Trophoniella eliasi, SALAzAR-Vallejo, 2012

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

Trophoniella eliasi n. sp.

( Fig. 8 )

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

TYPE MATERIAL. — Southwestern Atlantic Ocean. Holotype ( MACN 39283 ), R/ V Chairpesca 57 cruise, off Puerto Madryn, Argentina, in stomach contents of a ♂ “gatuzo” or fine-tailed shark, Mustelus schmitti Springer, 1939 , 65 cm long, caught in 117 m water depth, 26.IX.2005.

ADDITIONAL MATERIAL. — Southwestern Atlantic Ocean. 6 specimens ( MACN), 1 anterior and 5 median fragments, apparently not matching, stomach contents of a ♀ “gatuzo” or fine-tailed shark, M. schmitti , 56 cm long, off Siempre San Salvador, Puerto Madryn, Argentina, 22.VI.2005 (anterior fragment with sediment cover, most chaetae broken) ; 1 specimen ( MACN), anterior fragment, stomach contents of a ♀ “gatuzo” or fine-tailed shark, M. schmitti , 76 cm long, off Siempre San Salvador , Puerto Madryn, Argentina, 31.VIII.2005 (37 mm long, 5 mm wide,cephalic cage broken, 41 chaetigers; dissected for anterior end) ; 1 specimen ( MACN), without anterior end, broken in 3 fragments,stomach contents of a ♂ “gatuzo” or fine-tailed shark, M. schmitti , 74 cm long, San Salvador, Puerto Madryn, Argentina, 31.VIII.2005 (30 + 10 + 75 mm long, 27 + 9 + 94 chaetigers). — 1 specimen ( MACN), anterior fragment, off Puerto Madryn, Viernes Santo, Rede 04 cruise, stn 6 (41°08’S, 64°09’W), stomach contents of a ♀ “gatuzo” or fine-tailed shark, M. schmitti , 82 cm long, caught in 99 m water depth, 30.X-1.XI.2006. — 1 specimen ( MACN), broken in 2, damaged, off Puerto Madryn , Siempre San Salvador, stomach contents of a ♀ “pescadilla” or sea trout, Sympterigia bonapartei Müller & Henle, 1841 , 52 cm long, 110 m depth, 18.V.2007 (73 mm long, 5 mm wide, cephalic cage missing, about 55 chaetigers) ; 1 specimen ( MACN), anterior fragment, damaged, off Puerto Madryn, Siempre San Salvador, stomach contents of a ♀ “gatuzo” or fine-tailed shark, M. schmitti , 88 cm long, 16.VIII.2007. — 3 specimens ( MACN), an anterior and 2 median fragments, damaged, off Puerto Madryn, Siempre San Salvador, stomach contents of a ♀ “gatuzo” or fine-tailed shark, M. schmitti , 70 cm long, 110 m depth, 16.VIII.2007. — 1 specimen ( MNHN 884 ), anterior fragment, flaccid, probably preserved in ethanol, with a dissection along the anterior end, off Nova Iguasu, R/V Calypso , stn 108 (23°07’S, 43°11’W), 54 m, 7.XII.1961. — 1 specimen ( MNHN 884 ), flaccid, probably preserved in ethanol, without posterior end, off Rio Grande , R/V Calypso , stn 154 (32°15’S, 51°58’W), 18 m, 20.XII.1961 .

TYPE LOCALITY. — Off Puerto Madryn, in soft bottoms, in about 120 m depth.

DISTRIBUTION. — Apparently restricted to the central portion of Argentina, off Puerto Madryn, in soft sediments in 99-117 m depth, a frequent prey of some demersal fishes.

ETYMOLOGY. — The specific name is to honor Dr Rodolfo Elías, an Argentinian colleague who has concentrated his efforts on benthic ecology, and has made several publications on polychaete systematics from northern Argentina.

DESCRIPTION

Holotype (MACN 39283) without posterior end, breaking in parts, stiff, swollen anteriorly, softer,

tapering posteriorly ( Fig. 8A ), 91 mm long, 4 mm wide, cephalic cage (broken) 7 mm long, 86chaetigers. Tunic completely covered with fine sediment particles ( Fig.8B, C ),particles sparsely distributed,most particles removed by digestion (a non-type specimen with densely packed sediment grains,most chaetae broken). Body papillae mostly eroded; parapodial papillae long, capitate; dorsal papillae not forming tubercles;ventral papillae forming two longitudinal rows.

Anterior end not exposed, observed by dissection of a non-type specimen. Macerated. Cephalic hood short, smooth, margin papillose. Prostomium low, blackish. Eyes not seen. Caruncle well developed, probably extended along the whole branchial plate, median keel thick, wide, pale, lateral ridges darker. Palps lost, size-relationship with branchiae unknown, palp keels pale, rounded. Lips well developed, distorted by pharynx eversion. Branchiae maculated, cirriform, sessile on a partially digested tongue-like protuberance (posterior margin unknown), arranged in two lateral groups, in 5-6 longitudinal rows per group, with about 60 filaments per group; few filaments remaining. Nephridial lobes not seen.

Cephalic cage chaetae about 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 about eight chaetae per bundle.

Anterior dorsal margin of first chaetiger with a macerated, median, single, thin lobe ( Fig. 8C ), projected anteriorly (trifid in a non-type specimen), marginal papillae not seen. Anterior chaetigers (2- 4) with large notopodial lobes and long, inferior notopodial papillae, 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 5; neurohooks with anchylosed articles present from chaetiger 35. Gonopodial lobes not seen ( Fig. 8D ).

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. Notopodia with two prechaetal papillae, one postchaetal smaller papilla; neuropodia with one prechaetal and three postchaetal papillae; inferior notopodial papillae better developed in anterior chaetigers.

Median notochaetae arranged in short oblique series, 9-10 per notopodium, as long as 1⁄₄ body width; all notochaetae multiarticulated capillaries, short articles basally, medium-sized medially,longer articles distally ( Fig.8E , insert).Neurochaetae multiarticulated capillaries in chaetigers 1-18, replaced by hooks from about chaetiger 20, each with a very long median article and shorter articles basally and distally, tips bidentate ( Fig.8F ); by chaetiger 35, all neurochaetae anchylosed hooks ( Fig.8G ). Neurochaetae arranged in transverse series, median region with 7-8 per neuropodium, six in posterior chaetigers. Anchylosed neurohooks bidentate ( Fig. 8G , inserts), most with tips eroded, dark brown, distally tapering, less pigmented, with short rings continued to the subdistal region, most with tips broken, eroded, others with bidentate tips, accessory tooth acute, longer than fang.

Posterior end unknown.

Variation

The specimens were retrieved from the stomach contents of two different fish species, the “gatuzo” or fine-tailed shark, M. schmitti , the most frequent one, whereas the other, the “pescadilla” or sea trout, S. bonapartei , had a single specimen. The damage to the body was similar because most long chaetae were broken, whereas the sediment cover showed different degrees of particle removal, probably depending on how much time the polychaete had spent within the fish stomach. Thus, the body had different densities of particles although even those with fewer ones, retained the overall pattern throughout the body surface.

REMARKS

Trophoniella eliasi n. sp. resembles other species having fine sediment particles completely covering the body such as T. harrisae n. sp., T. hospita n. comb. and T. orensanzi n. sp. However, T. eliasi n. sp. differs from these three other species because it lacks dorsal tubercles, whereas the other species have them. It might be regarded that T. eliasi n. sp. is a smothered T. orensanzi n. sp. because the main difference is the lack of dorsal tubercles in the former. However, the tunic and its sediment cover in the corresponding region do not show any abrasion or fracture, and thus the lack of dorsal tubercles is a consistent difference between these two species. Further, these species are apparently living in different water depths; T. eliasi n. sp. was found in stomach contents of fishes caught in about 100 m depth, whereas T. orensanzi n. sp. thrives in shallow water, being found in about 9 m depth.

Figures

FIG. 8. — Trophoniella eliasi n. sp., holotype (MACN 39283): A, lateral view; B, anterior end, lateral view; C, anterior end, dorsal view; D, anterior end, ventral view; E, chaetiger 30, notopodium (insert: notochaetal basal, medial and distal regions); F, chaetiger 30, neuropodium (insert:central neurochaeta tip); G, chaetiger 52,neuropodium (inserts:tip of neurochaetae showing complete and eroded accessory tooth). Scale bars: A, 4 mm; B, 0.7 mm; C, 0.6 mm; D, 0.85 mm; E, 160 µm; F, 140 µm; G, 100 µm.