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1
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The origins of the cochlea and impedance matching hearing in synapsids

100%
Laaß M.
Acta Palaeontologica Polonica
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2016
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tom 61
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nr 2
The origin of tympanic hearing in early synapsids is still controversial, because little is known about their inner ear and the function of their sound conducting apparatus. Here I describe the earliest known tympanic ear in the synapsid lineage, the ear of Pristerodon (Therapsida, Anomodontia) from the Late Permian of South Africa, which was virtually reconstructed from neutron tomographic data. Although Pristerodon is not a direct ancestor of mammals, its inner ear with distinctive cochlear cavity represents a connecting link between the primitive therapsid inner ear and the mammalian inner ear. The anatomy of the sound conducting apparatus of Pristerodon and the increased sound pressure transformer ratio points to a sensitivity to airborne sound. Furthermore, the origins of the cochlea and impedance matching hearing in synapsids coincided with the loss of contact between head and substrate, which already took place at least in Late Permian therapsids even before the postdentary bones became detached from the mandible.
2
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Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

80%
Voigt S., Ganzelewski M.
Acta Palaeontologica Polonica
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2010
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tom 55
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nr 1
Ichnotaxonomic revision of two extended sequences of large tetrapod footprints from the Westphalian A Bochum Formation of western Germany suggests assignment of the specimens to the well−known Permo−Carboniferous ichnogenera Ichniotherium and Dimetropus. Trackway parameters and imprint morphology strongly support basal diadectomorphs and “pelycosaurian”−grade synapsid reptiles, respectively, as the most likely trackmakers. The ichnofossils thereby extend the first appearance of these two important groups of basal tetrapods by about 5–10 million years, to the early Late Carboniferous, which is in accordance with the minimum age for the evolutionary origin of the clades following widely accepted phylogenetic analyses. These trackways provide not only direct evidence bearing on activity and behaviour of large terrestrial tetrapods close to the origin of amniotes, but also serve as a valuable benchmark for the assessment of controversially interpreted vertebrate tracks from other localities of similar age.
3
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Modes of ventilation in early tetrapods: costal aspiration as a key feature of amniotes

80%
Janis C. M., Keller J. C.
Acta Palaeontologica Polonica
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2001
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tom 46
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nr 2
The key difference between amniotes (reptiles, birds and mammals) and anamniotes (amphibians in the broadest sense of the word) is usually considered to be the amniotic egg, or a skin impermeable to water. We propose that the change in the mode of lung ventilation from buccal pumping to costal (rib-based) ventilation was equally, if not more important, in the evolution of tetrapod independence from the water. Costal ventilation would enable superior loss of carbon dioxide via the lungs: only then could cutaneous respiration be abandoned and the skin made impermeable to water. Additionally efficient carbon dioxide loss might be essential for the greater level of activity of amniotes. We examine aspects of the morphology of the heads, necks and ribs that correlate with the mode of ventilation. Anamniotes, living and fossil, have relatively broad heads and short necks, correlating with buccal pumping, and have immobile ribs. In contrast, amniotes have narrower, deeper heads, may have longer necks, and have mobile ribs, in correlation with costal ventilation. The stem amniote Diadectes is more like true amniotes in most respects, and we propose that the changes in the mode of ventilation occurred in a stepwise fashion among the stem amniotes. We also argue that the change in ventilatory mode in amniotes related to changes in the postural role of the epaxial muscles, and can be correlated with the evolution of herbivory.
4
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A new discosauriscid seymouriamorph tetrapod from the Lower Permian of Moravia, Czech Republic

80%
Klembara J.
Acta Palaeontologica Polonica
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2005
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tom 50
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nr 1
A new genus and species, Makowskia laticephala gen. et sp. nov., of seymouriamorph tetrapod from the Lower Permian deposits of the Boskovice Furrow in Moravia (Czech Republic) is described in detail, and its cranial reconstruction is presented. It is placed in the family Discosauriscidae (together with Discosauriscus and Ariekanerpeton) on the following character states: short preorbital region; rounded to oval orbits positioned mainly in anterior half of skull; otic notch dorsoventrally broad and anteroposteriorly deep; rounded to oval ventral scales. Makowskia is distinguished from other Discosauriscidae by the following characters: nasal bones equally long as broad; interorbital region broad; prefrontalpostfrontal contact lies in level of frontal mid−length (only from D. pulcherrimus); maxilla deepest at its mid−length; suborbital ramus of jugal short and dorsoventrally broad with long anterodorsal−posteroventral directed lacrimal−jugal suture; postorbital anteroposteriorly short and lacks elongated posterior process; ventral surface of basioccipital smooth; rows of small denticles placed on distinct ridges and intervening furrows radiate from place immediately laterally to articular portion on ventral surface of palatal ramus of pterygoid (only from D. pulcherrimus); oblique anterior margin of transverse flange of pterygoid directed anteromedially−posterolaterally; cultriform process of parasphenoid relatively short and slightly rounded; ventral surface of the posterior plate of parasphenoid heavily sculptured (only from D. pulcherrimus and Ariekanerpeton); distal ends of fourth and fifth presacral ribs distinctly anteroposteriorly broadened, and extend into the hook−like, posteriorly directed processes; shaft of ?last caudal rib anteroposteriorly broadened; posterior stem of interclavicle narrows anteriorly and posteriorly from broadened mid−length section.
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