Amphicteis ninonae Jirkov, 1985

Parapar, Julio, Helgason, Gudmundur V., Jirkov, Igor & Moreira, Juan, 2011, Taxonomy and distribution of the genus Amphicteis (Polychaeta: Ampharetidae) collected by the BIOICE project in Icelandic waters, Journal of Natural History 45 (23 - 24), pp. 1477-1499 : 1486-1487

Amphicteis ninonae Jirkov, 1985

( Figures 4D–F , 5 )

Amphicteis ninonae: Jirkov, 1985: 1894–1897 (textfigure); Jirkov, 2001: 472–473 (textfigure).

Amphicteis gunneri: Augener, 1928: 779 (partim?); Annenkova, 1929: 497, fig. 47 (partim); Ditlevsen, 1937: 39–40 (partim?) - non Sars, 1935.

Material examined

BIOICE sample 2014 (four specimens); 2045 (one); 2046 (two); 2057 (one); 2070 (eight); 2085 (six); 2089 (one); 2094 (one); 2110 (one); 2113 (one); 2129 (three); 2145 (three); 2167 (one); 2174 (two); 2315 (one); 2319 (one); 2328 (eleven); 2359 (one); 2372 (one); 2572 (one); 2575 (three); 2576 (three); 2592 (one); 2594 (three); 2603 (two); 2604 (one); 2606 (four); 2610 (one); 2613 (one); 2619 (three); 2626 (one); 2627 (six); 2666 (four); 2673 (two); 2683 (one); 2792 (two); 2901 (one); 3099 (one); 3115 (one); 3252 (four); 3638 (five).

Occurrence

In all, 101 specimens of A. ninonae (5.65% of the total) were collected in 40 BIOICE samples. In contrast to A. gunneri , this species seems to be restricted to the north and east coasts of Iceland. Depth range: 134–2067 m; temperature range: −0.8 to 7.57 ◦ C.

Reported distribution

Norwegian Sea, Arctic Seas ( Hansson 1998; Deubel 2000). Our findings confirm the presence of this species in Icelandic waters, which was previously reported by Jirkov (2001).

Remarks

Amphicteis ninonae has often been confused with A. gunneri and to some extent perhaps also with A. midas . Nevertheless the low boreal distribution proposed for A. midas (see Hartley, 1985:311) against the high-latitude distribution of A. ninonae (see above), makes it difficult to believe that both species occur in sympatry. Following Jirkov (1985:1896; 2001:472), Amphicteis ninonae is primarily characterized by the colour (dark brown), and number (8–16) and shape (blunt tips) of paleae ( Figure 4D, E and key below). We agree with Jirkov (1989:111) that A. ninonae has abdominal rudimentary notopodia. The BIOICE specimens are usually larger than those of A. gunneri and the number of paleae seems to have a weaker correlation with body size ( Figure 5 ).

Figures

Figure 4. Amphicteis gunneri (Sars, 1835). Scanning electron micrographs from IMNH 24080. (A) Pair of nephridial pori (arrows) located on the ridge connecting the two groups of branchiae; (B) anterior end, dorsal view; (C) paleae, distal end. Amphicteis ninonae Jirkov, 1985, scanning electron micrographs, (IMNH 24081). (D) Anterior end, dorsal view; (E) paleae, distal end; (F) abdominal neuropodia with uncini.

Figure 5. Number of paleae versus body width in BIOICE specimens of Amphicteis gunneri (Sars, 1835) and Amphicteis ninonae Jirkov, 1985.