Armandia paraintermedia, 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 : 590-595

Armandia paraintermedia n. sp.

( Figs 1 E, 10–12, 18B)

Material examined: Thirty-seven specimens in sixteen samples. Holotype: AM W.44243, MI QLD 2370. Paratypes: AM W.43901, MI QLD 2337; AM W.44107, MI QLD 2355; AM W.44113, MI QLD 2356; AM W.44112, MI QLD 2360; AM W.47325, MI QLD 2370 (2); AM W.44238, MI QLD 2374; AM W.45131, MI QLD 2379, in EtOH; AM W.44546, MI QLD 2381, in EtOH; AM W.44550, MI QLD 2389; AM W.44556, MI QLD 2397 (3); AM W.45130, MI QLD 2432, in EtOH; AM W.45217, MI QLD 2440 (15); AM W.47326, MI QLD 2440 (2 on SEM stub); AM W.45218, MI QLD 2440 (3 in EtOH); AM W.45409, MI QLD 2444 (2).

Diagnosis. Parapodia biramous, with prechaetal lobe, ventral lobe and small dorsal cirrus on each parapodium; prechaetal lobe asymmetrical provided with a ventrally displaced tip. Anal tube about as long as wide, squareshaped; opening at posterior margin with a long ventral incision, provided with one long internal anal cirrus, thick at base and distally tapered, projecting outwardly; posterior margin provided with 3 pairs of elongate, finger-like, paired anal cirri, almost as long as total anal tube length, thinner than pair of basal cirri.

Description. Based on holotype. Specimen complete, 7.0 mm long and 0.5 mm wide, with 29 chaetigers. Body slender, slightly tapering towards anterior end and truncated at posterior end ( Fig. 11 A). Prostomium conical provided with a pair of small red eyes and one larger dorsal one ( Fig. 10 A), palpode well-developed but short ( Figs 10 A, 11B). One pair of ring-shaped nuchal organs ( Fig. 10 A); pharynx eversible, oral tentacles not seen ( Fig. 11 C– E). Branchiae present from CH 2– CH 26; last three chaetigers ( CH 27– CH 29) abranchiate; branchiae long surpassing parapodium of following chaetiger ( Fig. 11 F), slightly decreasing in length and width in CH 24– CH 26. Parapodia biramous, with prechaetal lobe, ventral lobe and small dorsal cirrus on each parapodium. Prechaetal lobe asymmetrical provided with a ventrally displaced tip present from CH 1– CH 29 ( Figs 10 D–I, 12A–C). Lateral eyespots anterior to parapodia on CH 7– CH 17, orange, circular; those of CH 16 and specially CH 17 smaller than others. Simple capillary chaetae in two bundles, notochaetae generally longer than neurochaetae, those of posterior chaetigers very long ( Figs 10 C, 12D–E). Anal tube about as long as wide, square-shaped ( Figs 10 B, 12D–E); as long as last 2 chaetigers; opening at posterior margin with a long ventral incision ( Fig. 10 C), provided with one long internal anal cirrus, thick at base and distally tapered, projecting outwardly ( Fig. 10 B, not present in holotype). Anal tube posterior margin provided with 3 pairs of elongate, finger-like, paired anal cirri, almost as long as total anal tube length ( Figs 10 B, 12E–F), thinner than pair of basal cirri ( Figs 10 B–C, 12E).

Remarks. Examination of paratypes shows some variability for several characters. Lateral eyes are present from CH 7 to CH 15– CH 17, being smaller the first and the last 1–2. The chaetae from the last three chaetigers appear more deciduous than others. The number of papillae on the anal tube ranges from 1–3 pairs in small specimens (4 mm in length) to 11 pairs in larger specimens (8 mm). The pair of basal cirri may be short and therefore difficult to distinguish from the other cirri ( Fig. 12 D–F). The eversible pharynx has digitiform protuberances which bear abundant ciliature and projects beyond the border of the mouth ( Fig. 11 D–E). The branchiae are present from CH 2 to CH 27, showing two abranchiate chaetigers rather than three. In abranchiate chaetigers, there is a small dorsal elevation in the postchaetal lobe in the same place where the branchia are present in branchiate chaetigers ( Fig. 10 D, I), similarly as it happens in A. dolio n. sp.

The shape and size of the anal tube of Armandia paraintermedia n. sp. ( Fig. 10 B) is similar to that of other species of Armandia ( Figs 13 , 17 A, C); some of these species have been reported in Australia but their type localities are far away such as it happens for A. intermedia Fauvel, 1902 ( Fig. 13 B) and A. maculata Webster, 1884 ( Fig. 13 F). Other related species from SE Asia are A. cf. melanura Gravier, 1905 ( Fig. 13 G), A. amakusaensis ( Fig. 13 A) and A. lanceolata Willey, 1905 ( Fig. 13 E). Armandia intermedia was described by Fauvel (1902) from West Africa and later reported in South Africa ( Day 1967; Fig. 13 C) and Australia ( Hutchings 2000; Fig. 13 D); this species bears an anal tube similar to that of A. paraintermedia n. sp. which has paired cirri, one pair of basal cirri and ventral unpaired cirrus (“2 grosses papilles ventrales courtes, séparées par une longue papille impaire, médiane, ventrale”; Fauvel 1902). Armandia intermedia differs, however, from A. paraintermedia n. sp. by having the last three chaetigers which are abranchiate instead of two, lateral eyes in 13 chaetigers ( CH 7– CH 19) instead of 11 ( CH 7– CH 17) and a constant number of paired cirri (9 pairs) instead of 1–11 pairs. Specimens from South Africa as described by Day (1967) have 27–29 chaetigers, branchiae start in CH 2, the last 23 chaetigers are abranchiate, lateral eyes are present in 12 chaetigers ( CH 7– CH 18), the unpaired anal cirrus is comparatively longer (see Fig. 13 C) and shows a high degree of variability in the number of paired anal cirri (10–20; “dorsal clavate papillae” sensu Day (1967)). Day (1967) does not mention the presence of the pair of ventral cirri but they seem to be present according to the drawing provided in that paper ( Day 1967, Fig. 25.2.g; see also Fig. 13 C).

Armandia maculata was described from Bermuda ( Webster 1884) ( Fig. 18A ) and later reported in New Zealand by Augener (1924) and Benham (1950) ( Fig. 18 B). The drawing of specimens of the Gulf of Mexico provided by Uebelacker (1984) ( Fig. 13 F) shows an anal tube similar to those of A. paraintermedia n. sp. and A. intermedia ; the drawing and the description show, however, little detail about paired anal cirri (“0–28 digitiform to filiform marginal papillae”; Uebelacker 1984) and therefore this does not allow reliable comparisons among these species. Nevertheless, A. maculata seems to differ by having the three last chaetigers which are abranchiate ( CH 27– CH 29) and fewer lateral eyes ( CH 13– CH 17), a larger size (19–22.1 mm in length and 2–2.6 mm in width vs. 7.0 mm and 0.5 mm respectively in A. paraintermedia n. sp.). In conclusion, the reports of A. intermedia in Australia ( Fig. 13 D) and those of A. maculata in New Zealand may either refer to A. paraintermedia n. sp. or to a new species.

Saito et al. (2000) describe A. amakusaensis from the South of Japan ( Figs 13 A, 18A) and compared it to A. intermedia and A. leptocirris Grube, 1878 from the Philippines ( Fig. 17 F). Armandia paraintermedia n. sp. is similar to A. amakusaensis but they differ in the length and shape of the unpaired ventral anal cirrus; this cirrus is quite long and provided with numerous constrictions in A. amakusaensis . Furthermore, the paired anal and basal cirri are also much thinner in the former species ( Fig. 13 A; Saito et al. 2000, Fig. 3 i–k). On the other hand, A. leptocirris mostly differs from A. paraintermedia n. sp. and A. intermedia in the shape and size of the anal tube, and the shape of the body and appearance of the unpaired ventral cirrus as well.

Finally, Eibye-Jacobsen (2002) reports two species from the Andaman Sea ( Fig. 18 B), namely A. cf. melanura Gravier, 1905 ( Fig. 13 G), originally described from the Red Sea ( Fig. 18A ) and A. lanceolata Willey, 1905 , from the Sri Lankan coast ( Fig. 18A ); the latter was also reported by Hartmann-Schröder (1984) as A. cf. lanceolata from Western Australia and Gibbs (1971) from the Solomon Islands. Both species have an anal tube which is similar to that of A. paraintermedia n. sp., but they have paired anal cirri which are much shorter and lack the pair of basal ventral cirri and an unpaired ventral cirrus.

Etymology. The name of the new species refers to its morphological similarity to Armandia intermedia Fauvel, 1902 from West Africa (see Remarks below).

Habitat / Distribution. Armandia paraintermedia n. sp. was the most abundant and widespread opheliid at Lizard Island, and was found both all around LI (89.2%) and outer sites (10.8%) ( Fig. 1 E). Present from the intertidal to 24 m depth on a wide variety of bottom types (sand, coral rubble, calcareous algae, sponges and coral sand).

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 3. Armandia bifida n. sp. (holotype AM W. 44696). A. Anterior end, left side, lateral view; B. Posterior end, dorsal view; C. Posterior end, right side, lateroventral view; (D – I) Parapodia, left side: D. CH 1, lateral view; E. CH 3, lateral view; F. CH 4, dorsolateral view; G. CH 6, lateral view; H. CH 36, dorsal view; I. CH 38, dorsal view. White arrows pointing notches of prechaetal lobes ventral ramus. Dotted line in C showing potential contour of unpaired anal cirrus (broken in this specimen) according to that preserved in paratype W. 44117. Proximal part of chaetae only illustrated in D and H.

FIGURE 10. Armandia paraintermedia n. sp. (holotype AM W. 44243). A. Anterior end, left side, lateral view. B. Posterior end, left side, latero-dorsal view. C. Posterior end, ventral view. (D – I) Parapodia, right (D – G) and left (H – I) side: D. CH 1, anterolateral view; E. CH 2, dorsal view; F. CH 5; dorsal view; G. CH 8, dorsal view; H. CH 26, anterolateral view; I. CH 28, anterolateral view. White arrows marking position of prechaetal lobe tip. Dotted line in B depicting approximate shape and position of missing unpaired anal cirrus and extra dorsal paired anal cirri. Proximal part of chaetae only illustrated in D, E and I.

FIGURE 11. Armandia paraintermedia n. sp. SEM micrographs (paratype AM W. 47326). A. Complete specimen, ventral view; B. Distal end of prostomium, ventral view; C. Anterior end, ventral view; D. Detail of mouth and ventral groove; E. Ciliated oral tentacles inside the mouth; F. CH 3 – CH 5 in ventral view.

FIGURE 12. Armandia paraintermedia n. sp. SEM micrographs (paratype AM W. 47326). A. CH 6; B. CH 9; C. CH 19; D. Posterior end, right side, ventrolateral view; E. Posterior end, left side, ventrolateral view; F. Detail of anal tube marginal papillae.

FIGURE 13. Posterior body region of species of Armandia similar to A. paraintermedia (all redrawn from originals). Organized alphabetically and by date; type locality or collecting site between brackets (see text). A. A. amakusaensis (in Saito et al. 2000); B. A. intermedia (in Fauvel 1902); C. A. intermedia (in Day 1967); D. A. intermedia (in Hutchings 2000); E. A. lanceolata (in Eibye-Jacobsen 2002); F. A. maculata (in Uebelacker 1984); G. A. cf. melanura (in Eibye-Jacobsen 2002).

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).

FIGURE 18. A. World map showing type localities of several Armandia species reported from East Asia and Australasia. B. Map showing records of Armandia species described (grey circles) or reported (white circles) in East Asia and Australasia. 1. Grube (1878); 2. Webster (1884); 3. Kükenthal (1887); 4. Fauvel (1902); 5. Willey (1905); 6. Gravier (1905); 7. Augener (1924); 8. Caullery (1944); 9. Benham (1950); 10. Gallardo (1967); 11. Gibbs (1971); 12. Knox & Cameron (1971); 13. Hutchings & Rainer (1979); 14. Hartmann-Schröder (1974); 15. Hartmann-Schröder (1979); 16. Hartmann-Schröder (1981); 17. Hartmann-Schröder (1984); 18. Hutchings & Murray (1984); 19. Hartmann-Schröder (1986); 20. Saito et al. (2000); 21. Eibye-Jacobsen (2002); 22. Al-Hakim & Glasby (2004); 23. Morton & Bamber (2008); 24. This study.