Nectocaris, a Cephalopod-like Animal from the Burgess Shale  

Nectocaris pteryx was originally described with arthropod-like and chordate-like characters, on the basis of one obliquely preserved specimen from the Walcott Quarry.  91 new specimens from the Burgess Shale permit a re-interpretation of this enigmatic creature. 

The predatory animal had a cephalic “nozzle” connected to a large body cavity.  Upon entering this cavity through two anterior openings, water was passed through a pair of internal gills into a central canal; it was subsequently exhaled through the flexible nozzle.  This exhalent flow would have resulted in a jet of water which could be used in propulsion.  This system of organs is strongly reminiscent of the modern cephalopods, and Nectocaris shares further characters with this group: it possesses the earliest known camera-type eyes, and a pair of long, flexible tentacles (which were probably used to manipulate prey). The extent of its unmineralized dorsal integument resembles the span of the shell in early larval stages of modern Nautilus.

The currently accepted theory of cephalopod evolution suggests that they originated from a benthic chambered monoplacophoran-like ancestor, which became buoyant and then nektonic.  Nectocaris, which extends the record of cephalopod-like organisms from the Late to Middle Cambrian, is strongly dissimilar from the ancestral cephalopod which such a model would predict.