Kaili Formation

Fossil Sites

Fossils from the Kaili Formation of Guizhou Province, China

513 to 501 million years ago

Also see:
Fossil Sites
Chengjiang Maotianshan Shales
Burgess Shale


Another Perspective of the Cambrian Explosion

The Kaili Biota of Guiznou Province China, like the fantastic Chengjiang Biota of the Maotianshan Shales and Burgess Shale Fauna, is a Lagerstatte preserving 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 (some 513 to 501 million years old). 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. Trilobites and eocrinoids with hard parts that are faily easily preserved are the most common fossils, but many animals with only soft tissues are also preserved, including naraoiids, Microdictyon, Wiwaxia, and Marrella. There are 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 their rapid radiation. A second location has been found some 100 km to the southwest of the original site recently, affording additional opportunities to study this diverse faunal assemblage. 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 fossil 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. Indeed, some researchers believe that high rates of uplift and erosion led to increased deposition of fine sediments in the continental margins, making such exquisite preservation possible. As a consequence, some deem the stepwise evolution of life as more illusion than fact. Whatever the case, these and future discoveries will go a long way towards providing a clearer picture of this wonderful time in the evolution of life on earth we call the Cambrian Explosion.

Kaili Formation Fossils

Bathynotus keuichousensis Trilobite
Peronopsis Agnostid Trilobite
Sinoeocrinus Eocrinoid
Sinoeocrinus Eocrinoid
Family Eocrinidae

Kaili References