Laubieriopsis soyoae, Jimi & Fujimoto & Ogawa & Fujita & Shigenobu & Imura, 2020

Jimi, Naoto, Fujimoto, Shinta, Ogawa, Akito, Fujita, Yoshihisa, Shigenobu, Yuya & Imura, Satoshi, 2020, Two new species of Fauveliopsidae (Annelida, Sedentaria) from submarine caves and deep sea, Japan, Zootaxa 4878 (2), pp. 385-391 : 389-390

Laubieriopsis soyoae sp. nov. Jimi

(New Japanese name: Soyo-sube-imomushi-gokai)

( Figure 3 )

Type material. Holotype (NSMT-Pol H-825): 13 mm long, 0.3 mm wide, and 50 paratypes (NSMT-Pol P-826): 10–15 mm long (n=50), 0.3 mm wide (n=50), 24 chaetigers (n=50); free living, sand sediment, off Mikura Island , Tokyo, Japan, by a beam trawl ( Fig. 1C, D ), at a depth of 1114–1171 m, collected by NJ. One paratypes (ICHUM- 6161): fragmented, used for SEM observation.

Description. Holotype (NSMT-Pol H-825) body complete, 13 mm long, 0.3 mm wide, with 24 chaetigers, cylindrical, not swollen in middle region ( Fig. 3A, 3B ). Living colour transparent ( Fig. 3A ). Prostomium partially exposed, fused to peristomium ( Fig. 3C ). Mouth opening ventral, T-shaped. Integument iridescent, smooth, not papillated. Genital papillae unpaired ( Fig. 4B ), low oval projections, present on right side of posterior margin of chaetiger 8. Anterior segments without annulations.

Parapodia biramous, lateral, projected along chaetigers 1–3, inconspicuous in subsequent body region. Interramal papillae, non-pedunculate. All chaetae brownish.

Chaetigers 1–3 ( Fig. 3D ), with chaetae directed anteriorly: notopodia and neuropodia with four curved acicular chaetae per bundle. In chaetiger 4 and following chaetigers ( Fig. 3E ), chaetae directed laterally or posteriorly: notopodia and neuropodia with short acicular and long capillary chaetae. Acicular chaetae smooth, tips entire, without denticles in tips. Capillary chaetae smooth.

Pygidium without anal cirri and papillae ( Fig. 3F ), withdrawn into posterior segment; chaetae shape same in median chaetigers; anus terminal.

Etymology. The species is named after the R/V Soyo -maru. The type specimens from off Mikura Island were collected by the gear present on the ship. The specific name is a noun in the genitive case.

Distribution. Only known from the type locality, off Mikura Island, Tokyo, Japan, at a depth of 1114–1171 m.

Remarks. Laubieriopsis soyoae sp. nov. can be distinguished from the other members of the genus by the following features: i) 24 chaetigers, ii) chaetigers 1–3 without annulations, and iii) acicular chaetae with tips entire, without denticles. This species most resembles L. arenicola ( Riser, 1987) by having acicular chaetae with tapered smooth tips and body with more than 21 chaetigers; however, annulations in chaetigers 1–3 are only present in L. arenicola ( Riser 1987; Salazar-Vallejo et al. 2019), and the body has 25 chaetigers. Laubieriopsis hartmanae has been known from Japan ( Levenstein 1970; Imajima 2009; Salazar-Vallejo et al. 2019). The new species can be discriminated from L. hartmanae by having 24 chaetigers, instead of only 16, and genital papillae on chaetiger 8, instead of being present between chaetigers 6–7.

Figures

FIGURE 1. Photos of sampling sites. A, Daidokutsu cave, off Ie Island; B, same, sediments of the cave, silt; C, beam trawl off Mikura Island; D, sand collected by the beam trawl.

FIGURE 3. Laubieriopsis soyoae sp. nov. (A) holotype (NSMT-Pol H-825). (B–F) paratype (ICHUM-6161). A, fresh specimen, lateral view; B, fixed specimen, anterior end, lateral view; C, fixed specimen, prostomium, frontal view; D, fixed specimen, chaetae of chaetigers 1–3; E, fixed specimen, chaetae of median chaetigers; F, pygidium, ventral view. Scale bars = 2.5 mm (A); 1 mm (B); 200 μm (C); 200 μm (D); 100 μm (E); 200 μm (F). Abbreviation: ac, acicular chaetae; cc, capillary chaetae; noc, notochaetae; nuc, neurochaetae; pe, peristomium; pr, prostomium; sa, sigmoid acicular chaetae. White arrows indicate internal papillae.

FIGURE 4. Papillae of the new species. (A) body papilla of Fauveliopsis antri sp. nov. (B) genital papilla of Laubieriopsis soyoae sp. nov. Scale bars = 5 μm (A); 125 μm (B).