Eteoninae Bergström, 1914
Protomystides Czerniavsky, 1882
Protomystides? sp. 1
Voucher. VINSON WEST: station 1MFA.
Diagnosis. Small, slender species; voucher specimen complete, but pygidium damaged; 6.5mm long and 0.3mm wide (including parapodia) for 70 segments; preserved specimen pale yellow in colour, although posterior part of the body with light orange pigmentation, particularly on dorsal and ventral cirri.
Prostomium subpentagonal (about as wide as long); eyes absent; with two pairs of prostomial appendages of similar form, short and cirriform: pair of antennae and pair of palps. Proboscis not observed. Tentacular cirri all missing, their number and arrangement uncertain (scars not clearly observed even after staining).
Dorsal cirri oval, not inflated, not pigmented (except for the posterior part of the body, where orange in colour). Ventral cirri similar to dorsal cirri, but smaller, not pigmented (except for the posterior part of the body). Neuropodia conical, chaetigerous lobes, of similar length; with one acicular and up to 7 chaetae. Chaetae compound spinigers, with unidentate blades of varying lengths, decreasing in size ventrally – the dorsalmost chaeta with extremely long thin blades, the ventralmost chaetae with short almost falciger-like blades; chaetal rostrum asymmetrical with series of smaller serrations. Pygidium not clearly observed, damaged.
Additional observations: Voucher VINSON WEST: station 38MFB is very similar to the species above, but it is strongly pigmented, with body dark yellow to orange in colour and both dorsal and ventral cirri with dark red pigments; specimens is very short fragment of 15 segments (1.2mm long; 0.3mm wide), but anterior end is well preserved. Specimen has 4 pairs of tentacular cirri and it is consistent with genus Protomystides. Four pairs of tentacular cirri in 1+2+1 arrangement (cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3), all slender, cylindrical, with long, tapered ends; cirri of segment 1 and ventral cirri of segment 2 shorter than dorsal cirri of segments 2 and cirri of segment 3, which are long reaching to about segment 7. Chaetal blades are broken off. It is not clear currently if the two vouchers represent the same species given the differences in colouration.
Remarks. Currently, there are no known species in genus Protomystides known form the area. Further work will be necessary to establish if Falkland Islands specimens represent new species, which is for now assigned to morphospecies Protomystides sp. 1. The two colourmorphs may represent different species, but we are currently unable to resolve this problem without greater number of well-preserved specimens and molecular evidence.
