Petersenaspis capillata (Nonato, 1966) Nonato, 1966

Sendall, Kelly & Salazar-Vallejo, Sergio I., 2013, Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae), ZooKeys 286, pp. 1-74 : 55-56

Petersenaspis capillata (Nonato, 1966) comb. n. Figure 18

Sternaspis capillata Nonato, 1966: 79-83, figs l– 9; Nonato and Luna 1970: 94, figs 87-88.

Type material.

Brazil. Two syntypes (MCEM 1333), Vitoria Island, 23°45'18"S, 44°00'54"W, 52 m, 1965.

Additional material.

Brazil. 1 spec. (MCEM 1309), Florianopolis, 27°45'51"S, 48°03'00"W, 95 m, 15-III-1998. 1 spec. (MCEM 1310), Ararangua, 29°15'00"S, 48°41'00"W, 101 m, 23-III-1998. 1 spec. (MCEM 1311), Florianopolis, 27°46'49"S, 47°40'45"W, 138 m, 16-III-1998. 1 spec. (MCEM 1312), Cricifuna, 28°41'22"S, 48°18'24"W, 109 m, 22-III-1998. 4 spec. (MCEM 1313), Imbituba, 28°05'00"S, 48°06'00"W, 100 m, 16-III-1998. 6 spec. (MCEM 1314), Imbituba, 28°05'00"S, 48°06'00"W, 100 m, 16-III-1998.

Description.

Syntypes (MCEM 1333) with body bright white, clean with barely visible minute filamentous papillae covering most of cuticle (Fig. 18A), more densely on segments 7 and 8. Faint single rows of clusters of papillae along dorsal surface of last few segments. Body up to 20 mm long, 4.5 mm wide, 33 segments.

Prostomium hemispherical, opalescent, conspicuous (Fig. 18B, C). Peristomium rounded, equalized at position of mouth, with some papillae. Mouth circular, extends from base of prostomium to anterior edge of first chaetiger.

First three chaetigers with about 10 bright bronze, recurved, spatulate hooks, without subdistal dark areas (Fig. 18B, C). Genital papillae protrude ventrally from body wall between segments 7 and 8. Pre-shield region with 8 segments, with single lateral bundles of few capillary chaetae protruding from body wall.

Ventro-caudal shield brick red, papillose, with ribs faintly defined but no concentric lines, nor sediment particles; suture extends throughout shield. Anterior margins rounded; anterior depression very shallow; anterior keels not exposed. Lateral margins rounded, expanded medially, reduced posteriorly. Fan truncate, barely projected beyond posterior shield corners (Fig. 18A, D), margin smooth, with median notch.

Marginal shield chaetal fascicles include 11 lateral ones, chaetae of each fascicle in oval arrangement, and 10 posterior fascicles, chaetae in oval arrangement. The 11th lateral fascicles include one or two fine capillary chaetae, four times as long as others. Posterior fascicles positioned close to midline. Peg chaetae not visible, nor additional delicate capillary chaetae between lateral and posterior fascicles.

Branchiae numerous, not emerging from a distinct plate but from body wall; branchial area covered with thin, long interbranchial papillae, increasing in density towards margin of ventro-caudal shield (Fig. 18E).

Remarks.

Petersenaspis capillata (Nonato, 1966) comb. n. resembles Petersenaspis palpallatoci sp. n. because their shields have abundant long papillae, poorly defined ribs and no concentric lines. The main difference between them is the relative shield shape. In Petersenaspis capillata the anterior margin is barely projected forward and the posterior margin has a median notch, but no lateral notches, whereas in Petersenaspis palpallatoci the anterior margins are more projected forward and its posterior margin has a shallow median notch, plus two lateral notches. Other differences in the relative number of shield chaetal fascicles are less reliable because of chaetal fragility.

Distribution.

Only known from Central and Southern Brazilian localities, in 52-138 m depth. Omena and Amaral (1997) recorded this species from intertidal areas as well.