Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Tommotiida

Sortuj według:

Ogranicz wyniki do:

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

The tommotiid Camenella reticulosa from the Early Cambrian of South Australia: morphology, scleritome reconstruction, and phylogeny

100%

Skovsted C. B., Balthasar U., Brock G. A., Paterson J. R.

Acta Palaeontologica Polonica

2009

tom 54

nr 3

525-540

The tommotiid Camenella reticulosa is redescribed based on new collections of well preserved sclerites from the Arrowie Basin (Flinders Ranges), South Australia, revealing new information concerning morphology and microstructure. The acutely pyramidal mitral sclerite is described for the first time and the sellate sclerite is shown to be coiled through up to 1.5 whorls. Based on Camenella, a model is proposed by which tommotiid sclerites are composed of alternating dense phosphatic, and presumably originally organic−rich, laminae. Camenella is morphologically most similar to Lapworthella, Kennardia, and Dailyatia, and these taxa are interpreted to represent a monophyletic clade, here termed the “camenellans”, within the Tommotiida. Potential reconstructions of the scleritome of Camenella are discussed and although a tubular scleritome construction was recently demonstrated for the tommotiids Eccentrotheca and Paterimitra, a bilaterally symmetrical scleritome model with the sclerites arranged symmetrically on the dorsal surface of a vagrant animal can not be ruled out.

The oldest brachiopods from the lower Cambrian of South Australia

100%

Topper T. P., Holmer L. E., Skovsted C. B., Brock G. A., Balthasar U., Larsson C. M., Stolk S. P., Harper D. A. T.

Acta Palaeontologica Polonica

2013

tom 58

nr 1

The morphology and organophosphatic shell structure of the paterinate brachiopod Askepasma is documented using new and previously collected specimens from the lower Cambrian of South Australia. Lack of adequately preserved material has seen the majority of paterinate specimens previously reported from South Australia referred to the genus Askepasma and treated under open nomenclature. Large collections of paterinates from the lower Cambrian Wilkawillina, Ajax, and Wirrapowie limestones in the Arrowie Basin, South Australia have prompted redescription of the type species Askepasma toddense and the erection of a new species, Askepasma saproconcha sp. nov. Askepasma saproconcha sp. nov. currently represents the oldest known brachiopod from the lower Cambrian successions in South Australia with a FAD in pre−trilo− bitic (Terreneuvian, Cambrian Stage 2, lower Atdabanian) strata in the basal part of the Wilkawillina and Wirrapowie limestones. Askepasma toddense predominantly occurs in Abadiella huoi Zone equivalent strata (Unnamed Cambrian Se− ries 2, Stage 3, middle–upper Atdabanian) in the upper part of the lower Wilkawillina, Wirrapowie, and Ajax limestones. The shell microstructure of Askepasma suggests a proximal stem group position within the Brachiopoda and similarities with tommotiid taxa provides further evidence that the ancestry of crown group brachiopods is firmly entrenched within the Tommotiida.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Balthasar U.

2 Brock G. A.

2 Skovsted C. B.

1 Harper D. A. T.

1 Holmer L. E.

1 Larsson C. M.

1 Paterson J. R.

1 Stolk S. P.

1 Topper T. P.

1 2013

1 2009

Wyniki wyszukiwania

The tommotiid Camenella reticulosa from the Early Cambrian of South Australia: morphology, scleritome reconstruction, and phylogeny

The oldest brachiopods from the lower Cambrian of South Australia