Pycnoderma gracilis ( Hartman, 1961 ) Hartman, 1961

Salazar-Vallejo, Sergio I., 2011, Revision of Piromis Kinberg, 1867 and Pycnoderma Grube, 1877 (Polychaeta: Flabelligeridae), Zootaxa 2819, pp. 1-50 : 41-42

Pycnoderma gracilis ( Hartman, 1961) n. comb.

Figure 19

Piromis gracilis Hartman, 1961:123 –124, Pl. 29, Figs. 1–4 , Pl. 30, Figs. 1–9 (partim).

Material examined. Eastern Tropical Pacific. Holotype (LACM-AHF-529) and paratype (LACM-AHF-530), off San Jose Light, Guatemala, R/V Velero III, Sta. 930 (13°52ʹ35ʺ N, 91°01ʹ0 2ʺ W), 12–13 fathoms, 23 Mar. 1939.

Additional material. One almost complete specimen (LACM-AHF-2517), R/V Velero I II, Sta. 216 (00°35ʹ50ʺ N, 80°07ʹ0 0ʺ W), San Francisco Bay, Ecuador, 20 fathoms, 11 Feb. 1934. Anterior fragment (LACM-AHF-2518), R/V Velero III, Sta. 930 (13°52ʹ35ʺ N, 91°01ʹ0 2ʺ W), off San Jose Light, Guatemala, 12–13 fathoms, fine black sand, 23 Mar. 1939. Four specimens (MCZ-55893, three; MCZ-55984, one), Gulf of Nicoya Benthic Survey, Sta. 24 (09°49ʹ25ʺ N, 84°41ʹ20ʺ W), 11 m, 1 Oct. 1980, H. Dean, coll.

Description. Holotype an anterior fragment ( Fig. 19 A), laterally dissected previously; body cylindrical, slightly tapering posteriorly. Tunic thick, papillated, with many sediment particles; papillae long in anterior chaetigers, notopodial ones making large, truncate, conical lobes directed forwards ( Fig. 19 B). Dorsum and venter with two longitudinal rows of long papillae, protruding through tunic, not forming large lobes. Holotype 20 mm long, 3 mm wide, cephalic cage 3 mm long, 29 chaetigers.

Anterior end not exposed, previously dissected ( Fig. 19 D). Prostomium low cone, eyes small, dark brown. Caruncle long, well-developed, separating branchial lobes. Palps long, darker dorsally, palp keels rounded. Branchiae cirriform, distally dark, arising from tongue-like protuberance, with over 80 filaments per side. Some branchiae longer, others shorter, or as long as palps.

Cephalic cage chaetae as long as body width. Chaetigers 1–4 involved in the cephalic cage; chaetae arranged in a short row, chaetal fascicles dorso- and ventrolateral with 7–8 noto- and 5–6 neurochaetae per bundle. Anterior dorsal margin of chaetiger 1 with median trifid lobe, projecting anteriorly. Anterior chaetigers with long notopodial lobes, no large median papillae involved. Chaetigers 1–3 of similar size, notopodial lobes larger in chaetiger 3. Chaetal transition from cephalic cage to body chaetae gradual; bifid neurohooks from chaetiger 28, inconspicuous. Gonopodial lobes not seen.

Parapodia well developed, especially in anterior chaetigers, positioned at body corners. Median neuropodia ventrolateral. Notopodia with several long, cirriform, capitate papillae; papilla of anterior chaetigers forming large dorsal lobe, in median chaetigers forming postchaetal fans each with 4–5 papillae, intermediate papillae longer. Neuropodia smaller, with similar postchaetal papillae, in a fan with 3–4 papillae.

Median notochaetae arranged in longitudinal row, as lateral fan with 8–10 chaetae per bundle, each chaeta 1/3 as long as body width; all notochaetae multiarticulated capillaries with short articles basally and distally, long articles medially ( Fig. 19 F). Neurochaetae multiarticulated hooks in two sizes, longer in anterior chaetigers ( Fig. 19 G), shorter, bifid ones from chaetiger 28 ( Fig. 19 H), mostly with broken tips, arranged in transverse row, directed forward in holotype, six per bundle, three of each size group, continued to end of body ( Fig. 19 I).

Holotype without posterior end ( Fig. 19 A, C); one paratype complete, posterior end conical, anus terminal ( Fig. 19 E), without anal cirri.

Variation. One complete specimen (Sta. 216) has variable segment length: chaetigers 1–12 are medium sized, chaetigers 13–28 are short, and thereafter are elongated (or badly preserved) from chaetiger 28. One of the specimens that was included in the original description (station 767) does not belong to this species; it has straight neurohooks with very short anchylosed articles throughout the body, and three longitudinal series of black papillae; it is an undescribed species of Trophoniella .

Remarks. As stated above, Piromis includes only species with bifid multiarticulated neurohooks. After an examination of different specimens from the type locality, it was determined that because of the presence of neurohooks with few or very few articles in posterior chaetigers, Piromis gracilis does not belong in the genus Piromis . These specimens are extremely similar to the holotype and are regarded as conspecific; further, because they have neurohooks with a single long article in posterior chaetigers, consequently, the species has been transferred to Pycnoderma .

Pycnoderma gracilis ( Hartman, 1961) n. comb. resembles P. glasbyi n. sp. (see above) because both have their body covered by small sediment particles. They differ because P. gracilis has dorsal lobes along a few anterior chaetigers, the sediment particles are densely packed, and the posterior neurospines are bidentate, whereas P. glasbyi n. sp. lacks dorsal lobes, the sediment particles are sparse and the posterior neurospines are bifid.

Distribution. The type material comes from two localities in the Eastern Tropical Pacific, from Guatemala and Ecuador, in 20– 40 m.

Figures

FIGURE 1. Piromis arenosus Kinberg, 1867. A. Syntypes in lateral view. B. Thicker syntype, anterior end, dorsal view. C. Same, posterior end, lateral view. D. Non-type specimen (LAMNH- 5210), anterior end dissected, slightly collapsed, palps and most branchiae removed (BS: branchial scars, Ca: caruncle, DL: dorsal lip, LL: lateral lip, Pr: prostomium, PS: palp scar). E. Thicker syntype, notochaetae portions, basal, medial and distal with an insert of the tip. F. Non-type specimen (LAMNH-AHF- 2506), neurochaetae from a median chaetiger with an insert of one tip. G. Same, neurochaetae from a posterior chaetiger with an insert of a tip. Scale bars: A: 6 mm, B: 1.5 mm, C – D: 1 mm, E: 25 µm, F: 90 µm, G: 40 µm.

FIGURE 2. Piromis amoureuxi n. sp. A. Holotype (MNHN- 900), twisted. B. Same, anterior end in dorsal view. C. Same, median segments in lateral view, showing sediment particles dorsally and laterally. D. Paratype (MNHN- 900 a), anterior end, palps and most branchiae detached (BD: branchial scars, LL: lateral lip, PS: palp scar). E. Holotype, anterior notopodium. F. Same, close-up of notochaetal regions, left, median and distal. G. Same, neurochaetae from a median chaetiger. H. Same, neurochaetae from a posterior chaetiger. Scale bars: A: 1 mm, B – C: 0.5 mm, D: 0.3 mm, E: 100 µm, F: 10 µm, G: 50 µm, H: 25 µm.

FIGURE 3. Piromis brisegnoi n. sp. A. Holotype (LAMNH-AHF- 2509), lateral view. B. Same, anterior end, lateral view showing abundant chaetae and long papillae. C. Non-type specimen, anterior end, frontal view, palps and branchiae removed (BS: branchial scars, LL: lateral lip, PS: palp scar, VV: ventral lip). D. Holotype, notochaetae from an anterior chaetiger. E. Same, neurochaetae from a median chaetiger, insert showing the tips. F. Same, neurochaetae from a posterior chaetiger, insert showing the tip. Scale bars: A: 5 mm, B: 1.5 mm, C: 0.5 mm, D: 150 µm, E: 60 µm, F: 50 µm.

FIGURE 4. Piromis capulata (Moore, 1909) n. comb. A. Holotype (CAS- 19721), complete in lateral view. B. Same, anterior end, lateral view. C. Same, anterior end, dorsal view, notice the eroded areas. D. Non-type specimen (USNM- 40484), anterior end, dorsal view. E. Same, anterior end, palps and most branchiae detached (BS: branchial scars, LL: lateral lip). F. Same, right neuropodium showing the gonopodial lobe with an asterisk in the base. G. Holotype, notochaetal regions, basal, median, distal. H. Same, median neuropodia with an insert showing the tips. Scale bars: A: 5 mm, B: 2.3 mm, C: 1.5 mm, D – E: 2 mm, F: 325 µm, G: 100 µm, H: 50 µm.

FIGURE 5. Piromis eruca (Claparède, 1868). A. Neotype (MNHN-A 507), complete in lateral view. B. Same, anterior end, lateral view. C. Same, anterior end, dorsal view. D. Paraneotype, head, palps and branchiae detached (BS: branchial scars, DL: dorsal lip, LL: lateral lip). E. Non-type specimen (MNHN-A 185), exposed anterior end, palps and branchiae detached (BS: branchial scars, Ca: caruncle, Pr: prostomium, PS: palp scar). F. Paraneotype, notochaetal regions, basal, median, distal and an enlargement of the tip. G. Same, neurochaetae from a median chaetiger, insert showing one tip. H. Same, neurochaetae from a posterior chaetiger, insert showing one tip. Scale bars: A: 3 mm, B: 1 mm, C: 1 mm, D – E: 0.5 mm, F: 50 µm, G: 200 µm, H: 25 µm.

FIGURE 6. Piromis fauchaldi n. sp. A. Holotype (LACM- 2511), complete. B. Same, anterior end, dorsal view. C. Paratype (LACM-AHF 1733), anterior end, ventral view showing some epizoic hydroids. D. Holotype, head, palps and branchiae removed (BS: branchial scars, Ca: caruncle, Pr: prostomium, PS: palp scar). E. Paratype (LACM-AHF- 2512), notochaetae from an anterior chaetiger showing basal, median and distal regions. F. Same, neurochaetae from a median chaetiger, insert showing chaetal tips. G. Same, neurochaetae from a posterior chaetiger, insert showing chaetal tips. Scale bars: A: 2 mm, B – C: 1 mm, D: 250 µm, E: 50 µm, F: 75 µm, G: 100 µm.

FIGURE 7. Piromis kisemboanus (Augener, 1918) n. comb., non-type specimens. A. Complete (MNHN- 507), lateral view. B. Same, anterior end, lateral view. C. Same, anterior end, dorsal view. D. Same, medium parapodium. E. Another specimen (USNM-unnumb.), notochaetae from an anterior notopodium showing articulation in basal, medial and distal regions. F. Another specimen (MNHN- 507), anterior neurochaetae, insert showing chaetal tips. G. Another specimen (USNM-unnumb.), posterior neurochaetae, insert showing chaetal tips. Scale bars: A: 2 mm, B – C: 0.5 mm, D: 0.25 mm, E: 66 µm, F: 50 µm, G: 100 µm.

FIGURE 8. Piromis robertsi (Hartman, 1951). A. Holotype (LAMNH- 526), complete, lateral view. B. Same, anterior end, dorsal view. C. Same, anterior end, ventral view. D. Non-type specimen (USNM- 75920), parapodium from chaetiger 9. E. Holotype, details of notochaeta from chaetiger 75. F. Non-type specimen, neurochaetae from chaetiger 9. G. Holotype, neurochaetae from chaetiger 67. Scale bars: A: 4 mm, B – C: 0.5 mm, D: 0.45 mm, E: 506 µm, F: 120 µm, G: 72 µm.

FIGURE 9. Piromis suni n. sp. A. Holotype (SMF- 15348), without posterior end, dorsal view. B. Same, anterior end, dorsal view. C. Same, anterior end, ventral view. D. Paratype, series of notochaeta from chaetiger 31, showing different article length in basal, medial and distal parts. E. Same, neurochaetae from chaetiger 11. F. Holotype, neurochaetae from chaetiger 31. Scale bars: A: 2 mm, B – C: 0.5 mm, D: 75 µm, E, F: 180 µm.

FIGURE 19. Pycnoderma gracilis (Hartman, 1961) n. comb. A. Holotype (LACM-AHF- 529), lateral view. B. Same, anterior end, lateral view. C. Same, terminal portion, lateral view. D. Same, head, frontal view (BS: branchial scars, LL: lateral lip, Pr: prostomium, PS: palp scar). E. Non-type specimen (LACM-AHF- 2517), almost complete, oblique lateral view. F. Same, notochaetae of chaetiger 12. G. Same, neurochaetae of same chaetiger. H. Same, neurochaetae of chaetiger 50. I. Same, neurochaetae from chaetiger 100. Scale bars: A: 2 mm, B: 1 mm, C: 0.75 mm, D: 0.3 mm, E: 1.7 mm, F. 125 µm, G: 170 µm, H: 60 µm, I: 55 µm.