- The Paleontological Society
New specimens of the arthropod Pectocaris Hou, 1999 have yielded important new information. The entire body of Pectocaris spatiosa Hou, 1999 is known. Odaraia? eurypetala Hou and Sun, 1988 is transferred to Pectocaris. In addition to the finlike lateral flukes, setal imprints and new specimen indicate a median fluke as in the Burgess Shale Odaraia. The cephalic region bears stalked eyes and the crustacean characteristics first and second antennae and mandibles. The mandibles are succeeded by about 53 pairs of branchiopod-type appendages, each corresponding to a head or body segment. Branchiopod characters include endites with setae turned backwards, the elongation of the telson, and its fluke-shaped rami. Pectocaris has a fairly basal position in the phylogenetic tree of the extant crustaceans and probably belongs to the branchiopod crustaceans. It is the first arthropod with definite crustacean characteristics described from strata from below the Upper Cambrian.