Ophryotrocha eutrophila, Wiklund, Helena, Glover, Adrian G. & Dahlgren, Thomas G., 2009

Wiklund, Helena, Glover, Adrian G. & Dahlgren, Thomas G., 2009, Three new species of Ophryotrocha (Annelida: Dorvilleidae) from a whale-fall in the North-East Atlantic, Zootaxa 2228, pp. 43-56 : 49-50

Ophryotrocha eutrophila sp. nov. ( Figs 3 A–F)

Material examined: Northern North Atlantic, coastal Skagerrak, 58° 53.1’ N; 11° 06.4’ E, female with eggs, 8 mm long, 32 chaetigers, preserved in formaldehyde from experimental tank with bone material sampled from a minke whale carcass, which was implanted at 125 m dept, holotype ( SMNH T- 7818); same location, four specimens, two males and two females, preserved in formaldehyde, paratype (NHM2009.27); same location, seven specimens preserved in formaldehyde, two specimens preserved in osmium for SEM, and several specimens preserved in ethanol for DNA extraction.

Description: Colour transparent, females with eggs distinctly larger than males ( Figs 3 A, B). Body shape elongated, of generally uniform width, tapering slightly at posterior end.

Prostomium with digitiform paired antennae inserted dorsally. Palps papilliform, inserted laterally on prostomium. No eyes. Mandibles rodlike, with anterior dentition. K-type maxillae with smooth forceps and 7 pairs of free denticles ( Fig. 3 D). Maxillae of P-type with 7 free denticles ( Fig. 3 E).

Two peristomial achaetous segments, parapodia uniramous with short dorsal and ventral cirri ( Fig. 3 F), supraacicular simple chaetae with serration distally, subacicular chaetae compound, blades with serration ( Fig. 3 C), subacicular chaetal lobe with simple chaeta.

Pygidium with terminal anus, two pygidial cirri laterally inserted and an unpaired appendage ventrally placed.

Distribution: Known from an aquarium containing bones taken from a minke whale carcass at 125 m depth (58°53.1’N; 11°06.4’E) in the Koster area in Sweden.

Reproduction: Egg masses form a tube in which the female crawl, the tube loosely attached and not covered by a hard surface like in O. labronica ( Paxton & Åkesson, 2007) . No data on the distribution of eggs or sperm among the segments of the worms.

Etymology: Ophryotrocha eutrophila is named after its habitat choice, seemingly liking organically enriched environments (eutrophic=organically enriched, philus=like).

Remarks: This species resembles O. puerilis in jaw morphology. Ophryotrocha eutrophila is dimorphic, with males commonly smaller than females and possess K-type maxillae, similar to O. puerilis . Ophryotrocha eutrophila is genetically different from O. puerilis and differs in the absence of eyes and the presence of a well developed median pygidial stylus. Ophryotrocha eutrophila is also similar to O. fabriae Paxton & Morineaux, 2009 described from a hydrothermal vent on the Mid-Atlantic Ridge. It differs from O. fabriae in the form of the mandibles. Accession numbers for DNA sequences from O. eutrophila , published on GenBank: GQ415460 (16S), GQ415475 ( COI), GQ415494 (H3).

Figures

FIGURE 3. Ophryotrocha eutrophila sp. nov., (A) live photo of male specimen, (B) live photo of smaller male and larger female, (C) SEM micrograph of chaetae, (D) light micrograph of K-type jaws, (E) light micrograph of P-type jaws, (F) light micrograph of parapodium. Scale bar in (C) is 20 µm and in (D), (E) and (F) 100 µm.