Armandia tubulata, Parapar, Julio & Moreira, Juan, 2015

Parapar, Julio & Moreira, Juan, 2015, Six new species of the genus Armandia Filippi, 1861 (Polychaeta, Opheliidae) from Lizard Island (Great Barrier Reef, Australia), Zootaxa 4019 (1), pp. 577-603 : 595-599

Armandia tubulata n. sp.

( Figs 1 F, 14–16, 18B)

Material examined. Seven specimens in three samples. Holotype: AM W.47327, MI QLD 2370. Paratypes: AM W.47328, MI QLD 2337; AM W.47329, MI QLD 2340; AM W.47330, MI QLD 2370 (3); AM W.47331, MI QLD 2370, on SEM stub.

Diagnosis. Parapodia biramous, with prechaetal lobe, ventral lobe and dorsal cirrus on each parapodium; prechaetal lobe short and asymmetrical, with a ventrally displaced tip. Anal tube long and narrow, tube-like. Tube opening directed posterio-ventrally, appearing obliquely truncate in lateral view; not laterally compressed; posterior border provided with 6 pairs of finger-like anal cirri of about 1/5 as long as dorsal tube length; paired basal cirri and internal unpaired anal cirrus.

Description. Based on holotype. Specimen complete, 11.0 mm long and 1.0 mm wide, with 29 chaetigers. Body slender, slightly tapering towards anterior end and truncated at posterior end. Prostomium conical, provided with a pair of lateral, small red eyes and a dorsal one ( Fig. 14 A); palpode well-developed but short and narrow, twisted ( Figs 14 A, 15A). One pair of ring-shaped nuchal organs ( Fig. 15 B); pharynx eversible ( Fig. 14 A), oral tentacles not seen (but present in paratypes; Fig. 15 C). Branchiae present from CH 2– CH 26; last three chaetigers ( CH 27– CH 29) abranchiate; branchiae short, slightly surpassing parapodium of following chaetiger, not decreasing in length in posterior chaetigers. Parapodia biramous, with prechaetal lobe, ventral lobe and dorsal cirrus on each parapodium ( Figs 14 D–I, 15E–F, 16A–D). Prechaetal lobe short and asymmetrical, with a ventrally displaced tip. Lateral eyespots anterior to parapodia on CH 7– CH 17, orange, horizontally oval; those of CH 7 and CH 15– CH 17 smaller than others. Simple capillary chaetae in two bundles, notochaetae generally longer than neurochaetae. Anal tube long and narrow, tube-like, of same width along its length ( Figs 14 B, 16E–F). Anal tube opening directed posterio-ventrally, appearing obliquely truncate in lateral view; not laterally compressed; ventrally as long as about 2 chaetigers, dorsally as long as about 3 chaetigers ( Figs 14 C, 16E). Posterior border provided with 6 pairs of finger-like anal cirri of about 1/5 as long as dorsal tube length ( Fig. 14 B); paired basal cirri and internal, unpaired anal cirrus not observed (but present in one paratype, see below).

Remarks. The shape of the anal tube of A. tubulata n. sp. resembles that of A. leptocirris Grube, 1878 and A. andamana Eibye-Jacobsen (2002) . Armandia leptocirris was described from the Philippine Islands, and later reported in Sri Lanka ( Willey 1905), the Solomon Islands ( Gibbs 1971) and South Africa ( Day 1967, Fig. 25.2.h, as A. leptocirrus ). The drawing of A. leptocirris presented by Day (1971) ( Fig. 17 F) shows an anal tube long and obliquely truncated in lateral view, quite similar to that of A. tubulata . Nevertheless, in A. leptocirris the anal tube is opened posterio-dorsally instead of postero-ventrally. Armandia andamana has not been reported since it was described by Eibye-Jacobsen (2002). This species is similar to A. longicaudata but it lacks an unpaired anal cirrus which is present instead in A. longicaudata and A. tubulata n. sp.

The paratypes of A. tubulata n. sp. measure 9–11 mm in length, and show that the size and the number of chaetigers are constant. One paratype (AM W.47329) has an internal unpaired ventral cirrus. The branchiae are lacking in the last three chaetigers; those and the first chaetiger show a small dorsal elevation in the postchaetal lobe, as it happens in A. dolio n. sp. and A. paraintermedia n. sp. ( Fig. 14 D, I).

Etymology. The epithet tubulata (L.) refers to the tubular shape of the anal tube.

Habitat / Distribution. A sublittoral species only found in SW LI coast, and almost restricted to Vicki’s Reef sampling sites (85.7%) ( Fig. 1 F). Found from 1 to 10 m depth on different bottom types (dead coral rubble, fine sand and calcareous algae).

Figures

FIGURE 1. Map of the study area showing collecting sites of each species described. Arrows facing to cross-shelf sampling sites: Abbreviations: MGR = MacGillivray Reef, NDI = North Direction Island, YR = Yonge Reef.

FIGURE 14. Armandia tubulata n. sp. (holotype AM W. 47331). A. Anterior end, left side, lateral view; B. Posterior end, left side, latero-dorsal view; C. Posterior end, ventral view. (D – I) Parapodia, right side: D. CH 1, lateral view; E. CH 2, lateral view; F. CH 3, lateral view; G. CH 9, dorsal view; H. CH 21, anterior view; I. CH 29, dorsal view. White arrow marking position of prechaetal lobe tip.

FIGURE 15. Armandia tubulata n. sp. SEM micrographs (paratype AM W. 47331). A. Anterior end, left side, lateroventral view; B. Detail of nuchal organ and CH 1; C. Detail of oral tentacles protruding from mouth; D. CH 1 – CH 4, left lateroventral view; E. CH 3, frontal view; F. CH 12 – CH 13, lateral view.

FIGURE 17. Posterior body region of species of Armandia described or reported in the South East Asia and Australia, all redrawn from original; type locality or collecting site between brackets (see text). Organized alphabetically and by date. A. A. andamana (in Eibye-Jacobsen 2002); B. A. bilobata (in Hartmann-Schröder 1986); C. A. bipapillata (in Hartmann-Schröder 1974); D. A. broomensis (in Hartmann-Schröder 1979); E. A. exigua (in Kukenthal 1887); F. A. leptocirris (in Day 1967); G. A. longicaudata (in Caullery 1944); H. A. longicaudata (in Day 1967); I. A. secundariopapillata (in Hartmann-Schröder 1984).