Maotianshan Shales fossil record. Phylum Porifera (sponges; 15 species) and Priapulida (16 species) are also well represented. Other phyla represented are Brachiopoda, Chaetognatha, Cnidaria, Ctenophora, Echinodermata, Hyolitha, Nematomorpha, Phoronida, and Chordata. Possible molluscs include "Wiwaxia" and "Nectocaris". About one in eight animals are problematic forms of uncertain affinity, some of which may have been evolutionary experiments that survived for only a brief period as benthic environments rapidly changed in the Cambrian. Chengjiang is the richest source of the lobopodia, a group including many early panarthropods, with six genera represented: "Luolishania", "Paucipodia", "Cardiodictyon"," Hallucigenia" (also known from the Burgess Shale), "Microdictyon", and "Onychodictyon".
Bacterial phyla threshold definition by Hugenholtz and Pace: Since then several other candidate phyla have been identified:) Since then a candidate phylum called Poribacteria was discovered, living in symbiosis with sponges and extensively studied. (Note: the divergence of the major bacterial lineages predates sponges) Another candidate phylum, called Tectomicrobia, was also found living in symbiosis with sponges. And "Nitrospina gracilis", which had long eluded phylogenetic placement, was proposed to belong to a new phylum, Nitrospinae. Other candidate phyla that have been the center of some studies are TM7, the genomes of organisms of which have even been sequenced (draft), WS6 and Marine