Polynoidae Malmgren, 1867

Neal, Lenka, Wiklund, Helena, Muir, Alexander I., Linse, Katrin & Glover, Adrian G., 2014, The identity of juvenile Polynoidae (Annelida) in the Southern Ocean revealed by DNA taxonomy, with notes on the status of Herdmanella gracilis Ehlers sensu Augener, Memoirs of Museum Victoria 71, pp. 203-216 : 208

Polynoidae Malmgren, 1867

Juvenile, indeterminable

Figures 2 , 3 .

Material examined. Over 2000 specimens, from BIOPEARL I and II expeditions to the Amundsen Sea, Antarctic, in March 2006 and March 2008, cruise numbers JR144 and 179, station numbers listed in table 1, depth 500 m.

Description. Voucher material. Length excluding palps 1.5 mm, 14–15 segments, 8 pairs of elytra. Colour of preserved specimen white to creamy yellow, in live specimens anterior body translucent, the posterior body bright yellow to orange. Prostomium bilobed, rhomboid to oval, anterior lobes rounded but without cephalic peaks; 2 pairs of small, black, subdermal eyes present, anterior pair positioned medially at widest part of prostomium. 3 antennae; median antenna often missing and only large antennophore present, inserted distally on prostomium, two lateral antennae inserted anteroventrally on prostomium, styles short, slender, papillated. Pair of long (twice length of prostomium), thick, smooth palps present, narrowing distally. Proboscis when extended with 2 pairs of amber-coloured jaws and 9 pairs of small, equal-sized triangular papillae on the rim. Two pairs of tentacular cirri present, lateral to prostomium, styles slender, papillated, tentaculophores of similar size, tentacular segment with notochaetae, few, stout, serrated. Parapodia biramous, notopodia smaller than neuropodia with long, slender, papillated dorsal cirrus; notochaetae present in moderate numbers, stout, straw-like in colour, serrated, much shorter than neurochaetae; neuropodia with long, slender ventral cirrus inserted proximally; neurochaetae numerous, extremely long, thin, almost capillary-like, all unidentate. Elytra often missing, when present small, ovoid, translucent with rough surface, with sparse microtubercules only, some elongated papillae irregularly present on surface and fringe. Pygidium conical, anal cirri not observed.

Remarks. The specimens morphologically agree with the description of Herdmanella gracilis Ehlers, 1908 ; however, it was decided not to assign them to this species without a molecular assessment considering that the specimens are likely to be juveniles, and the type locality (East Africa) is far distant from the Amundsen Sea.

Figures

Figure 2. Juvenile Polynoidae: a, image of live specimens agreeing morphologically with Herdmanella gracilis Ehlers, 1908; b, detail of specimen; c, drawing of H. gracilis from the orginal description published by Ehlers (1908).

Figure 3. Presence of cephalic peaks in juvenile polynoids: a, type 1 juvenile of Harmothoe fuligineum—cephalic peaks clearly present (arrowed); b, type 2 juvenile—cephalic peaks absent, consistent with H. gracilis Ehlers, 1908.