Clam Worms

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

Description: The polychaete Nereis gracilis (Hansen, 1878). This motile species is known exclusively from deep waters (range 930-2222 m) and has been recorded from the deeper parts of the Norwegian Sea, the Laptev Sea and probably the Sea of Beaufort. As with many deep-sea species very little is known about its biology. Nereis gracilis is likely to be an omnivorous scavenger with the specimen from Dalsnuten being approximately 15 cm long. Item Type: Image Title: Nereis gracilis Copyright: SERPENT project Species: Nereis gracilis Behaviour: Motile and likely to be an omnivorous scavenger Site: Atlantic -- Norwegian -- Dalsnuten Site Description: Seafloor Depth (m): 1452 Latitude: 66 deg 34' 33" N Longitude: 3 deg 32' 46" E Countries: Norway -- Norwegian Sector Habitat: Benthic Rig: Aker Barents Project Partners: Shell, Aker Drilling, Oceaneering ROV: Magnum 142 Deposited By: Miss Moira MacLean Deposited On: 23 February 2011

Figure 5.Nereis eugeniae Kinberg, 1865 (after Ehlers 1897): A anterior end, dorsal view B chaetiger 12 C chaetiger 37 D neuropodial heterogomph spiniger, posterior chaetiger E neuropodial heterogomph falciger, posterior chaetiger.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

Nereidid larvae are usually found at the 3-4 chaetiger stage in our samples. They have visible antennae and tentacular cirri projecting from the sides of the head, as well as a pair of anal cirri. The parapodia are well-developed and there are usually dark or reddish spots visible at the bases of two adjacent pairs, as shown above. This is presumably Nereis sandersi Blake, the only nereidid at 9°N.

Nereidid larvae are usually found at the 3-4 chaetiger stage in our samples. They have visible antennae and tentacular cirri projecting from the sides of the head, as well as a pair of anal cirri. The parapodia are well-developed and there are usually dark or reddish spots visible at the bases of two adjacent pairs, as shown above. This is presumably Nereis sandersi Blake, the only nereidid at 9°N.

Nereidid larvae are usually found at the 3-4 chaetiger stage in our samples. They have visible antennae and tentacular cirri projecting from the sides of the head, as well as a pair of anal cirri. The parapodia are well-developed and there are usually dark or reddish spots visible at the bases of two adjacent pairs, as shown above. This is presumably Nereis sandersi Blake, the only nereidid at 9°N.

The prostomium (right) has two antennae and two large, two-segmented palps. The peristomium (segment behind the prostomium) has 4 pairs of tentacular cirri. This photo is a 3d composite made from a series of photos using a Keyence digital microscope. Photo by Dave Cowles, July 2009

This dorsal view of the posterior body shows the prominent, straplike ligules with attached terminal cirrus which are characteristic of this species.

This dorsal view of the parapodia shows the small aciculae with larger ventral and even larger dorsal lobes (ligules).

Most of the setae are compound (composed of more than one segment). Closer examination by compound microscope would show this to be a homogomph falcigerous seta. A falciger is a seta in which the tip is comparatively blunt and curved. A homogomph seta is a compound seta in which the basal segment ends in a slightly expanded capsule, the two sides of which are of approximately equal height (as opposed to heterogomph, in which one side of the capsule is extended well out past the other).

Nereis vexillosa, about 24 cm long, found at Padilla Bay. (Photo by: Dave Cowles, July 2009 )

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

Randers Fjord