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Burgess Shale-type microfossils from the middle Cambrian Kaili Formation, Guizhou Province, China

100%

Harvey T. H. P., Ortega-Hernandez J., Lin J.-P., Yuanlong Z., Butterfield N. J.

Acta Palaeontologica Polonica

2012

tom 57

nr 2

Diverse carbonaceous microfossils, including exceptionally preserved remains of non−biomineralizing metazoans, are reported from a basal middle Cambrian interval of the Kaili Formation (Guizhou Province, China). The application of a gentle acid maceration technique complements previous palynological studies by revealing a larger size−class of acritarchs, a richer assemblage of filamentous microfossils, and a variety of previously unrecovered forms. Metazoan fossils include Wiwaxia sclerites and elements derived from biomineralizing taxa, including chancelloriids, brachiopods and hyolithids, in common with previously studied assemblages from the early and middle Cambrian of Canada. In addition, the Kaili Formation has yielded pterobranch remains and an assemblage of cuticle fragments representing “soft−bodied” worms, including a priapulid−like scalidophoran. Our results demonstrate the wide distribution and palaeobiological importance of microscopic “Burgess Shale−type” fossils, and provide insights into the limitations and potential of this largely untapped preservational mode.

Trunk ornament on the palaeoscolecid worms Cricocosmia and Tabelliscolex from the Early Cambrian Chengjiang deposits of China

100%

Han J., Liu J., Zhang Z., Zhang X., Shu D.

Acta Palaeontologica Polonica

2007

tom 52

nr 2

Cricocosmia jinningensis, one of the most abundant palaeoscolecid worms from the Lower Cambrian Chengjiang deposits of south China, was originally described as bearing double longitudinal rows of lateral conical sclerites on the trunk. New observation reveals that the ventral trunk bears an additional set of ventral sclerites while the lateral sclerites display a tubercle−bearing (inner surface) and net−like (outer surface) microstructure similar to that of Tabelliscolex hexagonus. These findings mean that: (1) Cricocosmia shows a dorso−ventral and antero−posterior differentiation in trunk ornament; (2) as seen from the microstructure, Cricocosmia is close to Tabelliscolex hexagonus, supporting the idea that lobopodians and arthropods, both of which show an upper capping layer in the outer sclerites, are more closely related than the palaeoscolecidans; and (3) the similarities among the scalids, pharyngeal teeth and the trunk spines of palaeoscolecidans are superficial. Tabelliscolex maanshanensis sp. nov., characterized by an inner concentric circlet of laminae in each tubercle of the lateral trunk plate, is proposed herein. Element mapping reveal that four known pathways of preservation can be found co−occurring in a single specimen of Cricocosmia or Tabelliscolex, which sheds new light on the preservation of the Chengjiang fossils.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Butterfield N. J.

1 Han J.

1 Harvey T. H. P.

1 Lin J.-P.

1 Liu J.

1 Ortega-Hernandez J.

1 Shu D.

1 Yuanlong Z.

1 Zhang X.

1 Zhang Z.

1 2012

1 2007

Wyniki wyszukiwania

Burgess Shale-type microfossils from the middle Cambrian Kaili Formation, Guizhou Province, China

Trunk ornament on the palaeoscolecid worms Cricocosmia and Tabelliscolex from the Early Cambrian Chengjiang deposits of China