Home > Nectocaris pteryx
3D animation of Nectocaris pteryx.
ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM
3D model of Nectocaris pteryx.
ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM
Reconstruction of Nectocaris pteryx.
© MARIANNE COLLINS
Nectocaris pteryx (ROM 59656) – Part (left images) and counterpart (right images). Ventral view of a complete specimen showing the funnel directed towards the front and a small trilobite in the central cavity. Specimen length (with tentacles) = 64 mm. Specimen dry – polarized light (left, and middle right), wet – polarized light (middle left, and right). Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 59658) – Part (left images) and counterpart (right images). Ventral view of a complete specimen showing well preserved fins. Specimen length (with tentacles) = 45 mm. Specimen dry – polarized light (left, and middle right), wet – polarized light (middle left, and right). Raymond Quarry.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 59660) – Part and counterpart. Ventral view of a complete specimen showing funnel. Specimen length (with tentacles) = 58 mm. Specimen wet – polarized light. Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 59661). Slab with three specimens (top image); two are complete, preserved in lateral views (close-ups of parts and counterparts below), and one is incomplete, preserved in ventral or dorsal view. Image width (top image) = 291 mm. Specimen dry – polarized light (top), wet – polarized light (all close-ups). Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 59662) – Part and counterpart. Probable dorsal view of a complete specimen showing putative mouthparts between the bases of the tentacles. Specimen length (with tentacles) = 60 mm. Specimen wet – polarized light. Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 59668) – Part (left images) and counterpart (right images). Probable dorsal view of a complete specimen showing putative mouthparts between the bases of the tentacles. Specimen length (with tentacles) = 57 mm. Specimen dry – polarized light (left, and middle right), wet – polarized light (middle left, and right). Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (ROM 60079) – Part and counterpart. Dorsal view of a complete specimen showing folded tentacles. Specimen length (with tentacles) = 45 mm. Specimen dry – polarized light. Collins Quarry on Fossil Ridge.
© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON
Nectocaris pteryx (USNM 198667) – Holotype. Side view of a small specimen. Specimen length = 19 mm. Specimen dry – direct light (left), wet – polarized light (right). Walcott Quarry
© SMITHSONIAN INSTITUTION – NATIONAL MUSEUM OF NATURAL HISTORY. PHOTOS: JEAN-BERNARD CARON
Nectocaris is regarded as an early stem-group mollusc close to the cephalopods. This stem-group also includes Vetustovermis from the Middle Cambrian Emu Bay Shale of Australia, and the Lower Cambrian Petalilium from the Chengjiang deposit in China (Smith and Caron, 2010).
Nectocaris – from the Greek nekto, “swimming,” and the Latin caris, “shrimp,” based on its original interpretation as an arthropod.
pteryx – from the Greek pteryx, “fins,” in reference to the presence of fins.
Burgess Shale and vicinity: none.
Other deposits: none.
The Walcott, Raymond and Collins Quarries on Fossil Ridge.
As with Odontogriphus, another Burgess Shale animal related to molluscs, Walcott collected the first specimen of Nectocaris between 1909 and 1924. The fossil was photographed by Walcott, and its print sat with the unidentified specimen in the Smithsonian collections until noticed and described by Simon Conway Morris in 1976. Due to the lateral compression of the fossil, his resulting reconstruction was laterally-oriented. The funnel, bent back over the front, resembled the head-shield of an arthropod, and yet the fin, folded along the top of the organism, looked much like the ray-bearing dorsal fin of a chordate. A chordate affinity was further suggested by the myomere-like appearance of the bars, and although Conway Morris did not offer a firm diagnosis, Simonetta (1988) promoted a chordate status (Insom et al., 1995).
Meanwhile, Glaessner had described Vetustovermis, based on an ill-preserved specimen from Australia’s Emu Bay Shale, and because of its segmented appearance he suggested an affinity with annelid worms (Glaessner, 1979). Other workers noted the similarity of some Chengjiang fossils to this specimen and described them as slug-like relatives of the molluscs (Chen et al., 2005). During this period, the Royal Ontario Museum had been collecting similar fossils, which Desmond Collins recognized as representatives of Nectocaris. These were eventually described as stem-group cephalopods (Smith and Caron, 2010). The relationships among members of this clade are difficult to determine, and it may require further fossil finds to establish their diversity and range. The absence of a shell in Nectocarisindicates that cephalopods, which were previously thought to have evolved later in the Cambrian from snail-like monoplacophorans, did not require a buoyant shell to start swimming, but derived their shell independently of other mollusc lineages.
The body of Nectocaris is kite-shaped and can reach up to 72 mm in length, including two flexible tentacles that extend forwards from the head, which also bears a pair of camera-type eyes on short stalks. A long, nozzle-like funnel originates under the base of the head. The main body has wide lateral fins with transverse bars; a large axial cavity contains paired gills.
Nectocaris is known from 90 specimens on Fossil Ridge, mostly from the Collins Quarry; it is rare or absent at most other Burgess Shale localities. Only two specimens, including the holotype, have been found in the Walcott Quarry.
A free-swimming predator or scavenger, Nectocaris would have fed on small prey items with its prehensile tentacles in a similar fashion to squid today. Its primary mode of propulsion would have been in the flexing of its fins; it may have supplemented this by squirting water from its funnel. The funnel was also used to inhale and exhale water, which entered the animal’s body cavity to oxygenate the large internal gills.
CHEN, J.-Y., D.-Y. HUANG AND D. J. BOTTJER. 2005. An Early Cambrian problematic fossil: Vetustovermis and its possible affinities. Proceedings of the Royal Society B: Biological Sciences, 272(1576): 2003-2007.
CONWAY MORRIS, S. 1976. Nectocaris pteryx, a new organism from the Middle Cambrian Burgess Shale of British Columbia. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 12: 703-713.
GLAESSNER, M. F. 1979. Lower Cambrian Crustacea and annelid worms from Kangaroo Island, South Australia. Alcheringa, 3(1): 21-31.
INSOM, E. A. PUCCI AND A. M. SIMONETTA. 1995. Cambrian Protochordata, their origin and significance. Bollettino di Zoologia, 62(3): 243-252.
SIMONETTA, A. M. 1988. Is Nectocaris pteryx a chordate? Bollettino di Zoologia, 55(1-2): 63-68.
SMITH, M. AND J.-B. CARON. 2010. Primitive soft-bodied cephalopods from the Cambrian. Nature, 465: 469-472.
http://www.nature.com/nature/journal/v465/n7297/full/nature09068.html