Sosane trigintaduo, 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 : 153

Sosane trigintaduo sp. nov.

( Figs. 10 A–H; 17A)

Specimens examined. Holotype: NSMT-Pol. H 564, Bungo Channel, 32°43.0'N, 132°32.3'E – 32°42.9’N, 132°32.0'E, 84−99 m, KT 99-18, St. DG-1, 12.1999, (1cs). Paratype: NSMT-Pol P 565, Off Tsushima Island, 34°15.1'N, 130°15.0'E – 34°15.0'N, 130°14.9'E, 100 m, Soyo-maru, SO 08-D5, 7.2008, (1af).

Description. Length 9 mm, width 1 mm. Prostomium with middle lobe delimited by incision, without glandular ridges or eyes ( Fig. 10 A, B, C). Buccal tentacles without groove, smooth. Lower lip crenulated ( Fig. 10 B). Four pairs of cirriform branchiae ( Fig. 10 A); three pairs of branchiae in transverse row in segment II, 1 pair of branchiae in segment IV; branchial groups separated by wide median gap; 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 emerging next to notopodia of segment IV ( Fig. 17 A). Chaetae in segment II absent. Notopodia with limbate capillary notochaetae from segment III, present in 16 segments. Notopodia in fourth-to-last thoracic unciniger elevated, basally inflated, apically conical, not connected by dorsal ridge ( Fig. 10 D, E); notochaetae of modified unciniger in fan-like arrangement on convex side of notopodia, with hirsute tips ( Fig. 10 F). Neuropodial tori with uncini from segment VI, present in 13 thoracic uncinigers. Cirri and papillae in thoracic parapodia absent. Last segment of continuous ventral shields indeterminable. One intermediate unciniger. Eight abdominal uncinigers. Rudimentary notopodia and glandular pads in intermediate and abdominal uncinigers absent. Pinnules without cirri or papillae. Pygidium with terminal anus and one pair of short ventrolateral cirriform anal cirri ( Fig. 10 G). Thoracic and abdominal uncini with crest of numerous teeth above rostral tooth and basal prow ( Fig. 10 H).

Remarks. Sosane trigintaduo sp. nov. is the first species of the genus with 13 thoracic uncinigers and the modification located in the fourth-to-last thoracic unciniger. We consider Sosane trigintaduo sp. nov. the possible link between the genus Lysippe and the remaining Sosane species, as discussed in the phylogenetic analysis.

Etymology. The species name “ trigintaduo ” is Latin for thirty-two, which refers to the 32 notopodia (16 pairs)–a unique character state in the genus Sosane .

Distribution. Sagami Bay, Pacific coast of central Honshu, in ca. 100 m.

Figures

FIGURE 10. Sosane trigintaduo sp. nov. A: anterior end, dorsal view, 36 x, B: anterior end of a paratype, lateral view, 34 x, C: prostomium, dorsal view, 36 x, D: posterior end, dorsolateral view, 32 x, E: thoracic unciniger 10, anterior view, 60 x, F: modified notochaeta of thoracic unciniger 10, 1100 x, G: posterior end, ventral view, 64 x, H: thoracic uncinus, 990 x.

FIGURE 17. ID-cards of reported species with modified notopodia. A: Sosane trigintaduo sp. nov., B: Sosane uebelackerae sp. nov., C: Sosane wireni, D: Tanseimaruana boninensis gen. et sp. nov., E: Zatsepinia jirkovi sp. nov., F: Zatsepinia rittichae. Abbreviation: V = velum, other abbreviations as shown in figure 16.