Paradoneis mikeli Aguirrezabalaga & Gil, 2009

Sikorski, Andrey, 2017, The Paraonidae (Annelida: Sedentaria) from Norway and adjacent seas, with two new species, four new records, and a redescription of Paraonides nordica Strelzov, 1968 based on type material, Zootaxa 4320 (1), pp. 41-67 : 55

Paradoneis mikeli Aguirrezabalaga & Gil, 2009

( Fig. 6 )

Paradoneis mikeli Aguirrezabalaga & Gil, 2009: 644 –649, figs 12–13.

Material examined. 2520 Visund Nord VIN–03; 61.4212°N–2.5715°E; 377 m; 23.05.2002; one specimen. 2520 Visund Nord VIN–04; 61.4300°N–2.5620°E; 380 m; 24.05.2002; one specimen. 3940 Askeladd Beta SA–02; 71.4750°N–20.4476°E; 278 m; 26.06.2007; two specimens. 3940 Askeladd Beta SA–10; 71.4789°N–20.4405°E; 275 m; 27.06.2007; one specimen. 5796 Linnorm ON–09; 64.4163°N–6.9609°E; 300 m; 09.06.2012; one specimen.

Description. Largest specimen complete, 6.8 mm long, 0.2 mm wide for 67 chaetigers. Body slender, cylindrical, coiled when preserved. Prostomium triangular, anteriorly rounded, slightly wider than long ( Fig. 6A ); median antenna and apical sensory organ absent; pair of nuchal organs as deep nuchal slits, extending obliquely ( Fig. 6A ); frequently a pair of brown pigmented areas behind nuchal organs ( Fig. 6A ); secondary ciliary organs absent. First four notopodial (prebranchial chaetigers) postchaetal lobes short and triangular ( Fig. 6A ); on branchial region, slightly longer and progressively thinner, becoming digitiform ( Fig. 6A, B ); on postbranchial region, similar in length but more slender as more posterior the chaetiger ( Fig. 6C ). Branchiae from chaetiger 5, 14–15 pairs, ciliated on their inner margin, lanceolate and short, up to 4 times as long as wide ( Fig. 6A, B ). Noto- and neurochaetae as numerous curved bilimbated capillaries in prebranchial and branchial regions ( Fig. 6A, B ); in postbranchial region straighter, notochaetae clearly thinner than corresponding neurochaetae ( Fig. 6C ); from chaetiger 4–8 bearing 1–3 forked notopodial chaetae with tines differing in length, long tine slightly more slender, inner edges bearing long and dense spinulation ( Fig. 6E ); modified neurochaetae absent. Pygidium as a rounded lobe, bearing a pair of flask-shaped cirri on a ventro-lateral position ( Fig. 6D ).

Remarks. Paradoneis mikeli Aguirrezabalaga & Gil, 2009 is a species very similar to the widely distributed and well know P. lyra ( Southern, 1914) . However, detailed examination can be useful to separate the two species, since P. mikeli possesses four instead of three prebranchial chaetigers; in addition, the branchiae are clearly shorter ( Aguirrezabalaga & Gil 2009). Other diagnostic characters of P. mikeli are the lack of true eyespots and the frequent presence of pigmentation around nuchal organs, which can be confused with eyes. The specimens herein recorded share all these characters, rendering the identification accurate.

Distribution. Bay of Biscay ( Aguirrezabalaga & Gil 2009). First record out of the type locality and new record for Norway and adjacent waters.

Figures

FIGURE 6. Paradoneis mikeli Aguirrezabalaga & Gil, 2009. A. Anterior end, lateral view; B. Left parapodium of chaetiger 11, anterior view; C. Right parapodium of chaetiger 42, anterior view; D. Pygidium, lateral view; E. Forked notochaetae of chaetiger 42. Scale bar: A, D: 0.19 mm; B, C: 95 µm; E: 30 µm.