Pista chloroplokamia, Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015

Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015, Terebellidae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 484-576 : 516-522

Pista chloroplokamia n. sp.

( Figs 1 I–J; 21–25)

Material examined. Holotype: AM W.44613, MI QLD 2400, Coconut Beach, 14°40'53"S, 145°28'12"E, reef flat, extreme low tide. Paratypes: AM W.44599, MI QLD 2396, complete, in excellent state of preservation, ~ 20 mm long, 1.8 mm wide at mid-thorax, ~ 2 mm wide at beginning of abdomen, mounted on SEM pin; AM W.47712, CReefs, LI–10–039, MI QLD 2203, Lagoon, 14°41'14"S, 145°27'18"E, 3 specimens, all incomplete, one of which in excellent state of preservation, with 33 segments, both pairs of branchiae present, 10 mm long, ~ 5 mm wide, dissected and put in a separate vial, other two specimens also incomplete, one with 30 segments, the other with 18– 19; AM W.44713, CReefs, LI–10–021, MI QLD 2195, Watsons Bay, 14°39'26"S, 145°27'03"E, incomplete specimen, in excellent state of preservation, with 53 segments, ~ 11 mm long, ~ 0.7 mm wide; AM W.44962, MI QLD 2429, posteriorly incomplete, 5 mm long, 1 mm wide, gravid.

Other material examined. AM W.40289, Outer Yonge Reef, GBR, 14°36'S, 145°38'E, 11 Jan 1975.

Comparative material examined. Holotype of Pista curtiuncinata Hartmann-Schröder, 1981 , HZM P16500. Holotype of Pista kimberliensis Hutchings & Glasby, 1990 , AM W.203525. Holotype of Pista pectinata Hutchings, 1977 , AM W.6795. Holotype of Pista pegma Hutchings & Smith, 1997 , AM W.22574. Holotype of Pista trina Hutchings, 1977 , AM W.6798. Holotype of Pista trunca Hutchings, 1977 , AM W.6973. Holotype of Pista typha Grube, 1878 , MPW 518. Holotype of Pista violacea Hartmann-Schröder, 1984 , NTM W.1644.

Description. In life, orange to red body and branchiae, with diffuse green buccal tentacles ( Fig. 1 I–J). Transverse prostomium attached to dorsal surface of upper lip; basal part with numerous isolated eyespots laterally, covered by lobes on segment 1, and distinctly thin row at base of prostomium with scattered isolated eyespots, leaving wide mid-dorsal gap; distal part of prostomium shelf-like. Peristomium forming lips, hood-like upper lip, short, about as wide as long, circular; short and swollen lower lip, button-like ( Figs 21 A, E, J; 22A, E, I). Segment 1 narrow, with pair of large lobes directed anteriorly and reaching tip of upper lip; lobes originating dorso-laterally, at level of first pair of branchiae; dorsal edges oblique, lobes higher laterally, distally rounded, connected to each other by thinner indented membrane ventrally, partially exposing lower lip; anterior margins of anterior segments as protruding crests dorsally, segment 2 with pair of short, rounded ventro-lateral lobes, connected to each other by mid-ventral crest; segment 3 with pair of developed lateral lobes, larger than those of segment 2, rounded, almost semicircular lobes, originating ventrally at level of dorsal edges of neuropodia and laterally to branchiae dorsally; segment 4 with pair of much shorter distally rounded lobes, almost inconspicuous ( Figs 1 J; 22A–H, J–M; 22A–K; 23A). Anterior segments slightly inflated dorsally. Paired dorso-lateral arborescent branchiae present on segments 2–3, usually first pair distinctly larger and inserted more dorsally, but frequently missing one or both branchiae of a pair, and also members of a pair differing in size; each branchia with conspicuous, crenulate basal stem, and secondary stems originating all at same level and dichotomously branching for some levels, with lateral ciliary track and short tips ( Figs 21 B, D, F, H, K, M; 22A–K; 23A–C). Smooth, slightly corrugated anteriorly mid-ventral shields present from segment 2 to termination of notopodia, on segment 20, rectangular shields, of uniform width throughout, progressively longer until segment 12; from segment 15 shields brownish instead of white ( Figs 21 A, E–F, J–L; 22A, E, I). Notopodia beginning on segment 4, extending until segment 20; notopodia short, rectangular, first four pairs inserted progressively more laterally, then longitudinally aligned ( Figs 21 A–M; 22A–L; 23A–B, D, G–I). Broadly-winged notochaetae in both rows, rounded geniculate wings, broader on one side, those from anterior row with twisted tips and in posterior row with wings at tips only ( Figs 23 D, G–K; 24I, 25A, F). Neuropodia present from segment 5, as low, almost sessile ridges until termination of notopodia, as low rectangular pinnules thereafter ( Figs 21 A–G, I–L, N; 22A–B, D–E, G–J, L; 23E–F). Neurochaetae as long-handled avicular uncini on segments 5–7, with thin, poorly developed handles originating from heel only, progressively less conspicuous; from segment 8, handles absent; uncini arranged in partially intercalated double rows on segments 11–20; avicular uncini throughout, with short, triangular and distally rounded heel, rounded prow, dorsal button at mid-length, almost inconspicuous after termination of notopodia, and crest with 5 rows of numerous, progressively shorter secondary teeth, on anterior segments and after notopodia terminate, 4 rows on segments 11–20 ( Figs 24 A– G, J–N; 25B–E, G). Nephridial and genital papillae on segments 5–9, between parapodial lobes ( Fig. 22 B, D, G–H, J, L). Pygidium crenulate, with slightly larger ventral papillae ( Figs 21 A–D, N; 24H).

Remarks. Pista chloroplokamia n. sp. is characterized by the presence of lobes on all anterior segments, those of segment 1 being directed anteriorly and covering the upper lip; presence of two pairs of arborescent, dichotomously branching branchiae, with secondary stems originating all together; long-handled uncini only present in segments 5–7; and nephridial and genital papillae present on segments 5–9, between parapodial lobes, while many species in this genus have genital papillae on segments 6 and 7 only, posterior and dorsal to notopodia. Out of the 14 species of Pista known to occur in Australian waters, five have arborescent branchiae: P. s i n us a Hutchings & Glasby, 1988, P. trina Hutchings, 1977 , P. trunca Hutchings, 1977 , P. turawa Hutchings & Glasby, 1988 , and P. violacea Hartmann-Schröder, 1986 . In addition, P. p e gm a Hutchings & Smith, 1997 from New Zealand also has arborescent branchiae. Of these, P. t r i n a has three pairs of branchiae whereas all the others and Pista chloroplokamia n. sp. have two pairs.

The new species has long-handled uncini only in the first three rows of thoracic uncini, and these are poorly chitinised, which is similar to P. violacea and P. pegma . Other Australian species have long-handled uncini present on all thoracic neuropodia. Pista chloroplokamia n. sp. can be distinguished from P. violacea by the poor development of a lateral lobe on segment 4, whereas in the latter species it is a small rectangular lobe. These two species also clearly differ in the development of the branchiae, as in P. violacea there are few branches and branchiae are poorly developed in contrast to the well developed branchiae of P. chloroplokamia n. sp.

Pista pegma , known only from New Zealand, can be easily distinguished by the arrangement of the lateral lobes, segment 1 with well developed lobes connected mid-dorsally by shallow U-shaped structure, segment 2 with elongate rectangular lobe, segment 3 with large semi-circular lobes and continuing across the dorsum forming a thickened dorsal glandular shelf, which is completely absent in P. chloroplokamia n. sp. For these reasons this taxon is described as a new species.

Etymology. During the Lizard Island Workshop, specimens of this species, which were relatively common in our samples, were referred to as “ Pista green tentacles ” by participants. Due to this, we have named the species after the green buccal tentacles, from the Greek words “ chloro ” for green and “ plokamia ” for tentacles.

Type locality. Coconut Beach, 14°40'53"S, 145°28'12"E, Lizard Island, GBR, Australia.

Distribution. Known only from the Lizard Island region.

Figures

FIGURE 1. Live specimens. A – B. Nicolea murrayae n. sp. AM W. 44603, MI QLD 2397; C. Nicolea vaili n. sp. AM W. 44487, MI QLD 2335; D. Pista anneae n. sp. AM W. 44513, MI QLD 2370; E – H. Reteterebella lirrf n. sp. AM W. 44545, MI QLD 2416; I – J. Pista chloroplokamia n. sp., AM W. 44613, MI QLD 2400. Photos: A – J—Alexander Semenov.

FIGURE 21. Pista chloroplokamia n. sp. AM W. 44613: A – D. Entire worm, ventral, left and right lateral, and dorsal views, respectively; E – H. Anterior end, ventral, left and right lateral, and dorsal views, respectively; I. Transition between anterior and posterior body, left lateral view; J – M. Close ups of the anterior end, ventral, left and right lateral, and dorsal views, respectively; N. Close up of the posterior end, right lateral view. Numbers refer to segments. Abbreviations: ll = lower lip; ul = upper lip. Scale bars: A – D = 1.5 mm, E – H = 0.6 mm, I – N = 0.3 mm.

FIGURE 22. Pista chloroplokamia n. sp. AM W. 44599: A – D. Anterior end in ventral, right lateral, dorsal and left lateral views, respectively; E – H. Closer views of the anterior end, ventral, dorsal, right and left lateral views, respectively; I – J. Close ups of the anterior end, ventral and right lateral views, respectively; K. Close up of the branchiae and notopodia of segments 4 – 6; L. Close up of the parapodia of segments 4 – 10, left lateral view. Numbers refer to segments; unspecified arrows point to nephridial and genital papillae. Abbreviations: ll = lower lip. Scale bars: A – C = 500 µm, D, F, H = 300 µm, E, G = 400 µm, I – J = 200 µm, K – L = 100 µm.

FIGURE 23. Pista chloroplokamia n. sp. AM W. 44599: A – C. Progressively closer views of the branchiae; D, G – K. Notochaetae, segments 5, 19, 20, 11, 11 (2), and 5, respectively; E. Posterior end, left lateral view; F. Posterior chaetigers, left lateral view. Scale bars: A – B, F = 100 µm, C = 15 µm, D, G = 30 µm, E = 200 µm, H, 20 µm, I, K = 10 µm, J = 7 µm.

FIGURE 24. Pista chloroplokamia n. sp. AM W. 44599: A – B. Uncini of the segment 7 under different magnifications; C – D. Closer views of uncini, segment 20; E. Posterior uncini, segment 32; F – G. Posterior uncini; H. Close up of the pygidium. AM W. 47712: I. Notochaetae, segment 15; J – N. Anterior uncini, segments 5, 10, 7, 8, and 9, respectively. Scale bars: A = 4 µm, B = 8 µm, C = 7 Μm, D, F – G = 3 µm, E = 6 µm, H = 50 µm, I = 30 µm, J – K, M – N = 15 µm, L = 10 µm.