Trophoniella minuta (SALAzAR-Vallejo, 2012)

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

Trophoniella minuta

(Blanchard in Gay, 1849) n. comb. ( Fig. 21 )

Siphostoma minutum Blanchard in Gay, 1849: 36. — Rozbaczylo 1985: 161.

Pherusa minuta – Quatrefages 1866: 480.

Pherusa heteropapillata Hartmann-Schröder, 1965: 227 , figs 222, 223. — Rozbaczylo 1985: 160.

TYPE MATERIAL. — Southeastern Pacific Ocean. Holotype of S. minutum ( MNHN 628), Chile (specific locality not stated, probably Valparaiso), 1834, Fontaine (complete, some parapodia removed, body wall with a transverse anterior fracture; 14 mm long, 3 mm wide, cephalic cage 4 mm long, 59 chaetigers; first anchylosed neurohooks in chaetiger 6). — Paratypes of P. heteropapillata ( ZMH unnumb.), off Puerto Estero Cisne, Isla James, Los Chones Archipelago, Chile, mussel-bed, shallow water, 11.VII.1958, Stuardo (4 complete 40-43 mm long, 5.0- 10.5 mm wide, cephalic cage 10.0- 10.5 mm long, 82-84 chaetigers; all with anchylosed neurohooks from chaetiger 6; description based on the best paratype).

ADDITIONAL MATERIAL. — Southeastern Pacific Ocean. 1 specimen ( MCZ 55674), Paraca Bay, Peru, no further data (108 mm long, 11 mm wide, cephalic cage 10.5 mm long, 87 chaetigers). — 1 specimen ( MCZ 55675), Valparaiso, Chile, no further data (70 mm long, 10 mm wide, cephalic cage 9 mm long, 78 chaetigers). — 1 specimen ( LACM-AHF 2498 ), most chaetae undamaged, R/ V Velero III, stn 376 (14°15’35”S, 76°11’35”W), E of Viejas (or Independencia) Island, Independencia Bay , Peru, 7 fathoms, rock, 13.I.1935 (15 mm long, 4 mm wide, cephalic cage 6 mm long, 60 chaetigers; gonopodial lobes visible once the tunic is removed, low rounded lobes on the anteroventral surface of chaetiger 5) .

DISTRIBUTION. — From Peru to Chile, in shallow water along rocky or mixed bottoms.

DESCRIPTION

Holotype ( MNHN 628 )pale,soft,preserved in alcohol ( Fig.21A ) . Paratypes of Pherusa heteropapillata (ZMH unnumb.) large, dark, stiff ( Fig.21D ).Body fusiform, wider anteriorly, tapering posteriorly, 43 mm long, 9 mm wide, cephalic cage 10 mm long, 84 chaetigers. Tunic sparsely papillated, without sediment particles ( Fig. 21B, C ), surface wooly with fine to very fine sediment particles ( Fig. 21E ). Body papillae thin, globose, most not exposed,few larger papillae arranged in longitudinal rows, two dorsal, four ventral, distally exposed (more clearly seen in holotype).

Cephalic hood not exposed; anterior end observed by dissection of one paratype; cephalic hood short, dark, margin apparently smooth.Prostomium blackish, low; eyes large, black. Caruncle well developed, reaching the margin of branchial lobe; median keel rounded, grayish, tapering posteriorly, becoming flat by the middle of branchial lobe; marginal ridges flat, darker than median keel. Palps reduced, very short, the left one longest, about ¼ as long as branchial lobe, smooth; palp keels reduced, low, rounded.Lips fused in an oral tube (details incomplete because it was damaged by dissection). Branchiae cirriform, maculated, on a tongue-like protuberance, separated in two lateral groups, arranged in rows; each group with about 200 filaments, basal branchiae longest, decreasing in size towards the margin. Nephridial lobes short, filiform, basally darker, placed in the inner basal margin of branchial groups, not clearly separated from them.

Cephalic cage chaetae about ¼ as long as body length, or as long as body width. Chaetigers 1-3 involved in the cephalic cage; chaetae arranged in short dorsolateral series in chaetigers 1-2, lateral in chaetiger 3; chaetiger 1 with 12 noto- and six neurochaetae; chaetiger 2 with six chaetae per bundle, chaetiger 3 with 6-7 chaetae per bundle. Anterior dorsal margin of first chaetiger much contracted, not visible dorsally or ventrally. Anterior chaetigers without long papillae. Chaetigers 1-3 of about the same length. Chaetal transition from cephalic cage to body chaetae abrupt; falcate, anchylosed neurohooks present from chaetiger 6. Gonopodial lobes not seen (MCZ 55674 with black tiny papillae in chaetiger 5; only seen after removing the tunic).

Parapodia poorly developed, chaetae emerging from the body wall ( Fig. 21E ). Parapodia lateral; median neuropodia ventrolateral. Noto- and neuropodia low, with two larger papillae per bundle, one suprachaetal, the other infrachaetal. Noto- and neuropodia distant to each other.

Median notochaetae arranged in transverse series; 11-12 per bundle, as long as ¼ body width; all notochaetae multiarticulated capillaries, each with articles short along the chaeta ( Fig. 21F ). Neurochaetae multiarticulated capillaries in chaetigers 1-5, becoming shorter in chaetigers 4-5;falcate anchylosed neurohooks from chaetiger 6, dark brown, arranged in J-patterns, 5-6 per bundle, each with short rings present to the median region, subdistally tapering, with oblique striae, surface rough, tip entire ( Fig. 21G ).

Posterior end blunt, pygidium with anus terminal, without anal cirri.

REMARKS Trophoniella minuta n. comb. resembles other species lacking sediment on the tunic and having digitate or slighlty capitate body papillae, like T. jareckiorum n. sp. from the Caribbean Sea and T. salazarae n. sp. from the Mexican Pacific coast. However, T. minuta n. comb. differs because it has about 10 notochaetae per bundle and has an often smooth and transparent tunic, at least along the anterior region, whereas the two other species have fewer notochaetae and their tunics are papillated and opaque, either whitish as in T. jareckiorum n. sp., or grayish to reddish as in T. salazarae n. sp. The reduction of palp size is noteworthy; they could be in regeneration, but it is very rare that both palps had been lost almost at the same time, because they have slightly different size.See T. grandis n. comb. for other remarks on the use of the names originally applied by Blanchard and later modified by Quatrefages.

Figures

FIG. 21. — Trophoniella minuta (Blanchard in Gay,1849) n. comb.: A, holotype (MNHN 628), lateral view; B, same, anterior end, lateral view; C, same, anterior end, ventral view; D, paratypes of Pherusa heteropapillata Hartmann-SchrÖder, 1965 (ZMH unnumb.), lateral view; E, same, cross sections of median chaetigers with and without tunic (greenish hue is due to methyl green staining); F, same, notopodium of chaetiger 13 and notochaetal median and distal regions; G, same,neuropodium of chaetiger 20.Scale bars:A, 1.7 mm; B, F, 0.7 mm; C, 0.8 mm; D, 10 mm; E, 1.4 mm; G, 180 µm.