Kawingasaurus

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Kawingasaurus
Temporal range: Late Permian
~259–254  Ma
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Kawingasaurus fossilis.JPG
Skeleton
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder: Anomodontia
Clade: Dicynodontia
Family: Cistecephalidae
Genus: Kawingasaurus
Cox, 1972
Type species
Kawingasaurus fossilis
Cox, 1972

Kawingasaurus is an extinct genus of dicynodont therapsid from the Late Permian Usili Formation of Tanzania. It is a member of the family Cistecephalidae, and like other cistecephalids it is thought to have been fossorial. It is a member of the family Cistecephalidae. Cistephalidae includes genera Cisteceohalus, Cistecephaloides and Kawingasaurus. Greek for Saurus meaning “lizard” appears as a suffix denoting a reptilian origin. Living between 254.17 and 259.9 million years ago in the late Permian and believed to have the first and last recorded appearance in this time period. It lived in deep burrows as a suggested by most burrowing [1] dicynodonts from evaluation of cranial sutures, vestibule inflation and enlarged stapes foot plates which are thought to be functionally correlated with bone-conduction hearing; all observed in fossorial vertebrates which use seismic signals as communication. [2]

Contents

History of discovery

Dicynodontoides was very briefly first described by Sir Richard Owen in his catalog of fossil reptilia in 1876. He described them as being “a very peculiar family of reptiles from the Trias of South Africa with a remarkable skull and a single pair of huge sharp-pointed tusks growing downward. [3] ” Owen described these singular animals to have no other kind of teeth except for a beak-like mouth. [3] At least 13 specimens were referred to C. microrhinus and C. Planiceps were not described in detail to provide photos or museum numbers for them. [2] A first detailed description of these fossils was provided by von Huene (1942) [4] who mentioned notable differences of characteristics of Cistecephalus such as smaller orbits, smaller sized skulls and a flattened snout region despite ascribing the fossils to Cistepahlus planiceps (now considered a junior synonym of C. microrhinus). [5]

In 1936, seven skulls, parts of the vertebrae, a mandible, ribs and parts of the girdles were excavated by German geologist and engineer Ernst Nowack and his wife Maria Nowack on an expedition in the Ruhuhu area of Southwest Tanzania. [6] [2] The fossils were preserved as a part of Nowack's collection in the Institut und Museum fur Geologic and Paläontologie der Universitat Tubingen (GPIT No. U 31). [6] Later, in 1972 Cox [7] investigated the fossils and found further differences between Cistephalus and the excavated skulls. A tapering shape of the skull in lateral and dorsal view, slenderness of the zygomatic arches, and anterior extension of the squamosal to meet the maxilla led to Cox [2] [7] establishing the new genus and species, since Owen's initial description [3] of the group in 1876, K. fossilis due to significant evidence of distinct differences from Cistecephalus.

Paleoenvironmental Information

Kawingsaurus Fossils were discovered in the Usili Formation which was a late Permian geologic formation in Tanzania. British geologist G. M. Stockely first studied this formation and the fossils within in 1932 and divided it into units labeled K1-K8. [8] Later in 1957, paleontologist Alan J. Charig discovered more fossils and renamed the K6 unit the Kawinga Formation. [8] Since then it has been renamed the Usili Formation. [5] Kawingasaurus fossilis’ locality was found in Kingori of the Arusha Region of Tanzania. The material found for Kawingasauerus at this site included UT K 52, skull and dentary; UT K 56, skull; UT K 55, 5 skulls and post crania. [8]

Description

While the size of Kawingasaurus specimen is not explicitly mentioned, Cistecephalus could reach up to 60 centimeters in length. [9] Kawingasaurus is a relatively small dicynodont with a described “unusual” postcranial anatomy. In 1972, Cox's investigation led to the discovery that the humerus and scapulocoracoid were very massive, stout and extremely twisted. [7] [2] Like most digging vertebrates, the forelimbs are much more broad than the hind limbs and have enlarged digits. A great interest was taken in the skull and hearing apparatus of Kawingasaurus to gain insight into adaptations for fossorial lifestyle.  In particular, the inner ear, stapes, mandible, quadrate-quadratojugal complex was analyzed in preserved K. Fossilis specimen. [2] Cox came to the conclusion that Kawingasaurus was likely adapted to a fossorial lifestyle. [10] [7] An almost complete skull of K. fossilis (inventory number GPIT/RE/9272) and the mandible (inventory number GPIT/RE/9274) was measured from the tip of the snout to the condyles at 40.5 mm in length. [2] The width of the skull in the occipital region was measured at 37.0 mm. [2]

Underground fossorial animals are sensitive to low-frequency sound and have modifications to their auditory components [11] compared to terrestrial species. The volume of the vestibule relative to the size of K. fossilis proved to be very inflated at 182.00 mm^3 compared to other nonmammalian synapsids. [2] According to Cox (1962) and Olsen (1944), the vestibule of the inner ear for “typical anomodonts us described as elongated and slender whereas the vestibule of the inner ear found in Kawingasaurus is extremely inflated with an ellipsoidal shape. [2] The inner ears occupy most of the space of the caudal region of the skull. It was also found that Kawingasaurus has enlarged stapes footplates (measured at 13.91 mm^2)  thought to be correlated with bone-conduction hearing observed in fossorial vertebrates. [2] The triangular head as well as spatulate snout was likely used for digging and seismic signal detection by tapping against tunnel walls for perception of sound. [2] The ventrolateral orientated stapes are thought to better transmit seismic sound from the ground to the fenestra vestibuli than horizontal orientated stapes. [2] Due to a low sound pressure level transformer ratio of 2-3, Kawingasaurus is thought to have seismic sensitivity of the middle ear and a reduced sensitivity to sounds that travel airborne. [2] The quadrate-quadratojugal complex, a thin plate-like bone, transmits sound from the articular to the stapes via minor vibrations of the quadrate process. [2] The ventral parts of the quadrate as well as the quadratojugal are fused to a single unit. [10] The quadrate of K. fossilis is similar to other anomodonts.

The otic capsule also known as the bony housing of the inner ear of K. fossilis is inflated due to vestibule inflation. [2] The external shape of the otic capsules is reliant on the shape of the vestibule as well as the anterior semicircular canals [10] and ampullae. [10] The otic capsules have significance due to sound transmission mechanisms via the snout, skull roof and otic capsules. On the right side of a preserved mandible, the remains of a small reflected lamina suggests that it covered parts of the recessus mandibularis serving as a sound receiving component. [2] As in other nonmammalian synapsids, the mandible and jaw articulation found in Kawingasarus likely served for both hearing and feeding. [10]

Paleobiology

Diet

Kawingasaurus was an herbivore in the Late Permian Usili Formation in Tanzania. The exact dietary patterns are not fully understood as it is possible that this species may have varied in degrees of omnivory or insectivory. Due to its sloping skull, it was likely that Kawingasaurus was a grazer. [9]

Locomotion

Kawingasaurus had a short neck and laterally-directed shoulder joint. [10] The forelimbs were short and powerful. Its manus were broad with fused phalanges. The hind limbs were flexible and likely used to move dirt out of the way showing similarities to modern burrowing mammals. [11] The form of locomotion for this species is thought to be quadrupedalism.

Classification

Kawingasaurus belongs to the family Cistephalidae and shares this family with Sauroscaptor, Cistecephalus, and Cistecephaliodes genus. It was not until C. Barry Cox established this genus in 1972, [7] when Kawingasaurus came to be. The cladogram below shows the phylogenetic position of Kawingasaurus.

Bidentalia

Paleoecology

Kawingasaurus appears to have been endemic to the Karoo Basin of South Africa. [11]

Related Research Articles

<i>Cistecephalus</i> Extinct genus of dicynodonts

Cistecephalus is an extinct genus of dicynodont therapsid from the Late Permian of southern Africa. It was a small, specialised, burrowing dicynodont, possibly with habits similar to a modern mole. The head was flattened and wedge-shaped, the body long, and the forelimbs very strong, with similarities in structure to the forelimb of modern burrowing mammals.

<i>Diictodon</i> Extinct genus of dicynodonts

Diictodon is an extinct genus of pylaecephalid dicynodont that lived during the Late Permian period, approximately 255 million years ago. Fossils have been found in the Cistecephalus Assemblage Zone of the Madumabisa Mudstone of the Luangwa Basin in Zambia and the Tropidostoma Assemblage Zone of the Teekloof Formation, Tapinocephalus Assemblage Zone of the Abrahamskraal Formation, Dicynodon Assemblage Zone of the Balfour Formation, Cistecephalus Assemblage Zone of the Middleton or Balfour Formation of South Africa and the Guodikeng Formation of China. Roughly half of all Permian vertebrate specimens found in South Africa are those of Diictodon. This small herbivorous animal was one of the most successful synapsids in the Permian period.

<i>Eodicynodon</i> Extinct genus of dicynodonts

Eodicynodon is an extinct genus of dicynodont therapsids, a highly diverse group of herbivorous synapsids that were widespread during the middle-late Permian and early Triassic. As its name suggests, Eodicynodon is the oldest and most primitive dicynodont yet identified, ranging from the middle to late Permian and possessing a mix of ancestral Anomodont/therapsid features and derived dicynodont synapomorphies.

<i>Endothiodon</i> Extinct genus of dicynodonts

Endothiodon is an extinct genus of medium to large dicynodont from the Late Permian. Like other dicynodonts, Endothiodon was an herbivore, but it typically lacked the two tusks that characterized most other dicynodonts and instead had long rows of teeth inset in the jaws that replaced in waves. The anterior portion of the upper and lower jaw are curved upward, creating a distinct beak that is thought to have allowed them to be specialized grazers.

<i>Myosaurus</i> Extinct genus of dicynodont from the lower Triassic

Myosaurus is a genus of dicynodont synapsids. Myosaurus was a small, herbivorous synapsid that existed around the early Triassic period. All of the fossils found of this species were found in Antarctica and South Africa. Compared to other fossils found from species that existed during this time, the Myosaurus is not common in the fossil record. This is due to a shortage of discovered fossils that possess characteristics unique to the Myosaurus. Notably, under 130 fossil fragments have been found that have been classified as Myosauridae, and almost all have been skulls. These skulls can be classified as Myosaurus because this species, unlike other dicynodonts, do not possess tusks or postfrontal teeth. The only species identified in the family Myosauridae is the Myosaurus gracilis, or M. gracilis. It should be recognized that the Myosaurus is almost always referred to as the M. gracilis in scientific research.

<i>Dicynodontoides</i> Extinct genus of dicynodonts

Dicynodontoides is a genus of small to medium-bodied, herbivorous, emydopoid dicynodonts from the Late Permian. The name Dicynodontoides references its “dicynodont-like” appearance due to the caniniform tusks featured by most members of this infraorder. Kingoria, a junior synonym, has been used more widely in the literature than the more obscure Dicynodontoides, which is similar-sounding to another distantly related genus of dicynodont, Dicynodon. Two species are recognized: D. recurvidens from South Africa, and D. nowacki from Tanzania.

<i>Daptocephalus</i> Extinct genus of dicynodonts

Daptocephalus is an extinct genus of dicynodont synapsid, which was found in Late Permian strata, in a biozone known precisely for the presence of fossils of this dicynodont, the Daptocephalus Assemblage Zone, in the Karoo Basin in South Africa. An additional species, D. huenei, is known from the Usili Formation in Tanzania and was formerly assigned to the genus Dicynodon before a study in 2019 recognised that the type specimen belonged to Daptocephalus.

<i>Eosimops</i> Extinct genus of dicynodonts

Eosimops is an extinct genus of pylaecephalid dicynodonts. They were small synapsids superficially resembling modern mammals. Eosimops is known from several skull specimens, as well as one complete skeleton. Eosimops lived during the Middle Permian of South Africa.

<i>Geikia</i> Extinct genus of dicynodonts

Geikia is an extinct genus of dicynodont therapsids from the late Permian. The abundance and diversity of dicynodonts during this period, combined with incomplete or inadequately prepared specimens, have led to challenges in determining relationships within this taxon. Only two species, Geikia locusticeps and Geikia elginensis have been assigned to this genus. While this is the currently accepted classification, fossil record limitations have led to repeated debate on the genus assignments of these species.

<i>Aulacephalodon</i> Extinct genus of dicynodonts

Aulacephalodon is an extinct genus of medium-sized dicynodonts, or non-mammalian synapsids, that lived during late Permian period. Individuals of Aulacephalodon are commonly found in the Lower Beaufort Group of the Karoo Supergroup of South Africa. Rising to dominance during the Late Permian, Aulacephalodon was among the largest terrestrial vertebrate herbivores until its extinction at the end of the Permian. Two species have been named, the type species, A. bainii, and a second species, A. peavoti. However, debate exists among paleontologists if A. peavoti is a true member of the genus Aulacephalodon. Aulacephalodon belongs to the family Geikiidae, a family of dicynodonts generally characterized by their short, broad skulls and large nasal bosses. Sexual dimorphism has been identified in A. bainii.

<i>Kombuisia</i> Extinct genus of dicynodonts

Kombuisia is a genus of dicynodont from Early to Middle Triassic of South Africa and Antarctica. Two species were described for the genus: Kombuisia frerensis (type) and Kombuisia antarctica.

<span class="mw-page-title-main">Dicynodontoidea</span> Extinct infraorder of dicynodonts

Dicynodontoidea is an infraorder of dicynodont therapsids that includes the famous dicynodont Dicynodon, Lystrosaurus and the Triassic Kannemeyeriiformes, as well as numerous other closely related species. The name was coined by American paleontologist Everett C. Olson in 1941 as an infraorder, despite using the typical "-oidea" suffix of superfamilies, and was later redefined under a phylogenetic context in 2009 by paleontologist Christian F. Kammerer.

Syops is an extinct genus of dicynodont therapsid. The type species S. vanhoepeni was first named in 1938 as Dicynodon vanhoepeni. Fossils of the genus have been found in the Cistecephalus Assemblage Zone in the Usili Formation of the Ruhuhu Basin, Tanzania and the Upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia. Its phylogenetic placement is somewhat uncertain, with multiple different studies finding it as either a basal geikiid, rhachiocephalid a dicynodontoid more derived than the most basal genera but less derived than Lystrosauridae, or a lystrosaurid.

<span class="mw-page-title-main">Cistecephalidae</span> Extinct family of dicynodonts

Cistecephalidae is an extinct family of dicynodont therapsids from the Late Permian of South Africa, India and Zambia. It includes the genera Cistecephalus, Cistecephaloides, and Kawingasaurus. Cistecephalids are thought to have had a fossorial or burrowing lifestyle, with adaptations such as broad skulls, strong forelimbs, and squat bodies. A similar group of dicynodonts called the pylaecephalids were also fossorial, although to a lesser extent than cistecephalids. Cistecephalids showed a high level of endemism, with each of the five known species unique to a single region.

<span class="mw-page-title-main">Usili Formation</span> Geologic formation in Tanzania

The Usili Formation is a Late Permian geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Permian, including temnospondyls, pareiasaurs, therapsids and the archosauromorph Aenigmastropheus.

<span class="mw-page-title-main">Anomocephaloidea</span> Extinct clade of therapsids

Anomocephaloidea is a clade of basal anomodont therapsids related to the dicynodonts known from what is now South Africa and Brazil during the Middle Permian. It includes only two species, Anomocephalus africanus from the Karoo Basin of South Africa and Tiarajudens eccentricus from the Paraná Basin of Brazil. Anomocephaloidea was named in 2011 with the discovery of Tiarajudens, although Anomocephalus itself has been known since 1999.

<i>Bulbasaurus</i> Extinct genus of dicynodonts

Bulbasaurus is an extinct genus of dicynodont that is known from the Lopingian epoch of the Late Permian period of what is now South Africa, containing the type and only species B. phylloxyron. It was formerly considered as belonging to Tropidostoma; however, due to numerous differences from Tropidostoma in terms of skull morphology and size, it has been reclassified the earliest known member of the family Geikiidae, and the only member of the group known from the Tropidostoma Assemblage Zone. Within the Geikiidae, it has been placed close to Aulacephalodon, although a more basal position is not implausible.

<i>Thliptosaurus</i> Extinct genus of dicynodonts

Thliptosaurus is an extinct genus of small kingoriid dicynodont from the latest Permian period of the Karoo Basin in KwaZulu-Natal, South Africa. It contains the type and only known species T. imperforatus. Thliptosaurus is from the upper Daptocephalus Assemblage Zone, making it one of the youngest Permian dicynodonts known, living just prior to the Permian mass extinction. It also represents one of the few small bodied dicynodonts to exist at this time, when most other dicynodonts had large body sizes and many small dicynodonts had gone extinct. The unexpected discovery of Thliptosaurus in a region of the Karoo outside of the historically sampled localities suggests that it may have been part of an endemic local fauna not found in these historic sites. Such under-sampled localities may contain 'hidden diversities' of Permian faunas that are unknown from traditional samples. Thliptosaurus is also unusual for dicynodonts as it lacks a pineal foramen, suggesting that it played a much less important role in thermoregulation than it did for other dicynodonts.

Kembawacela is an extinct genus of cistecephalid dicynodont from the Late Permian of East Africa. The genus contains two known species, the type species Kembawacela kitchingi from the Madumabisa Mudstone Formation of Zambia described in 2019, and a second species, K. yajuwayeyi, from the Chiweta Beds of Malawi described in 2022. Like other cistecephalids, Kembawacela was specialised for a fossorial, burrowing lifestyle similar to modern day moles. It is unique amongst cistecephalids for the presence of a pair of tusks in the upper jaw, characteristic of many other dicynodonts but lost in other cistecephalids. It is likely that Kembawacela was a locally endemic species of cistecephalid in the Luangwa Basin of Zambia.

Taoheodon is an extinct genus of dicynodont therapsid from the Sunjiagou Formation in the Shanxi province of China, dated to the Wuchiapingian age of the Late Permian. Its type and only known species is T. baizhijuni. Taoheodon was a close relative of the well known Dicynodon, and may represent a biogeographical link between the South African Dicynodon and similar dicynodonts found in Laos.

References

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