Armandia mariacapae, Moreira, Juan & Parapar, Julio, 2017

Moreira, Juan & Parapar, Julio, 2017, New data on the Opheliidae (Annelida) from Lizard Island (Great Barrier Reef, Australia): five new species of the genus Armandia Filippi, 1861, Zootaxa 4290 (3), pp. 483-502 : 492

Armandia mariacapae n. sp.

( Figs 1 , 6 )

Material examined. Three specimens in three samples. Holotype: AM W.49294, MI QLD 2421. Paratypes: AM W.49295, MI QLD 2355 (1); AM W.44697, MI QLD 2414 (1).

Diagnosis. Parapodia biramous, with prechaetal lobe, dorsal cirrus and ventral lobe on each parapodium; prechaetal lobe asymmetrical, with conspicuous elongated, triangular tip in all chaetigers, tip directed posterodorsally. Branchiae present from chaetiger 2 to last body chaetiger, digitiform, about as long as chaetae, not conspicuously decreasing in length in posterior chaetigers. Anal tube long, narrow, slightly wider at mid-length, about two times as long as wide; anal tube opening directed postero-ventrally; posterior margin with up to 10 pairs digitiform paired marginal papillae, about 0.5 times length of anal tube; paired basal papillae about as long as others, distal third inflated; internal unpaired cirrus ringed, about 0.5 times length of anal tube.

Description. Based on holotype. Specimen complete, 20.5 mm long and 0.9 mm wide, with 33 chaetigers. Body slender, slightly tapering towards anterior end; posterior end wide and truncated. Prostomium conical; palpode well developed but short and narrow, clavate ( Fig. 6 A). Two lateral small eyes deeply embedded in prostomium. One pair of ring-shaped nuchal organs; pharynx hidden after fixation; oral tentacles not seen. Segmental limits among chaetigers not defined. Branchiae present from CH 2 to last body chaetiger ( CH 33), digitiform, as long as or slightly shorter than notochaetae, not decreasing noticeably in length in posterior chaetigers. Parapodia biramous, with prechaetal lobe, dorsal cirrus and ventral lobe on each parapodium ( Fig. 6 B– F). CH 1 with small dorsal postchaetal elevation ( Fig. 6 B). Prechaetal lobe asymmetrical with conspicuous elongated, triangular tip in all chaetigers, tip directed postero-dorsally, slightly shorter than proximal part of prechaetal lobe. Dorsal cirrus oval to rounded. Ventral lobe wide, well developed in all chaetigers. Lateral reddish eyespots anterior to parapodia on 11 chaetigers ( CH 7– CH 17); those of CH 7 and CH 17 slightly smaller than others. Simple capillary chaetae in two bundles of 5–8 chaetae each in anterior chaetigers and 2–4 in posterior ones; notochaetae longer than neurochaetae, well surpassing level of dorsum only in first chaetigers. Ventral groove deep, well defined along the body. Anal tube long, narrow, slightly wider at mid-length, about two times as long as wide ( Fig. 6 G). Anal tube opening directed postero-ventrally; not laterally compressed; dorsally as long as about 4 chaetigers, ventrally as long as about 3 chaetigers; ventral incision about 0.7 times length of ventral side. Posterior margin provided with 10 pairs of long, digitiform marginal papillae of about 0.55 times length of dorsal tube; several lateral ridges running from base of marginal papillae along anal tube entire length; paired basal papillae about as long as others, distal third inflated; unpaired anal cirrus, ringed, at least 0.5 times dorsal tube length.

Variation. The two paratypes are similar to holotype but smaller (5.9–11.0 mm long and 0.25–0.6 mm wide, respectively) and with less chaetigers (27, 31); the smaller paratype bears three prostomial eyes, the prechaetal lobe tip is triangular but slightly rounder in comparison, and the lateral ridges of the anal tube are ill-defined in comparison to the other paratype and holotype.

Remarks. Armandia mariacapae n. sp. can be distinguished from other species by features of the parapodia and anal tube. The closest species according to general body appearance and anal tube are A. dolio and A. tubulata ; however, the new species mostly differs in bearing a prechaetal lobe that is provided with a conspicuous, large triangular tip from CH 1 to the end of body instead of being shorter and rounded as it happens in the other two species. On the other hand, A. secundariopapipallata also bears a prechaetal lobe with triangular, elongated tip but the anal tube is much shorter and paired basal papillae are much larger and provided in turn with small papillae. Specimens of A. cf. melanura Gravier, 1905 from the Andaman Sea as reported by Eibye-Jacobsen (2002) also show well-developed prechaetal lobe tips but those become truncated in posterior chaetigers; furthermore, the author acknowledges that this material may well correspond to two different species according to the number of chaetigers and branchiae.

Etymology. This species is dedicated to our colleague and friend Dr. María Capa because of her kindness, friendship and many contributions to the knowledge of marine annelids.

Habitat / Distribution. Specimens were collected in intertidal and sublittoral sand at 0–12 m at several localities around LI (holotype: in front of LIRS) ( Fig. 1 , Table 1).

Figures

FIGURE 1. Map of the study area showing collecting sites of new species described herein. Arrow in Yonge Reef symbol facing to cross-shelf site.

FIGURE 6. Armandia mariacapae n. sp. (holotype AM W. 49294). A, anterior end, left side, lateral view; (B – F) Parapodia, left side, lateral (B, C) and dorsolateral view (D – F): B, CH 1; C, CH 2; D, CH 3; E, CH 7; F, CH 33. G, posterior end, left side, lateral view. White arrows pointing prechaetal lobe tip; B – F, same scale.