Jianfengia: An Exceptionally Rare Arthropod from Chengjiang

Description: This unusual arthropod is known as Jianfengia multisegmentalis. The species is known from very few examples (Hou’s most recent book states about TEN), 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 specimen is a member of the “great appendage arthropods” known as the opabinids after Opabinia from the Burgess Shale Fauna. Jianfengia was the most primitive of the opabinids. Other members from Chengjiang are Alalcomeaeus and Leanchoilia. The pointed endopods are thought to have been poorly suited for walking; perhaps this one swam just above the seafloor in a search for prey. The taxon is unknown outside the Chengjiang Biota. This is a truly exceptional specimen, one that few will ever be able to hold in a collection, whether private or that of a museum.