Iphione corbariae, 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 : 52-54

Iphione corbariae sp. nov.

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Fig. 21

Type material. Saya de Malha Bank (Indian Ocean, N off Mauritius). Holotype ( MNHN IA 2021-682 ), Mission SAYA, RV Agulhas II, Sta. DW 5424 (11°28’ S, 62°01’ E), 171– 150 m, 12 Nov. 2022, S. Hourdez et al., coll.

Diagnosis. Iphione with median antenna reduced to nuchal papilla; elytra fimbriate, fimbriae short, globose; macrotubercles cushion-shaped without distal spines, in a single row; cirrigerous segments with dorsal cirrophores with basal tubercle projected, tip pale; neurochaetae bidentate; ventral cirrostyles bases blackish.

Description. Holotype (MNHN IA 2021-682) bent ventrally ( Fig. 21A ), 15 mm long, 10 mm wide, 29 chaetigers; first three right and two left elytra previously removed; right elytron 6 and left parapodium of chaetiger 12 removed for observation. Elytra exposed areas brownish, protected areas yellowish, notochaetae whitish, neurochaetae yellowish; right palp pale purple, lateral ceratophores brownish, left tentaculophore with black spots ( Fig. 21B ); venter pale, ventral cirri with cirrostyles base blackish.

Elytra yellowish with 2–3 dark spots, fimbriae minute along lateral margins ( Fig. 21C , insets). Macrotubercles in a single row, cushion-shaped ( Fig. 21 , inset left); a few microtubercles in lateral margins.

Prostomium bent ventrally, oval, twice wider than long, with deep longitudinal depression along anterior prostomial half ( Fig. 21B ). Anterior lobes projected into ceratophores, brownish, slightly longer than prostomium, ceratostyles lost. Right palp pale purple, bent ventrally, slightly shorter than tentacular cirri. Eyes black, positioned along prostomial margin, anterior and posterior eyes of similar size, separate, with a smaller black spot between them. Nuchal papilla visible dorsally, pale.

Tentacular segment dorsally reduced, with black spots, lower cirrus left, slightly longer than palps, base blackish, chaetae not seen. Facial tubercle blackish, barely visible dorsally.

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

Median cirrigerous segments ( Fig. 21D ) with dorsal cirri barely surpassing chaetal tips, slightly swollen subdistally; dorsal cirrophores smooth, basal tubercle of dorsal cirrophore projected, basally blackish, distally pale. Notochaetae abundant, whitish, delicate capillaries with series of transverse funnel-shaped spinose rows, tips bare. Neuropodia with supracicular lobe 2–3 times longer than wide, with small papillae. Neurochaetae abundant, yellowish, basally smooth, subdistally with series of denticles, tips bidentate, many with accessory denticle broken ( Fig. 21E ). Ventral cirri pale, base of cirrostyle blackish.

Anus not seen.

Etymology. The specific epitheth is after Dr. Laure Corbari, a French carcinologist of the Muséum National d’Histoire Naturelle, Paris, in recognition of her achievements in organizing several sampling expeditions, and after her activities as an editor of the series Tropical Deep Sea Benthos. The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Remarks. Iphione corbariae sp. nov. resembles I. treadwelli Pettibone, 1986 described from Hawaii because they are the only species having elytra provided with cushion-shaped macrotubercles, arranged in a single row, and minute fimbriae. The main differences lie in the type of neurochaetae, and pigmentation pattern of some parapodial features. In I. corbariae neurochaetae are bidentate, and the basal tubercle of dorsal cirrophores is basally blackish, distally pale, whereas I. treadwelli has unidentate neurochaetae, and basal tubercles with blackish tips and pale bases. Further, in I. corbariae , the bases of ventral cirrostyles are blackish, whereas they are pale in I. treadwelli . Another difference relies in the pigmentation pattern of elytra. In I. corbariae median elytra have 2–3 darker spots each, whereas in I. treadwelli no such spots are present, with elytra being rather homogeneously pigmented, either yellowish or blackish.

Distribution. Only known from the type locality, in mixed bottoms at moderate depths (150–171 m).

Figures

FIGURE 21. Iphione corbariae sp. nov., holotype (MNHN IA 2021-682).A. Dorsal view. B.Anterior end, dorsal view. C. Right elytron 6, dorsal view (insets: macrotubercle indicated by an asterisk, and lateral fimbriae). D. Chaetiger 12, left parapodium, posterior view. E. Same, tips of median and upper neurochaetae. Scale bars: A, 1.4 mm; B, 0.6 mm; C, 1 mm; D, 0.3 mm; E, 40 µm.