Fuxianhuia protensa Arthropod Death Assemblage from Chengjiang

This primative arthropod is known as Fuxianhuia protensa. The species is known from several hundred examples, with this one from the most famous location of all, Maotianshan (Mao Tian Hill), site of the discovery of the Chengjiang Biota by Hou Xian-guang in 1984. The diversity of soft-tissue fossils is astonishing: algae, medusiforms, sponges, priapulids, annelid-like worms, echinoderms, arthropods (including trilobites), hemichordates, chordates, and the first agnathan fish make up just a small fraction of the total. Numerous problematic forms are known as well, some of which may have represented failed attempts at diversity that did not persist to the present day.

The systematic placement of Fuxianhuia is still under debate, with some considering it a basal euarthropod. The discoverer of the Chengjiang Biota and a coworker erected a new family and a new superclass called Proschizoramia which was characterized as a group at any early stage in the evolution of arthropods with biramous limbs. The taxon is unknown outside the Chengjiang Biota. This is an unusual death assemblage with THREE examples. The largest, most complete one is on a plane slightly higher than the other two, so they may not all have been simultaneously entombed. They certainly followed each other into death relatively quickly, however, given their articulation.