Lamispina miurai, Higashida & Jimi & Kajihara, 2020

Higashida, Yuki, Jimi, Naoto & Kajihara, Hiroshi, 2020, Lamispina miurai sp. nov. (Annelida: Flabelligeridae) from off Aomori, Japan, Species Diversity 25, pp. 329-342 : 331

Lamispina miurai sp. nov.

[New Japanese name: Miura-sasanoha-habouki] ( Fig. 1 )

Diagnosis. Body surface without sand particles. Cephalic cage well developed, twice as long as body width (widest chaetiger). Anchylosed lamispine present in chaetiger 4 and succeeding posterior chaetigers, without accessory tooth, with tips curved and subdistally serrated.

Material examined. Holotype: NSMT-Pol H-814, 21 mm long, 3 mm wide (widest chaetiger), 42 chaetigers (incomplete), sex unknown, off Aomori, 226–228 m depth, 4 October 1988, collected by Prof. Tomoyuki Miura. Paratypes: ICHUM 5768, 2 specimens, 12–16 mm long, 1.5–2.0mm wide (widest chaetiger), 21–34 chaetigers (incomplete), sex unknown, collection data same as holotype.

Description of holotype. Body cylindrical, tapered in posterior region, yellowish after fixation ( Fig. 1A–C ). Body surface without sand particles ( Fig. 1A, B ). Body papillae long, thin, digitate, 1/4 times as long as parapodial papillae, arranged in 5–6 irregular transverse bands per segment; sediment particles attached on base. Gonopodial lobes absent. Gonopores absent.

Prostomium low cone; brown eyes present; caruncle developed; lateral and ventral lips expanded; dorsal lip not well developed ( Fig. 1C ). Palps broken. Branchiae broken; scars arranged in continuous dorsal series, eight in number ( Fig. 1C ). Nephridial lobes present.

Cephalic cage well developed, twice as long as body width (widest chaetiger). Chaetigers 1–3 comprising cephalic cage; chaetiger 1 with 9 notochaetae and 5–6 neurochaetae; chaetiger 2 with 4 notochaetae and 5–6 neurochaetae; chaetiger 3 with 4–5 notochaetae and 3–4 neurochaetae (some chaetae broken). Chaetal transition from cephalic cage to body chaetae abrupt ( Fig. 1A ).

Parapodia poorly developed. Noto- and neuropodial low lobes with 8–12 internal papillae and 7–10 postchaetal papillae; 8–9 chaetae per notopodia; 6–7 chaetae per neuropodia. Notochaetae multiarticulated capillaries, brownish, with approximately 65 articles; articles medium-sized basally, long medially and distally ( Fig. 1E, H, I ). Neurochaetae multiarticulated capillaries in chaetigers 1–3, brownish; anchylosed lamispines present in chaetiger 4 and succeeding posterior chaetigers, brownish, without accessory tooth, with approximately 80 articles same-sized, with tips curved and subdistally serrated ( Figs. 1D, F, G ).

Posterior end of body unknown.

Etymology. This species is named after Prof. Tomoyuki Miura who donated his specimens that contained the type specimens to ICHUM. The specific name is a noun in the genitive case.

Distribution. Only known from the type locality, off Aomori, Japan, 226–228 m in depth.

Remarks. Lamispina miurai sp. nov. resembles L. carrerai Salazar-Vallejo, 2014 , L. chilensis Salazar-Vallejo, 2014 , L. gymnopapillata ( Hartmann-Schröder, 1965) , L. horsti ( Haswell, 1892) , and L. kerguelarum ( Grube, 1877) in that their body is not covered by sand or large sediment particles ( Grube 1877; Haswell 1892; Hartmann-Schröder 1965; Salazar-Vallejo 2014). In L. miurai sp. nov., the tip of the lamispine is curved and subdistally serrated unlike in the other species. Besides that, L. miurai sp. nov. differs from L. horsti and L. kerguelarum by the structure of the cephalic cage, which is formed by chaetigers 1–3 in L. miurai sp. nov., but by chaetigers 1–2 in the latter two. In L. miurai sp. nov., the length of the cephalic cage is twice as long as the body width, while it is 3.5 times longer than wide in L. chilensis , and six times longer than wide in L. carrerai . In L. miurai sp. nov., the branchial scars are arranged in a continuous dorsal series; in L. gymnopapillata , however, they are arranged in two groups, with four bases forming a continuous row, other bases into two lateral groups, each comprised of two scars.

Figures

Fig. 1. Photographs of Lamispina miurai sp. nov., holotype, NSMT-Pol H-814. A, Anterior end, dorsal view; B, anterior end, ventral view; C, prostomium, frontal view; asterisks indicating branchial scars, white arrows pointing to nephridial lobes, black arrow pointing to eyes; D, chaetiger 34, neurochaetae; E, chaetiger 34, notochaetae; F, enlarged view of neurochaetae; G, tip of neurochaeta; H, base of notochaetae; I, tip of notochaeta. Abbreviations: Ca, caruncle; LL, lateral lip; PS, palp scar; VL, ventral lip. Scale bars: A, B, 1mm; C, 500µm; D, E, F, 100µm; G, 10µm; H, I, 100µm.