Prionospio (Prionospio) dubia Day, 1961

Dagli, Ertan & Çinar, Melih Ertan, 2009, Species of the subgenera Aquilaspio and Prionospio (Polychaeta: Spionidae: Prionospio) from the southern coast of Turkey (Levantine Sea, eastern Mediterranean), with description of a new species and two new reports for the Mediterranean fauna, Zootaxa 2275, pp. 1-20 : 6

Prionospio (Prionospio) dubia Day, 1961

Prionospio malmgreni var. dubia Day, 1961:489 –490, fig. 3.

Prionospio (Prionospio) dubia: Maciolek 1985:336 –339, figs. 2–3; Imajima 1990a:118 –121, figs. 8–9; Blake 1996:130 – 133, fig. 4.12.

Material examined. ESFM –POL/05–1856, 1 specimen, 30 September 2005, Finike Bay, G18, 36º16΄31΄΄N, 30º10΄50΄΄E, 75 m, mud; ESFM –POL/05–2030, 3 specimens, 30 September 2005, Finike Bay, G19, 36º16΄0 6΄΄N, 30º11΄31΄΄E, 100 m, mud; ESFM –POL/05–1882, 2 specimens, 6 October 2005, Fethiye Bay, G32, 36º38΄42΄΄N, 29º03΄18΄΄E, 100 m, mud; ESFM –POL/05–1945, 1 specimen, 6 October 2005, Fethiye Bay, G30, 36º39΄24΄΄N, 29º04΄44΄΄E, 50 m, sandy mud.

Diagnosis. Largest specimen complete, 0.6 mm wide, 20.9 mm long, with 82 chaetigers. Prostomium rounded anteriorly, with a narrow caruncle reaching to posterior part of chaetiger 1. Eyes absent. Branchiae numbering four pairs; first and fourth pairs with long digitiform pinnules; first pair extending to chaetiger 6– 7; fourth pair short, reaching to chaetiger 7; second and third branchiae apinnate, similar in size. Noto- and neuropodial lamellae smallest on chaetiger 1; largest on chaetigers 3–4. Dorsal crests absent. Ventral sabre chaeta first present on chaetiger 18, numbering 1–2 per parapodium. Multidentate hooded hooks first appearing on neuropodia of chaetigers 18–20 and notopodia of chaetigers 37–48.

Remarks. The specimens examined in the present study agree with the original and subsequent descriptions of the species ( Day 1961; Maciolek 1985; Imajima 1990; Sigvaldadóttir & Mackie 1993). As reported by Maciolek (1985), Imajima (1990a) and Sigvaldadóttir & Mackie (1993), P. (P) dubia has a high variability in the first occurence of hooded hooks and sabre chaetae.

Ecology. The maximum population density (30 individuals.m -2) of this species was encountered on muddy substratum at 100 m depth at station G19 (Finike Bay).

Distribution. Western and Eastern North Atlantic, Pacific Ocean, Indian Ocean and Mediterranean Sea ( Blake 1996; Imajima 1990a; Çinar & Ergen 1999); 17–2379 m.