Annenkova mastigophora (Annenkova, 1952)

Salazar-Vallejo, Sergio I., 2012, Revision of Flabelligera Sars, 1829 (Polychaeta: Flabelligeridae) 3203, Zootaxa 3203 (1), pp. 1-64 : 39-41

Annenkova mastigophora ( Annenkova, 1952) n. comb.

Figures 16–17

Flabelligera mastigophora Annenkova in Uschakov 1950:206 nomen nudum.

Flabelligera mastigophora Annenkova 1952:151, Fig. 6; Ushakov 1955:306(1965:283), Fig. 113E,F; Levenstein 1966:43; Jirkov & Filippova 2001:361, Figs. 1–2.

Type material. Arctic Ocean. Lectotype ( ZIRAS-27061 ), anterior fragment, Okhotsk Sea , near Saint Jonas Island ( 58°41' N, 147°45' E), trawl, 121 m, mud, 22 Aug. 1912, Derbek, coll. One paralectotype ( ZIRAS-27064 ), partly dehydrated, broken in two, Chukchi Sea, R / V Krasnoarmeetz, Stat. 49/110 ( 71°05' N, 172°51' W), 45 m, clay and sand, 15 Aug. 1933, Koldakov, coll. (two hooks in chaetigers 2–15). One paralectotype ( ZIRAS-27065 ), mature female, almost complete, soft, apparently fixed in alcohol, broken in two pieces, a large fragment and a few posterior chaetigers, Chukchi Sea, R / V Krasnoarmeetz, Stat. 58/119 ( 68°10.5' N, 168°02' W), 53 m, sandy mud, dredge, 15 Aug. 1933, Koldakov, coll. (2–3 neurohooks in chaetigers 2–21). One paralectotype ( ZIRAS-27066 ), anterior fragment, soft, in poor condition, apparently fixed in alcohol, broken in two pices, Chukchi Sea, R / V Krasnoarmeetz, Stat. 43/104 ( 69°02' N, 175°12' W), 51 m, beam trawl, sandy clay, 13 Aug. 1933, Koldakov, coll. (2 neurohooks in chaetigers 2–14, and in other posterior ones).

Additional material. Northeastern Pacific Ocean, Bering Sea. One anterior fragment ( CAS-26832 ), Navarin Basin , Alaska, Stat. 11 ( 59°43.7' N, 175°01.2' W), 122.6 m, 10 May 1980. One median fragment (SIO- RAS-unnumb.), Bering Sea, R / V Vitjaz, Stat. 548 (median fragment, with most of its tunic on site, 55 mm long, 6 mm wide, 36 chaetigers). A large specimen without anterior end, and an anterior fragment (SIORAS-unnumb.), Bering Sea, R / V Vitjaz, Stat. 566 (larger fragm. 102 mm long, 11 mm wide, 80 chaetigers; pygidium exposed) .

Description. Lectotype (ZIRAS-27061) anterior fragment, pale; body oval in cross section, heavily contracted, segments very short ( Fig. 16A); 42 mm long, 7.5 mm wide, cephalic cage (damaged) 7 mm, 45 chaetigers. Tunic densely papillated, mostly eroded, with little fine sediment cover on it, remaining in interparapodial areas (very thick in some non-type specimens in SIORAS).

No cephalic hood ( Fig. 17A, B). Prostomium low cone, four dark brown eyes (in CAS-26832). Caruncle well developed, separating branchial lobe, projecting beyond branchial plate margin ( Fig. 17C). Palps thick, slightly darker and shorter than branchiae, corrugated; palp bases rounded, elevated. Dorsal lip reduced. Lateral lips rounded, large; ventral lip reduced, fragile. Branchiae separated into two lateral groups; about 100 filaments per side, shorter towards sides. Nephridial lobes not seen.

Cephalic cage chaetae about as long as body width (1.5 longer than body width in CAS-26832, Fig. 17A, B). Only chaetiger 1 involved in the cephalic cage; notochaetae of chaetiger 2 as long as cephalic cage chaetae, about 40 noto- and 30 neurochaetae per side.

Anterior dorsal margin of first chaetiger smooth (papillae probably eroded). Chaetigers 1–3 decreasing in size posteriorly. Chaetal transition from cephalic cage to body chaetae abrupt, neurohooks present from chaetiger 2. Gonopodial lobes in chaetigers 5–6 ( Fig. 16B), pale, rounded.

Parapodia well developed, ventrolateral, some covered by tunic remains. Median neuropodia ventrolateral. Notopodia truncate, long lobes, especially in anterior chaetigers, with long papillae in interparapodial spaces. Neuropodia long conical lobes, with long papillae in interparapodial spaces ( Fig. 16D). Noto- and neuropodia close to each other.

Median notochaetae arranged in short transverse rows; all notochaetae multiarticulated capillaries, as long as 1/2–1/3 body width, about 7–8 per ramus, with short articles basally, medium/sized medially, long distally ( Fig. 16C). Neurochaetae multiarticulated neurohooks from chaetiger 2 ( Fig. 17D), two hooks in chaetigers 2–11(15), each with handles with 1–2 articles ( Fig. 17E), then mostly one per ramus with single articulation ( Fig. 17F). Posterior chaetigers with neurohooks anchylosed ( Fig. 16E, F). Handle articulation medially placed, variable; some neurohooks with 3–4 progressively longer articles ( Fig. 17D), others with a single articulation ( Fig. 17E), or without articulations, looking smooth ( Fig. 16E–G). Crest very long, as wide as handle or narrower, tapering, often with a thin, variably curved arista ( Fig. 16E, F), apparently articulated; if tip erodes, basal part well-defined, rounded ( Fig. 16G); width:length ratios difficult to estimate because of crest bending and fractures, straight crests with width:length ratio 1:8–14.

Posterior end lost in types; one non-type specimen ( SIORAS) with posterior end tapering; pygidium with anus terminal, without anal cirri .

Remarks. The combination Flabelligera mastigophora was introduced by Uschakov (1950:206), but because it included a short diagnosis (whip-like crest of multiarticulated falcigers) must be regarded as a nomen nudum. The original type series is in poor shape; the best preserved specimen has been designated as the lectotype; the paralectotypes provide enough morphological details as to be included in the same species, but they are poorly preserved.

Distribution. Restricted to Arctic or subarctic shallow waters, being recorded for the Okhotsk, Chukchi and Bering Seas, in shallow water soft bottoms.