Lepidastheniella comma (Thomson, 1902)

Barnich, R & Fiege, D, 2004, Revision of the genus Lepidastheniella Monro, 1924 (Polychaeta: Polynoidae: Lepidastheniinae) with notes on the subfamily Lepidastheniinae and the description of a new species, Journal of Natural History 38, pp. 863-876 : 868-870

Lepidastheniella comma (Thomson, 1902)

(figure 1A–J)

Polynoe comma Thomson, 1902: 241 ; Augener, 1924a: 12, figure 5.

Lepidasthenia comma: Ehlers, 1907: 6 ; Benham, 1909: 237.

Lepidametria comma: Augener, 1924b: 287 .

Lepidastheniella comma: Monro, 1924: 44 (in ‘Remarks’ section); figures 7, 8; Benham, 1950: 5, figure 1.

Lepidastheniella monroi Benham, 1950: 9 , figure 2.

Type material. Lepidastheniella comma , syntypes: four specimens (spms) (dry, 3 cs, 1 af, 2 mf), OMD IV241 (Coll. Benham, Jar 51) A99-166, November 1899, Moeraki, commensal in terebellid tube. Lepidastheniella monroi , syntype: one spm (cs), BMNH 1907.5 .1.48, Masked Island , New Zealand, in sand under boulders between tide marks .

Additional material. One spm (bad shape), OMD IV185 (Coll. Benham, Jar 48), in same jar as specimen of Lepidonotus polychroma , leg. Powell, labelled Lepidametria (Augener) comma . One spm (dry), OMD IV243, 12 March 1930, E3, 7 fathoms, off Rangitoto Beach, det. Benham as Lepidasthenia comma . One spm (dry, indeterminable), OMD IV128 (Coll. Benham, Jar 11), April 1931, Auckland harbour (dredge), leg. Powell, labelled as Lepidametria (Augener) comma .

Description (mainly based on the available syntype of L. monroi , supplemented by observations on the syntypes of L. comma , e.g. pigmentation of dorsum and elytra and chaetal characters). Dorsum with pigmented transverse stripes. Anterior end (figure 1A): prostomium without cephalic peaks; median antenna with ceratophore in anterior notch, style smooth, abruptly tapering sub-distally, with pigmented bands basally and sub-distally; lateral antennae inserted terminally, with distinct ceratophores, styles smooth, abruptly tapering sub-distally, with pigmented band basally; anterior pair of eyes dorsolaterally on widest part of prostomium, posterior pair dorsally closely behind anterior pair; palps papillate, tapering; facial tubercle present at upper lip of mouth. Tentaculophores (segment 1) inserted laterally to prostomium, without chaetae, with a pair of dorsal and ventral tentacular cirri with styles smooth, abruptly tapering sub-distally, with pigmented bands basally and subdistally. Second segment with first pair of elytra, sub-biramous parapodia, and long, ventral buccal cirri; notochaetae slender, spinous; neurochaetae with distinct rows of spines distally and pointed unidentate tips.

Numerous pairs of elytra (40 pairs in syntype of L. monroi ), inserted on segments 2, 4, 5, alternating to end of body, last three to four segments cirrigerous; elytra covering dorsum only in anterior part of body; elytral margin smooth; anteriormost elytra with small, conical microtubercles in anterior half, number of microtubercles diminishing gradually, middle and posterior elytra smooth; elytral surface with several pigmented patches, central part often with more strongly pigmented band or area (comma-shaped) (figure 1B–D). Styles of dorsal cirri smooth, in anterior segments abruptly tapering sub-distally and with pigmented band, in more posterior ones tapering gradually; anteriormost reaching beyond tips of neurochaetae (figure 1A), more posterior ones shorter; styles of ventral cirri smooth, tapering, shorter than neuropodia (figure 1E).

Parapodia sub-biramous, smooth; notopodia reduced; neuropodia truncate, notched dorsally and ventrally, with elongate distally rounded lobes; tips of noto- and neuro-acicula not penetrating epidermis; about same number of noto- and neurochaetae (up to 20) (figure 1E). Notochaetae shorter than neurochaetae, slender with long pointed tips and distinct rows of spines (figure 1F). Neurochaetae stout, falcate, with rows of spines distally, without crest, tips unidentate; in upper neurochaetae tips more or less straight, in lower ones slightly hooked (figure 1G–J).

Nephridial papillae beginning at segment 8.

Remarks. According to Benham (1950), Lepidastheniella comma shows only few (up to four) short delicate notochaetae and neurochaetae with hooked tips and few rows of spines, while L. monroi is characterized by many long, thick notochaetae and neurochaetae not hooked distally and with more numerous rows of spines. Our investigations of all available type specimens and additional material of both species showed no significant differences. Although the syntypes of L. comma and the other investigated specimens must have dried out at some time and notochaetae are difficult to discern, we counted distinctly more than four notochaetae per parapodium. In our opinion differences given by Benham (1950) for the shape of noto- and neurochaetae are insignificant, since these are characters which vary within one parapodium depending on the position of the chaeta (see figure 1G–J). Moreover, the description given in Thomson (1902) for L. comma corresponds well with the characters observed in the investigated syntype of L. monroi , which confirms our opinion that L. monroi Benham, 1950 is a junior synonym of L. comma (Thomson, 1902) .

Measurements. Specimen figured: syntype of Lepidastheniella monroi ( BMNH 1907.5.1.48): L 67 mm and W 6 mm for 79 segments.

Distribution. New Zealand (Moeraki, Auckland Harbour, Rangitoto Beach, Tagua Bay, Carnley Harbour, Musgrave Harbour, Masked Island) (see also Benham, 1950).

Habitat. Free-living in sand or commensal with terebellids.