Oxydromus bunbuku 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 : 73-77

publication ID	https://doi.org/ 10.12782/specdiv.24.69
publication LSID	lsid:zoobank.org:pub:75375441-6EC0-4C7F-B5A1-DEDAC2753C6C
persistent identifier	https://treatment.plazi.org/id/03868D7F-012D-537A-FEEE-FA47C69EF8DD
treatment provided by	Felipe
scientific name	Oxydromus bunbuku Uchida
status	sp. nov.

Treatment

Oxydromus bunbuku Uchida View in CoL , sp. nov.

[Japanese name: Bunbuku-otohime] ( Figs 3 View Fig , 4A, B View Fig )

Ophiodromus berrisfordi View in CoL (non Day 1967): Uchida 1988: 78; Uchida 1992: 321, pl. 63, fig. 8.

Ophiodromus bunbuku Uchida, 2004: 46–48 View in CoL , fig. 7, pl. 1, fig. 3 (unavailable specific name, without explicit fixation of name-bearing types).

Oxydromus bunbuku View in CoL (specific name unavailable): Villalobos-Guerrero and Harris 2012: 24 (referred in checklist); Rizzo and Salazar-Vallejo 2014: 281 (in key).

Type material. Holotype: (NSMT-Pol H-693), Takegashima Marine Park Area No. 2, Shikoku, Tokushima Prefecture (33°32′33″N, 134°19′2″E), 5 m depth, commensal with Brissus latecarinatus (Leske 1778) , coll. H. Misaki, 19 February 1988. Seven paratypes: one (NSMT-Pol P-694), Kushimoto, Wakayama Prefecture (33°28′12″N, 135°46′27″E), lower intertidal, associated with B. latecarinatus , 2 June 1977; one (NSMT-Pol P-695), Sabiura, Kushimoto, Wakayama Prefecture (33°28′51″N, 135°44′45″E), SCUBA diving, 3 m depth, associated with B. latecarinatus , coll. Sh. Ui, 21 March 1982; two (NSMT-Pol P-696), Takegashima Marine Park Area No. 2, Shikoku, Tokushima Prefecture (33°32′33″N, 134°19′2″E), 5 m depth, commensal with B. latecarinatus , coll. H. Misaki, 19 February 1988; three ( NSMT Pol-697), Myogashima Islet, Kushimoto, Wakayama Prefecture (33°27′45″N, 135°47′39″E), SCUBA diving, 25 m depth, associated with B. latecarinatus , coll. K. Nomura, 17 April 1992.

Other material examined. One (HU), Okinoshima, Tateyama, Chiba Prefecture (34°59′26″N, 139°49′8″E), SCUBA diving, associated with B GoogleMaps . agassizii Doderlein, 1885, coll . I GoogleMaps . Soyama , 7 July 1995; one (HU), Tsuruga Bay, Fukui Prefecture, Sea of Japan (35°40′18″N, 136°2′50″E), SCUBA diving, 5 m depth, associated with B GoogleMaps . agassizii, coll . I GoogleMaps . Soyama , 17 May 1999 .

Diagnosis. Holotype 16 mm long for 46 chaetigers, body uniformly dark brown ( Fig. 4A, B View Fig ). Lateral antennae as long as the prostomium; median antenna very short; palps bi-articulated as long as lateral antennae, palpostyle twice as long as palpophore; two pairs of elliptical, orange eyes, anterior ones larger ( Fig. 3A, B View Fig ). Parapodia sub-biramous ( Fig. 3E, F View Fig ). Notopodial cirrophores very long, without marked constriction ( Fig. 3E, F View Fig ) and embedded fine notoaciculae ( Fig. 3F, G View Fig ); notochaetae absent. Neuropodial prechaetal lobe with papilliform projection on its outer margin ( Fig. 3F View Fig ); with two supra- ( Fig. 3H, I View Fig ) and two subacicular ( Fig. 3L, M View Fig ) compound chaetae with long blades; rest neurochaetae with short blades ( Fig. 3J, K, N View Fig ). Pygidiun with a pair of long anal cirri ( Fig. 3D View Fig )

Etymology. Named from the Japanese names of the spatangoid, commensal hosts Brissus latecarinatus (minami-ohbunbuku) and B. agassizii (oh-bunbuku).

Remarks. The detailed description and drawings of the type materials were presented in Uchida (2004). Within the genus, only O. berrisfordi Day, 1967 , from SW Africa, have long notopodial cirrophores and a very short median antenna ( Day 1967). However, the new species can be distinguished of it by the lack of constriction in its notopodial cirrophores, and by the papilliform instead of long, triangular projection on prechaetal lobe.

Although most hesionids are free-living organisms that can be found as carnivores in consolidated or soft substrates, including the interstitial environment, at least 14 species have developed symbiotic life strategies ( Martin and Britayev 1998; Britayev and Antokhina 2012; Britayev et al. 2013; Chim et al. 2013). Usually, symbiont hesionids act as facultative commensals of echinoderms ( Rizzo and Salazar-Vallejo 2014), but in some cases the relationship is highly host-specific ( Britayev et al. 2013). Chim et al. (2013) conducted a field and laboratory study on the biology of the close species O. cf. angustifrons (see their taxonomic discussion), associated with two echinoid species and reported no harmful effects, as the polychaetes apparently fed on small animals that were associated with the food of the echinoid. The worms exhibited an actively territorial behavior against other worms trying to settle on a previously occupied urchin and a quick return to this substrate when separated. Although O. cf. angustifrons was associated with clypeasteroid irregular urchins and O. bunbuku sp. nov. was associated with spatangoid urchins, a similar relationship with the host is presumed. Up to date, no free-living specimen has been reported, so the species is probably an obligate commensal of irregular urchins.

Oxydromus constrictus Uchida , sp. nov. [New Japanese name: Kubire-haya-otohime] ( Figs 4C, D View Fig , 5 View Fig , 6 View Fig )

Ophiodromus constrictus Uchida, 2004: 48–50 View in CoL , fig. 8, pl. 1, fig. 4 (unavailable specific name, without explicit fixation of name-bearing types).

Oxydromus constrictus View in CoL (specific name unavailable): Villalobos-Guerrero and Harris 2012: 24 (referred in check list); Rizzo and Salazar-Vallejo 2014: 281 (in key).

Type material. Holotype: (NSMT-Pol H-698), Sabiura, Kushimoto , Wakayama Prefecture (33°28′51″N, 135°44′45″E), SCUBA diving, 10 m depth, coll. K. Nomura, 22 September 1992. One paratype: (NSMT-Pol P-699), same field data as for holotype, 23 September 1994. GoogleMaps

Additional material examined. Five specimens ( UAM Pol-1-12-6-1-A), Ooto Beach (31°25′10″N, 130°10′24″E), Kataura, Kasasa-cho , Minami-satsuma-shi, Kagoshima Prefecture; attached to Metalia sternalis (Lamarck, 1816) (Euechinoidea, Irregularia) inhabiting a subtidal sandy bottom; coll GoogleMaps . Dr GoogleMaps . D. Uyeno; 28 July 2015.

Diagnosis. Holotype 17 mm log for 50 chaetigers, body uniformly dark brown, with central paler area on prostomium ( Fig. 4C View Fig ). Lateral antennae longer than prostomium; median antenna fusiform, 1/4 as long as the lateral ones; palps as long as lateral antennae, palpostyles 2–3 times longer than palpophores; two pairs of elliptical, whitish eyes, anterior ones larger ( Fig. 5A View Fig ). Parapodia sub-biramous ( Fig. 5C–F View Fig ). Notopodia with long cirrophores, bearing abrupt constriction at two thirds of their length, distal part of cirrophore clearly thinner ( Fig 5E View Fig ); notochaetae absent. Neuropodial prechaetal lobe bearing a long triangular projection ( Fig. 5D, E View Fig ); two supra-acicular neurochaetae with long blades ( Fig. 5H, I View Fig ), rest with short blades ( Fig. 5G View Fig ); subacicular neurochaetae with short blades ( Fig. 5J, K View Fig ). Pygidiun with a pair of long anal cirri ( Fig. 5B View Fig )

Description of newly collected material. Largest specimen complete, 15 mm long, 2.5 mm wide without parapodial lobes, 36 chaetigers. Prostomium ( Fig. 6A, B View Fig ) oval, twice longer than wide. Palps ( Fig. 6B View Fig ) biarticulate; palpostyle tapering, palpophores short, stout, conical, one-third as long as palpostyle. Lateral antennae ( Fig. 6B, C View Fig ) conical, slightly longer than palps. Median antenna ( Fig. 6B, C View Fig ) piriform, very short, one-quarter as long as lateral ones, inserted frontally. Eyes red, large, ( Fig. 6A, B View Fig ), oval, lenticulate; anterior eyes clearly larger than posterior ones. Six pairs of tentacular cirri ( Fig. 6C View Fig ), long, unequal; cirrophores stout, cylindrical; cirrostyles tapering, longest ones as long as body width. Notopodial lobes absent. Neuropodial lobes rectangular; bearing noticeable triangular prechaetal projection, one third as long as lobe ( Fig. 6D View Fig ); with 1–3 (usually 2), stout neuroaciculae, straight, not protruding. Dorsal cirri with irregularly wrinkled or smooth cirrostyles ( Fig. 6D View Fig ), slender, 2–3 times longer than body width; cirrophores ( Fig. 6D, E View Fig ) truncated cones, half as long as neuropodial lobes, with clear constriction at two thirds of their length. Neurochaetae compound falcigers (up to 40 per bundle), 10–20 supra-acicular, 14–20 sub-acicular, with long or short serrate blades ( Fig. 6F, G View Fig ), with unidentate tips bearing thin subdistal tendon. Ventral cirri ( Fig. 6D View Fig ) distal, tapering, half as long as parapodial lobes. Pygidium rounded; bearing two anal cirri, longer and stouter than dorsal cirri of last chaetigers. Pharynx muscular, coarse, with subdistal ring; papillae absent. Live specimens with dorsally brown-striped segments and white prostomium ( Fig. 4D View Fig ); preserved specimens with colour fading in variable degrees.

Etymology. The specific name refers to the conspicuous constriction in the cirrophores of notopodial cirri.

Remarks. The detailed description of the type materials was presented in Uchida (2004). Oxydromus constrictus sp. nov. is very similar to O. angustifrons ( Grube 1878) , described from Philippines Islands ( Grube 1878) and that also occurs in Japan ( Uchida 2004). However, it can be easily separated from the second species by the strong constriction on notopodial cirrophores. Furthermore, the neurochaetae of O. constrictus sp. nov. bear short blades and the longbladed chaetae are restricted to supra-acicular position, whereas the neurochaetae of O. angustifrons bear proportionately longer blades, and long-bladed chaetae are present in both supra- and sub-acicular positions.

This species was at first collected as free living ( Uchida 2004). However, the newly collected specimens of O. constrictus sp. nov. were found crawling among the spines ( Fig. 4D View Fig ) on the surface of individuals of Metalia sternalis ( Spatangoida , Brissidae ). The relationship of this species with its host seems to be similar to that described for the above described O. bunbuku sp. nov., although in this case the commensalism is facultative.