Iphione hirotai Izuka, 1912

Salazar-Vallejo, Sergio I., Piotrowski, Christina N. & Paulay, Gustav, 2024, Revision of Iphione Kinberg, 1856 (Annelida, Aphroditiformia, Iphionidae), Zootaxa 5548 (1), pp. 1-84 : 34

Iphione hirotai Izuka, 1912

Iphione hirotai Izuka, 1912: 63–65 , Pl. 7, Figs 8–15 .

Iphione muricata : Fauvel 1936: 51; Imajima & Hartman 1964: 17 (non Savigny in Lamarck, 1818).

Remarks. Iphione hirotai Izuka, 1913 resembles I. ovata Kinberg, 1856 , described from Hawaii and widely distributed from the Red Sea to the Eastern Pacific ( Piotrowski et al. 2024). We did not have any specimens of the former species but, after the original description, and as indicated in the key above, the main differences are in the shape of nuchal lappets, and in the size and number or macrotubercles in elytra. Thus, I. hirotai has a truncate nuchal lappet, and its macrotubercles are digitate, up to twice longer than wide, arranged in 5–6 rows (body 14 mm long), whereas I. ovata has round nuchal lappet, and its macrotubercles are conical, 2–5 times longer than wide, and arranged in 3–5 rows (size-dependent).

Izuka (1912) illustrated the elytra with smooth margins and with macrotubercles arranged in 5–6 rows. Because the presence of fimbriae was regarded as irrelevant, it was regarded as a junior synonym of I. muricata ( Augener 1922: 5–6; Okuda 1937: 266). Imajima & Hartman (1964: 17) indicated neurochaetae were unidentate, with 11–12 rows of serrations, but Izuka (1912: 65, Pl. 7, Fig. 15 ) indicated 2–3 rows. Pettibone (1986: 16) noted there was no type material, and regarded it as a junior synonym of I. ovata Kinberg, 1856 . Against this synonymy, it should be noted the lack of basal tubercle in dorsal cirrophores, as indicated by Izuka (1912, Pl. 7, Fig. 12 ), whereas it is present in I. ovata .

Distribution. Originally described with a single specimen from one locality in Japan (Peel Island, Bonin Islands).

Figures

FIGURE 8. Iphione fimbriata de Quatrefages, 1866, reinstated, paratype of I. fustis Hoagland, 1920 (USNM 18969).A.Anterior end, dorsal view, after Methyl green staining. B. Anterior elytra, above: right elytron from chaetiger 2; below: left elytron from chaetiger 4. C. Left elytron from median chaetiger, dorsal view (insets: fimbriae, and smaller marginal spines). D. Chaetiger 14, left parapodium, posterior view after Methyl green staining. E. Same, upper and medial neurochaetae. F. Same, medial and lower neurochaetae. Scale bars: A, 1.1 mm, B, 1 mm; C, 2 mm; D, 0.6 mm; E, 100 μm; F, 80 μm.

FIGURE 9. Iphione fimbriata de Quatrefages, 1866, reinstated, paratype of I. fustis Hoagland, 1920 paratype (USNM 18968), elytra previously removed, seen from above.A. Second right elytron. B. Third right elytron. C. Fourth right elytron. D. Fifth left elytron. E. Sixt left elytron. F. Non-type specimen (USNM 81972), anterior end, dorsal view. G. Another specimen from same lot, pharynx previously dissected, seen from inside, depressed by glass slide. Scale bars: A, 0.7 mm; B, G, 0.8 mm; C, 1.1 mm; D, E, 0.6 mm, F, 1.3 mm.

FIGURE 10. Iphione henshawi Pettibone, 1986, paratype (USNM 5439). A. Anterior end, dorsal view. B. First elytron, dorsal view (inset: close-up of fimbriae). C. Right anterior elytron, with some calcareous epibionts. D. Left posterior elytron (inset: close-up of macrotubercles and spines). E. Cirrigerous right parapodium, posterior view. F. Same, neurochaetae of mid-bundle. G. Same, neurochaetae of lower bundle. Scale bars: A, 1.8 mm; B, C, 1.4 mm; D, 2.6 mm; E, 1.1 mm; F, G, 0.7 mm.

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 12. Iphione treadwelli Pettibone, 1986, holotype (USNM 5435). A. Right lateral view (head points to the right). B. Same, anterior region, after Methyl green staining. C. Previously detached median left chaetiger. D. Chaetiger 12, left parapodium, posterior view, after Shirlastain-A staining (inset: upper neurochaetae tips). Scale bars: A, 0.8 mm; B, C, 0.4 mm; D, 150 µm.

FIGURE 13. Iphione treadwelli Pettibone, 1986, paratype (USNM 81934).A. Dorsal view. B.Anterior end, dorsal view. C. Left median elytron, dorsal view. D. Same, marginal macrotubercle and fimbriae. E. Same, fimbriae. Scale bars: A, 0.7 mm; B, 0.4 mm; C, 0.2 mm; D, 0.1 mm; E, 50 μm.

FIGURE 14. Iphione treadwelli Pettibone, 1986, non-type specimen (ECOSUR). A. Dorsal view. B. Right elytron 6, dorsal view (asterisks indicate enlarged areas). C. Same, one macrotubercle. D. Same, outer fimbriae. E. Left parapodium of chaetiger 12, posterior view (inset: close-up of basal tubercle showing darker glandular area). F. Same, upper neurochaetae. Scale bars: A, 0.9 mm; B, 0.6 mm; C, 140 μm; D, 30 μm; E, 0.2 mm; F, 50 μm.

FIGURE 15. Iphione coriolis Hanley & Burke, 1991, holotype (MNHN TYPE 574). A. Anterior end, dorsal view. B. Right elytron from median chaetiger. C. Left elytron from postmedian chaetiger. D. Chaetiger 12, right parapodium, posterior view. Scale bars: A, B, 0.4 mm; C, 0.5 mm; D, 0.2 mm.