Caulleryaspis gudmundssoni, Sendall, Kelly & Salazar-Vallejo, Sergio I., 2013

Sendall, Kelly & Salazar-Vallejo, Sergio I., 2013, Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae), ZooKeys 286, pp. 1-74 : 49-51

Caulleryaspis gudmundssoni sp. n. Figure 16

Type material.

Atlantic Ocean, Iceland. Holotype (IMNH 10280), and 5 paratypes (IMNH 10282), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2429 (63°02.30'N, 21°50.80'W), 1072 m, sandy silt, 3-VII-1993. 16 additional paratypes as follows: 1 (IMNH 10281), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2430 (63°07.90'N, 19°57.20'W), 1016 m, no sediment data, 3-VII-1993. 3 (IMNH 10283), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2404 (63°02.30'N, 21°50.80'W), 827 m, sandy silt, 1-VII-1993. 2 (IMNH 10284), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2415 (63°00.18'N, 21°54.63'W), 819 m, no sediment data, 2-VII-1993. 1 (IMNH 10285), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2414 (63°00.30'N, 21°00.76'W), 808 m, sandy silt, 2-VII-1993. 4 (2 IMNH 10286, 2 MNHN 1555), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2475 (63°04.20'N, 21°34.90'W), 842 m, sandy silt, 5-VII-1993. 1 (IMNH 10287), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2409 (62°52.37'N, 21°43.62'W), 1080 m, silt with large rock, 2-VII-1993. 1 (IMNH 10288), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2468 (63°10.00'N, 21°30.90'W), 452 m, sandy silt, 5-VII-1993. 3 (IMNH 10289), BIOICE Program, R.V. Bjarni Saemundsson, Sta. 2431 (63°04.08'N, 19°51.33'W), 1207 m, sandy silt, 3-VII-1993.

Description.

Holotype (IMNH 10280) with body stout and of equal width over the anterior, preshield and shield regions (Fig. 16A). Colour tan, speckeld with small sediment particles. Abundant, minute cuticular papillae, incorporating fine sediment particles, except in the areas where introvert hooks emerge. Segments seven and eight with more cuticular papillae near genital papillae. Cuticular papillae not present, even dorsally near ventro-caudal shield, but a few may be present on more posterior segments. Body 7.5 mm long, 3.5 mm wide, about 28 segments.

Prostomium hemispherical, conspicuously extended, white, opaque. Peristomium small, oval, bearing some papillae closer to mouth. Mouth oval, small, completely covered by papillae, extends from prostomium to anterior border of second segment.

First three chaetigers with 10-15 falcate, flat introvert hooks per bundle, closely associated, each with subdistal dark areas. Genital papillae protrude ventrally from intersegmental furrow between segments 7 and 8. Pre-shield regions with 7 segments, smooth, some bearing small groups of fine, short capillary chaetae.

Ventro-caudal shield completely covered by a thick coating of adhered particles, unusually flexible; suture not visible (Fig. 16 A–C). Anterior margins apparently rounded (shape blocked by sediment cover); anterior depression deep; anterior keels not exposed. Ribs, concentric lines or fan not visible. Lateral margins rounded, expanded medially, reduced posteriorly. Fan truncate, barely reaching posterior corners. Other features not visible.

Marginal chaetal fascicles include 10 lateral ones, and only three short, small posterior fascicles (other ones apparently broken), each with 3-4 chaetae concentrated near posterolateral edge of shield. Peg chaetae robust, stout in cross basal section, pale gold, emerge directly from a raised portion of shield, close to posterior margins (Fig. 16 A–C). Additional two couplets or triplets of fine short capillary chaetae between peg chaetae and first posterior shield chaetae fascicles.

Branchiae few, very slender coiled filaments on two roughly parallel plates; longer, more slender, straight filamentous papillae closer to anus.

Etymology.

The species name is derived after Dr. Gudmundur Gudmundsson, from the Iceland Natural History Museum in recognition of his long-standing support for our research activities. The epithet is a noun in the genitive case.

Type locality.

Off southeast of Vestmannaey jar, Iceland, 1072 m.

Remarks.

Caulleryaspis gudmundssoni sp. n. resembles Caulleryaspis laevis (Caullery, 1944) comb. n. because both species have sediment particles covering their soft shields. These species differ in the relative development of the anterior shield depression and especially on the relative development of peg chaetae. In Petersenaspis gudmundssoni the anterior depression is deep and the peg chaetae are robust, being easily noticed over the shield itself, whereas in Caulleryaspis laevis the anterior depression is shallow and the peg chaetae are not well developed.

Distribution.

Only known from the type locality off southwest Iceland, in sediments of 452-1207 m depth.