Caulleryaspis nuda, Salazar-Vallejo, Sergio I. & Buzhinskaja, Galina, 2013

Salazar-Vallejo, Sergio I. & Buzhinskaja, Galina, 2013, Six new deep-water sternaspid species (Annelida, Sternaspidae) from the Pacific Ocean, ZooKeys 348, pp. 1-27 : 5-7

Caulleryaspis nuda sp. n. Figure 3

Type material.

Northeastern Pacific, Oregon. Holotype (CAS 129027h) and nine paratypes (CAS 129027p), variably damaged, Sta. BMT 557 (48°9.0'N, 127°4.2'W), 2519 m, 10 Sep. 1971, A. Carey, coll. (complete paratypes 9-11 mm long, 3-5 mm wide; left shield plate 1.8-2.1 mm long, 1.9-2.4 mm wide; oocytes 200 µm in smaller paratype).

Additional material.

Northeastern Pacific, Oregon. Thirty-three specimens (CAS 128953), Sta. BMT 556 (48°7.7'N, 127°4.8'W), 2519 m, 10 Sep. 1971, A. Carey, coll. (complete 8.0-11.5 mm long, 3.5-5.5 mm wide; left shield plate 1.5-2.5 mm long, 1.5-2.4 mm wide; oocytes 200 µm).

Description.

Holotype (CAS 129027h) with integument almost completely removed, some fragments remain in mid-body; body wall broken midventrally and dorsally (Fig. 3A). Integment and ventro-caudal shield pale brown, body wall whitish, introvert darker than abdomen. Body papillae mostly removed along with integument; papillae probably homogeneously distributed throughout body. Body 13 mm long, 5 mm wide, about 28 segments; left ventro-caudal shield 2.0 mm long, 2.2 mm wide.

Prostomium minute globose, ovoid, paler than peristomium. Peristomium small, oval, papillae lost. Mouth oval, small slightly wider than prostomium, barely projected, covered by papillae (Fig. 3B).

First three chaetigers with about 16 falcate, tapered introvert hooks per bundle, each with subdistal dark areas, slightly paler distally. Genital papillae not seen. Pre-shield region with 7 segments; capillary chaetae not seen (some paratypes with capillaries in 2-4 segments).

Ventro-caudal shield completely covered by a thin, delicate coating of adhered fine sediment particles, mostly removed from shield; suture not visible (Fig. 3C). Anterior margins rounded; anterior depression deep; anterior keels not exposed. Ribs barely defined, concentric lines not visible. Lateral margins rounded, expanded medially, reduced posteriorly. Fan with a deep wide median notch, projected beyond the margins of posterior corners.

Marginal chaetal fascicles include 10 lateral and only 4 short, small posterior ones (others probably broken; some paratypes with up to six posterior bundles); lateral bundles with 7-8 chaetae each, posterior bundles with 5-6. Peg chaetae not visible (one paratype with minute, barely visible peg chaetae). Additional chaetal fascicles not visible.

Branchiae lost. Interbranchial filaments lost. Branchial plates convergent, anteriorly expanded, rounded. Some paratypes with broken body wall include oocytes, each about 200 µm.

Variation.

All paratypes have shields without sediment particles firmly adhered or concentric lines (Fig. 3 D–F). The anterior depression is deep, the anterior margins are projected, and the radial ribs are progressively better developed as growth proceeds. The posterior, median notch is well developed in all stages.

Etymology.

The specific name is derived from the Latin adjective nudus (a, um): naked, to indicate that unlike other species in the genus, its shield does not have firmly adhered sediment particles on it. The epithet is in the genitive case.

Remarks.

Caulleryaspis nuda sp. n. is unique because its ventro-caudal shield is soft as typical for the genus, but instead of having a thick sediment particles cover, it has a very thin layer made by loosely adhered, fine sediment particles, which can be easily eroded or brushed off. However, the general shield outline of Caulleryaspis nuda resembles the one present in Sternaspis williamsae sp. n. (see below), and the latter can even incorporate some sediment particles, but they differ because in Caulleryaspis nuda , the shield does not have a thin, stiff, yellowish layer but rather a convex, delicate, pliable margin.

Distribution.

Only known from off Oregon, U.S.A., in 2519 m depth.