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A microvertebrate assemblage from the Early Triassic of Poland

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Borsuk-Bialynicka M., Cook E., Evans S. E., Maryanska T.

Acta Palaeontologica Polonica

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1999

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tom 44

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nr 2

167-188

The Early Triassic microvertebrate assemblage from karst deposits of Czatkowice quarry, Kraków Upland, Poland, has been dated as of latest Olenekian age at youngest. The assemblage contains mainly small reptiles: three to four possible genera of procolophonids, a small predatory archosaur of proterosuchid or pre-proterosuchid grade, a prolacertiform, and one or two genera attributable to Lepidosauromorpha, one of them, very small, being a possible stem-lepidosaurian. Furthermore there are some less numerous amphibians, including the first European salientian (stem-frog) - Czatkobatrachus polonicus Evans & Borsuk-Bialynicka, 1998, as well as fishes. The bones are disarticulated but fairly well preserved. The assemblage provides a glimpse of the Early Triassic diversity of small taxa, otherwise poorly known, and has a considerable potential in highlighting the earliest phylogeny of such groups as lepidosauromorphs and salientians which are virtually unknown from other roughly contemporaneous horizons. The Czatkowice microvertebrate community appears to have lived under the mesic conditions of a freshwater oasis with the otherwise arid circumequatorial belt of Scythm Northern Pangea.

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The scapulocoracoid of an Early Triassic stem-frog from Poland

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Borsuk-Bialynicka M., Evans S. E.

Acta Palaeontologica Polonica

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2002

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tom 47

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nr 1

The scapulocoracoid of Czatkobatrachus polonicus Evans and Borsuk−Białynicka, 1998, a stem−frog from the Early Triassic karst locality of Czatkowice (Southern Poland), is described. The overall type of scapulocoracoid is plesiomorphic, but the subcircular shape and laterally oriented glenoid is considered synapomorphic of Salientia. The supraglenoid foramen is considered homologous to the scapular cleft of the Anura. In Czatkobatrachus, the supraglenoid foramen occupies an intermediate position between that of the early tetrapod foramen and the scapular cleft of Anura. The cleft scapula is probably synapomorphic for the Anura. In early salientian phylogeny, the shift in position of the supraglenoid foramen may have been associated with an anterior rotation of the forelimb. This change in position of the forelimb may reflect an evolutionary shift from a mainly locomotory function to static functions (support, balance, eventually shock−absorption). Laterally extended limbs may have been more effective than posterolateral ones in absorbing landing stresses, until the specialised shock−absorption pectoral mechanism of crown−group Anura had developed. The glenoid shape and position, and the slender scapular blade, of Czatkobatrachus, in combination with the well−ossified joint surfaces on the humerus and ulna, all support a primarily terrestrial rather than aquatic mode of life. The new Polish material also permits clarification of the pectoral anatomy of the contemporaneous Madagascan genus Triadobatrachus.

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A stem-group frog from the Early Triassic of Poland

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Evans S. E., Borsuk-Bialynicka M.

Acta Palaeontologica Polonica

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1998

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tom 43

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nr 4

573-580

Described on the basis of disarticulated postcranial bones (vertebrae, humeri, ilia) from karst deposits of Scythian age at the locality of Czatkowice in the Kraków Upland, Poland, Czatkobatrachus polonicus gen. et sp. n. is the first salientian known from the Triassic of the Northern part of Pangea. It may be only slightly younger (about 5 MA) than Triadobatrachus massinoti (Piveteau, 1936) from Madagascar, the only Early Triassic salientian known hitherto. Czatkobatrachus resembles Triadobatrachus but is more derived in some features of the vertebrae and elbow joint. It provides evidence of a global distribution of stem-frogs at the very beginning of the Mesozoic, and suggests that the origin of the group must be sought in the Permian.

Ograniczanie wyników

3 Acta Palaeontologica Polonica

3 Borsuk-Bialynicka M.

3 Evans S. E.

1 Cook E.

1 Maryanska T.

1 2002

1 1999

1 1998

A microvertebrate assemblage from the Early Triassic of Poland

The scapulocoracoid of an Early Triassic stem-frog from Poland

A stem-group frog from the Early Triassic of Poland