cf. Novafabricia sp. 1
Novafabricia Fitzhugh, 1990
cf. Novafabricia sp. 1
Voucher. Vinson West: Station 2MFA
Diagnosis. Very small, short species; voucher complete specimen with branchial crown; length 1.1mm plus 0.25mm for branchial crown; body width 0.1mm; body cylindrical, narrow, tapered anteriorly and posteriorly; preserved specimens white to pale yellow; body with eight thoracic and three abdominal chaetigers.
Branchial crown with three pairs of radioles; distal ends filamentous, same width as pinnules; ventral filaments absent. Anterior margin of anterior peristomial ring a low ridge dorsally and laterally; ventrally a well-developed tongue-like lobe. Peristomial eyes not observed.
Superior thoracic notosetae elongated, narrowly hooded. Inferior thoracic notosetae and pseudospatulate chaetae not confirmed (due to damage and very small size of specimen); thoracic acicular uncini in a single irregular row, 5 per fascicle. Abdominal uncini, not observed in detail using light microscopy.
Pygidium conical lobe, pygidial eyes no observed.
Remarks. This species is represented by an extremely small, fragile and somewhat damaged specimen therefore not all characters could have been established. The combination of observed characters points to genus Novofabricia because of collar with well-developed ventral lobe, absence of ventral filaments however the degree of fusion of ventral lips with radiole and distribution of pseudospatulate chaetae cannot be established with certainty.
Genus Novafabricia is represented by a single species so far known from the area investigated here. N. chilensis was described from Chile, shallow water. However even though FI specimen is problematic, it is possible to detect some differences to N. chilensis, which has black peristomial and pygidial eyes present in preserved specimens and thoracic acicular uncini are in distinct double rows with 9-14 per fascicle, rather than 5 uncini arranged in a single row as in FI specimens. Another genus reported from deeper Southern Ocean waters is Raficiba, Fitzhugh 2001, represented by Raficiba barryi, which differs from FI specimen by presence of black peristomial and pygidial eyes and more elongate, scoop-like shape of the collar. FI specimen most likely represents another new species in the family Fabriciidae, third reported in this study. However, greater number of well-preserved specimens will be necessary to establish all characters and generic identity with confidence.
