Ophryotrocha vellae, Paxton, Hannelore & Åkesson, Bertil, 2010

Paxton, Hannelore & Åkesson, Bertil, 2010, The Ophryotrocha labronica group (Annelida: Dorvilleidae) — with the description of seven new species, Zootaxa 2713, pp. 1-24 : 12-13

publication ID	https://doi.org/ 10.5281/zenodo.199650
DOI	https://doi.org/10.5281/zenodo.6207391
persistent identifier	https://treatment.plazi.org/id/03D50762-FFDC-FF89-DFF8-F90BBA8BAA77
treatment provided by	Plazi
scientific name	Ophryotrocha vellae
status	sp. nov.

Treatment

Ophryotrocha vellae View in CoL sp. nov.

Figure 1 View FIGURE 1 F, 2C, E, 4C, 4F; Table 1

Ophryotrocha obscura nom. nud. Pleijel & Eide, 1996: 648; Dahlgren et al. 2001. Ophryotrocha Sanya View in CoL sp. 2 Dahlgren et al., 2001; Heggøy et al. 2007.

Material examined. Type material: Holotype (AM W36884), complete female specimen, 3.8 mm long, 0.40 mm wide without parapodia (preserved) for 19 chaetigers; allotype (AM W36885) complete male specimen, 1.7 mm long, 0.20 mm wide without parapodia (preserved) for 17 chaetigers; 10 paratypes (AM W36886); 10 paratypes ( SMNH T- 8034); cultured from specimens collected at Sanya, South Hainan, China, in 1995. Other material: Live cultures from same collection.

Description. Length of most live adults 3–4 mm (13–15 chaetigers), maximum length 5 mm (20 chaetigers). Live animals ( Fig. 1 View FIGURE 1 F) translucent, preserved opaque white. Pigmentation consisting of very small lateral red spots on some chaetigers. Prostomium ( Fig. 2 View FIGURE 2 C) anteriorly rounded, with pair of short ovate antennae; palps absent; two eyes medially connected; four nuchal organs ( Fig. 2 View FIGURE 2 C, E). Two peristomial achaetous segment-like rings.

Parapodia uniramous ( Fig. 2 View FIGURE 2 F), lacking dorsal and ventral cirri, with dorsal protrusion, with retractile ventral lobe; 2–3 supra-acicular simple chaetae, 3–4 subacicular heterogomph falcigers and inferiormost simple chaeta; distal part of simple chaetae and blades of falcigers coarsely serrated. Pair of pygidial cirri present, pygidial median stylus absent in adults. Rosette glands ( Fig. 4 View FIGURE 4 C), one per segment, present middorsally on posteriormost segments of mature animals, up to six in males four in females.

Mandibles with elongate shafts and bifid serrated cutting plates with 23–27 tiny pointed teeth at anterior edge. Maxillary apparatus of P- and K-type in both sexes, with falcate P-1-forceps, bidentate P2-forceps, Kforceps right bidentate, left falcate.

Reproduction and development. Gonochoristic; chromosomes 2n = 6; diameter of eggs 110 µm; released larvae without parapodia, with long pygidial median stylus; stylus subsequently lost ( Fig. 4 View FIGURE 4 F).

Etymology. This species is named in honour of Ms. Nicole Vella, in gratitude for her assistance with SEM and photography.

Remarks. The type material results from a strain collected in 1995, named ‘ O. Sanya sp. 2’, cultured and subsequently identified as a new species through crossbreeding experiments with other members of the O. labronica group. At that time the culture of O. obscura nom. nud., discovered in 1978 in a pet store aquarium in Gothenburg, Sweden, with no indication of its origin, had already perished, preventing any crosses between these two strains. Molecular studies of the mitochondrial 16S gene demonstrated that the investigated sequence in O. obscura nom. nud. and O. Sanya sp. 2 was identical ( Dahlgren et al. 2001). This demonstrated that the two strains are members of the same species which is here described as O. vellae .

Ophryotrocha vellae is closely related to O. labronica , O. costlowi and O. permanae and cannot be morphologically distinguished from these species. The only difference we could establish is that the diameter of O. vellae eggs is only 110 µm, while it is 120–130 in the other three species.

Distribution. East China Sea: Sanya, Hainan.