Eclysippe sp. 1
Ampharetinae Malmgren, 1866
Eclysippe Eliason, 1955
Eclysippe sp. 1
Voucher. Sea Lion: station 90MFB
Diagnosis. Voucher is a complete specimen, 14mm long and 0.6mm wide. Thorax consists of paleae bearing segment and 15 chaetigers, 12 of these uncinigers; abdomen with 12 uncinigers. Thorax divided into two regions: (1) anterior thoracic chaetigers (chaetigers 1-9) short (first two particularly crowded) with well developed ventral glandular pads, using Shirla-stain, bands on ventrum of these chaetigers particularly strong in uncinigers 1 and 2; chaetiger 10 transitory between two regions; (2) posterior thoracic chaetigers (=last 5) very long, glandular pads not developed. First and second notopodia smaller than on subsequent segments, close together, first pair in particular obscured by segment with paleae and branchial ridge. Abdominal segments without rudimental notopodia or neuropodial cirri. Pygidium formed of two small lobes.
Prostomium Ampharete-type, trilobed (appear as a single triangular lobe), without glandular ridges. Lower lip crenulated. Paleae present, arising from large cylindrical lobes, about 10 per fascicle, pale yellow in colour, very slender, long (reaching the anterior end of prostomium), tapering into thin tips. Three pairs of branchiae arranged in one row, two groups separated by a narrow median gap; styles of branchiae mostly missing, only two still attached in voucher, these are smooth, long, slender and cylindrical; all branchiophores of equal size, connected laterally giving impression of raised ridge, long - obscuring prostomium dorsally.
Notochaetae few, long, smooth, narrowly limbate. Thoracic uncini with 6 small teeth above rostral tooth arranged in two alternating vertical rows; first two abdominal neuropodia of thoracic type; following abdominal neuropodia with different uncini, each with 5 teeth in lateral view, forming paw pattern in frontal view.
Remarks. Falkland Island specimens are most similar to Northern European species Eclysippe vanelli (Fauvel, 1936), which has been widely reported, but it appears there are some inconsistencies particularly in the form of abdominal uncini. Jirkov (2011) commented that Eclysippe belongs to a group of ampharetid genera where the first two abdominal uncinigers are of thoracic type. Holthe (1986) and Jirkov (2001) used drawings taken from Eliason (1955) to show abdominal uncini of different type to thoracic ones, however Aguirrezabalaga and Parapar (2014) reported abdominal uncini (posterior to abdominal uncinigers 1 and 2) similar to thoracic ones. The shape of posterior abdominal uncini is markedly different from those in thorax in Falkland Island specimens and different from those figured by Eliason (1955). Paleae also appear to be much longer in FI specimens than those in E. vanelli. We suggest that FI specimens probably represent a new species, however further work would be necessary to examine specimens of Eclysippe vanelli from other geographical location and most importantly, the type specimen of Fauvel (1936). The other two currently recognised species of Eclysippe are different from FI specimens. Eclysippe eliasoni (Day, 1973) has 13-14 abdominal segments, notopodia 1 and 2 well spaced and not protruding from large cylindrical lobes (based on drawing provided by Day, 1973), type locality Beaufort, North Carolina in 200 m (see notes about the status of this species in WoRMS database). Pacific species Eclysippe trilobata (Hartman, 1969) differs in body shape without extreme lengthening of the thorax (ch. 1-6 shorter, separated ventrally by a deep furrow, rest of the thorax with slightly longer chaetigers, based on re-description by Hilbig, 2000), paleae are stouter and abdominal uncini described as similar to thoracic ones.
