Eusyllinae Malaquin, 1893
Pionosyllis Malmgren, 1867
Pionosyllis? sp. 1
Vouchers. VINSON WEST: stations 2MFB, INFLEX: station 1MFA.
Diagnosis. Both voucher specimens incomplete specimens; medium sized species; 2 -2.3mm long, 0.8mm wide, for 17 and 20 chaetigers.
Prostomium trapezoidal to pentagonal; 2 pairs of eyes in trapezoid arrangement, anterior pair large cup-shaped, posterior pair smaller spherical. Palps broad, rounded folded downwards, fused basally. Three pairs of antenna, all styles missing, scars observable upon staining. Pharynx extends through 7 or 8 chaetigers; everted pharynx with large, single, dorsal tooth located on anterior margin of pharynx, opening surrounded by a crown of 10 soft papillae. Proventricule extends through approximately 10 chaetigers from chaetiger 7/8 to 16/17. Peristomium dorsally reduced, covered by first chaetiger; with a pair of tentacular cirri, long, slender, weakly articulated.
Parapodia uniramous; dorsal cirri mostly missing, where present, long, slender, weakly articulated (but not forming true articles) alternating in length; ventral cirri short and broad, ovate.
Chaetae all compound in 20 chaetigers, all located ventral to single, straight, blunt-tip acicula; directly ventral to acicula 2 slender spinigers, with very long slender blades, distally distinctly bi-dentate, margin with short serrations; other chaetae about 12 falcigers with varying length of blades (length decreasing ventrally), blades rather wide, with distinctly serrated margin, distally bidentate; simple chaetae not observed in 20 chaetigers. Pygidium unknown.
Remarks. This specimen belongs to genus Pionosyllis (or possible to other closely related genera, see San Martin et al. 2009 for details). Of the previously reported species from the geographical area of interest here, FI specimens show affinities with Pionosyllis cf. ehlersiaeformis Augener, 1913 recorded from the area by Hartmann-Schröder and Paraehlersia dionisi (Núñez & San Martín, 1991) (Pionosyllis elephantensis Hartmann-Schröder & Rosenfeldt, 1992 is considered a junior synonym of this species) , which both possess long spinigers. More complete specimens are needed to be confirm the identity of Falkland specimens, for the time being we suggest morphospecies name Pionosyllis sp. 1.
