Iphione hyndmani, 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 : 57-61

Iphione hyndmani sp. nov.

urn:lsid:zoobank.org:act:1C85364D-5298-4873-A1A2-7285B0B798B2

Figs 24–26 , 36

Iphione muricata : Pettibone 1986: 13, Fig. 4 (partim, only USNM 19192; non (Savigny in Lamarck, 1818)).

Type material. Hong Kong. Holotype ( UF 5695 ), Port Island (22°30’03.744” N, 114°21’23.22” E), 1 m, patchy coral, rocks, sand, 27 Oct. 2017, G. Paulay & J. Moore, coll. COI barcode: GenBank PQ423938 Paratype ( UF 5689 ), Tung Ping Chau (22°32’33.504” N, 114°26’18.816” E), 1 m, patchy coral, rocks, sand, 25 Oct. 2017, G. Paulay & J. Moore, coll.

Additional material

Hong Kong. One specimen ( AM 19902 ), Peng Chau , Mirs Bay, southern tip of Hong Kong, 10 m, rocks, 15Apr.1986, P.A. Hutchings, coll. (bent ventrally, some elytra previously removed; elytra brownish, oblique longitudinal band barely visible; macrotubercles in two rows, progressively smaller posteriorly; basal tubercle of dorsal cirrophores not projected; body 26 mm long, 14 mm wide, 29 chaetigers) . One specimen ( AM 19977 ), Cox Head Rock , 19 Apr. 1986 (bent ventrally; some elytra previously detached; elytra yellowish with oblique longitudinal band barely visible; macrotubercles in two rows, progressively smaller posteriorly; basal tubercle of dorsal cirrophore not projected; body 18 mm long, 11 mm wide, 29 chaetigers) . One specimen ( AM 20023 ), Sui Mun (deep pass), off Double Haven, 15 m, rocks, 7 Apr. 1986, P. Hutchings, coll. (bent ventrally; elytra brownish with an oblique longitudinal black band; macrotubercles in two rows, decreasing in size posteriorly; basal tubercle of dorsal cirrophore not projected; body 24 mm long, 10 mm wide, 29 chaetigers) . One specimen ( AM 20050 ), Chik Chau , Dragons Head, 15 m, 6 Apr. 1986, P. Hutchings, coll. (bent ventrally; pharynx exposed, jaws with two accessory denticles; elytra brownish with an oblique longitudinal black band; macrotubercles mostly broken, in 3–4 rows progressively smaller posteriorly; basal tubercle of dorsal cirrophore not projected; body 22 mm long, 14 mm wide, 29 chaetigers) . One specimen ( UF 5839 ), Shelter Island , patchy coral (22°19’51.6” N, 114°17’34.8” E), 2–5 m, sand bottom with large rocks, 2 Nov. 2017, J. Moore, coll. (bent ventrally; elytra brownish with an oblique longitudinal black band and some dispersed black spots, some epibionts present; macrotubercles in 5–6 rows, progressively smaller posteriorly; cirrigerous segments with basal tubercle of dorsal cirrophores not projected; neurochaetae unidentate with masses of filamentous bacteria on their tips; body 23 mm long, 14 mm wide, 29 chaetigers) .

Mascarene Islands. One specimen ( NMWZ 2001.060 .ooo1), Rodrigues Expedition 2001, Sta. 3RIO, Île aux Fous, 0.5 m, under rocks, no date, P.G. Oliver, coll. (complete; left elytron 3 previously removed, left parapodium of chaetiger 12 removed for observation (kept in container); elytra with abundant epibionts, an ill-defined oblique black band; fimbriae short, present along external margins; macrotubercles in 3–4 rows, progressively smaller posteriorly; cirrigerous segments with basal tubercle not projected; body 33 mm long, 16 mm wide, 29 chaetigers) .

Australia. Two specimens ( AM 199666 ), Queensland, Kewarra Beach , 23 Sep. 1980, D. Hoese, coll. (smaller specimen bent ventrally, anterior end smashed, larger one markedly bent; some elytra previously detached; elytra yellowish with an oblique longitudinal black band; macrotubercles in 3–4 rows, progressively smaller posteriorly; cirrigerous segments with basal tubercle not projected; smaller specimen 10.5 mm long, 6.5 mm wide, 29 chaetigers) . Four specimens ( NMV F224150 ), Queensland, Dingo Beach, north of Proserpine (20°05´S, 148°30´E), intertidal, in old shell attached to underside of rocks, 3 Aug. 2009, T.J. Hales, coll. (slightly bent ventrally; elytra dirty yellow to brownish, with oblique dark band in larger specimens; some elytra previously removed; elytra with 3–4 rows of low conical macrotubercles; dorsal cirrophores with basal tubercle not projected; neurochaetae unidentate; body 17–28 mm long, 10.5–16.5 mm wide, 29 chaetigers) .

Federated States of Micronesia, Caroline Islands. Two specimens ( UF 204 ), Pohnpei Island, Sokehs Island, Dock at Pier (06°58’58.8” N, 158°10’33.6” E), 1–5 m, reef adjacent to mangrove forest, no date (fixed in 75% ethanol), J. Starmer, coll. (elytra with abundant fine sediment particles and whitish epibionts; dark oblique bands better defined in small specimen (although most elytra detached; prostomium distorted, anterior and posterior eyes in a single row, anterior eyes dorsal); larger specimen with eyes displaced posteriorly, anterior eyes lateral; macrotubercles in three rows; cirrigerous segments with dorsal cirrophore with basal tubercle not projected; body 15–28 mm long, 8–14 mm wide, 29 chaetigers) . One specimen ( UF 205 ), Pohnpei Island, Lenger Island, next to Japanese Dock at Clam Hatchery (06°59’24.0” N, 158°13’48.0” E), 2–3 m, reef flat, under rock, 13 Mar. 2003 (fixed in 75% ethanol), J. Starmer, coll. (elytra detaching from body, with fine sediment particles and whitish epibionts; dark oblique bands not visible; eyes unpigmented; macrotubercles in 3–4 rows; cirrigerous segments with dorsal cirrophore with basal tubercle not projected; body 26 mm long, 14 mm wide, 29 chaetigers) .

Fiji. One specimen ( AMNH 1615 ), Suva, 1920, A.L. Treadwell, coll. (no further data; left parapodia of chaetigers 9, 12, 13, and 7 anterior elytra previously removed (some kept in container); elytra with macrotubercles in three rows, microtubercles approaching elytral margin, not surpassing it; dorsal cirrophore with basal tubercle not projected, smooth; body 28 mm long, 13 mm wide, 29 chaetigers) . One specimen ( UF 73 ), Viti Levu Island , Man Friday Resort, 80 km West of Suva, 0–2 m, fringing reef, freely moving on rocks, 2 Feb. 1989, B. Holthuis & G. Paulay, coll. (elytra yellowish with some whitish epibionts, without black marks; macrotubercles in three rows; cirrigerous segments with dorsal cirrophore with basal tubercle barely projected; body 12 mm long, 5.5 mm wide, 29 chaetigers) . One specimen ( USNM 19192 ), Suva, 1920, A.L. Treadwell, coll. (no further data; dried out, bent ventrally; some elytra examined, macrotubercles in three rows, microtubercles surpassing eroded elytral margin giving a denticulate outlook; dorsal cirrophore with basal tubercle not projected; not measured) .

Diagnosis. Iphione with median antenna reduced to nuchal papilla (rarely with a full antenna); elytra fimbriate, filaments markedly longer than wide; macrotubercles spine-like up to twice longer than wide, with distal spines, in 3–5 rows, first row with macrotubercles slightly larger than those in other rows; cirrigerous segments with dorsal cirrophores with basal tubercle indistinct; neurochaetae unidentate.

Description. Holotype (UF 5695) complete; first three and sixth right elytra, left first four and sixth and seventh elytra removed; left parapodia of chaetigers 13 and 14, and right parapodia of chaetiger 12 removed; body 32 mm long, 14 mm wide, 29 chaetigers. Elytra brownish with an oblique blackish band, and darker posterior margins, some elytra with whitish epibionts ( Fig. 24A ); notochaetae whitish, neurochaetae golden. Body wall pale, parapodia with large coelomic spaces; venter pale, ventral cirrophores blackish.

Elytra with fimbriae, better developed along median and posterior segments, variably eroded, extended along almost all exposed elytral margin but submarginal along lateral margins, marginal along posterior margins. Macrotubercles conical, largest ones 3–4 times longer than wide, arranged in 3–4 rows, longer towards external lateral elytral areas ( Fig. 24C, D ).

Second pair of elytra with macrotubercles in 2–3 rows, following elytra with macrotubercles in 3–4 rows, posterior rows irregular; larger macrotubercles towards lateral marginal areas, progressively smaller towards posterior margins, if eroded, making elytral margin denticulate. Fimbriae delicate, short, along lateral and posterior margins, fimbriae with thin spinous stem, and distal soft tubules, each about twice as long as fimbria stem.

Prostomium as long as wide ( Fig. 24B ), with anterior incision running along all prostomial surface. Anterior lobes projected into ceratophores, blackish, longer than prostomium, and about twice longer than ceratostyles, ceratostyles markedly thinner than ceratophores, tapered. Palps thick, twice longer than lateral antennae, brownish, with longitudinal rows of papillae, tips mucronate. Eyes black, anterior ones placed behind the medial prostomial region, projected laterally, visible dorsally, posterior eyes in posterior prostomial corners. Nuchal papilla blackish, rounded.

Tentacular segment dorsally reduced, with a few chaetae present; tentacular cirri 2/3 as long as palps, resembling lateral antennae. Facial tubercle blackish, visible dorsally.

Segments 2–4 directed anteriorly. Second segment visible dorsally, nuchal lappet semicircular, wider than long, not covering nuchal papilla. Ventral buccal cirri inserted ventrally, three times longer than following ventral cirri, projected beyond chaetal tips. From segment 3 one pair of globular dorsal nodules per segment, barely projected dorsally; first pair not connected by transverse ridges. Segments 2–3 with fine neurochaetae, barely swollen subdistally, with a longer region covered by series of transverse denticulations.

Median cirrigerous segments ( Fig. 24E ) with dorsal cirri surpassing chaetal tips, subdistally swollen; dorsal cirrophore smooth, basal tubercle not projected. Cirrostyle subdistally swollen, with papillae along its surface. Notochaetae very abundant, pale to transparent, with series of transverse funnel-shaped spinose rows, tips bare. Neuropodia with neurochaetal lobe posterior margin with small papillae. Neurochaetae thin, abundant, basally smooth, subdistally swollen, sometimes with a pale or dark core, with many rows of fine denticulations along swollen region, tips falcate, sharp ( Fig. 24E , insets).

Anus visible in middorsal areas of last two pairs of elytra.

Variation. The paratype (UF 5689) is bent ventrally ( Fig. 25A ); elytra yellowish with oblique black band and middorsal posterior elytral areas darker; macrotubercles conical, larger laterally, decreasing in size dorsally and posteriorly ( Fig. 25B ), arranged in 3–4 rows, last row irregular. Cirrigerous segments with dorsal cirrophore contracted, not surpassing neurochaetal lobe, ceratostyle papillose, subdistally swollen, surpassing neurochaetal tips ( Fig. 25C ). Pharynx with smooth surface, with small glandular areas; pharynx opening with two series of globose papillae, 12 on the upper part, 12 in the lower one, and a middorsal muscular lobe behind middorsal papilla ( Fig. 25D ). Jaws brownish, sharp, each with two accessory denticles. In lateral view, the subdistal reinforcement for adductor muscles is roughly semicircular ( Fig. 25E ), glandular areas not projected, arranged in roughly parallel series along pharynx.

The additional specimens were 10.5–28.0 mm long, 6.5–16.5 mm wide. The number of rows of macrotubercles is size dependent, with smaller specimens having only two rows.

Etymology. The specific name is derived after Philip Hyndman, husband of Chrissy Piotrowski, in recognition of her long-term love and support of her research activities.

Remarks. Iphione hyndmani sp. nov. resembles I. fimbriata de Quatrefages, 1866 , reinstated, from the Torres Strait (incl. I. fustis Hoagland, 1920 from the Philippines), as redescribed above, by having elytra with macrotubercles progressively smaller posteriorly and arranged in 3–4(5) rows. However, the main difference is in the development of the basal tubercle of the dorsal cirrophore, because in I. hyndmani it is barely visible whereas in I. fimbriata it is a large projected lobe. Pettibone (1986: 13, Fig. 4A ) illustrated one specimen with a very long, thin median antenna, about as long as reaching tips of lateral ceratophores, and that the dorsal cirrophore was granulose or maculate. However, in this specimen (USNM 19192) a filiform median antenna is present, about as long as to reach the anterior prostomial depression, it has a distinctive ceratophore, ¼ as long as ceratostyle ( Fig. 26 ), or about half as long as Pettibone illustrated it, whereas it is missing in all other specimens identified as I. hyndmani , where only a small papilla is visible, as usual among all other members of the genus. The apparent granular or pigmented base of dorsal cirrophores (see Pettibone 1986, Fig. 4D ), we think it was an interpretation of the inner contents of a dried-out specimen, because the surface is smooth, not granular nor pigmented. Consequently, that specimen (USNM 19192) is herein regarded as belonging to I. hyndmani , and we also think that median antennae are extremely rare among Iphione species, and this can be regarded as an atavism. Another indication for this is that the other specimen from the same locality (AMNH 1615) does not have the median antenna and completely matches I. hyndmani . Nevertheless, it could be that the median antenna is present among Iphione species, but being extremely fragile, it becomes detached during manipulation or fixation, and what remains in almost all specimens is the basal knob, and no traces of the median ceratophore have been found after the study of many specimens. This would also imply that there is an abscission zone in the borderline between the basal knob and the bottom of the median ceratophore, such that when it becomes detached, there would be no tissue fragments over the rather smooth, clean basal knob. This happens in lateral antennae but there it is the ceratostyle what becomes lost, and the tips of ceratophores look clean, without tissue fragments. This could be clarified during the study of living specimens, and about their capabilities of regeneration.

Iphione hyndmani is sister to I. ankeri sp. nov. (see below) in the COI tree ( Fig. 36 ).

Distribution. Recorded from the Mascarene Islands east to Micronesia and Fiji, on reefs and in rocky or mixed bottoms in shallow water (0–15 m).

Figures

FIGURE 4. Iphione muricata (Savigny in Lamarck, 1818), restricted. A. Syntype MNHN 334, dorsal view. B. Same, anterior elytron (inset: fimbriae from another elytron). C. Same, median elytron. D. Chaetiger 14, left parapodium, posterior view after removal of notochaetae. E. Same, median neurochaetal tips. F. Syntype MNHN 335, two detached elytra before cleaning. G. Same, median elytron. H. Same, posterior elytron. I. Fimbriae of posterior elytron. J. Chaetiger 12, left parapodium, posterior view, after removal of notochaetae. Scale bars: A, 2 mm; B, 0.7 mm; C, 1 mm; D, 0.4 mm; E, 30 µm; F, 1.3 mm; G, 1.2 mm; H, 1.6 mm; I, 30 µm; J, 0.6 mm.

FIGURE 24. Iphione hyndmani sp. nov., holotype (UF 5695). A. Anterior end, dorsal view after removal of some elytra. B. Same, close-up of prostomium and appendages. C. Right elytron 2 (above), and left elytron 4, dorsal view. D. Left elytron 6, dorsal view. E. Chaetiger 14, left parapodium, posterior view after removal of notochaetae and Methyl green staining (insets: above, upper neurochaetae; below, lower neurochaetae). Scale bars: A, 2 mm; B, 1.1 mm; C, 1 mm; D, 0.9 mm; E, 0.6 mm.

FIGURE 25. Iphione hyndmani sp. nov., paratype (UF 5689). A. Dorsal view. B. Sixth right elytron, dorsal view. C. Chaetiger 12, right parapodium, posterior view (notochaetae removed) after Methyl green staining (AMGS). D. Pharynx, frontal view (AMGS). E. Same, right lateral view (AMGS). Scale bars: A, 1.2 mm; B, D, 0.5 mm; C, 0.2 mm; E, 0.6 mm.

FIGURE 26. Iphione hyndmani sp. nov., non-type specimen (USNM 19192). A. Anterior region, dorsal view, after Shirlastain- A. B. Close-up of prostomium. Scale bars: A, 0.8 mm; B, 0.2 mm.

FIGURE 36. Maximum Likelihood phylogeny of Iphione species with localities and catalog numbers. Numbers above branches are bootstrap support (>70 only) (PNG: Papua New Guinea) (modified after Piotrowski et al. 2024).