Three new species of Ophryotrocha (Annelida: Dorvilleidae) from a whale-fall in the North-East Atlantic
Author
Wiklund, Helena
Author
Glover, Adrian G.
Author
Dahlgren, Thomas G.
text
Zootaxa
2009
2228
43
56
journal article
10.5281/zenodo.190259
b75bbaf2-5c4f-4224-92dc-89492eddbb04
1175-5326
190259
Ophryotrocha scutellus
sp. nov.
(
Figs 1
A–D)
Material examined: Northern North Atlantic, coastal Skagerrak,
58° 53.1’ N
;
11° 06.4’ E
, female with eggs,
6 mm
long, 29 chaetigers, preserved in formaldehyde from experimental tank with bone material sampled from a minke whale carcass, which was implanted at
125 m
depth,
holotype
(
SMNH
T-
7816); same location,
2 specimens
, preserved in formaldehyde,
paratypes
(NHM2009.25); same location, one specimen preserved in osmium for SEM, and several specimens preserved in ethanol for
DNA
extraction. Fishfarm in Mele, Hardangerfjord,
60°21.27’N
;
6°20.89’E
,
104 m
depth, several specimens preserved in formalin.
Description: Body shape elongated, uniform width for majority of body length, tapering slightly at posterior end. Colour transparent, with white eggs visible in females. (
Fig. 1
A).
Prostomium round and dorso-ventrally flattened, disc-like. Eyes lacking. Long cirriform paired antennae inserted dorsally, reaching to first chaetiger, equally long palps cirriform inserted lateroventrally on prostomium. Jaws of P-type, mandibles rod-like without any serration. Maxillae with seven pairs of free denticles (
Fig. 1
B).
Two peristomial achaetous segments. Parapodia uniramous with long dorsal and ventral cirri and cirriform acicular lobe, supraacicular chaetae simple, subacicular chaetae compound with serrated blades (
Figs 1
C–D). Subacicular chaetal lobe with simple chaeta.
FIGURE 1.
Ophryotrocha scutellus
sp. nov.
, (A) live photo, (B) light micrograph of jaws, (C) light micrograph of parapodium, (D) SEM micrograph of chaetae. Scale bars in (B) and (C) are 100 µm, in (D) 20 µm.
Pygidium with terminal anus, two pygidial cirri as long as antennae and palps laterally and a short, nublike unpaired appendage ventrally.
Distribution: Known from a minke whale carcass at
125 m
depth (
58°53.1’N
;
11°06.4’E
) in the Koster area in
Sweden
, and from sediment sampled at
104 m
depth beneath a fish farm in Hardangerfjord (
60°21.27’N
;
6°20.89’E
) in
Norway
.
Reproduction: Eggs present in females from chaetiger 5 and in all segments to posterior end of body. No data available on the presence of sperm.
Ecology: Live observation in aquarium experiments show adult specimens crawling on filamentous bacterial mats on the whale bones, and bacterial pellets are present in the worms guts, indicative of a bacterial diet.
Etymology:
Ophryotrocha scutellus
is named after its flattened disc-like head, scutella is the latin word for flat dish or saucer.
Remarks:
Ophryotrocha scutellus
has a rounded dorso-ventrally flattened head-form, shaped like a disc. Another
Ophryotrocha
that is reported to have flattened prostomium is
O
. platykephale
, from which
O
. scutellus
differs in jaw morphology, form of parapodia and absence of branchiae. Accession numbers for
DNA
sequences from
O
. scutellus
,
published on GenBank:
GQ415469
(16S),
GQ415488
(
COI
),
GQ415506
(H3).