Iphione hourdezi, Salazar-Vallejo & Piotrowski & Paulay, 2024

Salazar-Vallejo, Sergio I., Piotrowski, Christina N. & Paulay, Gustav, 2024, Revision of Iphione Kinberg, 1856 (Annelida, Aphroditiformia, Iphionidae), Zootaxa 5548 (1), pp. 1-84 : 55-57

Iphione hourdezi sp. nov.

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Fig. 23

Type material. New Caledonia. Holotype ( MNHN IA 2000-2100 ), Cruise SPANBIOS (https://doi. org/10.17600/18000701), RV Alis, Sta. CP 5289 (21°27’ S, 166°12’ E), 171–193 m, 29 Jul. 2021, S. Hourdez, coll.

Additional material. Fiji. One specimen ( MNHN IA 2023-55 ), Cruise MUSORSTOM 10, RV Alis, Sta. CP 1363 (18°12’23.3964” S, 178°33’0.6156” E), 144-150 m, 15 Aug. 1998 (complete, brownish; right elytra 1–3, 5 and left parapodia of chaetigers 14, 16 removed for observation (kept in container); elytra brownish, with two rows of blunt macrotubercles; cirrigerous segments with dorsal cirrophore with basal tubercle projected; neurochaetae almost straight; body 29 mm long, 15 mm wide, 28 chaetigers) .

Diagnosis. Iphione with median antenna reduced to nuchal papilla; elytra with margins fimbriate, fimbriae minute; macrotubercles blunt conical with distal spines, often eroded, in two rows, first row with macrotubercles markedly larger than those in other rows; cirrigerous segments with dorsal cirrophores with basal tubercle projected; neurochaetae acicular, unidentate.

Description. Holotype (MNHN IA 2000-2100) slightly bent ventrally ( Fig. 23A ), 26 mm long, 19 mm wide, 29 chaetigers; first 4 pairs of elytra, right elytron 6, and left parapodium of chaetiger 12 removed for observation. Elytra grayish, notochaetae whitish, neurochaetae golden; palps, lateral antennae, and tentacular cirri black; venter pale, ventral cirri pale.

Elytra grayish without black spots, fimbriae short, bent over elytra ( Fig. 23C ), outer fimbriae short, apparently sessile ( Fig. 23C , inset 1), posterior fimbriae pedunculate ( Fig. 23C , inset 2). Macrotubercles arranged in two rows, digitate, first row with macrotubercles slightly larger than those present in second row, tips blunt. Microtubercles in two marginal rows, decreasing in size middorsally.

Prostomium bent ventrally, oval, twice wider than long, with deep longitudinal depression along anterior prostomial half ( Fig. 23B ).Anterior lobes projected into ceratophores, blackish, about twice longer than prostomium, ceratostyles bent ventrally. Palps black, left one longer than antennae and tentacular cirri, right palp in regeneration, short, pale. Eyes black, positioned in posterior prostomial half, anterior and posterior eyes of similar size, very close to each other laterally. Nuchal papilla not visible dorsally, blackish.

Tentacular segment dorsally reduced, cirri slightly shorter than palps, chaetae not seen. Facial tubercle blackish, visible dorsally.

Segments 2–4 directed anteriorly. Second segment not visible dorsally; nuchal lappet distinct, semicircular, wider than long. Ventral buccal cirri inserted ventrally, about twice longer than those present in following segments. From segment 3, one pair of depressed, separate dorsal nodules per segment, only first pair visible, others covered by elytra. Segments 2–3 with neurochaetae thin, similar to those present in following chaetiers.

Median cirrigerous segments ( Fig. 23D ) with dorsal cirri slightly surpassing chaetal tips, barely swollen subdistally; dorsal cirrophores smooth, basal tubercle projected. Notochaetae abundant, whitish, delicate capillaries with series of transverse funnel-shaped spinose rows, tips bare. Neuropodia with neuracicular lobe 4–5 times longer than wide with a large, globular, subdistal papilla. Neurochaetae acicular, thin, golden, abundant, basally smooth, slightly swollen subdistally, with series of denticulations, tips straight, sharp ( Fig. 23E ). Ventral cirri pale.

Anus dorsal, positioned between elytral pairs 12 and 13.

Etymology. The specific name is after Dr. Stéphane Hourdez, a deep-sea French ecologist, in recognition of his studies on benthic fauna, and because he collected the holotype of this species. The name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Remarks. Iphione hourdezi sp. nov. resembles I. malifera Piotrowski, 2014 from the Philippines by having digitate macrotubercles, although elytra in I. hourdezi have homogeneous pigmentation, whereas I. malifera has elytra with oblique longitudinal black bands. However, I. hourdezi differs from this and from any other species in the genus by having thin neurochaetae with straight tips, whereas in all other species neurochaetae are thick, with falcate tips, mostly unidentate, with a few species having bidentate neurochaetae.

Distribution. New Caledonia to Fiji, in mixed bottoms in platform depths (144–193 m).

Figures

FIGURE 23. Iphione hourdezi sp. nov., holotype (MNHN IA 2000-2100). A. Dorsal view. B. Anterior end, dorsal view after removal of elytral pairs 1–4. C. Right elytron 6, dorsal view (insets: 1, lateral fimbria; 2, posterior fimbria). D. Chaetiger 12, left parapodium, posterior view after removal of notochaetae (inset: ventral cirri and basal papillae). E. Same, upper, middle and lower neurochaetal tips. Scale bars: A, 2.9 mm; B, 0.9 mm; C, 1.4 mm; D, 1.2 mm; E, 170 µm.