Petersenaspis salazari Wu & Xu, 2017, sp. nov.
Creators: name: Wu, Xuwen
name: Xu, Kuidong
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Terebellida
Sternaspidae
Petersenaspis
Petersenaspis salazari

description: Petersenaspis salazari sp. nov.
Figures 1, 2
Type material. South China Sea. Holotype: MBM 020924, R/ V Hanggong, Sta. 6093, 19°30’N, 112°30’E, 174 m, coarse sand and mud, coll. Shoupeng Shen, 8 Feb. 1960. Paratype: MBM 020958 (1 spec.), R/V 171, Sta. 6123, 18°30’N, 111°30’E, 182 m, sandy mud, coll. Xiutong Ma, 11 Apr. 1959. Anterior end retracted, 14.8 mm wide; abdomen 10.6 mm long; left shield plate 3.61 mm long, 3.04 mm wide.
Description. Holotype (MBM 020924) complete, 24.4 mm long, 7.5 mm wide; abdomen 16.1 mm long; left shield plate 3.40 mm long, 3.10 mm wide. Abdomen pale to yellowish, introvert lighter in color than abdomen, nearly completely exposed, constriction or waist segments relaxed (Fig. 2 A). Abdomen with sediment particles firmly adhered (Fig. 2 G).
Prostomium hemispherical, projected, translucent pale. Eyespots not seen. Peristomium round, smooth, with few papillae, barely extend laterally and ventrally to anterior margin of first chaetiger. Mouth circular, projected, wider than prostomium, covered by minute papillae (Fig. 2 A, B).
First three chaetigers each with 8–13 brown to dark brown hooks per side. Hooks sub-distally expanded, obliquely truncate, forming a spearhead-like structure with a central furrow (Fig. 2 B, F); hooks gradually shortened towards ventrolateral side. Introvert with well-defined clusters of papillae; papillae dark brown, numerous, arranged in four bands in anterior segments (Fig. 2 B). Genital papillae tapering, distally truncate, covered by minute sediment particles, protruding ventro-laterally from inter-segmental groove between segments 7 and 8. Anterior abdomen with 8 segments (Fig. 2 A); minute papillae evenly distributed on ventral side; well-defined clusters of papillae in a transverse row starting from segment 10, encircling each segment from lateral side to dorsum (Fig. 2 G). Capillaries not seen.
Ventro-caudal shield pale to blue, darker in central area; concentric lines absent, radial stripes present on lateral plates, ribs faintly developed (Fig. 2 D, E). Anterior margins rounded, anterior depression deep, anterior keels covered by translucent integument layer. Suture extending throughout shield, becoming wide in posterior part. Lateral margins rounded, smooth, expanded medially, reduced posteriorly. Posterolateral corners poorly defined. Posterior margin of fan smooth with a deep median notch, almost flat to slightly convex, surrounded by filamentous papillae (Fig. 2 D, E).
Marginal chaetae golden yellow with metallic luster, including 12 lateral fascicles and 7 posterior ones (Fig. 2 D, E, G); lateral fascicles successively longer from anterior to posterior, chaetae arranged in slightly curved series; posterior fascicles almost as long as shield length, 2–4 chaetae per fascicle (Fig. 2 D, E). Peg chaetae short, not well-developed. A small fascicle of 3–4 delicate capillary chaetae inserted between peg chaetae and posteriormost lateral fascicle, 2 times longer than posterior chaetae.
Branchial filaments abundant (Fig. 2 G), inserted on two plates; branchial filaments slender, curled or spiraled, with fine sediment particles adhered; inter-branchial papillae filamentous, curled. Branchial plates long, nearly parallel or slightly convergent, prominent, with firmly adhered sediment particles (Fig. 2 C).
Etymology. Petersenaspis salazari is named to honor Dr. Sergio I. Salazar-Vallejo, in recognition of his contribution to the polychaete taxonomy.
Distribution. Continental shelf of the northern South China Sea (water depth 174–182 m) (Fig. 1).
Remarks. Sendall & Salazar-Vallejo (2013) erected Petersenaspis based on the sub-distally expanded introvert hooks and eight segments of the pre-shield abdomen. So far, the genus contains only two valid species, P. capillata (Nonato, 1966) from the Atlantic Ocean off the Central and Southern Brazil and P. palpallatoci Sendall & Salazar-Vallejo, 2013 from the sea areas of Philippine Islands to Malaysia.
Petersenaspis salazari sp. nov. resembles its congeners in the shield possessing faintly developed ribs, no concentric lines, suture extending throughout the shield, and lateral margins expanded medially and reduced posteriorly. However, P. salazari sp. nov. can be easily distinguished by the four bands of numerous dark papillae in the anterior segments which are absent in P. capillata and P. palpallatoci, the color of the introvert hooks (dark brown vs. bright bronze) and the shape of the branchial plates (slightly convergent vs. indistinct & divergent, respectively). Moreover, Petersenaspis salazari sp. nov. has blue pigmentation with radial stripes on the lateral plates, whereas in its congeners the shields are brick red and no radial stripes occur in P. capillata. In addition, the anterior margin is projected forward and the posterior margin possesses a deep median notch in P. salazari sp. nov., whereas in P. capillata the anterior margin is nearly truncate with a very shallow depression, and in P. palpallatoci the posterior margin has a median notch and two lateral notches.
description: Published as part of Wu, Xuwen & Xu, Kuidong, 2017, Diversity of Sternaspidae (Annelida: Terebellida) in the South China Sea, with descriptions of four new species, pp. 403-415 in Zootaxa 4244 (3) on pages 405-406, DOI: 10.11646/zootaxa.4244.3.8, http://zenodo.org/record/430600