Iphione richeri, 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 : 70-73

Iphione richeri sp. nov.

urn:lsid:zoobank.org:act:38FD0F78-3C1C-4284-852E-3A87B27888E0

Figs 31–33

Iphione muricata : Pettibone 1986: 14–15, Fig. 5 (Bikini Atoll) only Fig. 5 , non (Savigny in Lamarck, 1818).

Type material. New Caledonia. Holotype ( MNHN IA 2000-2101 ), Lagons de Nouvelle Calédonie , Campagne 10, Lagon Est, Sta. 724 (21°19.7’ S, 165°57.9’ E), 36–38 m, medium sand with foraminiferans and Halimeda , 12 Aug. 1986, B. Richer de Forges, coll.

Additional material

Indonesia. One specimen ( ZMA V471.11 ), Irian Jaya, RV Siboga Exped., Stat. 162 (between Loslos and Broken Islands, Salawatti, W coast), 18 m, dredge, sand, shells, 18 Aug. 1899 (data in variation; body 14 mm long, 9.5 mm wide, 29 chaetigers) . One specimen ( ZMA V471.2 ), Lesser Sunda Islands, Sapeh Strait, RV Siboga Exped., Sta. 49a (08°23.5’ S, 119°04.6’ E), 69 m, dredge, coral + shells, 14 Apr. 1899 (juvenile; some elytra and one anterior parapodium previously removed; elytra yellowish with oblique longitudinal brownish band; fimbriae long, discontinuous, in lateral and posterior margins; macrotubercles in two rows, decreasing in size posteriorly; cirrigerous segments with basal tubercle of dorsal cirrophores projected; neurochaetae unidentate, upper neurochaetae more straight, median and lower ones slightly falcate; prostomium oval, wider than long, lateral antennae as long as palps, lateral ceratophores twice longer than prostomium, ceratostyles slightly longer than ceratophores; palps with very long papillae, shorter basally, becoming 1/3 as long as palp width in distal third; tentacular cirri slightly longer than palps; eyes not seen; body 13 mm long, 8 mm wide, 29 chaetigers) . One specimen ( ZMA V471.22 ), Irian Jaya, RV Siboga Exped., Sta. 273 ( Aru Island , Pearl Banks, anchorage off Pulu Jedan), 13 m, trawl, dredge and divers, sand and shells, 23–26 Dec. 1899 (markedly bent ventrally; elytra yellowish with a wide oblique, longitudinal band and some central spots; macrotubercles in two rows; fimbriae lateral, very long, longest about 1/3 as long as minimal elytral width; not measured) .

Australia. One specimen ( AM 2935 ), Great Barrier Reef Expedition 1928–1929, Sta. 14 (14°40’12.0” S, 145°27’00.0” E), off Lizard Island , Queensland (no further data; slightly bent ventrally, some elytra and parapodia previously removed; elytra brownish with long fimbriae, without black spots, variably eroded; macrotubercles small, eroded, in a single row, close to posterior elytral margin; cirrigerous segments with basal tubercle of dorsal cirrophores projected; body 15.5 mm long, 9.5 mm wide, 29 chaetigers) .

Republic of Palau. One specimen ( UF 202 ), Koror State (07°20’20” N, 134°28’43” E), Lighthouse Basin , 48 m, lagoon bottom, silty sand, 4 Aug. 1995 (fixed in 75% ethanol), J. Starmer, coll.

Diagnosis. Iphione with median antenna reduced to nuchal papilla; elytra fimbriate, filaments markedly longer than wide; macrotubercles low conical with distal spines, in 1–2 rows along elytral margins; cirrigerous segments with dorsal cirrophores with basal tubercle indistinct; neurochaetae unidentate.

Description. Holotype (MNHN IA 2000-2101) fixed in ethanol, slightly bent ventrally ( Fig. 31A ), 14 mm long, 7.5 mm wide, 29 chaetigers; first four pairs of elytra removed for observing anterior end, left elytron 6 and left parapodium of chaetiger 12 removed for observation.

Elytra yellowish with an oblique longitudinal wide blackish band, laterally expanded along posterior elytral region, with a few smaller, irregular black spots, with white epibionts, with very long fimbriae ( Fig. 31C ). Macrotubercles small, conical, arranged in a single marginal row, conical, projected as small denticles.

Prostomium retracted, oval, wider than long, with a deep longitudinal depression along anterior prostomial half. Anterior lobes projected into ceratophores ( Fig. 31B ), bent ventrally, wider medially, transparent, slightly longer than prostomium, ceratostyles tapered, slightly shorter than palps. Palps pale, about three times longer than ceratophores. Eyes blackish, positioned in posterior prostomial half, anterior eyes lateral, slightly larger than posterior, marginal eyes. Nuchal papilla visible under nuchal lappet.

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

Segments 2–4 directed anteriorly. Second segment not visible dorsally; nuchal lappet semicircular, as wide as long. Ventral buccal cirri inserted ventrally, 2–3 times longer than following ventral cirri, surpassing chaetal tips. From segment 3, one pair of separate dorsal nodules per segment, markedly larger in segment 3, smaller in segment 4, not visible in segment 5. Segments 2–3 with finer neurochaetae, barely swollen subdistally, with a longer region provided with series of transverse denticulations.

Median cirrigerous segments ( Fig. 31D ) with dorsal cirri not surpassing chaetal tips, cirrostyle tapered, not subdistally swollen; dorsal cirrophores smooth, basal tubercle indistinct (due to rotting of body wall, indicated by transparency). Notochaetae whitish, very abundant, delicate capillaries with series of transverse funnel-shaped spinose rows, tips bare. Neuropodia with neuracicular lobe twice longer than wide, blunt; neurochaetal lobe with small digitate papillae. Neurochaetae golden, thick, abundant, basally smooth, subdistally swollen, with series of denticulations along swollen region, tips falcate, sharp ( Fig. 31E ).

Posterior end bent ventrally; anus not seen.

Etymology. The specific epithet is after Dr. Bertrand Richer de Forges, now retired, as a recognition for his long-term collecting efforts in New Caledonia, during one of the cruises he collected the holotype of this species. The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Variation. A 14 mm long specimen (ZMA V471.11) had elytra brownish without black spots ( Fig. 32A ). The fimbriae extend along lateral and posterior margins ( Fig. 32B ), longest filaments are ¼ as long as minimal elytral width along body, up to 20 times longer than wide ( Fig. 32B , inset); macrotubercles conical, small, in two rows displaced towards posterior margin, first row with macrotubercles slightly longer than those present in second row; microtubercles barely developed. Cirrigerous segments with basal tubercle of dorsal cirrophore projected as a single lobe ( Fig. 32C ). Neuropodia with acicular lobe blunt, with small papillae. Neurochaetal lobe with marginal papillae; neurochaetae abundant, basally smooth, subdistally swollen, with many rows of fine denticulations along swollen region, tips barely falcate, unidentate, sharp ( Fig. 32C , inset).

A juvenile specimen (UF 202), fixed in ethanol, is 10 mm long, 6 mm wide, 29 chaetigers, has most elytra detached; left parapodium of chaetiger 12 removed for observation (kept in container). Eyes displaced towards posterior prostomial half, fading off. Elytra yellowish with an oblique brownish band ( Fig. 33A ). Macrotubercles in 2–3 rows, fimbriae very long, especially along posterior margins, longest ones about half to one-third as long as elytral width ( Fig. 33B, C ). Parapodia soft; cirrigerous segments with dorsal cirrophore with a low, barely defined basal tubercle ( Fig. 33D ). Notochaetae abundant, white to transparent; neurochaetae golden, unidentate, tips falcate, with 20–30 transverse rows of denticles.

The additional specimens were 13.0– 15.5 mm long, 8.0– 9.5 mm wide. The macrotubercles are arranged in two rows, and these rows are displaced towards the posterior elytral margin.

Remarks. Some specimens resembling Iphione richeri sp. nov. were included in I. muricata (Savigny in Lamarck 1818) by Pettibone (1986). These two species have macrotubercles arranged in 2–3 rows, progressively smaller posteriorly. However, these two species differ on the position of the macrotubercular rows; in I. richeri they are displaced towards the posterior margin, whereas in I. muricata they extend along the posterior elytral half. Further, I. richeri differs from other species provided with short macrotubercles by having very long, thin fimbriae, with longest filaments about 1/7 as long as elytral minimal width (½–1/3 as long as elytron width in juveniles) or 25 times longer than wide.

Distribution. From Indonesia and Australia, east to Palau and New Caledonia and Marshall Islands ( Pettibone, 1986), in subtidal sandy bottoms (13–69 m).

Figures

FIGURE 5. Iphione muricata (Savigny in Lamarck, 1818), restricted, non-type specimen (CAS 227559). A. Dorsal view, depressed by glass slide. B. Left elytron 7, dorsal view (C–E: sections enlarged in following pictures). C. Close-up of fimbriae. D. Close-up of smaller, marginal spines. E. Close-up of larger, inner spines. F. Chaetiger 12, left parapodium, posterior view, notochaetae partially trimmed off (after Methyl green staining). G. Same, basal neurochaetal tips. Scale bars: A, 2.5 mm; B, 1.5 mm; F, 0.9 mm; G, 0.3 mm.

FIGURE 31. Iphione richeri sp. nov., holotype (MNHN IA 2000-2101). A. Dorsal view, last segments bent ventrally. B. Anterior end, after Shirlastain-A staining. C. Left elytron 6, dorsal view. D. Chaetiger 12, left parapodium, posterior view. E. Same, upper and middle neurochaetal tips. Scale bars: A, 1.3 mm; B, 0.5 mm; C, 0.7 mm; D, 0.3 mm; E, 100 µm.

FIGURE 32. Iphione richeri sp. nov., non-type specimen (ZMA V471.11). A. Bent ventrally, dorsal view, left elytron 6 and right elytra 6 and 7 removed. B. Right elytron 6, frontal view (inset: largest fimbriae). C. Chaetiger 12, left parapodium, posterior view (inset: upper neurochaetal tips). Scale bars: A, 1.1 mm; B, 0.7 mm, C, 0.3 mm.

FIGURE 33. Iphione richeri sp. nov., non-type specimen (UF 202). A. Dorsal view after Methyl green staining. B. Right elytron 6, dorsal view. C. Right elytron 7, dorsal view. D. Chaetiger 12, left parapodium, anterior view, notochaetae removed. Scale bars: A, 0.6 mm; B, C, 0.7 mm; D, 0.2 mm.