Ancistrosyllis cf. groenlandica McIntosh, 1879
Ancistrosyllis McIntosh, 1879
Ancistrosyllis cf. groenlandica McIntosh, 1879
Voucher. Sea Lion: station MFC1, TOROA: station T4FA (largest specimen); ENDEAVOUR: station E4FA.
Diagnosis. All vouchers incomplete, the largest specimen (TOROA), body wide, dorso-ventrally flattened; 12mm long and 1mm wide (including parapodia), for 42 chaetigers; colour in alcohol dark yellow to light orange, with patches of brown pigment on prostomium and dorsally on first four chaetigers. Integument with numerous small conical papillae, dorsal cirri with conical to goblet-shaped, distally serrated papillae. Prostomium small and inconspicuous with three short conical antennae and two bi-articulate palps. Two antennae inserted medio-laterally and median antenna on the posterior end of the prostomium; antennae of similar size. Palps indistinctly set off from prostomium; palpophores massive, basally slightly fused; palpostyles minute, conical, positioned antero-ventrally. Eyes absent. Proboscis retracted in all specimens. First segment achaetous, about as long as following segments; with two pairs of conical, cirri of similar size, inserted laterally.
Parapodia sub-biramous; notopodia reduced to single acicula; large curved hooks from chaetiger 5 until the end of fragment. Conical dorsal cirri of first chaetiger about twice as long as on following segment, further cirri slightly longer than second one; papillated with large conical to distinctly goblet-shaped, distally serrated papillae. Neuropodial lobes conical, short (tips of dorsal and ventral cirri surpassing it) each with a single acicula. Neurochaetae often broken off, only few observed; upper neurochaetae - laterally compressed, serrated, simple with bidentate tips, up to 5 chaetae of two lengths short and long; lower neurochaetae composed of few chaetae shorter and thicker than chaetae of upper group, spine-like, curved tip appear unidentate (secondary tooth may be broken off). Digitiform, papillated ventral cirri from 1st chaetiger, slightly shorter than dorsal cirri. Pygidium not observed.
Remarks. Of the known species of Ancistrosyllis Falkland specimens are most similar to A. groenlandica, McIntosh 1879 as ventral cirri begin from chaetiger 1 and dorsal hooks from chaetiger 5 (range in A. groenlandica is chaetiger 4-6, with chaetiger 5 most common). This species was described from 750m, Arctic Ocean, Greenland, Davis Strait, but since then has been reported from wide geographical and bathymetrical ranges and several authors provided re-description of this species (e.g. Blake, 1994; Böggemann, 2009), the goblet-shaped papillae were not reported before. The holotype of A. groenlandica is housed at NHM London and was re-examined as part of this study. Holotype is not in good condition, slightly desiccated, with most chaetae broken off. No goblet-shaped papillae were found in holotype, but it is not clear if this due to age/condition of the material (but these were not reported by McIntosh). Other differences include some subtle differences in the length of appendages (both specimens compared were of similar size). At present we do not consider these tentative differences sufficient to recognise Falkland specimens as a different species. Fresh material from the type locality as well as molecular evidence are needed to validate the supposed cosmopolitan distribution of A. groenlandica.
Comparative table of Ancistrosyllis cf. groenlandica from Falklands and A. groenlandica McIntosh, 1879 (based on re-examination of holotype).
|
Length of median antenna |
Length of neuropodia relative to associated dorsal and ventral cirri |
Form of papillae on dorsal cirri |
|
|
Ancistrosyllis sp. 1 |
about the same length as lateral antennae |
tips of both cirri surpassing the neuropodial acicular tip |
conical to goblet-shaped distally serrated |
|
Ancistrosyllis groenlandica, holotype of McIntosh, 1879 |
shorter than lateral antennae |
tips of both cirri shorter than neuropodial acicular tip |
rounded to conical |
REFERENCES
Böggemann, Markus 2009. Polychaetes (Annelida) of the abyssal SE Atlantic. Organisms Diversity & Evolution, 9, 252-428. , available online at http://www.sciencedirect.com/science/article/pii/S1439609209000464 page(s): 375.
Blake, J.A. 1994. Family Pilargidae Saint Joseph, 1899. pages 271-294. IN: Blake, J.A. and Hilbig, Brigitte. Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and Western Santa Barbara Channel. 4 - The Annelida Part 1. Oligochaeta and Polychaeta: Phyllodocida (Phyllodocidae to Paralacydoniidae). Santa Barbara Museum of Natural History. Santa Barbara
page(s): 265-267, fig. 10.1
McIntosh, W.C. 1879. On the Annelida obtained during the cruise of H.M.S. 'Valorous' to Davis Strait in 1875. Transactions of the Linnean Society of London, Ser. new series, 1: 499-511., available online at http://www.biodiversitylibrary.org/item/90111#page/663/mode/1up
page(s): 502-503, plate LXV figs. 3, 20
