Ampharete eupalea Chamberlin, 1920

Ampharete eupalea Chamberlin, 1920 View in CoL

Fig. 7 View Fig , 8 View Fig .

Ampharete eupalea Chamberlin, 1920: 25 View in CoL , Pl. V, fig 6, 7; type: №31, Victoria Memorial Museum, Ottawa; type locality: 70°24′N 161°25′W, 16–18 m; Berkeley, Berkeley, 1942: 201.

MATERIAL. 28 samples (173 specimens). Supplement Table.

DESCRIPTION. Up to 48 mm long. The middle lobe of the prostomium anteriorly rounded, about twice as long as the width. The buccal tentacles numerous (several dozen), with two rows of pinnules. The attachment points of the paleal chaetae form 270°–360° ( Fig. 7D View Fig ); they much thicker than the most developed notochaeta, but about the same length, reaching the anterior edge of the prostomium only when the prostomium drawn in; paleal chaetae themselves often straightened and pressed to the surface of the body; a similar position very rare in other species. In each group 16–32 chaetae (95% have more than 20) ( Fig. 9 View Fig ), the number of chaetae not size-depended when the size of the worm exceeds 8 mm. Branchostyles cirriform, smooth, not longer than the width of the body. The attachment points of all 4 pairs of branchostyles are arranged in one almost straight transverse line, only the third pair is slightly caudal. Median gap between the branchiae absent. The connection of the gills with the notopodia typical: 3rd from the outside connect- ed to the TC2 notopodia, the inner ones connected to the TC1 notopodia. One pair of nephridial papillae behind the branchiae clearly visible. 14 TC, 12 TU, 13 AU. Thoracic neuropodia and the two first AU tori, the rest — pinnuli. The ventral surface up to and including TU9 transformed into ñontinuous glandular ventral shields extending from notopodia to notopodia. No ventral shield on TU10, in its place there is a thickening that occupies the entire ventral abdominal surface of the anterior half of the segment. Abdomen with small rudimentary notopodia, gradually disappearing caudally. Pygidium with 2 long lateral cirri and numerous short papillae. Thoracic and abdominal uncini with 5–6 teeth in two rows. The tube detritus, usually more or less densely encrusted with grains of sand with a diameter of about 0.25 mm.

REMARKS. I identify my specimens as this species despite the number of AU of holotype on which the original description is based is unknown as it is uncomplete posteriorly by: (1) the shape of the tips of the paleal chaetae (compare Fig. 7 D, E and H View Fig ), (2) number of paleal chaetae (22–23 according original description), which is significantly greater than that of the other species of the superspecies (with exception of A. britayevi ), (3) they were found near the type locality (4) no other species matches the original description has been found in extensive investigated materials from the Chukchi and Bering Seas .

Ampharete crassiseta Annenkova, 1929 View in CoL , also described from the Far Eastern Seas, has the same number of paleal chaetae (17–24), but they gradually taper into a long thread-like top.

RANGE ( Fig. 10 View Fig ). Along Asia from the south of the Chukchi Sea to the south of Kamchatka and the Sea of Okhotsk along Kamchatka. Upper sublittoral, 17–89 m. Abundant in places, up to 64 specimens per square m .