Uncopodarke Uchida, 2019

Hiro, Uchida, omi, Lopéz, Eduardo & Sato, Masanori, 2019, New Hesionidae (Annelida) from Japan: Unavailable Names Introduced by Uchida (2004) Revisited, with Reestablishment of their Availability, Species Diversity 24, pp. 69-95 : 83-86

Genus Uncopodarke Uchida , gen. nov

Uncopodarke Uchida, 2004: 68 (nomen nudum, without type species fixation); Ruta et al. 2006: 101.

Diagnosis. Prostomium sub-conical, with two antennae, without facial tubercle. Palps minute (sometimes absent), inserted ventrally. Eyes minute. Six pairs of tentacular cirri on first three anterior segments. Chaetiger 1 uniramous, with compound claw-shaped chaetae and regular falcigers in neuropodia; parapodia of remaining chaetigers biramous, with noto- and neurocirri; notopodia reduced, with single acicula and pectinate chaetae; neuropodia with two aciculae (one stout and the other slender) and compound falcigers. Pygidium with two anal cirri; anal lamella entire. Antennae, palps, and all cirri without cirrophores.

Type species. Uncopodarke intermedia sp. nov., fixed by original designation.

Gender. Feminine.

Etymology. The generic name refers both to the presence of claw-shaped chaetae in the first chaetiger (uncus meaning hook) and the superficial similarity between the new genus and Podarke Ehlers, 1864 .

Remarks. All the characters described in the diagnosis, except the presence of claw-shaped compound chaetae in the first chaetiger and the lack of median antenna, are present in the species of Microphthalmus ( Parapar et al. 2004) . This lead to synonymize the two genera ( Westheide 2013) although we consider the exclusive traits of Uncopodarke gen. nov. important enough to erect a genus of its own.

Uncopodarke gen. nov. is also closely related to Struwela Hartmann-Schröder, 1959 . The two genera have a pair of antennae, a pair of eyes, and compound claw chaetae in an anterior segment. Prostomium and compound falcigers in the two genera, furthermore, are similarly shaped. Nevertheless, Uncopodarke gen. nov. differs from Struwela in the following characteristics: (1) the presence of palps; (2) the six pairs of tentacular cirri, instead of four; (3) the compound claw-shaped chaetae short and located in the segment immediately after the last tentacular one, in contrast to those very long and located in the second tentacular segment (4) the pygidium with a pair of anal cirri and a continuous anal lamella, in contrast to that with a pair of anal flaps; and (5) the parapodia biramous with notoacicula, pectinate notochaetae, and neurocirri (except for chaetiger 1), in contrast to those uniramous throughout, lacking notoacicula, notochaetae and neurocirri.

Uncopodarke gen. nov. is also similar to Hesionella Hartman, 1939 in the minute palps, the morphology of notopodia terminating into dorsal cirri, and the presence of six pairs of tentacular cirri and two antennae, but differs from it in the following characteristics: (1) the presence of eyes; (2) the presence of notochaetae (totally absent in Hesionella ); (3) the presence of claw-shaped neurochaetae in chaetiger 1 (segment 4); and (4) the pygidium without anal flaps.

Uncopodarke intermedia Uchida , sp. nov. [New Japanese name: Kagi-suna-otohime] ( Figs 13 , 14 )

Uncopodarke intermedia Uchida, 2004: 70–73 , figs 16, 17 (unavailable specific name, without explicit fixation of name-bearing types).

Microphthalmus intermedia (specific name unavailable): Westheide 2013: 417, 418 (in remarks of M. mahensis Westheide, 2013 ).

Material examined. Holotype: (NSMT-Pol H-758), Nachi-Katsuura, Nachi-Bay, Kii Peninsula , Wakayama Prefecture (33°38′18″N, 135°56′35″E), 2 m depth, sandy bottom, coll. H. Uchida; 27 September 1988. One paratype: (NSMT- Pol P-759), data as for holotype.

Diagnosis. Holotype 3.6 mm long for 31 chaetigers, body colorless. Median antenna lacking; lateral antennae subulate, shorter than prostomium ( Fig. 13A, C ). Palps minute ( Fig. 13B ). Dorsal tentacular cirri markedly longer than ventral ones ( Fig. 13A, B ). Parapodia of chaetiger 1 uniramous ( Fig. 13 F, G ); with 2–4 stout, claw-shaped compound neurochaetae with blades usually folded at joint and 2–3 compound regular neurochaetae ( Fig. 13F–H ). Remaining parapodia biramous. Notopodial lobes with single slender acicular chaeta and 1–2 pectinate chaetae with short, recurved blades ( Fig. 14D ). Neuropodial lobes with long prechaetal lobe ( Fig. 14A–C, G ), bearing 5–7 compound chaetae typical of the genus ( Fig. 14E, F ); most posterior lobes shorter ( Fig. 14H ) and bearing a single, capillary chaeta ( Fig. 14I ). Posterior end with continuous anal lamella ( Fig. 13D, E ).

Etymology. The name of the new species refers to the fact that it has some features intermediate between those of Hesionides-Microphthalmus group and Struwela .

Remarks. The detailed description of the type materials was presented in Uchida (2004). The new species resembles those in Microphthalmus , although it is easily distinguishable by the presence of neuropodial compound claw-shaped chaetae. Apart from this trait, Uncopodarke intermedia sp. nov. is very similar to two Microphthalmus species : M. ancistrosylliiformis Hartmann-Schröder, 1962 , from Chile, which has acicular notochaetae in chaetigers 2–4 (Hartmann- Schröder 1962b), and M. aciculata Hartmann-Schröder, 1962 , from Peru, that bears them in almost every chaetiger ( Hartmann-Schröder 1962a). However, the new species bears notopodial pectinate chaetae (absent in the two latter species) and its acicular notochaetae are slender instead of stout. Except for the presence of neuropodial claw-shaped chaetae in the first chaetiger, U. intermedia sp. nov. is very similar to M. westheidei Hartmann-Schröder, 1981 , from Western Australia ( Hartmann-Schröder 1981), in the shape of anal lamella, notopodial pectinate chaetae, and parapodial notocirri, together with the presence of simple neurochaetae in a few posteriormost chaetigers. However, the serration of compound neurochaetae in the new species is clearly thinner than in M. westheidei . Finally, M. riojai Reish, 1968 , from California, also has reduced palps ( Reish 1968), but they are long enough as to be observed in dorsal view.

Uncopodarke intermedia differs from Struwela noodti Hartmann-Schröder, 1959 from El Salvador (Hartmann- Schröder 1959), by the stouter compound claw-shaped chaetae in the anterior part of body. Additional differences between these two species have been discussed in remarks of the genus (see above).

Figures

Fig. 13. Uncopodarke intermedia gen. et sp. nov., holotype (NSMT-Pol H-758) (A, B, D, F–H) and paratype (NSMT-Pol P-759) (C, E). A, dorsal view of the anterior body. B, ventral view of the same. C, dorsal view of prostomium and antennae of a paratype. D, dorsal view of the posterior end. E, ventral view of the posterior end of a paratype. F, ventral view of right parapodium 1. G, posterior view of the same parapodium (neuropodial acicula omitted). H, compound claw chaeta from the same parapodium. Scale bar: 0.2mm for A; 0.1mm for B–D; 0.05mm for E–G; 0.02mm for H.

Fig. 14. Uncopodarke intermedia gen. et sp. nov., holotype (NSMT-Pol H-758). A, posterior view of right parapodium 2. B, posterior view of left parapodium 8. C, anterior view of the same parapodium. D, notochaetae in left notopodium 8. E and F, neuropodial compound chaetae. G, anterior view of right parapodium 39. H, posterior view of neuropodium of the left last chaetiger. I, simple chaeta from the last chaetiger. Scale bar: 0.05mm for A, C, H; 0.1mm for B, G; 0.02mm for D–F, I.