Anobothrus flabelligerulus, 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 : 146-148

Anobothrus flabelligerulus sp. nov.

( Figs. 6 A–H; 16C)

Specimens examined. Holotype: NSMT-Pol. H 555, off Emi, Boso Peninsula, 35°01.0'N, 140°04.6'E – 35°01.3'N, 140°05.1'E, 77–83 m, KT-76-16, St. C-2, 9.1976. Paratype: NSMT-Pol. P 556, same locality as holotype (9cs). Paratypes: off Emi, Boso Peninsula, NSMT-Pol 568, 34°51.5'N, 139°56.0'E, 95 m, KT-76-16, St. C6-1, 9.1976 (1cs); SMF 21691, 35°01.1'N, 140°04.4'E, 75 m, KT-76-16, St. C2-3, 9.1976 (5cs, 13af);. Additional specimens: Miyako Bay, 39°37.4'N, 141°59.1'E, 17 m, St. 6, 7.1967 (3cs). Yamada Bay, 39°28.9'N, 142°02.8'E, 53 m, St.12, 7.1967 (1cs, 2af). Otsuchi Bay, 39°21.2'N, 141°58.8'E, 63 m, 10.1978 (2cs); 39°20.5'N, 141°57.2'E – 39°20.6'N, 141°57.4'E, 43–45 m, 8.1979 (3cs); 39°21.9'N, 141°59.9'E – 39°21.6'N, 141°59.8'E, 84–85 m, 7.1985 (8cs); 39°22.4'N, 142°02.0'E – 39°22.6'N, 142°02.1'E, 113–120 m, 7.1985 (2cs). Tokyo Bay, 35°23.0'N, 139°45.0'E, 20 m, KT-73-6, St. TB-5, 6.1973 (2cs). Sagami Bay, 35°14.2'N, 139°34.5'E – 35°14.6'N, 139°34.4'E, 46 m, St. 14, 9.1979 (2cs); 35°08.6'N, 139°34.9'E – 35°09.0'N, 139°34.8'E, 83 m, St. 4, 9.1979 (2cs); 35°08.5'N, 139°34.7'E – 35°07.9'N, 139°34.6'E, 88–92 m, 10.1979 (1cs); 35°14.4'N, 139°28.7'E – 35°14.9'N, 139°27.4'E, 110–140 m, KT-70–4, St. Bt- 3, 5.1970 (2cs, 1af); 35°12.2'N, 139°12.6'E – 35°12.0'N, 139°12.9'E, 825 m, KT-70-4, St. Bt-1, 5.1970 (2cs); 35°00.3'N, 139°40.2'E – 35°00.2'N, 139°40.5'E, 300– 274 m, Shin'yo-maru, St. 5, 10.2003 (2cs). Off Shimoda, 34°44.8'N, 139°02.0'E – 34°44.9'N, 139°02.1'E, 87- 81 m, St. 6, 10.1981 (2cs). Suruga Bay, 35°01.6'N, 138°51.1'E – 35°02.5'N, 138°50.6'E, 88–99 m, KT-73-15, St. A, 10.1973 (2cs); 34°55.1'N, 138°44.1'E – 34°54.2'N, 138°44.1'E, 313– 304 m, KT-73-15, St. H, 10.1973 (3cs); 34°55.8'N, 138°43.8'E – 34°56.4'N, 138°43.8'E, 365–380 m, KT-76-3, St.003, 2.1976 (1cs); 34°54.4'N, 138°27.7'E – 34°54.4'N, 138°28.0'E, 56–64 m, KT-78-2, St. Z-13, 2.1978 (2af). Off Oga Peninsula, 39°53.6'N, 139°41.5'E – 39°53.6'N, 139°42.5'E, 101– 93 m, St. B-4, 6.1983 (3cs, 1af); 39°48.6'N, 139°50.6'E – 39°48.3'N, 139°50.1'E, 57–62 m, St. A-13, 6.1983 (3cs); 39°45.3'N, 139°48.8'E – 39°45.0'N, 139°48.3'E, 80–83 m, St. A-23, 6.1983 (6cs). Tosa Bay, 33°23.1'N, 133°37.4'E, 80 m, 2.1970 (1cs); 33°13.2'N, 133°40.1'E – 33°14.0'N, 133°41.1'E, 300 m, KT-88-22, St. 5-2, 12.1988 (6cs, 1af). Off Tsushima Island, 34°35.4'N, 129°06.0'E, 140 m, St. 17, 7.1968 (1cs). Off Sanriku, 39°14.4'N, 142°12.3'E – 39°14.9'N, 142° 12.4'E, 406–419 m, KT-85-11, St. SR14, 8.1985 (4af); 38°39.10'N, 142°02.22'E, 375 m, Wakataka-maru, 05- DE 380D, 11.2005 (5cs, 15af).

Additional material examined. Anobothrus nataliae Jirkov, 2008

Holotype and 3 paratypes: SIO RAS: East Pacific, off the coast of Peru, 9°56'0''S, 79°26'6''W, 891 m, Sigsbee trawl, R/V Dmitriy Mendeleev, st. 544, 31.07.1972.

Description. Length 5 mm, width 0.5 mm. Prostomium with middle lobe delimited by incision, without glandular ridges or eyes. Visible tips of buccal tentacles without ventral groove, smooth. Three pairs of cirriform branchiae in fused segments II + III, arranged in transverse row without median gap ( Fig. 6 A, B); branchial bases fused, leaving the segmental origin of branchiae indeterminable ( Fig. 16 C). Chaetae of fused segments II+III originating from segment II, very long and thick golden paleae with mucronate tips ( Fig. 6 C). Paleae numbering about 25 per fascicle, arranged in semi-circular fan with central dermal hump ( Fig. 6 B). Chaetae of segment III absent. Notopodia with limbate capillary notochaetae from segment IV, present in 14 segments. Notopodia in fourth-to-last thoracic unciniger elevated, connected by dorsal ridge ( Fig. 6 D); notochaetae of modified notopodia with hirsute tips ( Fig. 6 E). Neuropodial tori with uncini from segment VI, present in 12 thoracic uncinigers. Cirri and papillae in thoracic parapodia absent. Circular glandular band present in thoracic unciniger 3. Last segment of continuous ventral shields indeterminable. Two intermediate uncinigers. Ten abdominal uncinigers. Rudimentary notopodia and glandular pads in intermediate and abdominal uncinigers absent. Pinnules without cirri or papillae. Pygidium crenulated, with paired short lateral anal cirri ( Fig. 6 F). Nephridial papillae absent. Thoracic uncini with 8 teeth in two alternating rows above rostral tooth and basal prow ( Fig. 6 G, H). Abdominal uncini with crest of numerous teeth above rostral tooth and basal prow.

Remarks. The number of paleae ranges from about 24 to 27 per fascicle.

The new species is similar to Anobothrus paleatus Hilbig, 2000 , A. nataliae Jirkov, 2008 , and A. wakatakamaruae Imajima, 2009 . All four species have elevated notopodia with hirsute notochaetae, connected by a dorsal ridge in thoracic unciniger 9 (fourth-to-last). Other Anobothrus species have this modification in thoracic unciniger 8 (fifth-to-last). The four species also share number, morphology and arrangement of the paleae. A. flabelligerulus differs from these species by the presence of 3, rather than 4 pairs of branchiae. The only other species with 3 pairs of branchiae, A. dayi sp. nov. and A. laubieri , have elevated notopodia in thoracic unciniger 8, and much less developed chaetae in segment II.

We have examined the holotype and three paratypes of A. nataliae and consider the species a junior synonym of A. paleatus . Jirkov (pers. comm.) shares our opinion. The examination revealed that A. nataliae has papillated, rather than smooth buccal tentacles. In addition to the circular band in thoracic unciniger 3, the development of a circular glandular band in thoracic unciniger 2 varies between absent, inconspicuous, and prominent. These two observations lead us to the conclusion that A. wakatakamaruae , which has been described with circular glandular bands in thoracic uncinigers 2 and 3 and papillose buccal tentacles, is also a junior synonym of A. paleatus .

No papillae have been observed in the buccal tentacles of A. flabelligerulus . However, only the tips were visible in the holotype and one paratype.

Etymology. The species name means “carrier of fans” and refers to the prominent paleae that are reminiscent of a pair of fans.

Distribution. Northwest Pacific from Otsuchi Bay to Tosa Bay along the coast of Honshu, off Oga Peninsula in the Sea of Japan, and off Tsushima Island in the Korea Strait, in 17– 825 m.

Figures

FIGURE 6. Anobothrus flabelligerulus sp. nov. A: anterior end, lateral view, 64 x, B: prostomium and paleae, frontal view, 80 x, C: palea, 375 x, D: thoracic uncinigers 8 – 12, dorsal view, 65 x, E: modified notochaeta of thoracic unciniger 9, 1100 x, F: posterior end, ventrolateral view, 80 x, G, H: thoracic uncini, G: 1100 x, H: 1960 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.