Iphione ankeri, 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 : 49-51

Iphione ankeri sp. nov.

urn:lsid:zoobank.org:act:2845CE38-EE26-4B9F-9FB0-9BEF5BA35E2B

Figs 19 , 20 , 36

Type material. Mariana Islands, Guam. Holotype ( UF 1691 ), Apra Harbor , East side of Middle Shoals (13°26’42.0” N, 144°39’32.4” E), 1–15 m, lagoon patch reef, 17 Jun. 2010, N. Evans & F. Michonneau, coll. COI barcode: GenBank PQ 423922 Paratype ( UF 1704 ), Apra Harbor, near Machinist dry dock (13°26’37.1688” N, 144°39’34.0416” E, 22 Jun. 2010, no depth or substrate data, N. Evans, F. Michonneau, G. Paulay & A. Anker, coll. (body 11.5 mm long, 6.5 mm wide, 29 chaetigers; other data in variation).

Additional material. Mariana Islands, Guam. Four specimens ( UF 129 ), Apra Harbor , Sumay Cove (13°30’00.0” N, 144°48’00.0” E), 3–5 m, patch reef, under rubble, 24 Oct. 1999, L. Kirkendale, coll. (bent ventrally; one with pharynx fully exposed; elytra yellowish with an oblique brownish band, expanded laterally along posterior elytral margin; macrotubercles in two rows, sometimes the second row more irregular; cirrigerous segments with dorsal cirrophore with a projected globular basal tubercle; body 12–17 mm long, 7.0– 10.5 mm wide, 29 chaetigers) . Two specimens ( UF 131 ), Apra Harbor , across Sumay Cove (13°30’00.0” N, 144°48’00.0” E), 5 m, patch reef, under rubble, 10 Dec. 1999, L. Kirkendale, coll. (bent ventrally; elytra 1 and 6 removed for observation; elytra yellowish with a black oblique band and macrotubercles in two rows; dorsal cirrophore with basal tubercle projected; body 15–16 mm long, 7.0– 8.5 mm wide, 29 chaetigers) . One specimen ( UF 134 ) Apra Harbor , Western Shoals (13°30’00.0” N, 144°48’00.0” E), 16 m, rubble, 1 Apr. 1998, G. Paulay & B. Smith, coll. (slightly bent ventrally, many elytra and two parapodia previously removed (kept in container); eyes displaced towards posterior prostomial half; elytra yellowish, without black banding; macrotubercles in two rows, second row barely developed; dorsal cirrophores with basal tubercle barely projected; body 11.5 mm long, 6.5 mm wide, 28 chaetigers) . One specimen ( UF 217 ), Apra Harbor , Western Shoals, Southern Face (13°30’00.0” N, 144°48’00.0” E), 9 m, under coral, 15 Apr. 1997, J. Starmer, coll. (slightly bent ventrally; right elytra 6 and 7 removed for observation; elytra yellowish with an ill-defined oblique brownish band; macrotubercles in two rows, first row with larger ones; dorsal cirrophores with basal tubercle globular, well-defined; body 15.5 mm long, 9 mm wide, 29 chaetigers) .

Australia. One specimen ( UF 1754 ), Western Australia, Ningaloo Reef, North Black Rock (22°43’38.136” S, 113°38’45.816” E), 27 m, in rubble crevices, 30 May 2010, C. Bagnato & A. Anker, coll. (juvenile; elytra golden, oblique longitudinal bands barely defined; macrotubercles in two rows, larger along first row; dorsal cirrophores with basal tubercle globular; body 12 mm long, 6.5 mm wide, 29 chaetigers) .

Diagnosis. Iphione with median antenna reduced to nuchal papilla; elytra fimbriate, filaments barely developed, often as long as wide; macrotubercles spine-like up to twice longer than wide, with distal spines, in two rows, first row with macrotubercles slightly larger than those in other rows; cirrigerous segments with dorsal cirrophores with basal tubercle distinct; neurochaetae unidentate.

Description. Holotype (UF 1691), complete, bent ventrally ( Fig. 19A ); right elytra 1–4 and 6, left elytron 1, and both parapodia of chaetiger 12 removed, left parapodia of chaetigers 17–19 removed for molecular studies; body 16 mm long, 8.5 mm wide, 29 chaetigers. Elytra yellow with brownish oblique wide band, and diffuse pigmentation along posterior elytral region, some elytra with whitish epibionts; notochaetae whitish, neurochaetae golden. Body wall pale, parapodia with large coelomic spaces; venter pale, with adsorbed salts in spread granules, ventral cirrophores pale.

Elytra with fimbriae, variably eroded, restricted to a thin submarginal band along lateral margins in median elytra, continued along posterior margins in posterior elytra. Macrotubercles conical, about twice longer than wide, tips with a single spine; first row with macrotubercles barely longer than those present in second row.

First and second elytra with macrotubercles in one row ( Fig. 19B ), following elytra with macrotubercles in two rows; larger macrotubercles towards lateral margins, progressively smaller along series ( Fig. 19C ). Fimbriae delicate, with fine sediment particles, submarginal along lateral in median elytra, continued to posterior region in posterior elytra, fimbriae with a spinous stem, and distal soft tubules, each about as long as fimbria stem, some larger than stems also present.

Prostomium as long as wide, with anterior incision running along half prostomial surface. Anterior lobes projected into ceratophores, blackish, about as long as prostomium and as long as ceratostyles, ceratostyles markedly thinner than ceratophores, tapered. Palps thick, slightly longer than lateral antennae, pale, with longitudinal rows of papillae, right palp with tip tapered, left one mucronate. Eyes black, anterior and posterior eyes displaced posteriorly, almost fused laterally, barely visible dorsally, posterior eyes in posterior prostomial corners. Nuchal papilla pale, rounded, not visible dorsally.

Tentacular segment dorsally reduced, with a few chaetae present; tentacular cirri about as long as palps (observed ventrally). Facial tubercle pale, visible dorsally.

Segments 2–4 directed anteriorly. Second segment visible dorsally, nuchal lappet semicircular, wider than long, completely covering nuchal papilla. Ventral buccal cirri inserted ventrally, three times longer than following ventral cirri, barely 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. 19D ) with dorsal cirri surpassing chaetal tips, subdistally swollen; dorsal cirrophore smooth, contracted, basal tubercle globose, 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 papillae. Neurochaetae thin, abundant, basally smooth, subdistally swollen, sometimes with darker core, with many rows of fine denticulations along swollen region, tips falcate, sharp ( Fig. 19D , insets).

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

Variation. The paratype (UF 1704) is a juvenile, complete. Right elytra 1, 6, 7, left elytra 1 and 4, and parapodia of chaetigers 12 (both) and 13 (left) removed, and left parapodia of chaetigers 19, 20 removed for molecular analysis. The pharynx is fully exposed ( Fig. 20A ); it is conical, with a transparent barely rugose outer layer, and a muscular inner tube ( Fig. 20B, C ). The pharynx opening has two sets of papillae each with 10 papillae, dorsal and ventral, and a middorsal fleshy tubercle above the middorsal papilla. Jaws are brownish with red tips, each jaw has two accessory denticles, and the dorsal pair is more exposed ( Fig. 20D ) than the ventral one. Elytra have an oblique, ill-defined black band, and macrotubercles arranged in two rows, with macrotubercles slightly larger in first row ( Fig. 24E ); fimbriae well developed along lateral and posterior margins, with variable amounts of sediment particles covering the short spines along the stems and distal filaments longer than fimbriae stems ( Fig. 20E , insets).

The additional specimens were 11.5–17.0 mm long, 6.5–10.5 mm wide. Elytra have only two rows of macrotubercles and they are progressively smaller posteriorly.

Etymology. The specific name is derived after Dr. Arthur (Art) Anker, in recognition of his long-term involvement in the Marine Biodiversity Expeditions of the University of Florida, Gainesville, through his collecting efforts, including the collection of some specimens used for describing this species. The specific name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Remarks. Iphione ankeri sp. nov. resembles I. fimbriata de Quatrefages, 1866 , and I. hyndmani sp. nov. from Hong Kong because they have fimbriae short (less than 1/10 elytral width) and first row of macrotubercles slightly larger than those present in following rows. However, I. ankeri differs from the two other species by having fimbriae barely developed (against well-developed in the others), two rows of macrotubercles (against 3–5 in the others), and dorsal cirrophore with basal tubercle distinct (present in I. fimbriata , indistinct in I. hyndmani ). Further, neurochaetae can separate I. ankeri from I. fimbriata ; in I. ankeri they are golden, barely falcate, whereas in I. fimbriata neurochaetae are brownish, markedly falcate.

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

Distribution. Known from West Australia and Guam, in shallow reef habitats (1–27 m).

Figures

FIGURE 19. Iphione ankeri sp. nov., holotype (UF 1691). A. Dorsal view. B. Right elytra 1 and 2, dorsal view. C. Right elytron 6, dorsal view. D. Chaetiger 12, left parapodium, posterior view (insets: upper and lower neurochaetae). Scale bars:A, B, 1 mm; C, 0.5 mm; D, 0.2 mm.

FIGURE 20. Iphione ankeri sp. nov., paratype (UF 1704). A. Dorsal view. B. Pharynx, dorsal view. C. Pharynx, ventral view. D. Pharynx, oblique frontal view. E. Right elytron 7, seen from above (asterisks indicate enlarged areas inserted). Scale bars: A, 1.4 mm; B, C, 0.6 mm; D, 0.4 mm; E, 0.5 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 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).