Iphione wilsoni, 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 : 73-76

Iphione wilsoni sp. nov.

urn:lsid:zoobank.org:act:8EE1E870-B326-4A0A-B375-BE8782A39B0D

Figs 34 , 35

Iphione muricata : Hanley & Burke 1991: 39–41, Fig. 11 (non (Savigny in Lamarck, 1818)).

Type material. Australia. Holotype ( NMV F164310 ), Western Australia, Ashmore L30 Transect, SS05/2007 Sta. 188 (12°26’42.0” S, 123°36’03.6” E), 95 m, beam trawl, 6 Jul. 2007.

Additional material

Coral Sea. One specimen ( MAGNT W5511 ), Cruise Corail 2, RV Coriolis, Fairway Atoll ( Reef) , Sta. RH 88.46 (20°53’ S, 161°41’ E), 60 m, 20 Aug. 1988, J.R. Hanley, coll.

Indonesia. One specimen ( ZMA V471.5 ), Sulawesi, RV Siboga Exped., Sta. 125 ( Siau Island , anchorage off Sawan), 27 m, dredge, townet, Monaco trap, reef-exploration, stones, 18–19 Jul. 1899 (markedly bent ventrally; juvenile; right elytra 3, 6 and 9 removed for observation; elytra yellowish without black spots; macrotubercles in two rows, towards posterior margin, each erect, subcylindridal, brittle, with many spines along stem; no further dissected nor measured to avoid further damage) .

Diagnosis. Iphione with median antenna reduced to nuchal papilla; elytra with margins smooth, non-fimbriate; macrotubercles cylindrical or tapered, with distal spines, in six or more rows, first row with macrotubercles markedly larger than those in other rows; cirrigerous segments with dorsal cirrophores with basal tubercle projected; neurochaetae unidentate.

Description. Holotype (NMV F164310) bent ventrally ( Fig. 34A ), 22 mm long, 12 mm wide, 29 chaetigers; first four pairs of elytra previously removed; right elytron 6 and left parapodium of chaetiger 12 removed for observation.

Elytra yellowish with an oblique, irregular black band, and darker along posterior margins, almost without calcareous epibionts, without fimbriae ( Fig. 34B ). Macrotubercles arranged in 5–6 rows, subcylindrical, largest along external margins, markedly larger and bent middorsally, other erect or bent anteriorly, with spiny stems and stellate tips, each with 4–5 spines ( Fig. 34C ). Macrotubercles with spines more abundant along posterior margins ( Fig. 34D ).

Prostomium retracted, roughly hexagonal, as long as wide, with a deep longitudinal depression along anterior prostomial half. Anterior lobes projected into ceratophores, blackish, longer than prostomium, ceratostyles lost. Palps pale, three times longer than ceratophores. Eyes blackish, positioned in posterior prostomial half, anterior eyes lateral, 1/3–1/2 as large as posterior, dorsal eyes. Nuchal papilla not visible.

Tentacular segment dorsally reduced, cirri as long as palps, chaetae not seen, probably lost. Facial tubercle blackish, visible dorsally.

Segments 2–4 directed anteriorly. Second segment not visible dorsally; nuchal lappet hidden below anterior margin of segment 2, semicircular. Ventral buccal cirri inserted ventrally, longer than following ventral cirri, right one lost, left one not surpassing chaetal tips. From segment 3, one pair of depressed, separate dorsal nodules per segment, only first pair visible, the others distorted by body contraction. Segments 2–3 with finer neurochaetae, barely swollen subdistally, with a longer region covered by series of transverse denticulations.

Median cirrigerous segments ( Fig. 34E ) with dorsal cirri slightly surpassing chaetal tips (many cirrostyles lost), resembling tips of tentacular cirri; dorsal cirrophores smooth, basal tubercle projected. Notochaetae whitish, very abundant, delicate capillaries with series of transverse funnel-shaped spinose rows, tips bare. Neuropodia with neuracicular lobe 2–3 times longer than wide, blunt; neurochaetal lobe with small globular papillae. Neurochaetae golden, thick abundant, basally smooth, subdistally swollen, with series of denticulations along swollen region, tips falcate, sharp ( Fig. 34F ).

Anus dorsal, positioned between elytral pairs 12 and 13.

Etymology. This species is being named after Robin Wilson, a well-known polychaete specialist working in the Museums Victoria Research Institute, Australia, in recognition of his many publications on taxonomy of marine annelids, and by his support for our studies on scaleworms. The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Variation. A large specimen (MAGNT W5511) has a body rather truncate, instead of being oval, 30 mm long, 18 mm wide, 29 chaetigers. The anterior 7 pairs of elytra, and two left and one right parapodia previously removed (most elytra in container, parapodia lost), right parapodium of chaetiger 12 removed for observation. Elytra yellowish with an oblique longitudinal black band ( Fig. 35A, B ); macrotubercles subcylindrical, tapered, bent middorsally or anteriorly, smaller ones erect, tips stellate, arranged in 6 rows, progressively smaller posteriorly. Cirrigerous segments with basal tubercle of dorsal cirrophores projected ( Fig. 35C ); dorsal cirrostyles tapered, ventral cirrostyles mucronate; neurochaetal lobe with one long cirriform papillae, if seen in anterior view ( Fig. 35D , inset), other papillae globular; neurochaetae unidentate.

Remarks. Iphione wilsoni sp. nov. separates from other species of Iphione lacking elytral fimbriae by the type and shape of macrotubercles, and by the type of neurochaetae. In I. wilsoni macrotubercles are subcylindrical with tips stellate, whereas they are blunt in the other species, and it has unidentate neurochaetae, whereas they can be bidentate in some other species.

Hanley & Burke (1991: 39) illustrated what they regarded as I. muricata (Savigny in Lamarck, 1818). However, the elytra lack fimbriae and are different from I. muricata by having thinner, mostly erect macrotubercles, and the additional smaller ones have stellate tips. These specimens were not available but they seem conspecific with I. wilsoni .

Distribution. Western Australia through Indonesia to the Coral Sea, in deeper subtidal mixed bottoms (27–95 m).

Figures

FIGURE 11. Iphione henshawi Pettibone, 1986, non-type specimen (BPBM R481). A. Anterior end, dorsal view (elytra 1–3 removed). B. Left elytra 1–3, dorsal view. C. Elytron 3, close-up of fimbriae, some macrotubercles in the lower area. D. Same, close-up of macrotubercles. E. Cirrigerous left parapodium of median segment, posterior view. Scale bars: A, 0.8 mm; B, 1.4 mm; C, D, 0.3 mm; E, 0.5 mm.

FIGURE 34. Iphione wilsoni sp. nov., holotype (NMV F164319). A. Dorsal view. B. Right elytron 6, dorsal view. C. Same, close-up of external margin after Shirlastain-A. D. Another elytron, transverse section across central macrotubercles region. E. Chaetiger 12, left parapodium, posterior view after removal of notochaetae. F. Same, neurochaetal tips. Scale bars: A, 2.7 mm; B, 0.8 mm; C, E, 0.4 mm; D, 150 µm; F, 130 µm.

FIGURE 35. Iphione wilsoni sp. nov., non-type specimen (MAGNT w5511). A.Anterior left elytron. B. Median left elytron. C. Chaetiger 12, right parapodium, posterior view (after Methyl green staining). D. Same, anterior view (inset: tip of neuracicular lobe). Scale bars: A, 1.1 mm; B, 1.2 mm; C, 0.7 mm; D, 0.5 mm.