Ophryotrocha marinae, Zhang & Zhou & Yen & Hiley & Rouse, 2023

Zhang, Dongsheng, Zhou, Yadong, Yen, Nicole, Hiley, Avery S. & Rouse, Greg W., 2023, Ophryotrocha (Dorvilleidae, Polychaeta, Annelida) from deep-sea hydrothermal vents, with the description of five new species, European Journal of Taxonomy 864, pp. 167-194 : 181-185

Ophryotrocha marinae sp. nov.

urn:lsid:zoobank.org:act:5B66661D-DDF9-425D-860F-412872058C27

Figs 6–7

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

Ophryotrocha cf. akessoni – Salcedo et al. 2019: 6, table 1.

Etymology

Named in honor of Marina McCowin for her dedication in the study of the fauna associated with seeps and vents. Marina has studied Siboglinidae and Ophryotrocha marinae sp. nov. was notable for being associated in large numbers with the tubes of Oasisia alvinae Jones, 1985 ( Fig. 6A ).

Material examined

Holotype MEXICO • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); Gulf of California, Pescadero Basin , active hydrothermal vents; 23.960° N, 108.863° W; depth 3676–3756 m; 18 Apr. 2015; Greg Rouse leg.; collecting event: ROV Doc Ricketts dive 750 (specimens associated with tubes of Oasisia alvinae ); GenBank: OP311750 (COI);, ICML-EMU-13289 , (ex SIO-BIC A14109).

Paratypes MEXICO • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for holotype; GenBank: OP311749 (COI), KY701727 (16S), OP311651 (H3); SIO-BIC A6308 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for holotype; GenBank: OP311755 (COI); SIO-BIC A14108 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for holotype; GenBank: OP311751 (COI); SIO-BIC A14110 • 1 spec. (fixed in ethanol); same collection data as for holotype; SIO-BIC A14111 • ca 35 specs (10 fixed in formalin, ca 25 fixed in ethanol); same collection data as for holotype; SIO-BIC A14112 . • 11 specs (5 fixed in paraformaldehyde / glutaraldehyde, 6 fixed in ethanol); Gulf of California, Pescadero Basin , Auka Vent Field, region of P Vent and Z Vent ; 23.96° N, 108.86° W; depth 3648–3671 m; 3 Nov. 2021; Greg Rouse leg.; collecting event: ROV SuBastian dive 475; GenBank: OP561817 (COI); SIO-BIC A14031 .

Other material

MEXICO • 7 specs (3 fixed in formalin, 4 fixed in ethanol); Gulf of California, Pescadero Basin, Auka Vent Field, Matterhorn area , active hydrothermal vents; 23.95° N, 108.86° W; depth 3650 m; 14 Nov. 2018; Greg Rouse and Ekin Tilic leg.; collecting event: ROV SuBastian dive 193, sample S0193-S4 (suction sampler chamber 4, specimens associated with tubes of Oasisia alvinae ); SIO-BIC A9974 • 7 specs (2 fixed in formalin, 5 fixed in ethanol); same collection data as for preceding; SIO-BIC A9975 • 4 specs (fixed in ethanol); same locality as for preceding; 23.95369° N, 108.86231° W; depth 3668 m; 29 Oct. 2021; Greg Rouse leg.; collecting event: ROV SuBastia n dive 470, sample S0470-S3 (suction sampler chamber 3, among tube worms); SIO-BIC A13987 • 2 specs (1 anterior fragment fixed in ethanol, 1 anterior fixed in formalin and posterior fixed in ethanol and used for DNA extraction); Gulf of California, Pescadero Basin , Auka Vent Field, Z Mound area , active hydrothermal vents; 23.95616° N, 108.86191° W; depth 3688 m; 17 Nov. 2018; Greg Rouse and Ekin Tilic leg.; collecting event: ROV SuBastian dive 196, sample S0196-PC1 (push core 1 at microbial mat with venting); GenBank: OP311752 (COI); SIO-BIC A9987 • at least 15 specs (3 fixed in formalin, 12 fixed in RNAlater, additional material fixed in ethanol); same locality as for preceding; 23.9561° N, 108.8619° W; depth 3688 m; 21 Nov. 2018; Greg Rouse and Ekin Tilic leg.; collecting event: ROV SuBastian dive 200, samples S0200-S1 and S0200-S2 (suction sampler chambers 1 and 2, microbial mat with venting); SIO-BIC A10029 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311753 (COI); SIO-BIC A14114 • 4 specs (3 fixed in ethanol, 1 anterior fixed in formalin and posterior fixed in ethanol); Gulf of California, Pescadero Basin , Auka Vent Field, oily mat site southeast of Z Vent ; 23.95° N, 108.86° W; depth 3650–3662 m; 5 Nov. 2021; Greg Rouse leg.; collecting event: ROV SuBastian dive 477; SIO-BIC A14045 • 7 specs (6 fixed in paraformaldehyde, 1 fixed in ethanol); Gulf of California, Pescadero Basin , midway between Auka and JaichMaa ‘ja’ag Vent Fields ; 23.95369° N, 108.86231° W; depth 3663–3687 m; 1 Nov. 2021; Greg Rouse leg.; collecting event: ROV SuBastian dive 473; SIO-BIC A14007 • 11 specs (2 fixed in formalin, 9 fixed in ethanol); Gulf of California, Pescadero Basin , JaichMaa ‘ja’ag Vent Field, Cavern Tay Ujaa (Big Cave ), active hydrothermal vents; 23.94157° N, 108.85570° W; depth 3675 m; 18 Nov. 2018; Greg Rouse and Ekin Tilic leg.; collecting event: ROV SuBastian dive 197, sample S0197-S6 (suction sampler chamber 6, specimens associated with small tubes of Oasisia alvinae ); SIO-BIC A10002 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311754 (COI); SIO-BIC A14113 • ca 50 specs (fixed in ethanol); Gulf of California, Guaymas Basin , sedimented hydrothermal vents; 27.016° N, 111.410° W; depth 2012 m; 13 Nov. 2009; Anna-Louise Reysenbach leg.; collecting event: HOV Alvin dive 4558; SIO-BIC A14115 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311756 (COI); SIO-BIC A14116 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311757 (COI); SIO-BIC A14117 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; SIO-BIC A14118 • ca 15 specs (fixed in ethanol); Gulf of California, Guaymas Basin , sedimented hydrothermal vents; 27.015° N, 111.410° W; depth 2010 m; 15 Nov. 2009; Anna-Louise Reysenbach leg.; collecting event: HOV Alvin dive 4560; SIO-BIC A14119 • 1 speci. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311758 (COI); SIO-BIC A14120 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311759 (COI); SIO-BIC A14121 • 1 spec. (fixed in ethanol and the posterior end used for DNA extraction); same collection data as for preceding; GenBank: OP311760 (COI); SIO-BIC A14122 .

Description

In life, golden color with white eggs mid-body ( Fig. 7A–B ), opaque white after preservation. Body length 10.5 mm, with 50+ segments, slightly dorso-ventrally compressed, widest anteriorly, gradually tapering posteriorly ( Fig. 7A–B ). Prostomium rounded, wider than long, posterior medial area slightly raised, with paired digitiform antennae, tapering distally, inserted dorsally, paired digitiform palps similar in length with antennae, inserted ventral-laterally ( Fig. 7A ). Peristomium with two rings, subequal in length to the following segments ( Fig. 7A ). Eyes not visible. Mandibles heavily sclerotized, with rod-like shafts, sub-triangular shape cutting plates, with single blunt peak anteriorly, lateral wings weakly sclerotized ( Fig. 7C ). Maxillae P-type, forceps comb-like, with large main fang. Four rows of free denticles, the posterior-most free denticles (D1) comb-like, like the forceps, other free denticles shovel-shaped with fine teeth, D2–D4 smaller than D5–D7 ( Fig. 7D ). Parapodia uniramous, acicular lobe with rounded distal margin, dorsal cirri long digitiform, extending beyond distal margin of acicular lobe, ventral cirri short and stubby ( Fig. 7E ). Supra-acicular chaetae simple, distally serrated, tapering into a main fang ( Fig. 7F ). Sub-acicular chaetae compound, with serrated blades ( Fig. 7G ). Sub-acicular chaetal lobe usually with one simple chaeta ( Fig. 7H ). Pygidium with two digitiform cirri inserted laterally ( Fig. 7A ).

Distribution

Known from Gulf of California hydrothermal vents of the Pescadero Basin at over 3500 m and the Guaymas Basin sedimented vents at ~ 2000 m. Found in huge numbers on tubes of Oasisia ( Fig. 6A ), or on microbial mats near active flow ( Fig. 6B ).

Remarks

This species was initially reported in Goffredi et al. (2017) as Ophryotrocha cf. akessoni sp. 1 with a partial DNA sequence for mitochondrial 16S rRNA lodged on GenBank (KY701727). Ophryotrocha marinae sp. nov. most closely resembles Ophryotrocha jiaolongi described from hydrothermal vents of the Indian Ocean, including sharing distinctive mandibles that distinguish these two taxa from all other Ophryotrocha . Morphologically, O. marinae differs from O. jiaolongi based on body color, the form of antennae and palps, and in lacking a median pygidial papilla ( Table 3 ). In life, O. marinae is golden while O. jiaolongi is white and translucent. Ophryotrocha marinae also has antennae and palps that are distally tapering and longer than the length of prostomium, while in O. jiaolongi antennae and palps are shorter than the length of prostomium. The minimum COI uncorrected distance obtained between O. marinae and O. jiaolongi specimens was relatively small at 3.73% ( Table 2 ). Other relatively small distances that are currently known are up to 4.8% between O. notoglandulata Pfannenstiel, 1972 and O. japonicus Paxton and Åkesson, 2010 (both Japanese taxa) and 6.1% between O. flabella and O. globopalpata (both from deep waters of the eastern Pacific). Given the morphological differences between O. marinae and O. jiaolongi , the reciprocal monophyly based on numerous COI sequences and vast geographic separation, we regard them here as separate species. One notable difference between O. jiaolongi and O. marinae was that the latter species showed four rows of maxillae compared to the two rows in O. jiaolongi found by Zhang et al. (2017). As discussed above for O. charlottae sp. nov. it is possible that the outermost pair of rows represent molted jaws as has been observed in other Ophryotrocha by Paxton (2004).

Figures

Fig. 6. Ophryotrocha marinae sp. nov. A. Numerous specimens associated with the tubes of Oasisia alvinae Jones, 1985 (Vestimentifera) at active hydrothermal vents of the Pescadero Basin (Mexico). Image from ROV SuBastian dive S0495, courtesy of the Schmidt Ocean Institute. B. Numerous specimens associated with microbial mat on the seafloor at active hydrothermal vents adjacent to a large mass of Oasisia alvinae. Some of these were collected and formed lots (SIO-BIC A6308, A1408– 14112). Image from ROV Doc Ricketts dive 750 in the Pescadero Basin, courtesy of the Monterey Bay and Aquarium Research Institute.

Fig. 7.Ophryotrocha marinae sp. nov.A. Dorsal and ventral views of living paratype (SIO-BICA14031). B. Whole specimens from paratype (SIO-BIC A14112). C. Mandibles of specimen from paratype (SIO- BIC A6308). D. Maxillae of specimen from paratype (SIO-BIC A6308). E. Parapodium of holotype (SIO-BIC A14109). F. Simple supra-acicular chaetae of holotype (SIO-BIC A14109). G. Compound sub-acicular chaetae of holotype (SIO-BIC A14109). H. Simple sub-acicular chaeta of paratype (SIO- BIC A14109).