''Moschorhinus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 ...

therocephalia Therocephalia is an extinct clade of therapsids (mammals and their close extinct relatives) from the Permian and Triassic periods. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their te ...

synapsid Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant rept ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 '' Mos ...

with only one species: ''M. kitchingi'', which has been found in the

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

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 per ...

. It was a large carnivorous therapsid, reaching in total body length with the largest skull comparable to that of a

lion The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'', native to Sub-Saharan Africa and India. It has a muscular, broad-chested body (biology), body; a short, rounded head; round ears; and a dark, hairy tuft at the ...

in size, and had a broad, blunt snout which bore long, straight

canine Canine may refer to: Zoology and anatomy * Animals of the family Canidae, more specifically the subfamily Caninae, which includes dogs, wolves, foxes, jackals and coyotes ** ''Canis'', a genus that includes dogs, wolves, coyotes, and jackals ** Do ...

s. ''Moschorhinus'' appears to have ecologically replaced the

gorgonopsid Gorgonopsia (from the Greek Gorgon, a mythological beast, and 'aspect') is an extinct clade of Saber-toothed predator, sabre-toothed therapsids from the Middle Permian, Middle to the Upper Permian, roughly between 270 and 252 million years ago. ...

s as an

apex predator An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...

, and hunted much like a

big cat The term "big cat" is typically used to refer to any of the five living members of the genus ''Panthera'', namely the tiger, lion, jaguar, leopard, and snow leopard. All cats descend from the ''Felidae'' family, sharing similar musculature, c ...

. While most abundant in the Late Permian, it survived into the Early Triassic in small numbers 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 251.902 Mya. It is the sixth and last period o ...

, though these Triassic survivors had

stunted growth Stunted growth, also known as stunting or linear growth failure, is defined as impaired growth and development manifested by low height-for-age. Stunted growth is often caused by malnutrition, and can also be caused by Endogeny (biology), endogeno ...

Taxonomy

The genus name ''Moschorhinus'' is derived from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), 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 holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was Species description, formally described. It is either the single such physical example (or illus ...

, a skull (best preserved, 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 ...

), 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 municipal ...

. It was first described by paleontologist

Robert Broom Robert Broom Fellow of the Royal Society, FRS FRSE (30 November 1866 6 April 1951) was a British- South African medical doctor and palaeontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University ...

in 1920. It is now one of the best known and most recognizable therapsids of the supergroup. Broom had previously named another species of therocephalian in 1907 from

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

, ''

Scymnosaurus ''Scymnosaurus'' is a Nomen dubium, dubious genus of therocephalian therapsids from the Middle Permian of what is now South Africa based upon the fossils of large, but Incertae sedis, indeterminate, early therocephalians. The genus and its type s ...

warreni'', that he later moved to ''Moschorhinus'' in 1932 as ''M. warreni'', maintaining it as a distinct species. ''M. warreni'' was later recognised as a probable

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''M. kitchingi'' by Kitching in his unpublished PhD thesis, and a re-description of the holotype in 2023 by David Groenewald and Christian Kammerer confirmed this proposal. As the older name, ''M. warreni'' would have taxonomic priority over ''M. kitchingi'' for the species. However, Groenewald and Kammerer (2023) believed it would be premature to establish ''M. warreni'' as the correct name, pending a revision of akidnognathid therocephalian taxonomy and the possibility that even older names may have seniority. 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 251.902 Mya. It is the sixth and last period o ...

Lower Triassic The Early Triassic is the first of three epoch (geology), epochs of the Triassic Period (geology), Period of the geologic timescale. It spans the time between 251.9 annum, Ma and Ma (million years ago). Rocks from this epoch are collectively kno ...

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 under ...

Classification

''Moschorhinus'' is a

n, a member of 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 ...

Eutheriodontia Eutheriodontia is a clade of therapsids which appear during the Middle Permian and which includes therocephalians and cynodonts, this latter group including mammals and related forms. With the dicynodonts, they form one of two lineages of ther ...

and 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 ...

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

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

, along with other large, carnivorous therapsids 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 and growth *Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ec ...

once controlled by

s. Both groups were built much like

s. 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 and weighing . The skull is similar to that of the Gorgonopsids, with large

temporal fenestra Temporal fenestrae are openings in the temporal region of the skull of some amniotes, behind the orbit (eye socket). These openings have historically been used to track the evolution and affinities of reptiles. Temporal fenestrae are commonly (al ...

e (three in total as a synapsid) and a convexly bowed

. 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 West African Nile monitor, one species is also found in south America as an invasive species. A ...

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

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s, similar to the canines of saber toothed cats. 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 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 ...

. 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 Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

of I6.C1.M3, with 6

s, 1

, and 3

postcanine Cheek teeth or postcanines 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

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 ...

e. 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

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

e, 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 mainland clouded leopard, is a wild cat inhabiting dense forests from the foothills of the Himalayas through Northeast India and Bhutan to mainland Southeast Asia into South China. It w ...

(''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 bone The pterygoid is a paired bone forming part of the palate of many vertebrates, behind the palatine bone In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal specie ...

s, are greatly reduced or missing, and in ''Moschorhinus'' they are absent.

Skull roof

Tracing the roof of the skull, ''Moschorhinus'' possesses small

prefrontal bone The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most modern and ...

s 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 excepti ...

along the midline of the skull, which houses a very basic

pineal foramen A parietal eye (third eye, pineal eye) is a part of the epithalamus in some vertebrates. The eye is at the top of the head; is photoreceptive; and is associated with the pineal gland, which regulates circadian rhythmicity and hormone production ...

. Indentations can be seen in the

temporal fossa The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines above, and the zygomatic arch below. Its floor is formed by the outer surfaces of four bones of the skull. The fossa is filled by the te ...

e, depressions on either side of the crest, indicating the presence of many blood vessels and nerves supplying the brain.

Eye sockets

The

lacrimal bone The lacrimal bones are two small and fragile bones of the facial skeleton; they are roughly the size of the little fingernail and situated at the front part of the medial wall of the orbit. They each have two surfaces and four borders. Several bon ...

is larger than the reduced prefrontal, and forms the majority of the

eye socket In anatomy, the orbit is the cavity or socket/hole of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is ...

. 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 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 ...

and maxillary bones. The jugal ends at the eye socket, and is not convex, as in several later therocephalians.

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 (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxilla, they comprise the hard palate. Stru ...

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 (; ) 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 maxillary bones. The vomer forms ...

on the nose, forming part of the circumference of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nas ...

. 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 Southern Africa, southernmost country in Afri ...

'' shows stiff folds (

choana The choanae (: choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the pharynx, in humans and other mammals (as well as crocodilians and most skinks). They ...

l 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'' from ...

'' 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 event. This appears to have led to

, 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 an observed decrease in animal body size in genera that have survived a major extinction. There are several hypotheses as to why these patterns appear in the fossil record, some of which are: * simple preferential survival of ...

). 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 Akidnognathidae 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