Palaeontologia africana

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ISSN (print): 0078-8554 ISSN (electronic): 2410-4418 For queries regarding content of Palaeontologia africana collections please contact Jonah Choiniere by email : jonah.choiniere@wits.ac.za or Tel : 011 717 6684

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Author: search.filters.author.Damiani, Ross

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Now showing 1 - 5 of 5
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    Stereospondyl amphibians from the Elliot Formation of South Africa
    (Bernard Price Institute for Palaeontological Research, 1999) Warren, Anne; Damiani, Ross
    This paper documents the first members of the Chigutisauridae (Amphibia, Stereospondyli) from southern Africa and the first post-Triassic stereospondyls from that region. The material, from the Lower and Upper Elliot Formation, was associated with a diverse fauna including early mammals and dinosaurs. Most temnospondyls known to have survived the Triassic are brachyopoids, with large members of the Chigutisauridae present in the Jurassic and Cretaceous of Gondwana, and smaller members of the Brachyopidae in the Jurassic of Eurasia.
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    Barendskraal, a diverse amniote locality from the Lystrosaurus Assemblage Zone, Early Triassic of South Africa
    (Bernard Price Institute for Palaeontological Research, 2003) Damiani, Ross; Neveling, Johann; Modesto, Sean; Yates, Adam
    A diverse amniote fauna has been recovered from Lower Triassic Lystrosaurus Assemblage Zone exposures on the farm Barendskraal, near Middelburg in Eastern Cape Province, South Africa. The fauna includes the dicynodont therapsid Lystrosaurus sp., the therocephalian therapsids Tetracynodon darti, Moschorhinus kitchingi and Ericiolacerta parva, the archosauromorph reptiles Proterosuchus fergusi and Prolacerta broomi, and the procolophonoid reptiles Owenetta kitchingorum, Sauropareion anoplus and Saurodectes rogersorum. The locality is remarkable in that although it is fossil-rich, Lystrosaurus fossils do not appear to be as abundant as elsewhere in this assemblage zone, and the diversity of taxa at Barendskraal (at least nine species) is surpassed only by that of the famous HarrismithCommonage locality in the northeastern Free State province (at least 13 species). However, the fauna at Harrismith Commonage is typical of most other Lystrosaurus biozone localities in being dominated numerically by Lystrosaurus. Study of the tetrapod taxa from Barendskraal is providing new insights into procolophonoid phylogeny and survivorship across the Permo-Triassic boundary, as well as the stratigraphic ranges of various taxa in the Lower Triassic deposits of the Karoo Basin.
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    A non-mammaliaform cynodont from the Upper Triassic of South Africa: a therapsid Lazarus taxon?
    (BERNARD PRICE INSTITUTE FOR PALAEONTOLOGICAL RESEARCH, 2007) Abdala, Fernando; Damiani, Ross; Yates, Adam; Neveling, Johann
    The tetrapod record of the ‘Stormberg Group’, including the Lower Elliot Formation, in the South African Karoo is widely dominated by archosaurian reptiles, contrasting with the therapsid dominion of the subjacent Beaufort Group. The only therapsids represented by skeletal remains in the Upper Triassic Lower Elliot Formation are the large traversodontid cynodont Scalenodontoides macrodontes and the recently described tritheledontid cynodont Elliotherium kersteni. Here we present a fragmentary lower jaw that provides evidence of a third type of cynodont for the Upper Triassic of South Africa. The fossil is tentatively assigned to the Diademodontidae. The latter representative of this family is known from the Late Anisian, and its tentative record in the Norian Lower Elliot Formation, if confirmed, will represent a case of Lazarus taxon. Thus, Diademodontidae apparently disappeared from the fossil record by the end of the Anisian and then reappeared in the Norian of South Africa, a stratigraphic interval of some 21 million years. This new cynodont record, together with the recently described Tritheledontidae, show that cynodonts are now the second most diverse tetrapod group in the Lower Elliot fauna.
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    Early development of the mammalian superficial masseter muscle in cynodonts
    (BERNARD PRICE INSTITUTE FOR PALAEONTOLOGICAL RESEARCH, 2004) Abdala, Fernando; Damiani, Ross
    The masseter muscle is a hallmark of the jaw-closing mechanism of modern mammals, acting in concert with other mandibular adductor muscles to fine-tune oral food processing. The model explaining the origin of this muscle within non-mammalian therapsids involves the differentiation of a masseter-like muscle from a primitive external adductor, a downward migration of the masseter insertion on the mandible, and a division and distribution of the muscle to a condition that is similar to that in living mammals. The presence of a suborbital process of the jugal, which is interpreted as the site of origin for the superficial masseter, has been previously regarded as the earliest putative morphological evidence used to infer masseteric division. The suborbital process is first recorded in late Early Triassic (c. 245 Ma) cynognathian cynodonts. Here it is shown that primitive galesaurid cynodonts of earliest Triassic age (c. 251 Ma) display a distinct angulation of the zygomatic arch below the orbit, indicating the presence of a divided masseter amongst more basal cynodonts. This alters the timing of masseter muscle evolution by showing that the downward migration and division of the masseter occurred simultaneously, prior to the evolution of advanced cynodonts (=eucynodonts).
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    Early development of the mammalian superficial masseter muscle in cynodonts
    (Bernard Price Institute for Palaeontological Research, 2004-12) Abdala, Fernando; Damiani, Ross
    The masseter muscle is a hallmark of the jaw-closing mechanism of modern mammals, acting in concert with other mandibular adductor muscles to fine-tune oral food processing. The model explaining the origin of this muscle within non-mammalian therapsids involves the differentiation of a masseter-like muscle from a primitive external adductor, a downward migration of the masseter insertion on the mandible, and a division and distribution of the muscle to a condition that is similar to that in living mammals. The presence of a suborbital process of the jugal, which is interpreted as the site of origin for the superficial masseter, has been previously regarded as the earliest putative morphological evidence used to infer masseteric division. The suborbital process is first recorded in late Early Triassic (c. 245 Ma) cynognathian cynodonts. Here it is shown that primitive galesaurid cynodonts of earliest Triassic age (c. 251 Ma) display a distinct angulation of the zygomatic arch below the orbit, indicating the presence of a divided masseter amongst more basal cynodonts. This alters the timing of masseter muscle evolution by showing that the downward migration and division of the masseter occurred simultaneously, prior to the evolution of advanced cynodonts (=eucynodonts).