Nectocaris

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Nectocaris
Nectocaris

Nectocaris

Temporal occurrence
Middle Cambrian
505 to 500 million years
Locations
Systematics
Primordial mouths (protostomia)
Lophotrochozoa
Molluscs (mollusca)
Cephalopods (cephalopoda)
Nectocaridae
Nectocaris
Scientific name
Nectocaris
Morris , 1976

Nectocaris pteryx is an extinct living creature whose fossil remains have been found in Canadian Burgess Shale . The discoverer of the fossil site, Charles Doolittle Walcott , initially found only one fossil specimen, but did not find the time to describe it. This was onlymade up forin 1976 by Simon Conway Morris .

Morris described Nectocaris as a strange creature that had arthropod features on the head and front body , but those of chordates on the back, and could not classify Nectocaris taxonomically.

In the following three decades, 91 more fossil specimens of the genus were discovered. But it wasn't until 2010 that Nectocaris was recognized as a basal cephalopod by two scientists from the University of Toronto and the Royal Ontario Museum .

Nectocaris was a small cephalopod that only reached a length of two to five centimeters. It had a flounder-like, flattened, housing-less body with large side fins and stalk eyes. In contrast to today's cephalopods, which always have eight or more tentacles, Nectocaris only had two long tentacles.

Nectocaris forms with two other Cambrian taxa, Petalilium and Vetustovermis, the family of the Nectocaridae , which is characterized by paired gills, an elongated, open mantle cavity , broad lateral fins, a single pair of long tentacles with a large, flexible front funnel and a pair of eyes. The Nectocaridae extend the fossil tradition of cephalopods by 30 million years into the past. The first cephalopods before the adaptive radiation of shell -bearing cephalopods in the Ordovician were pelagic and moved by forcing water out of the mantle cavity. It has previously been assumed that cephalopods are descended from snail-like molluscs that were able to swim in open water with the help of gas-filled shells.

literature

  • Martin R. Smith, Jean-Bernard Caron: Primitive soft-bodied cephalopods from the Cambrian. In: Nature . No. 465, 2010, pp. 469-472, doi : 10.1038 / nature09068 .
  • Martin R. Smith: Nectocaridid ​​ecology, diversity and affinity: early origin of a cephalopod-like body plan. In: Paleobiology. Vol. 39, No. 2, 2013, ISSN  0094-8373 , pp. 291-321, doi : 10.1666 / 12029 .

Web links

Commons : Nectocaris  - collection of images, videos and audio files