IMMENSE Bathynotus keuichousensis Trilobite from Kaili

Description: 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, with eocinoids as the second most common fossil. It shares roughly 30 genera in common with Chengjiang and nearly 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 keuichousensis. 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 the Redlichiida. Trilobites from this timeframe were members of the Redlichiida, Ptychopariida, Corynexochida, and the Agnostida, with the balance of the orders appearing later in time. Members of this faunal assemblage are very rarely offered for sale; I have never seen a larger example offered before (see the photo comparing this monster with a normal-sized example).