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Lower Cambrian halkieriids and other coeloscleritophorans from Aksu-Wushi, Xinjiang, China

Published online by Cambridge University Press: 20 May 2016

S. Conway Morris
Affiliation:
Department of Earth Sciences, University of Cambridge, CB2 3EQ, U. K.
A. J. Chapman
Affiliation:
Department of Earth Sciences, University of Cambridge, CB2 3EQ, U. K.

Abstract

Halkieriids are known largely from isolated sclerites, although it is understood that originally they formed the scleritomes of slug-like animals in Lower Cambrian benthic environments. The Yurtus Formation (?Tommotian–Atdabanian equivalent) of the Aksu-Wushi area, west Xinjiang, China, has yielded abundant sclerites. These are secondarily phosphatized, but show considerable detail. The sclerites can be divided into three classes: cultrates, long palmates, and short palmates; definite siculates have not been recognized. In some samples elongate to semicircular shells co-occur with the sclerites; these may derive from the same halkieriid scleritome. The external surface of the shells may bear a subdued ornamentation. The concave interior, however, is remarkable on account of a unique structure consisting of a group of nodular-like units. These may be arranged in a low cone or dispersed in a small circle. In addition to the sclerites of halkieriids and their possibly associated shells, rarer material is attributable to the related group of siphogonuchitids.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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