Trophoniella grandis (SALAzAR-Vallejo, 2012)

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

Trophoniella grandis

(Blanchard in Gay, 1849) n. comb. ( Fig. 13 )

Siphostoma grande Blanchard in Gay, 1849: 35, 36. — Rozbaczylo 1985: 161.

Lophiocephala grandis – Quatrefages 1866: 485.

Stylarioides (Trophonia) capensis – Gravier 1909: 649, 650, pl. 18, figs 58, 59; 1910: C116, 117, pl. 10, figs 62, 63 (non McIntosh 1885).

Stylarioides capensis americana Monro, 1928: 96 , 97, fig. 16; 1933: 1057, 1058, textfig. 6A, B partim.

TYPE MATERIAL. — Eastern Pacific Ocean. 2 syntypes of Siphostoma grande , larger syntype ( MNHN 378 ), well preserved, smaller syntype ( MNHN 379 ), dried out, Coquimbo (29°57’11”S, 71°20’36”W), Chile, Gaudichaud (smaller syntype 104 mm long, 4 mm wide, cephalic cage 9 mm long, 178 chaetigers; first neurohooks in chaetiger 7, dorsal lobes in chaetigers 2 - 7). — 1 syntype of S. c. americana ( BMNH 1933.7.10.140), damaged, dorsally dissected, off Balboa, Panama, 1923/4, C. Crossland (12.5 mm long, 2 mm wide, cephalic cage 4 mm long, 49 chaetigers, first neurohooks from chaetiger 5; sediment cover previously removed) ; 1 syntype of S. c. americana ( BMNH 1933.7.10.141), damaged, dorsally dissected, broken in 2 pieces, off Balboa, Panama, 1923/4, C. Crossland (15 mm long, 1 mm wide, cephalic cage 4.5 mm long, 50 chaetigers, first neurohooks from chaetiger 5; sediment cover previously removed) .

ADDITIONAL MATERIAL. — Eastern Pacific Ocean. 1 mature ♀ ( CAS 168314 ), International Galápagos Scientific Project , southwest coast of Isla Pinta ( Abingdon Island ), Galápagos, tide pools, 25.V.1964, D. Q. Cavagnaro (48 mm long, 5 mm wide, cephalic cage chaetae 10 mm long; 68 chaetigers; first neurohooks from chaetiger 6; oocytes about 100 µm in diameter) .

DISTRIBUTION. — From the Galápagos Islands to the Tumbes Peninsula (Talcahuano,Concepción), Chile. Fauchald (1972: 414) erroneously listed Tumbes, Peru, as the type locality.

DESCRIPTION

Larger syntype of S. grandis (MNHN 378) grayish, posteriorly incomplete ( Fig. 13A ), soft, preserved in alcohol. Body fusiform, cylindrical, tapering posteriorly, 142 mm long, 10 mm wide, cephalic cage 10 mm long, 105 chaetigers.Tunic completely covered by a fine layer of fine sediment particles, less extended ventrally, especially in posterior chaetigers (smaller syntype with large sediment particles dorsally, smaller particles ventrally).Body papillated, pale, body wall pale (black in smaller syntype). Papillae mostly collapsed, ventrally arranged in four longitudinal rows or double papillar scars. Dorsal lobes in chaetigers 2 - 8.

Anterior end not exposed; not dissected to avoid further damage. Cephalic cage chaetae as long as body width. Chaetigers 1-4 involved in the cephalic cage; chaetae arranged as short dorsolateral series. Chaetiger 1 with 12-16 noto- and 10 neurochaetae, chaetiger 2 with 10 chaetae per bundle, chaetiger 3 with 10 chaetae per bundle, chaetiger 4 with nine noto- and eight neurochaetae.Anterior dorsal margin of first chaetiger with a short, conical, papillated, bifid lobe, directed ventrally. Chaetigers 2-8 with two large, dorsal papillae per segment, decreasing in size posteriorly, each as a rounded lobe, directed anteriorly ( Fig. 13B ). Chaetigers 1-3 of about the same length. Chaetal transition from cephalic cage to body chaetae abrupt; short, dark, anchylosed neurohooks starting in chaetiger 7. Gonopodial lobes not seen (BMNH 1933.7.10.140 with nephridial papillae long, in the external surface of branchial plate).

Parapodia poorly developed, chaetae emerge from the body wall. Parapodia lateral; median neuropodia ventrolateral. Noto- and neuropodia short, transverse slits; notopodia with two postchaetal papillae, neuropodia with three smaller postchaetal papillae. Noto- and neuropodia distant to each other.

Median notochaetae arranged in short transverse series, 11-12 per bundle, as long as ¼-1⁄₅ body width ( Fig. 13C ); all notochaetae multiarticulated capillaries, mostly broken distally, each with short articles, becoming slightly longer distally ( Fig. 13D ), tips falcate, hyaline. Neurochaetae multiarticulated capillaries in chaetigers 1-6; straight, anchylosed neurohooks from chaetiger 7, arranged in transverse series, 7-9 per bundle ( Fig. 13E ). Each hook dark brown, with short rings continued to the subdistal, slightly expanded region, blade less pigmented, finely obliquely striated, distally entire, falcate, surface rough with adsorbed materials.

Posterior end (in smaller syntype) tapering to a blunt cone; pygidium with anus terminal, without anal cirri.

Variation

There are several features that show certain sizedependency, especially the number of chaetae per bundle and the number of anterior segments with dorsal tubercles. The variation is limited, however, and under a certain range of variation, they can be employed to separate similar species having a relatively similar size. On the other hand, the start of neurohooks is consistent.

REMARKS

Trophoniella grandis n. comb. was described as Siphostoma grande in a major work on Chilean natural history involving several French scientists. However, Quatrefages (1866) did not acknowledge this; in fact, he had already employed the “Nob.” abbreviation before ( Quatrefages 1849). This comes from the Latin word “nobis”, meaning “to us” and it is equivalent to “mihi”, which means, in turn, “to me […] and used after a name to indicate the author’s responsibility for it” ( Stearn 1992). Thus, he introduced new names even when he was aware that a previous name had already been used for the same species (cf. Quatrefages 1866: 476 under Chloraema dubium as a new name, instead of Flabelligera (olim Siphostoma ) diplochaitus Otto, 1821). Therefore, because both names have been introduced for Chilean flabelligerids,in both cases the same epithet was employed, and because collecting trips to Chile was not frequent, both names must have the same type specimen, consequently become objective synonyms, and Blanchard’s name has priority. It must be stated that Quatrefages noticed the apparent lack of notochaetae in several anterior chaetigers, and this would explain why he moved the species to Lophiocephala Costa, which is a junior synonym of Stylarioides (Salazar-Vallejo 2011b) . The specimen was distorted during preservation; most of the tunic was detached from the body wall, and especially in anterior chaetigers, chaetae can be seen by transparency under the loose tunic, or the aligned chaetal scars can be seen in the corresponding sites. Trophoniella grandis n. comb. resembles T. ehlersi n. comb. because their tunics include fine sediment particles over the dorsal and ventral surfaces. They differ because in T. grandis n. comb. there are dorsal tubercles in the first few chaetigers, whereas in T. ehlersi n. comb. the anterior chaetigers do not have dorsal tubercles or notopodial lobes, and because in T. grandis n. comb. the falcate neurohooks start by chaetiger 7 whereas they start by chaetiger 5 in T. ehlersi n. comb.

Figures

FIG. 13. — Trophoniella grandis (Blanchard in Gay, 1849) n. comb., largest syntype (MNHN 378):A, lateral view; B, anterior end, dorsal view; C, notopodium from chaetiger 35; D, notochaetal basal, medial and distal regions; E, neurohooks from chaetiger 76 (insert: enlargement to show anchylosed articles). Scale bars: A, 5 mm; B, 2.9 mm; C, 0.4 mm; D, 45 µm; E, 180 µm.