Psamathe charpyi, Salazar-Vallejo, 2022

Salazar-Vallejo, Sergio I., 2022, New species of hesionid and phyllodocid polychaetes (Annelida, Errantia) from Clipperton Island, Zoosystema 44 (1), pp. 1-26 : 4

Psamathe charpyi n. sp.

( Fig. 1 )

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TYPE MATERIAL. — Holotype. Clipperton Island • 1 specimen; Sta. 10; 10°17.31’N, 109°12.19’W; coral rubble, suction pump; 13 m; 17.I.2005; J.-M. Bouchard, L. Albenga & L. Dugrais leg; MNHN-IA-TYPE2040.

DIAGNOSIS. — Psamathe with anterior eyes blackish, slightly larger than posterior ones; dorsal cirri longer than body width; ventral cirri reching tips of neurochaetal lobes; all neurochaetae compound, neurochaetal blades unidentate, 4-10× longer than wide.

ETYMOLOGY. — The specific epithet is derived after Dr Loïc Charpy, from the Centre d’Océanologie de Marseille, France, in recognition of his editorial coordination of the volume on Clipperton Island ( Charpy 2009). The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

DISTRIBUTION. — Only known from Clipperton Island, Eastern Pacific, in subtidal coral rubble (13 m depth).

DESCRIPTION

Body

Holotype (MNHN-IA-TYPE2040) anterior fragment; body colorless, subcylindrical, slightly wider posteriorly, 5.3 mm long, 1.4 mm wide, 22 chaetigers; all tentacular cirri lost, most dorsal cirri retained, tips lost ( Fig. 1A ). Right parapodia of chaetigers 10 and 14 removed to observe chaetae.

Anterior end

Prostomium slightly longer than wide ( Fig. 1B ), slightly wider anteriorly, lateral margins slightly curved. Lateral antennae lost, scars on anterior margin above palps. Palps directed ventrally, left palp lost, right palpostyle longer than palpophore, medially wider, tapered ( Fig. 1C ). Eyes large, blackish, positioned centrally on prostomium, anterior eyes slightly larger than posterior ones, directed anterolaterally. Nuchal organs following prostomial posterior corners. Tentacular belt partially visible dorsally. First two segments dorsally reduced, following two segments fused, distinct dorsally; anterior margin projected anteriorly, markedly wider than long, blunt. Eight pairs of tentacular cirri, all lost, cirrophores distinct.

Parapodia and chaetae

Parapodia (excluding chaetae) as long as body width, sesquiramous ( Fig. 1D ). Dorsal cirri with longer than wide articles, sometimes medially constricted.Prechaetal lobe subtriangular, blunt, as long as postchaetal round foliose lobe. Neurochaetae all compound heterogomph falcigers; upper and lower fascicle chaetae with shorter blades, longer in central fascicle chaetae; blades unidentate, 4-10× longer than wide, finely denticulate, basal denticles larger; guards reaching tip of denticle ( Fig. 1D , insets). Ventral cirri long, tapered, reaching tip of neurochaetal lobes.

Posterior region

Unknown.

REMARKS

Psamathe charpyi n. sp. resembles P. cirrata Keferstein, 1862 from the French Normandy coast because both species have ventral cirri reaching the tips of the neurochaetal lobes and all neurochaetae compound. They differ in the size of the eyes and of neurochaetal blades. In P.charpyi n. sp. eyes are almost of the same size, and the neurochaetal blades are 4-10× longer than wide, whereas in P. cirrata anterior eyes are 2-3× larger than posterior ones, and neurochaetal blades are 3-9× longer than wide. On the other hand, P. charpyi n. sp. differs from P. ancuda (Wesenberg-Lund, 1962) , described from Central Chile, in the shape and size of the ventral cirri, and in the size of the neurochaetal blades. In P. charpyi n. sp. ventral cirri are tapered, reaching the neurochaetal lobes tips, and neurochaetal blades are of different size, whereas in P. ancuda ventral cirri are blunt, not reaching the neurochaetal lobes, and all neurochaetae have blades of similar size.

Figures

FIG. 1. — Psamathe charpyi n. sp.,holotype (MNHN-IA-TYPE2040); A, anterior region,dorsal view (after Shirlastain-A);B, same,anterior end,dorsal view;C, same, ventral view; D, chaetiger 14, right parapodium, anterior view (insets: neurochaetal blades). Scale bars: A, 0.36 mm; B, 0.25 mm; C, 0.20 mm; D, 0.10 mm.