Ampharete longipaleolata Uschakov, 1950

Ampharete longipaleolata Uschakov, 1950 View in CoL

Figs 24–26 View Fig View Fig View Fig .

Ampharete longipaleolata Uschakov, 1950: 218–219 View in CoL , fig. 33 (type locality, restricted: pacific coast of the southern Kuril Islands , 414 m 14/9/1949); 1955: 367–368.

MATERIAL. 16 samples (45 specimens): 3 syntypes ZIN 1/15243; DGEH: Hydrobiolog 25, 500 m, 5/6/1984 (2); Hydrobiolog 129, 48°15′ N 141°11′ E 650 m, 7/8/1984 (1); Hydrobiolog 193, 46°00′ N 138°20′ E, 700 m, 4/9/1984 (1); Odissey 1.84. 16, 880 m (2); Odissey 33.13, 44°52′ N 149°27,7′ E, 920 m, 25/7/1987 (1); Odissey 34.1A, 42°12.76′ N 130° 59.22′ E 640 m, 7/12/1984 (6); IO RAN: Zhemchug 105, 2083 m (1); Zhemchug 111, 375 m (1); Vitjaz 2.31, 57°45.3′ N 153°45′ E, 440 m, 18/8/1948 (19); Vitjaz 2.34, 58°43′ N 155°56′ E, 296 m, 19/8/1948; Vitjaz 2.59, 57°00′ N 150°53,5′ E, 355 m, 29/8/1948 (2); Vitjaz 12.1739, 52°12′ N 154°28′ E, 359 m, 28/ 9/1952 (1); Vitjaz 12.1745, 53°3′ N 154°30′ E, 299 m, 29/9/1952; Vitjaz 12.1770, 56°30′ N 152°38′ E, 524 m, 4/10/1952 (4); Vitjaz 12.1781, 56°53′ N 152°36′ E, 551 m, 4/10/1952 (6); Vitjaz 39.5640, 44º41′N, 148º57′E, 10/09/ 1966, 780 m (1); Vitjaz 59.7458 42°15′N 131°40′ E, 630–750 m, 27/5/ 1976 (1).

DESCRIPTION. Up to 40 mm in length. The middle lobe of the prostomium blunt-rounded in front, at the base with a whitish glandular field, black eye spots outside the corners of the furrow. Palae unusually well developed. Their bases sharply enlarged, forming cylindrical outgrowths, from which the paleal chaetae come out, forming a complete spiral and even more. Chaetae light yellow, several times thicker and 4 times longer than the most developed notochaeta, extending far beyond the level of the anterior edge of the prostomium, by 2– 5 of its length ( Fig. 24A View Fig ). In each group 10–26 of them (in the syntypes 15–20), the number of paleal chaetae increases with the increase in the size of the worm ( Fig. 25 View Fig ). The tips of paleal chaetae sharply narrow into a short thread-like tip in worms large 20 mm, in smaller worms tips slowly tapering to filament. Many of the paleal chaetae disheveled at the end, which does not happen in other species of the superspecies. Branchophores form an almost straight line, the second pair of branchiae from the middle is slightly behind the others. Branchostyles smooth, bent back, they reach about C6. At the base of the internal branchophores a pair of small nephridial papillae. 14 TC, 12 TU. 13 AU. Rudimentary notopodia small, no neuropodial cirri. Neuropodia of the thorax, AU1 and AU2 tori, the rest — pinnuli. Pygidium with two long lateral cirri and more or less numerous low papillae. Notochaeta also very large, approximately equal in length to the width of the body narrow bilimbate. Uncini with two rows of teeth, usually 6 in each. Thoracic and abdominal similar. The tube loose, detritus-like, sometimes densely plastered with large grains of sand, the thickness of its walls much smaller than the diameter of the inner hole .

REMARK. In the ZIN collection of 14 specimens, mentioned in the original description, only 3 have been preserved (one without the end of the thorax) from st. 101 R/ V Toporok from a depth of 414 m. The original description also includes a find near Northern Sakhalin at a depth of 65 m, this material in ZIN collection is absent. Judging by the fact that all other known findings I have reviewed, located exclusively on slope, worms from 65 m should belong to a different species. Such species really exist and inhabits shallow depth near Sakhalin. It also have numerous very long paleae, but paleal chaetae slowly tapering to slim tips and it has 12 AU. Therefore, I consider it necessary to limit the type locality only to the area where the preserved syntypes were collected

RANGE ( Fig. 23 View Fig ). North-west Pacific, including Sea of Okhotsk and the Japan Sea, slope 375– 2083 m.

KEY TO IDENTIFICATION SPECIES OF AMPHARETE View in CoL (SUPERSPECIES FINMARCHICA View in CoL ) It is strongly recommended to identify several specimens together rather than single individual.

1. Paleal chaetae several times thicker than the most developed notochaetae, sharply pointed into a short filiform tip (may break off) ( Figs 3A–C View Fig , 7D, E View Fig , 12B–D View Fig , 15E–G View Fig , 18D View Fig , 20A–C View Fig , 24D–E View Fig ). Ampharete View in CoL ( finmarchica View in CoL ) ............................. 2

– Paleal chaetae, if present and thicker than the most developed notochaetae, gradually taper into a long filiform tip ( Fig. 2 View Fig ) ...... other Ampharete View in CoL

2. More than 40 paleal chaetae ............................. ............................... Ampharete britayevi sp.n.

– Less than 30 paleal chaetae ............................. 3

3. Paleal chaetae significantly exceed body width, protrude far beyond anterior margin of prostomium ( Fig. 24A View Fig ) .. Ampharete longipaleolata View in CoL

– Paleal chaetae are less than or equal to the body width, if they protrude beyond the anterior edge of the prostomium, then not significantly ( Figs 7A–C View Fig , 12A, E View Fig , 18A, B View Fig , 20A–D View Fig ) .................. 4

4. Less than 20 paleal chaetae ............................ 5

– 20–30 paleal chaetae ( Figs 7 View Fig , 9 View Fig ) ........................ ......................................... Ampharete eupalea View in CoL

5. 13 AU .............................................................. 6

– 16–18 AU ................................ Ampharete goesi View in CoL

6. North hemisphere ............................................ 7

– South hemisphere ........ Ampharete kerguelensis View in CoL

7. Tube inlay is covered by muddy-detritus, limbation of notochaetae narrow and equal ( Fig. 12K View Fig ) ................................... Ampharete finmarchica View in CoL

– Tube inlay is covered by exclusively fragments of bryozoans, shells, sea urchin spines, mica, etc., without trace of mud and detritus, limbation of at least some notochaetae wide and unequal ( Fig. 21E View Fig ) ................................ Ampharete kudenovi View in CoL