Juvenile Sinoeocrinus Eocrinoid from Kaili Biota
Time: Early Middle Cambrian
size is 20 mm across by 8 mm tall on a 50 mm by 52 mm matrix
Kaili Formation, Maiobanpo Section, Taijiang County, Kaili, Guizhou Province,
The 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 seem to
have had no holdfast to anchor them to the substrate. 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
eocrinoid is one of the basal progenitors of that Echinoderm radiation.
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. Members of this faunal assemblage are very rarely offered
for sale; the items I am offering now represent only the second
time I have been able to secure any examples.
fossil pictures to enlarge