Anobothrus fimbriatus, Imajima, Minoru, Reuscher, Michael G. & Fiege, Dieter, 2013

Imajima, Minoru, Reuscher, Michael G. & Fiege, Dieter, 2013, Ampharetidae (Annelida: Polychaeta) from Japan. Part II: Genera with elevated and modified notopodia, Zootaxa 3647 (1), pp. 137-166 : 145-146

Anobothrus fimbriatus sp. nov.

( Figs. 5 A–E; 16B)

Specimens examined. Holotype: NSMT-Pol. H 553, off Erimo, Hokkaido, 41°39.06'N, 144°07.54'E – 41°37.15'N, 144°07.56'E, 1997–2043 m, KT-07-29, St. E-3, 11.2007. Paratype: NSMT-Pol. P 554, same locality as holotype (1cs).

Description. Holotype incomplete, length 4 mm, width 0.7 mm. Prostomium with middle lobe delimited by incision, without glandular ridges or eyes ( Fig. 5 A). Buccal tentacles without ventral groove, papillated. Lower lip with distinct furrows and crenulated edge ( Fig. 5 A, B). Four pairs of cirriform branchiae in fused segments II + III ( Fig. 5 A, B); three pairs of branchiae in transverse row without median gap, 4th pair shifted caudally between 2nd outermost and innermost branchiae of transverse row; branchiae of segment II in 2nd outermost position of transverse row, branchiae of segment III in outermost position of transverse row, branchiae of segment IV in innermost position of transverse row, branchiae of segment V shifted caudally ( Fig. 16 B). Chaetae in fused segments II+III originating from segment III, with regular capillary notochaetae and notopodia, present in 15 segments. Notopodia in fifth-to-last thoracic unciniger elevated, connected by dorsal ridge ( Fig. 5 C); notochaetae of modified notopodia with hirsute tips ( Fig. 5 D). Neuropodial tori with uncini from segment VI, present in 12 thoracic uncinigers. Cirri and papillae in thoracic parapodia absent. Circular glandular band absent. Continuous ventral shields present to thoracic unciniger 8. Two intermediate uncinigers. Holotype incomplete, with 1 abdominal unciniger. Rudimentary notopodia and glandular pads in intermediate and abdominal uncinigers absent. Pinnules without cirri or papillae. Nephridial papillae absent. Thoracic and abdominal uncini with crest of numerous teeth above rostral tooth and basal prow ( Fig. 5 E).

Remarks. Holo- and paratype are incomplete. The holotype has 12 thoracic uncinigers, 2 intermediate and 1 abdominal unciniger. The paratype has 12 thoracic uncinigers and 1 intermediate unciniger.

The species is only the second of the genus without paleae in segment II. It can be distinguished from the only other species without paleae, Anobothrus apaleatus Reuscher, Fiege & Wehe, 2009 , by the distinctly crenulated lower lip, the well developed anterior notopodia and notochaetae, and the lack of the circular band in thoracic unciniger 2.

Etymology. The species name refers to the conspicuously frayed lower lip. Distribution. Off Erimo, Pacific coast of Hokkaido, in ca. 2000 m.

Figures

FIGURE 5. Anobothrus fimbriatus sp. nov. A: prostomium, dorsal view, 64 x, B: anterior end, lateral view, 49 x, C: thoracic unciniger 8, dorsolateral view, 68 x, D: modified notochaeta of thoracic unciniger 8, 530 x, E: thoracic uncinus, 1650 x.

FIGURE 16. ID-cards of reported species with modified notopodia. A: Anobothrus dayi sp. nov., B: Anobothrus fimbriatus sp. nov., C: Anobothrus flabelligerulus sp. nov., D: Sosane brevibranchiata sp. nov., E: Sosane sulcata.