Euclymeninae Arwidsson, 1906
Clymenura Verrill, 1900
Clymenura sp. 2
Voucher. SEA LION: station 3MFC.
Diagnosis. Voucher is a small to medium sized, incomplete specimen; 16mm long and 0.5mm wide for 15 chaetigers long fragment; preserved specimen pale yellow in colour. Chaetigers 1-2 very long (>2mm long), chaetigers 3 slightly shorter, chaetigers 4 – 8 short (about 1mm) and chaetigers 9 -14 about 0.5mm long, with chaetiger 15 getting longer again. Chaetigers 1-8 distantly separated by deep intersegmental grooves; chaetigers 9 -14 with segmentation indistinct, chaetiger 15 with distinct segmentation again. Chaetiger 8 with a large, semi-circular glandular pad on dorsum as typical for this genus, the pad as long as the chaetiger 8.
Prostomium with well-developed cephalic plaque; cephalic rim with lateral (one on each side) and single mid-dorsal notches, anteriorly with shallow dips near mid-anterior peak (not developed into palpode). Nuchal organs wide and straight, bordering a very low lying keel-like structure, covering nearly full length of cephalic plaque.
Notochaetae capillaries of two types – long, smooth, very narrowly-limbate chaetae (about 8 per fascicle) and more numerous (about 10 per fascicle) shorter capillaries. In chaetigers 1 -3 single neuropodial rostrate hook present, dentition of these uncini reduced; from chaetiger 4 approximately 8 rostrate uncini arranged in a single row; uncini with main fang and about 6 small teeth, with several thin fibrils (barbells) underneath the main fang; with manubrial constriction on its shaft. Posterior end and pygidium not observed. Tube not observed.
Remarks. Falkland Island specimens are consistent with genus Clymenura as they possess ventral pad on chaetiger 8; well-developed cephalic plaque and neuropodia of chaetigers 1-3 with a low number (one) of rostrate uncini. Currently, there are no known species of Clymenura from the region (Leiochone singularis Gravier, 1907 is considered a nomen dubium). Another specimen consistent with genus Clymenura and assigned to morphospecies Clymenrua sp. 1 likely represent a different species. It mainly differs in the length of chaetigers (Clymenura sp. 1 has shorter chaetigers anteriorly and longer posteriorly, while Clymenura sp. 2 has opposite trend), the length of cephalic keel and development of dentition of uncini in chaetigers 1 -3. No complete specimens were found to date.