Ophryotrocha pruittae sp. nov.

urn:lsid:zoobank.org:act: BE33115E-1B4C-405A-A425-AF518EE5E093

Fig. 8

Ophryotrocha cf. akessoni sp. 2 – Goffredi et al. 2017: supplemental, table 1.

Etymology

Named for Jessica Pruitt, an aficionada and expert on deep-sea Ophryotrocha.

Material examined

Holotype MEXICO • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); Gulf of California, Alarcón Rise, active hydrothermal vents; 23.377° N, 108.531° W; depth 2309 m; 22 Apr. 2015; Greg Rouse leg.; collecting event: ROV Doc Ricketts dive 754; GenBank: OP311761 (COI); ICML-EMU-13288, (ex SIO-BIC A13689).

Paratypes MEXICO • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for holotype; GenBank: KY701728 (16S), OP311652 (H3); SIO-BIC A6322 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14123 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14124 • 1 spec. (fixed in ethanol and most tissue used for DNA extraction); same collection data as for holotype; SIO-BIC A14125 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14126 • at least 4 specs (1 fixed in formalin, 3 individuals and additional fragments fixed in ethanol); same collection data as for holotype; SIO-BIC A14127 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14128 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14129 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14130 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14131 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14132.

Description

In life, golden color (Fig. 8A), opaque white after preservation. Body 10.5 mm long, 50+ segments of similar width through the body. Eyes not visible. Prostomium rounded, wider than long, with paired digitiform antennae inserted dorsally, paired digitiform palps inserted ventral-laterally, similar in length with antennae. Peristomium two equal rings, similar size to the following segments (Fig. 8A). Maxillae P-type, forceps comb-like, with large main large fang, fused together basally. Four rows of seven free denticles, the posterior most free denticles (D1) comb-like, similar to the forceps, other free denticles shovel-shaped with fine teeth, D2–D4 smaller than D5–D7 (Fig. 8B). Mandibles heavily sclerotized, shafts rod-like, cutting plates L-shape, anterior edge flat with pointed lateral peaks weakly sclerotized, lateral wings weakly sclerotized (Fig. 8C).

Parapodia uniramous, acicular lobe triangular with a blunt point distally, dorsal cirri cirriform, long, extend beyond distal margin of acicular lobe, ventral cirri short and stubby (Fig. 8D). Supra-acicular chaetae simple distally serrated, tapering into a large main fang, 2–5 per fascicle (Fig. 8D–E). Five to eight compound sub-acicular chaetae, with serrated blades (Fig. 8D, F). Sub-acicular chaetal lobe holds one or two simple chaetae (Fig. 8D, G). Pygidium with two short conical cirri inserted laterally (Fig. 8A).

Distribution

Only known from the Alarcón Rise vents in the southern Gulf of California at 2309 m depth.

Remarks

Ophryotrocha pruittae sp. nov. was initially reported in Goffredi et al. (2017) as Ophryotrocha cf. akessoni sp. 2 with a partial DNA sequence for mitochondrial 16S rRNA lodged on GenBank (KY701727). Ophryotrocha pruittae has a rounded prostomium, two equal segments of peristomium, digitiform antennae and palps and P-type maxillae, which are all features found in the vent-clade of Clade B. It differs from these species by having the mandibles with the L-shape cutting plates and two conical anal cirri, while O. marinae sp. nov. has triangular cutting plates and two digitiform anal cirri, O. akessoni / O. cf. akessoni has curved cutting plates, O. charlottae sp. nov. has subtriangular cutting plates and two lateral cirri and one median anal cirrus, O. kailae sp. nov. has curved cutting plates and two digitiform anal cirri (Table 3). Ophryotrocha pruittae showed four rows of maxillae. As discussed above for O. charlottae and O. marinae it is possible that the outermost pair of rows represent molted jaws as has been observed in other Ophryotrocha by Paxton (2004).