Flabelligera kozaensis Jimi, 2022

Jimi, Naoto, Hasegawa, Naohiro, Taru, Masanori, Oya, Yuki, Kohtsuka, Hisanori, Tsuchida, Shinji, Fujiwara, Yoshihiro & Woo, Sau Pinn, 2022, Five New Species of Flabelligera (Flabelligeridae: Annelida) from Japan, Species Diversity 27 (1), pp. 101-111 : 107

Flabelligera kozaensis Jimi , sp. nov.

[Japanese name: Koza-kanten-habouki] ( Fig. 5 )

Material examined. Holotype (NSMT-Pol H-875): 35 mm long, 3 mm wide, 56 chaetigers, complete body, Koza , Wakayama, Japan (33°29′57″N, 135°50′15″E), 34 m depth, 11 April 2021, collected by Naoto Jimi. Paratypes: four specimens (NSMT-Pol P-876), 30–45 mm long, 3–4 mm wide, 52–58 chaetigers, complete body, collected with the holotype.

Description. Body cylindrical posteriorly ( Fig. 5A ). Tunic thick, opaque, densely papillated, with cover of fine sediment particles. Sediment particles covering all of notochaetal and neurochaetal lobes. Body papillae short, thin, digitate. Gonopodial lobes not seen.

Cephalic cage chaetae about 1/9 body length, as long as body width ( Fig. 5B ). Chaetiger 1 comprising cephalic cage; chaetiger 1 with 37 notochaetae and 26 neurochaetae per side. Chaetiger 1 longer than chaetigers 2–3. Chaetal transition from cephalic cage to body chaetae abrupt, chaetiger 2 with multiarticulated neurohooks.

Prostomium rounded. Brown eyes present, two pairs, anterior eyes larger than posterior ones ( Fig. 5C ). Caruncle developed, wide, exceeding branchial plate margin, distally blunt ( Fig. 5C ). Lateral lips developed, fused to dorsal lip ( Fig. 5C ). Ventral lip triangular, without ventral projection. Palps pale, thick, slightly longer than branchiae, about four times thicker than branchiae. Palp scars rounded, elevated, dorsal margin well developed and elevated as papillae ( Fig. 5C ). Branchiae in two lateral groups, each with filaments in concentric rows, each group with 28 filaments. Nephridial lobes paired, lateral to caruncle, median distance of branchial groups.

Parapodia developed, lateral; median neuropodia ventrolateral. Notopodial lobes projected, digitate, truncate, exceeding tip of notochaetae, without different papillae. Neuropodial lobes projected, club shaped, without different papillae. Noto- and neuropodia widely separated. Notochaetae multiarticulated capillaries, transparent, 1/2 body width, 14 per bundle, with approximately 10 articles; articles mediumsized medially and distally. ( Fig. 5D–G ). Neurochaetae multiarticulated capillaries in chaetiger 1. Multiarticulate neurohooks present in chaetiger 2 and succeeding posterior chaetigers, golden, one per ramus, with 7 medium sized articles medially, other articles anchylosed, without short articles, articles absent in basally. Crest slightly wider than handle, width: length ratio 1: 4 ( Fig. 5H–I ).

Posterior end truncated; pygidium with anus terminal, not covered by tunic, thick muscular ring, without anal cirri.

Etymology. This species is named after the type locality (Koza).

Remarks. This species resembles F. salazarae SalazarVallejo, 2012 and F. haswelli Salazar-Vallejo, 2012 in having neurohook with short crests and smooth dorsal surface of body ( Salazar-Vallejo 2012). The new species can be discriminated from the two species by having better defined chaetal lobes, dorsal elevation of palp scars, and neurohooks without distinct short articles.

Figures

Fig. 5. Flabelligera kozaensis sp. nov., holotype (NSMT-Pol H-875). A, Whole body, lateral view, in live; B, anterior end, ventral view, in live; C, prostomium, frontal view; D, notochaetae, chaetiger 12; E, distal part of notochaetae; F, enlarged view of middle part of notochaetae; G, basal part of notochaetae; H, neurohook, chaetiger 12; I, enlarged view of middle part of neurohook. Scale bars: A, B, 1cm; C, 1mm; D, 200µm; E, 100µm; F, 50µm; G, H, 200µm; I, 100µm. Abbreviations: bs, branchial scar; ca, caruncle; cc cephalic cage; dp, dorsal side elevation of palp base; e, eye; ll, lateral lip; ps, palp scar.