Pycnoderma talehsapensis ( Fauvel, 1932 ) Fauvel, 1932

Salazar-Vallejo, Sergio I., 2011, Revision of Piromis Kinberg, 1867 and Pycnoderma Grube, 1877 (Polychaeta: Flabelligeridae), Zootaxa 2819, pp. 1-50 : 42-45

Pycnoderma talehsapensis ( Fauvel, 1932) n. comb.

Figure 20

Brada talehsapensis Fauvel, 1932:184 –185, Pl. 7, Fig. 17 , Text fig. 32; Fauvel, 1953:351 –352, Figs. 183a–d;? Kirkegaard, 1996:63.

Type material. Western Tropical Pacific, South China Sea, Thailand. One slide (IRFA-R30), with several parapodia from Brada talehsapensis Fauvel, 1932 , Sta. 30, Songkhla Lagoon (formerly known as Taleh-Sap), Thailand, N. Annandale coll.

Additional material. Western Tropical Pacific, Hainan Island, China. One specimen (SMF-15345), anterior fragment, Sanya Bay, Sta. B92-18B-13, dredge, 6 m, 25 Mar. 1992, R. Sun coll. One specimen (SMF-15346), anterior fragment, Sanya Bay, Sta. B92-17B-12, dredge, 6 m, 25 Mar. 1992, R. Sun coll. Indonesia. One anterior fragment (MZB-7) broken in two, Sta. NT2A (04°03.02ʹ N, 108°26.48ʹ E), Natuna Timur, 60 m, 29 Jul. 2001, I. Al Hakin coll. (cephalic cage about as long as reaching chaetiger 5(–6)). One anterior fragment (MZB-19), Sta. NT3A (04°06.62ʹ N, 108°23.48ʹ E), Natuna Timur, 64 m, 29 Jul. 2001, I. Al Hakin, coll. (cephalic cage about as long as reaching chaetiger 5). Two complete specimens (MZB-58), slightly damaged, Sta. NT8A (04°17.01ʹ N, 108°19.00ʹ E), Natuna Timur, 71 m, 30 Jul. 2001, I. Al Hakin, coll. (cephalic cage about as long as reaching chaetiger 5). One complete specimen (MZB-105), Sta. NB18A (03°40.28ʹ N, 107°56.00ʹ E), Natuna Barat, 56 m, 3 Aug. 2001, I. Al Hakin coll. (cephalic cage about as long as reaching chaetiger 5). One complete specimen (MZB-112), Sta. NB18B (03°40.28ʹ N, 107°56.00ʹ E), Natuna Barat, 56 m, 3 Aug. 2001, I. Al Hakin, coll. (cephalic cage about as long as reaching chaetiger 6). One anterior fragment (NTM-18472), Sta. NT2A (04°03.02ʹ N, 108°26.48ʹ E), East Natuna, 60 m, 29 Jul. 2001, I. Al Hakin, coll. (cephalic cage about as long as reaching chaetiger 6). One complete specimen (NTM-18620), Sta. NB17A (03°44.82ʹ N, 107°58.76ʹ E), West Natuna, 48 m, 3 Aug. 2001, I. Al Hakin coll. (used for description). One complete specimen (ZRC-418), Sta. NT7B (04°14.02ʹ N, 108°14.02ʹ E), Natuna Timur, 66 m, 30 Jul. 2001, I. Al Hakin, coll. (cephalic cage about as long as reaching chaetiger 5 chaetigers). Indian Ocean, Arabian Sea. One specimen (LACM-AHF-2519), anterior fragment, International Indian Ocean Expedition, R/V Anton Bruun, Sta. AB 201A (17º57ʹ N, 72º27ʹ E to 17º54ʹ N, 72º23ʹ E), 46–55 m, green mud and shells, 13 Nov. 1963. One specimen (LACM-AHF-2520), broken in two pieces, SW off Mumbai, W off Kelshi, Maharashtra, India, International Indian Ocean Expedition, Okah Point, Gulf of Kutch, Gujarat, India, R/V Anton Bruun, Sta. AB 222A (22º43ʹ N, 68º22ʹ E to 22º45ʹ N, 68º24ʹ E), 26–27 m, soft, sticky mud and clay, 18 Nov. 1963 (neurohooks from chaetiger 18). Bay of Bengal. Ninety-seven specimens (LACM-AHF-2521), juveniles, 53 complete, International Indian Ocean Expedition, Northern Indian Ocean, Stat RH 30, Madras, India, 2.5 km SE off harbor, directly east of the University building, 15 m, 18 Mar. 1964, H. Sanders coll. Persian Gulf. Four specimens (SMF- 15341), juveniles, Cruise GEOMAR 91, Sta. PG 1 KG, 1991, H. Zetsche coll. (neurohooks from chaetiger 15). One specimen (SMF-15342), juvenile, Cruise GEOMAR 91, Sta. PG 27 KG, 1991, H. Zetsche, coll. (neurohooks from chaetiger 15). Madagascar. Two specimens (SMF-15354), anterior fragments, some chaetae broken, Banc du Pracel, near Chesterfield Island, St. BP 25, 28 m, 11 Apr. 1970, R. Plante, coll. (neurohooks from chaetiger 16–19). One specimen (SMF-15358), most tunic eroded, most papillae broken, Nosy Mitsio, Nosy Be, St. 1, 22 Jun. 1970, R. Plante coll. (neurohooks from chaetiger 21). One specimen (SMF-15361), anterior fragment, Sud Nosy Iranja, St. 2/D, 37 m, 18 Nov. 1969, R. Plante coll. One specimen (SMF-15363), most body papillae eroded, Nord Mitsio, St. B / D, 8 May 1969, R. Plante coll. (neurohooks from chaetiger 20). Three specimens (SMF-15366), two complete, body papillae variously eroded, Banc du Pracel, near Chesterfield Islands, St. BP 31, 22 m, 12 Apr. 1970, R. Plante coll. (neurohooks from chaetiger 14–15). Ten specimens (SMF-15367), three complete, seven anterior fragments, Banc du Pracel, near Chesterfield Islands, St. BP 32, 33 m, 12 Apr. 1970, R. Plante coll. (neurohooks from chaetiger 15–19). Two specimens (SMF-15368), anterior fragments, Nosy Mitsio, St. 1, 8 May 1969, R. Plante, coll. One specimen (SMF-15371), without posterior end, some chaetae broken, St. BP 29, 13 m, 12 Apr. 1970, R. Plante, coll. (first neurohooks from chaetiger 23). Eight specimens (SMF-15372), three anterior, five median or posterior fragments, body papillae variously eroded, Western Anfiky 2, St. 2, 30 m, 17 Apr. 1969, R. Plante coll. One specimen (SMF-15374), without posterior end, Nosy Iranja, Sta. 4, Benne, 17 Sep. 1966, R. Plante, coll. (neurohooks from chaetiger 16). One specimen (SMF-15377), mature female, without posterior end, most body papillae eroded, B. Ambano, St. Bouee, 80 m, 7 Jun. 1969, R. Plante, coll. (neurohooks from chaetiger 14; oocytes in chaetigers 5-11). One specimen (SMF-15378), juvenile without posterior end, Baie des Ambaro, St. Bouee, 20 m, 15 Feb. 1969, R. Plante, coll. (neurohooks from chaetiger 14).

Description. Complete specimen (NTM-18620) thin, rust-reddish anteriorly, darker in chaetigers 14–22, median and posterior segments pale ( Fig. 20 A); tunic thin, finely papillated, fine sediment particles thinly covering body; papillae mostly small, thin, clavate, abundant all over body, some papillae longer, clavate in chaetal lobes. Specimen 17 mm long, 1 mm wide, cephalic cage 1 mm long, 59 chaetigers.

Cephalic hood not exposed, observed in two specimens (ZMB-58) with anterior end slightly exposed ( Fig. 20 D, E); hood short with papillated margin. Prostomium low cone; eyes tiny, black. Palps pale, thick, smooth; palp keels reduced. Lateral lips wide, projected because of contraction, dorsal and ventral lips reduced.

Branchiae all cirriform, each filament dark-banded, swollen distally; arising from branchial plate, widely separated medially in two groups, over a tongue-like protuberance, branchial groups posteriorly coalescent, ten filaments per side. Branchiae of similar length, slightly longer than palps. Nephridial lobes colorless, shorter than branchiae.

Cephalic cage chaetae as long as body width ( Fig. 20 B). Only chaetiger 1 involved in the cephalic cage. Chaetae arranged in short dorsal row (notochaetae) and short lateral row (neurochaetae); 6 noto- and 3–4 neurochaetae per bundle (all broken). Anterior dorsal margin of chaetiger 1 projected as small papillated cone. Anterior chaetigers without long papillae. Chaetigers 1–3 reduce in size posteriorly, with second parapodia displaced dorsally. Chaetal transition from cephalic cage to body chaetae gradual; compound neurohooks from chaetiger 15. Gonopodial lobes not visible.

Parapodia poorly developed, lateral. Median neuropodia lateral. Notopodia low rounded lobes, each with 2–3 clavate papillae ( Fig. 20 F). Neuropodia low rounded lobes, with some superior and inferior long capitate papillae. Noto- and neuropodia with 1–2 interramal papillae.

Median notochaetae arranged in a short transverse row, 4–5 per bundle, 1/3 as long as body width (posterior notochaetae about as long as body width); all notochaetae multiarticulated capillaries, articles medium-sized basally, shorter medially, longer distally ( Fig. 20 F); posterior notochaetae with very long articles medially, becoming shorter towards tip ( Fig. 20 G). Neurochaetae similar to notochaetae in anterior chaetigers, arranged in transverse row. Neurohooks from chaetiger 15, 4–5 per bundle, each with anchylosed articles basally, then with 1–2 long articles, blade long, lanceolate, aristate ( Fig. 20 H). Parapodia in slide IRFA-R30 has dried partly; soft body parts darkened, few anterior chaetae visible: notochaetae with long articles, neurochaetae with long articles, distally tapering but tips not visible.

Posterior end subdistally swollen ( Fig. 20 C); pygidium regenerating, short truncated cone (slightly projected in other specimens), anus terminal, without anal cirri.

Variation. Complete specimens are shorter than the type materials; however, the cephalic cage length is conservative because in most specimens it was about as long as the length of the anterior end up to chaetiger 5(6). However, the number of neurochaetae seems to be size-dependent because the largest specimen (MZB-7) had about seven neurochaetae, whereas most other smaller specimens had only three or four, and the smallest specimen (ZRC-418) had only two. The fragility of neurochaetae might explain why Fauvel did not notice the remaining chaetal bases and described the species as lacking neurochaetae in chaetiger 1. Branchiae are banded and even if they are retracted, they can be seen by transparency of the body wall, as a sort of internal black dot. The start of neurohooks is difficult to determine precisely because they are brittle, but they appear to start around chaetiger 15.

Remarks. Pycnoderma talehsapensis ( Fauvel, 1932) n. comb., differs from typical Brada species by having neurochaetae with very long, not anchylosed, articles as is the case in Brada . Pycnoderma talehsapensis differs from P. escobarae n. sp. and P. ferruginea especially in the relative length of the cephalic cage chaetae. Thus, they are shorter in P. talehsapensis while in both P. escobarae n. sp. and P. ferruginea they are much longer. Further, branchial filaments in P. talehsapensis are banded, whereas they are pale in P. ferruginea , and unknown in P. es c o - barae n. sp.

Distribution. Originally described from the Songkla Lagoon, Thailand, these specimens come from several localities in Indonesia, and the South China Sea, from shallow water soft bottoms (58–70 m). The specimens from the Persian Gulf and from Madagascar are regarded as members of the same species because they do not differ from the South China Sea specimens. The deep-water records by Kirkegaard (1996), although coming from the same region, could belong to a different species. His materials were not found in the Copenhagen museum, and clarifying this issue requires the examination of his specimens.

Figures

FIGURE 17. Pycnoderma glabra (Treadwell, 1901) n. comb. Holotype (USNM- 16162). A. Complete specimen, dorsal view (insert: anterior end, dorsal view). B. Same, anterior chaetigers, close up of tunic. C. Same, median chaetigers, close up of tunic. D. Notochaetae of anterior chaetiger, showing basal, medial and distal regions. E. Neurochaetae of anterior chaetiger (insert: close up showing articulation pattern). Scale bars: A: 1 mm, B, C: 0.4 mm, D: 40 µm, E: 65 µm.

FIGURE 20. Pycnoderma talehsapensis (Fauvel, 1932) n. comb. A. Complete specimen (NTM- 18620), dorsal view. B. Same, anterior end, ventral view. C. Same, posterior end, lateral view. D. Another specimen (MZB- 58), anterior end, dorsal view. E. Same, anterior end, ventral view showing maculated branchiae and round palps. F. Another specimen (NTM- 18620), parapodium from chaetiger 13. G. Same, parapodium from chaetiger 33. H. Same, enlargement of neurochaetae. I. Same, articulation of the former neurochaetae. Scale bars: A: 1 mm, B: 0.33 mm, C: 0.6 mm, D, E: 0.2 mm, F, G: 80 µm, H: 40 µm, I: 20 µm.