Nectocaris

Nectocaris

• Burgess Shale ( Canadian Rocky Mountains )

Nectocaris pteryx is an extinct creatures whose fossil remains have been found in Canada's Burgess Shale. The discoverer of the fossil deposit Charles Doolittle Walcott was initially only a fossil specimen, but did not find the time to describe it. This was made ​​up in 1976 by ​​Simon Conway Morris.

Morris described as strange creatures Nectocaris, which had the head and front body characteristics of arthropods, but behind those of chordates and Nectocaris could not place taxonomically.

Over the next three decades, 91 more fossil specimens of the genus were discovered. But Nectocaris only in 2010 was recognized by two scientists from the University of Toronto and the Royal Ontario Museum as basal cephalopods.

Nectocaris was a small cephalopods, which reached a length of only two to five centimeters. He had a flunderartig flattened, shell-less body with large side fins and protruding eyes. In contrast to today's cephalopod who have always eight or more tentacles, Nectocaris had only two long tentacles.

Nectocaris forms with two other Cambrian taxa, Petalilium and Vetustovermis the family of Nectocaridae, which is characterized by paired gills, an elongate, open mantle cavity, wide lateral fins, a single pair of long tentacles with a large, flexible anterior funnel and a pair of eyes. The Nectocaridae extend the stratigraphic range of the cephalopods by 30 million years into the past. The first cephalopods before the adaptive radiation housing bearing cephalopods in the Ordovician were pelagic, moving apace as she squeezed water from the mantle cavity. So far it was assumed that cephalopods are descended from slug-like molluscs that were using gas-filled enclosures able to swim in the open water.