Sinoeocrinus Eocrinoid Pair from Kaili Biota

Sinoeocrinus sp.

Phylum Echinodermata, Family Eocrinidae

Geological Time: Early Middle Cambrian

Size: 65 mm by 43 mm matrix

Fossil Site: Kaili Formation, Maiobanpo Section, Taijiang County, Kaili, Guizhou Province, China

Sinoeocrinus KailiThe Kaili Biota of Guiznou Province China, like the fantastic Chengjiang and Burgess Shale Fauna, preserve some of the earliest radiations of complex life known on the planet. The formation is some 220 m in thickness and spans the Late Early to Early Middle Cambrian. As such it is intermediate in age between the Changjiang and Burgess Shale Faunas. Representatives of some 110 genera are known, representing 11 phyla. The Kaili Biota includes both soft-bodied and skeletonized animals, and is dominated by trilobites. It shares roughly 30 genera in common with Chengjiang and nearly 40 with the Burgess Shale. There are also a number of eocrinoid Echinoderms, with three members of the gogiid genus Sinoeocrinus predominating. The Echinoderms remained a modest component of the Cambrian biota until favorable environmental shifts allowed for a rapid radiation. Many appear to have had no holdfast for anchoring to the seafloor. When hard substrates became more common, the eocrinoids were able to exploit their advantage. The rapid rise of the echinoderms that occurred during the Ordovician included the appearance of the first true crinoids.

This eocrinoid is one of the basal progenitors of the Echinoderm radiation in the Cambrian. The presence of Burgess Shale–like fauna over a large part of southwestern China shows that the faunal community was quite cosmopolitan in nature, indicating that preservation was more of a factor in finding these concentrations of animals than was the existence of isolated communities suitable for harboring these myriad life forms.

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