Bathynotus Trilobite from Kaili Biota

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, its age is intermediate between Changjiang and Burgess Shale Faunas. Representatives of some 110 genera are known among eveven phyla. The Kaili Biota includes both soft-bodied and skeletonized animals, and is dominated by trilobites, with eocinoids (i.e., dawn crinoids) as the second most common fossil. Kaili shares some 30 genera in common with Chengjiang and some 40 with the Burgess Shale. 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.

This trilobite is Bathynotus elongatus. Bathynotus was the patronymic genus of the Bathynotidae, a family whose ordinal status was in dispute. The members of the genus have recently been assigned to the Chengkouaspidae, a family within Order Redlichiida. Trilobites from this timeframe were members of one of only four different orders: Redlichiida, Ptychopariida, Corynexochida, or Agnostida, with the other trilobite orders appearing later in geologic time.