The jaw function and adaptive radiation of the dicynodont mammal-like reptiles of the Karoo basin of South Africa

Cox, C. B.

doi:10.1006/zjls.1997.0123

Cited by 12 publications

(22 citation statements)

References 20 publications

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“…The number of foramina, cavities and notches present in the skull and braincase give some evidence regarding the passage of the blood vessels and cranial nerves. Most of the blood vessels and cranial nerves postulated by various workers for other dicynodonts (Camp and Welles 1956;Cox 1959;Kemp 1969;Cluver 1971;King 1981 King , 1988 King , 1990 can be seen in E. mahalanobisi. The passage of the internal carotid artery is marked by a deep notch at the base of the basisphenoid tubera (Text- fig.…”

Section: Occipital and Otic Regionsmentioning

confidence: 96%

“…This recessed area in E. mahalanobisi skull is not very deep or large but the pseudotemporalis may have originated from the lateral surface of the epipterygoid as in Oudenodon (King 1981). Cox (1959Cox ( , 1964 considered the posteroventrally directed boss formed by the maxilla and jugal as the site of origin of strong masseter muscles in Endothiodon. There is a prominent boss in E. mahalanobisi (Text- fig.…”

Section: Areas Of Origin Of Jaw Adductor Musclesmentioning

confidence: 99%

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Endothiodont dicynodonts from the Late Permian Kundaram Formation, India

Ray

2000

Palaeontology

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ABSTRACT. The Kundaram Formation, a Lower Gondwana unit of the Pranhita-Godavari valley, contains the only known Permian dicynodonts in India. This dicynodont assemblage is dominated by Endothiodon. Two species (Endothiodon mahalanobisi sp. nov and Endothiodon uniseries Owen 1879) are described here. This is the first detailed study of Endothiodon from outside Africa. The study shows that Endothiodon jaw articulation permitted propalinal action when the opposing serrations in the upper and the lower jaw teeth occluded with the horn covered areas and helped in shearing and mastication. The presence of oblique wear facets on the upper and lower jaw teeth and a masseter-like muscle suggest a slightly lateral movement of the lower jaw which enhanced slicing of plant matter. A robust stapes with posterolateral notch constitutes the middle ear region though Endothiodon depended mainly on ground vibrations for hearing. Other features included a reduced olfactory sense and large eyes for vigilance and ease of detecting predators. Based on its vertebrate fauna, this fossiliferous Gondwana horizon of the Pranhita-Godavari valley is broadly correlated with the Tropidostoma and/or Cistecephalus Assemblage Zones of the Beaufort Group, Karoo Supergroup, South Africa. It indicates a probable Tatarian age for the Kundaram Formation.T H E dicynodonts are an extinct group of herbivorous therapsids of the Permian and Triassic periods. They diversified into numerous genera and species during the Late Permian but suffered a marked reduction in generic diversity at the onset of the Triassic. The success of these dicynodonts lay in acquiring certain unique features, particularly in their skull morphology, that helped them in adapting to herbivory. The Permian dicynodonts are mostly documented from the continents that formed Gondwana except for reports from Scotland, Russia and China.In India, the Kundaram Formation, a Lower Gondwana unit of the Pranhita-Godavari valley (Text- fig. 1A) yields the only Permian reptilian fauna (Kutty 1972;Ray 1997), though Permian fishes and amphibians are known from other Indian Gondwana basins. The vertebrate fauna of the Kundaram Formation consists of a dicynodont assemblage, dominated by Endothiodon. Other forms include Cistecephalus, Pristerodon, ?Oudenodon and Emydops-like forms. The non-dicynodont member is a captorhinid (Kutty 1972). Endothiodon is so far known from African countries like South Africa, Tanzania, Zambia and Mozambique. Some fragmentary remains of Endothiodon are also reported from Brazil. The paper presents the first detailed study of Endothiodon from outside Africa. G E O L O G I C A L S E T T I N GThe fossil material was recovered from the Kundaram Formation in the north-western part of PranhitaGodavari valley (Kutty 1972;Ray 1997) near Golet in Adilabad district, Andhra Pradesh (Text- fig. 1B). The Kundaram Formation, underlain and overlain by the Barakar and Kamthi Formations respectively (Table 1) is characterized by red mudstone, sandstone, sandstone-mudstone alternations an...

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Section: Occipital and Otic Regionsmentioning

confidence: 96%

Section: Areas Of Origin Of Jaw Adductor Musclesmentioning

confidence: 99%

Endothiodont dicynodonts from the Late Permian Kundaram Formation, India

Ray

2000

Palaeontology

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“…The triturating surface of the jaws consisted virtually exclusively of a horny beak. Cox (1998) concluded from the structure of the bony surfaces that there were three parts to the beak. A medial anterior dentary beak bit within the front margins of the palate, presumably with a cropping function.…”

Section: Eodicynodonmentioning

confidence: 99%

“…3.12(d)) has the uniquely dicynodont structure of more or less equal lateral and medial convex condyles on the quadrate and corresponding but elongated articular condyles on the lower jaw. King et al (1989) believed that the feeding mechanism of Eodicynodon had achieved the essential dicynodont arrangement but that the degree of propaliny was still less than occurred in later dicynodonts, a view reiterated by King (1994) and Cox (1998). (Rubidge 1990).…”

Section: Eodicynodonmentioning

confidence: 99%