New insights into the biology of the Permian genus<i>Cistecephalus</i>(Therapsida, Dicynodontia)

Nasterlack, Tobias; Canoville, Aurore; Chinsamy, Anusuya

doi:10.1080/02724634.2012.697410

Cited by 36 publications

(46 citation statements)

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“…Huene (1942), Cox (), and Cluver () already observed the tapering shape of the skull of Kawingasaurus with broad occipital region and flattened snout. Similar broad, box‐like skulls also occur in closely related members of the Cistecephalidae such as Cistecephalus and Cistecephaloides and were believed to be functionally associated with digging (Keyser, ; Cluver, ; Cluver, ; Nasterlack et al, ). This interpretation is supported by the similar shapes of the skulls of modern fossorial rodents (Agrawal, ; Samuels and Valkenburgh, ), amphisbaenians (Rose and Emry, ), which also use their head for digging.…”

Section: Resultsmentioning

confidence: 93%

Bone‐conduction hearing and seismic sensitivity of the late permian anomodontKawingasaurus fossilis

Laaß

2014

Journal of Morphology

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An investigation of the internal cranial anatomy of the anomodont Kawingasaurus from the Upper Permian Usili Formation in Tanzania by means of neutron tomography revealed an unusual inner and middle ear anatomy such as extraordinarily inflated vestibules, lateroventrally orientated stapes with large footplates, and a small angle between the planes of the anterior and lateral semicircular canals. The vestibule has a volume, which is about 25 times larger than the human vestibule, although Kawingasaurus has only a skull length of approximately 40 mm. Vestibule inflation and enlarged stapes footplates are thought to be functionally correlated with bone-conduction hearing; both morphologies have been observed in fossorial vertebrates using seismic signals for communication. The firmly fused triangular head with spatulate snout was probably used for digging and preadapted to seismic signal detection. The quadrate-quadratojugal complex was able to transmit sound from the articular to the stapes by small vibrations of the quadrate process, which formed a ball and socket joint with the squamosal. Mechanical considerations suggest that the ventrolaterally orientated stapes of Kawingasaurus was mechanically better suited to transmit seismic sound from the ground to the fenestra vestibuli than a horizontal orientated stapes. The low sound pressure level transformer ratio of 2-3 in Kawingasaurus points to a seismic sensitivity of the middle ear and a vestigial or reduced sensitivity to airborne sound. Three hypothetical pathways of bone conduction in Kawingasaurus are discussed: 1) sound transmission via the spatulate snout and skull roof to the otic capsules, 2) relative movements resulting from the inertia of the mandible if sound is percepted with the skull, and 3) bone conduction from the substrate via mandible, jaw articulation, and stapes to the inner ear.

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Section: Resultsmentioning

confidence: 93%

Bone‐conduction hearing and seismic sensitivity of the late permian anomodontKawingasaurus fossilis

Laaß

2014

Journal of Morphology

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“…In terrestrial taxa, long bones display a compact cortex surrounding a well‐differentiated medullary cavity, generally devoid of bone trabeculae. This tubular structure has long been considered to be the ancestral state of the appendicular skeleton in the amniotes (Francillon‐Vieillot et al ., ), although fossils of Permian amniotes raise doubts about this statement because they often display an extensive medullary spongiosa (Canoville & Laurin, ; Nasterlack, Canoville & Chinsamy, ). Conversely, most aquatic taxa lack a free medullary cavity, which is replaced either by a spongiosa of variable compactness, or by entirely compact tissues, yielding amedullary bones (Fawcett, ).…”

Section: Introductionmentioning

confidence: 99%

Microanatomy of the amniote femur and inference of lifestyle in limbed vertebrates

Quemeneur

Buffrénil

Laurin

2013

Biol J Linn Soc Lond

100

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The femoral microanatomy of 155 species of extant amniotes (57 species of mammals, 15 species of turtles, 56 species of lepidosaurs, and 27 species of birds) of known lifestyle is studied to demonstrate a possible link between some basic parameters of bone structure and specific lifestyles, as well as phylogenetic relationships between taxa. Squared change parsimony with random taxon reshuffling and pairwise comparisons reveal that most compactness and size parameters exhibit both phylogenetic and ecological signals. A discriminant analysis produces several inference models, including a ternary model (aquatic, amphibious, terrestrial) that yield the correct lifestyle in 88% of the cases. These models are used to infer the lifestyle of three extinct Permian temnospondyls: Eryops megacephalus, Acheloma dunni, and Trimerorhachis insignis. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 644–655.

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“…The NMT were among the first terrestrial tetrapods to have a wide variety of body sizes and to adapt to various types of locomotion, from a sprawling to parasagittal posture [Kemp, 2005;Fröbisch, 2006], and exploit a variety of ecological niches, from arboreal to subterranean [Smith, 1987;Fröbisch and Reisz, 2009;Nasterlack et al, 2012]. Their fossils are found today on every continent, including Antarctica [Kitching et al, 1972;Colbert and Kitching, 1981].…”

Section: Eq In Early Therapsidamentioning

confidence: 99%

Endocranial Casts of Pre-Mammalian Therapsids Reveal an Unexpected Neurological Diversity at the Deep Evolutionary Root of Mammals

Benoît

Fernández²,

Manger³

et al. 2017

Brain Behav Evol

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The origin and evolution of the mammalian brain has long been the focus of scientific enquiry. Conversely, little research has focused on the palaeoneurology of the stem group of Mammaliaformes, the Permian and Triassic non-mammaliaform Therapsida (NMT). This is because the majority of the NMT have a non-ossified braincase, making the study of their endocranial cast (sometimes called the “fossil brain”) problematic. Thus, descriptions of the morphology and size of NMT endocranial casts have been based largely on approximations rather than reliable determination. Accordingly, here we use micro-CT scans of the skulls of 1 Dinocephalia and 3 Biarmosuchia, which are NMT with a fully ossified braincase and thus a complete endocast. For the first time, our work enables the accurate determination of endocranial shape and size in NMT. This study suggests that NMT brain size falls in the upper range of the reptilian and amphibian variation. Brain size in the dicynodont Kawingasaurus is equivalent to that of early Mammaliaformes, whereas the Dinocephalia show evidence of a secondary reduction of brain size. In addition, unlike other NMT in which the endocast has a tubular shape and its parts are arranged in a linear manner, the biarmosuchian endocast is strongly flexed at the level of the midbrain, creating a near right angle between the fore- and hindbrain. These data highlight an unexpected diversity of endocranial size and morphology in NMT, features that are usually considered conservative in this group.

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New insights into the biology of the Permian genusCistecephalus(Therapsida, Dicynodontia)

Cited by 36 publications

References 50 publications

Bone‐conduction hearing and seismic sensitivity of the late permian anomodontKawingasaurus fossilis

Bone‐conduction hearing and seismic sensitivity of the late permian anomodontKawingasaurus fossilis

Microanatomy of the amniote femur and inference of lifestyle in limbed vertebrates

Endocranial Casts of Pre-Mammalian Therapsids Reveal an Unexpected Neurological Diversity at the Deep Evolutionary Root of Mammals

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