Aponuphis bellani, Paxton, 2017

Paxton, Hannelore, 2017, Three new species of Aponuphis (Annelida: Onuphidae) from eastern Australia, Zootaxa 4344 (2) : -

Aponuphis bellani n. sp.

Figure 1E ; 2F, G; 4, 5; Table 1

Material examined. Holotype: Incomplete specimen, 22 mm long (78 chaetigers), 1.0 mm wide; New South Wales, Cape Banks, 34°00’S – 151°16.00’E, 65–70 m, 3 Jan–18 Jan 1991, sta. 4-373 (AM W. 49451).

Paratypes: Twenty incomplete to almost complete specimens up to 38 mm (120 chaetigers), 0.6–1.0 mm wide.

Cape Banks: 34°00’S–151°16.00’E, 65–70 m, 3 Jan–18 Jan 1991, sta. 4-365 (AM W.49452:1).

Cobblers , Bate Bay: 34°04.6’S – 151°13.00’E, 45–50 m, 25 Jun–26 Jul 1990, sta. C64 (AM W.49453:3) ; 34°05.9’S–151°12.00’E, 65–70 m, 25 Jun–26 Jul 1990, sta. C77 (AM W.49454:1); same data, sta. C78 (AM W.49489:1); 34°04.6’S – 151°13.00’E, 65–70 m, 29 Oct–14 Nov 1990, sta. 3-136 (AM W.49455:2) ; 34°04.6’S– 151°13.00’E, 45–50 m, 3 Jan–18 Jan 1991, sta. 4-322 (AM W.49456:1).

Wattamolla, off Providential Head: 34°08.00’S–151°08.50’E, 45–50 m, 29 Oct–14 Nov 1990, sta. 3-73 (AM W.49457:2); same data, sta. 3-78 (AM W.49458:3); 34°08.00’S – 151°08.50’E, 65–70 m, 29 Oct–14 Nov 1990, sta, 3-95 (AM W.49459:1) ; 34°08.00’S–151°08.50’E, 65–70 m, 3 Jan–18 Jan 1991, sta. 4-287 (AM W.49460:1).

Bass Point: 34°36’S–150°54’E, 45–50 m, 25 Jun–26 Jul 1990, sta. BP45 (AM W.49461:1); 34°36’S–150°54’E, 65–70 m, 29 Oct–14 Nov 1990, sta. 3-46 (AM W.49462:2); 34°36’S–150°54’E, 35–40 m, 3 Jan–18 Jan 1991, sta. 4-223 (AM W.49463:1).

Additional material examined: Three complete specimens, 8–15 mm long (50–130 chaetigers), 0.4–0.5 mm wide; 50 incomplete to almost complete specimens, 0.4–1.0 mm wide.

Cape Banks: sta. 3-171 (AM W.49464:1); sta. 3-189 (AM W.49465:1).

Cobblers, Bate Bay: sta. C35 (AM W.49466:3); sta. 3-134 (AM W.49467:1); sta. 3-141 (AM W.49468:1); sta. 3-144 (AM W.49469:1); sta. 4-332 (AM W.49470:1); sta. 4-335 (AM W.49471:2); sta. 4-340 (AM W.49472:2); sta. 4-343 (AM W.49473:1).

Wattamolla, off Providential Head: sta. 3-75 (AM W.49474:2); sta. 3-89 (AM W.49475:1); sta. 3-90 (AM W.49476:2); sta. 3-94 (AM W.49477:1); sta. 4-273 (AM W.49478:2); sta. 4-280 (AM W.49479:1); sta. 4-284 (AM W.49480:1); sta. 4-291 (AM W.49481:1); sta. 4-292 (AM W.49482:6); sta. 4-293 (AM W.49483:1); sta. 4-295 (AM W.49484:4).

Bass Point: sta. BP14 (AM W.49519:1); sta. BP33 (AM W.49520:2); sta. BP45 (AM W.49521:1); sta. 3-13 (AM W.49522:5); sta, 3-33 (AM W.49523:2); sta, 3-35 (AM W.49524:2); sta. 3-36 (AM W.49525:1); sta. 3-41 (AM W.49526:1); sta. 3-42 (AM W.49527:2); sta. 3-47 (AM W.49528:2); sta. 4-232 (AM W.49529:1).

Type locality. Pacific Ocean, off Cape Banks, New South Wales, Australia, 34°00’S – 151°16.00’E, depth 65– 70 m.

Diagnosis. Median longitudinal stripe; prostomium anteriorly incised; antennae with 3–5 ceratophoral rings, styles to chaetiger 3–15; 4 pairs of modified parapodia with bi- to tridentate short-appendaged pseudocompound hooks; subacicular hooks from chaetiger 23–28; branchiae absent; transparent, smooth tube.

Description. Freshly preserved specimens overall cream coloured; about half of specimens with median longitudinal brown pigment stripe on dorsal surface starting from chaetiger 5–15 to near end of body ( Fig. 1E ); in holotype from chaetiger 5 to about 70.

Prostomium wider than long, anteriorly rounded, with slight median incision ( Fig. 2F, G ). Pair of small anterior eye spots between frontal lips and palps, another pair, ranging from single spot to group of up to 4 spots between palps and lateral antennae. Ceratophores of palps and antennae short, with 2–4 proximal rings and longer distal ring, palpostyles about 5 times as long as palpophores, reaching chaetiger 1 (1–2); lateral antennostyles to chaetiger 12 (6–13), median antennostyles to 10 (3–10). Nuchal grooves straight with narrow middorsal separation. Peristomial cirri absent.

First 4 pairs of parapodia modified, directed slightly anterolaterally and slightly prolonged. Prechaetal lobe rounded; postchaetal lobe subulate ( Fig. 4A, B ), gradually reduced from chaetiger 10, becoming small knob from chaetiger 25, absent from chaetiger 50. Dorsal cirri initially subulate, becoming smaller and digitiform by chaetiger 20 ( Fig. 4C ) but remaining as slender cirrus to almost end of body; ventral cirri subulate to digitiform on anterior 4 chaetigers, then replaced by glandular pads. Branchiae absent.

Mostly tridentate pseudocompound hooks with short hoods, numbering 4–5, present on anterior 4 chaetigers; all short-appendaged. Distal tooth large and falcate, middle tooth well developed, lowermost tooth small to tiny ( Fig. 4D–F ) to being totally absent and clearly bidentate ( Fig. 4G ) in some lowermost hooks. Median hooks slightly thicker and with shorter appendage ( Fig. 4F ). Hardly any pectinate chaetae present in anterior body region; single pectinate chaetae with 10–12 teeth in slightly oblique comb in median to posterior region ( Fig. 4H ). Limbate chaetae starting on chaetiger 4 as 2–3 long upper chaetae in addition to pseudocompound hooks ( Fig. 4B ), upper and shorter lower limbate chaetae from chaetiger 5 until lower bundle replaced by two hooded bidentate subacicular hooks from chaetiger 26 (21–29).

Pygidium with two pairs of very thin anal cirri; dorsal pair as long as pygidium and terminal 20 segments, ventral pair about one eighth thereof. Mandibles very delicate, cutting plates thinly calcified, protomandibles hardly visible ( Fig. 4I ). Maxillae ( Fig. 4J ) transparent, only sclerotized between carriers and MI and attachment lamellae; maxillary formula: Mx I = 1+1; Mx II = 7+7; Mx III = 7+0; Mx IV = 4+6; MV = 1+1. Transparent, tightfitting tubes without any attached foreign particles ( Fig. 5A ). Under greater magnification tubes showing layered construction and external fine ridges ( Fig. 5B–D ).

Remarks. The features of the new species have been compared to its congeners and discussed above (see Remarks to A. annae n. sp. and Table 1).

Etymology. It is a pleasure to dedicate this species to Dr. Gérard Bellan in recognition of his extensive studies of the polychaete fauna of the Mediterranean Sea.

Biology. No ovigerous specimens or brooded specimens were observed; the smallest settled specimen was 8 mm (50 chaetigers) in length, 0.5 mm in width.

Habitat and distribution. Aponuphis bellani n. sp. was the second most common of the three new species in the four sampling areas, being present in 45 out of 100 stations. Whilst it was collected in depths between 35–70 m, its abundance peaked at 65–70 m ( Fig. 7 ).

Figures

FIGURE 1. Diagrammatical dorsal views of anterior ends of Aponuphis spp., showing variations in pigmentation. A, Aponuphis annae n. sp., morph A; B, same, morph B; C, same, morph C; D, same, morph D; E, A. bellani n. sp.; F, A. danicae n. sp.

FIGURE 2. Scanning electron micrographs of Aponuphis annae n. sp. (A – E) and A. bellani n. sp. (F, G). A, anterior part of body, dorsal view; B, enlarged head region of A, same view; C, pectinate chaeta from chaetiger 14; D, 15 - chaetiger juvenile, dorsal view; E, enlarged head region of juvenile, same view; F, anterior part of body, dorsal view; G, enlarged head region of F, same view.

FIGURE 4. Aponuphis bellani n. sp., line drawings. A, parapodium of chaetiger 1, anterior view; B, parapodium of chaetiger 4, same view; C, parapodium of chaetiger 26, same view; D, upper tridentate pseudocompound hook from chaetiger 1; E, median tridentate pseudocompound hook from same; F, median tridentate pseudocompound hook from chaetiger 4; G, lower bidentate pseudocompound hook from chaetiger 1; H, pectinate chaeta from chaetiger 50; I, mandibles; J, maxillae.

FIGURE 5. Aponuphis bellani n. sp., scanning electron micrographs. A, specimen in tube; B – D, progressively enlarged image to show microstructure of tube.

FIGURE 7. Depth distribution of Aponuphis. annae n. sp. and A. bellani n. sp. at combined locations and collecting sites.