ...

s in either side of the upper jaw. The incisors are housed in the premaxillae. They are large, curve slightly, and have a bell-shaped cross-section. They had smooth cutting surfaces, and, unlike those of other therocephalians, lacked facets or striae resulting from abrasion and wear. The large saber-like canines are held within the maxillae, and are quickly identifiable features of ''Moschorhinus''. They are especially thick and strong, and uniquely circular in cross-section. In length, these sabers are comparable to gorgonopsids. While there is no real modern analogue, the most similar living example would be the

clouded leopard The clouded leopard (''Neofelis nebulosa''), also called the mainland clouded leopard, is a wild cat inhabiting dense forests from the foothills of the Himalayas through mainland Southeast Asia into South China. In the early 19th century, a cl ...

(''Neofelis nebulosa''). Like other therocephalians, ''Moschorhinus'' had a reduced number of postcanines which were housed in the maxillae. In most therocephalians, the “teeth,” or rather toothlike projection (denticulations) of the pterygoid bones, are greatly reduced or missing, and in ''Moschorhinus'' they are absent.

Skull roof

Tracing the roof of the skull, ''Moschorhinus'' possesses small prefrontal bones above the eyes, followed by large, widened frontal bones. The parietals form a narrow

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 exceptiona ...

along the midline of the skull, which houses a very basic pineal foramen. Indentations can be seen in the temporal fossae, depressions on either side of the crest, indicating the presence of many blood vessels and nerves supplying the brain.

Eye sockets

The lacrimal bone is larger than the reduced prefrontal, and forms the majority of the eye socket. The lacrimal has a bony boss (a rounded knob) on the orbit, and a large foramen towards its inner side. The lower edge of the eye socket is formed the jugal and maxillary bones. The jugal ends at the eye socket, and is not convex, as in several later thercephalians.

Palate

Overall, the palate is convex, with a broad, triangular vomer, with paired tubercles, rounded projections pointing ventrally, similar to other akidnognathids. The

palatine bone In anatomy, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ''pa ...

s (forming the back of the roof of the mouth) are enlarged and thick, especially on their outer edges where they are joined to the maxilla. On their inner edges, the palatines are joined to the pterygoid and

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxill ...

on the nose, forming part of the circumference of the nasal cavity. Between the palatine and maxilla, just behind the canines, are large foramens, presumably to allow for nerves. A slanting ridge along the middle of the palatine presumably supported a soft palate, which allowed air to travel between the nose and the lungs. The sabers require the mouth to open widely for use, making feeding difficult. The closely related ''

Promoschorhynchus ''Promoschorhynchus'' is a genus of akidnognathid therocephalians from the Late Permian and Early Triassic of South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded ...

'' shows stiff folds ( choanal crest) on the border of the nasal passage and the throat, used to keep it open and to allow for breathing while eating. The development of a secondary palate in the skull gradually evolved in therocephalians, and the choanal crest is featured in all later therocephalians.

Paleobiology

It is presumed that ''Moschorhinus'' was a cat-like predator, being able to pierce skin and hold onto struggling prey with its long canines. This is the first record of this kind of hunting technique. Given its sturdily designed, thick snout, enormous canines, and powerful jaw muscles, ''Moschorhinus'' appears to have been a daunting predator.

Paleoecology

Many vertebrate fossils have been uncovered in the Karoo Basin. Other therocephalians from the same rock level are ''

Tetracynodon ''Tetracynodon'' is an extinct genus of therocephalian. Fossils of ''Tetracynodon'' have been found in the Karoo Basin of South Africa. Two species are known: the type species ''T. tenuis'' from the Late Permian and the species ''T. darti'' fro ...

'' and ''

''. ''Moschorhinus'' specimens were the only large therocephalians. ''Moschorhinus'' seems to have gone extinct in the Early Triassic at 251 mya after the

by 252 mya, along with 80–95% of animal species, due to a mass

hypoxia Hypoxia means a lower than normal level of oxygen, and may refer to: Reduced or insufficient oxygen * Hypoxia (environmental), abnormally low oxygen content of the specific environment * Hypoxia (medical), abnormally low level of oxygen in the tis ...

event. This appears to have led to stunted growth, intense seasons, reduced ecosystem diversity, and a loss of forests. Fossil evidence shows that Triassic ''Moschorhinus'' grew faster than Permian ones, resulting in reduced body size in the former, largely believed to be an effect of the harsher environmental variability after the Permian Extinction (

Lilliput effect The Lilliput effect is a decrease in body size in animal species which have survived a major extinction. There are several hypotheses as to why these patterns appear in the fossil record, some of which are: the survival of small taxa, dwarfing of la ...

). Permian skulls average in length, while that of Triassic skull is only . Nonetheless, Triassic ''Moschorhinus'' were the largest therocephalians of their time.

References

{{Taxonbar, from=Q1093062 Lopingian synapsids of Africa Akidnognathids Early Triassic synapsids of Africa Fossil taxa described in 1920 Taxa named by Robert Broom Lopingian genus first appearances Changhsingian genera Induan genera Early Triassic genus extinctions