Trophoniella orensanzi, SALAzAR-Vallejo, 2012

SALAzAR-Vallejo, Sergio I., 2012, Revision of Trophoniella Hartman, 1959 (Polychaeta, Flabelligeridae), Zoosystema 34 (3), pp. 453-519 : 453-519

Trophoniella orensanzi n. sp.

( Fig. 22 )

Pironis [sic] arenosus – Rullier & Amoureux 1979: 183 (non Kinberg 1867).

TYPE MATERIAL. — Southwestern Atlantic Ocean , Uruguay. Holotype ( MUNHINA 1116 ), R/V Hero cruise, stn 3A (34°20’S, 53°47’W), off Valizas, N-NW Cabo Polonio, sands, 9 m, 21.VII.1972, J. M. Orensanz.

ADDITIONAL MATERIAL. — Southwestern Atlantic Ocean, Brazil. 2 specimens ( MNHN 884), anterior fragments, off Rio Grande, R/V Calypso , stn 154 (32°15’S, 51°58’W), 18 m, 20.XII.1961.

TYPE LOCALITY. — Off Valizas, Uruguay, in 9 m depth sediments.

DISTRIBUTION. — From Rio Grande, Brazil to Cabo Polonio, Uruguay, in shallow-water sands, in 9-18 m depth.

ETYMOLOGY. — This species is named after my friend and colleague, Dr José M. (Lobo) Orensanz, in recognition of his interesting publications on polychaetes, as a means to thank him for his confidence and support, and because he collected the holotype.

DESCRIPTION

Holotype (MUNHINA 1116) incomplete, anterior fragment, wider anteriorly, tapering posteriorly, medially compressed, slightly damaged ( Fig. 22A ), 33 mm long, 4 mm wide, cephalic cage 9 mm long, 36 chaetigers. Tunic completely covered with fine sediment particles. Body papillae mostly eroded; parapodial papillae long, capitate; dorsal papillae forming large, blunt, anteriorly directed, dorsal triangular tubercles, present in chaetigers 3-10 ( Fig. 22B, C ), decreasing in size posteriorly; ventral papillae arranged in two groups per segment, each with 3-5 papillae, probably forming sediment lobes ( Fig. 22D ), too eroded to confirm their distribution.

Anterior end not exposed, not dissected to avoid further damage; specific details unknown.

Cephalic cage chaetae twice as long as body width. Chaetigers 1-2 involved in the cephalic cage; chaetae arranged in short series, dorsolateral in chaetiger 1, lateral in chaetiger 2; chaetiger 1 with 12 noto- and 10 neurochaetae per side; chaetiger 2 with 10 noto- and 14 neurochaetae per side, without epizoans. Anterior dorsal margin of first chaetiger with a median, single, acute lobe, projected anteriorly, with 2-3 marginal papillae. Anterior chaetigers (1-4) with long notopodial papillae forming notopodial lobes, directed anteriorly, diminishing in size posteriorly. Chaetigers 1-3 becoming progressively longer. Chaetal transition from cephalic cage to body chaetae gradual; bidentate multiarticulate neurohooks from chaetiger 6; anchylosed neurohooks present from chaetiger 36. Gonopodial lobes small, rounded, near to neurochaetae in chaetiger 5 (right side, left one damaged).

Parapodia better developed in anterior chaetigers; median and posterior ones with short notopodial lobes, chaetae emerging from the body wall. Parapodia lateral; median neuropodia ventrolateral. Noto- and neuropodia with one prechaetal papilla; other papillae inconspicuous.

Median notochaetae arranged in short longitudinal series, becoming oblique by chaetiger 15; 10-12 per bundle ( Fig. 22E ), as long as 1⁄₃ body width; all notochaetae multiarticulated capillaries, each with articles short basally, becoming medium-sized medially, long distally ( Fig. 22F ). Anterior and median neurochaetae multiarticulated, 7-8 per bundle, bidentate capillaries in chaetigers 1-15, most with tips broken; chaetigers 16-35 with similar chaetae but with 1-2 longer, median articles ( Fig. 22G ); anchylosed, bidentate falcigers from chaetiger 36, arranged in oblique series, 5-6 per bundle, with short rings present almost to the tip, subdistally tapering, most with tips broken, one bidentate, eroded ( Fig. 22H ).

Posterior end unknown.

REMARKS

Trophoniella orensanzi n. sp. belongs to the group of species provided with fine sediment particles covering the body and having both notopodial and dorsal tubercles. Besides T. orensanzi n. sp., the group includes T. harrisae n. sp. and T. hospita n. comb.; they differ by the relative extension of the dorsal tubercles along the body; they are less extended in T. orensanzi n. sp. being present up to chaetiger 10, whereas they can reach chaetiger 25 in T. hospita n. comb., or chaetiger 40 in T. harrisae n. sp. Further, this is the only species from the group being recorded from the Atlantic Ocean, whereas the two others are found in the eastern Pacific Ocean.

Figures

FIG. 22. — Trophoniella orensanzi n. sp., holotype (MUNHINA 1116): A, dorsal view; B, anterior end, lateral view; C, anterior end, dorsal view; D, anterior end,ventral view with sediment grains eroded; E, chaetiger 17, notopodium; F, notochaetal basal, medial and distal regions; G, chaetiger 26, neurochaetae (insert: chaetal tips); H, chaetiger 36, neurochaetae (inserts: chaetal tips). Scale bars: A, 3.3 mm; B, 2 mm; C, 1 mm; D, 0.9 mm; E, 250 µm; F, 75 µm; G, 260 µm; H, 225 µm.