Amphictene guatemalensis (Nilsson, 1928)

Garcia-Garza, Maria E. & de Leon-Gonzalez, J. A., 2014, A new species of Amphictene (Annelida, Pectinariidae) from the Gulf of Mexico, with a redescription of Amphictene guatemalensis (Nilsson, 1928), ZooKeys 367, pp. 1-9 : 4-6

Amphictene guatemalensis (Nilsson, 1928) Figure 3

Pectinaria (Amphictene) guatemalensis Nilsson, 1928: 46 fig. 14 a–f.

Amphictene guatemalensis . Hartman 1959: 479; Hutchings and Peart 2002:102; Fauchald 1977:120.

Material examined.

Holotype (HZM V-1755), west coast of Central America, San José de Guatemala, Guatemala. [13°55'28"N, 90°47'25"W] coll. Captain R. Paeslin.

Description.

Holotype complete, divided in two fragments, 14 mm long (10 mm anterior fragment, and 4 mm posterior fragment), 4 mm wide, with 19 segments. Cephalic veil formed by semicircular lobe insert at base of paleae forming shelf on buccal tentacles. Cephalic veil margin with 20 long, thin cirrus, inserted anterior end each cirrus with slightly wider base, decreasing in width distally. Opercular plate covered by numerous papilliform structures without any apparent order, with 9 pairs of long and slightly curved paleae, ending in thin filament. Opercular margin with 13 subtriangular cirri (Fig. 3A).

First pair of tentacular cirri inserted on anterior-posterior margin of first segment; second pair of tentacular cirri inserted on lateral margin of second segment. Second segment dorsally indistinguishable, very soft epithelium, with six pairs of glandular cirri on ventral side, subtriangular, fading distally, in central part of segment with a quadrangular plate having numerous small papillae. Third segment with oval central lobe, and pair of lower lateral expansions. Fourth segment with four glandular lobes, robust, subtriangular, fused in pairs, and oval central lobe. Two pairs of lateral branchiae inserted in segments 3 and 4, forming series of flat and free lamellae. Chaetigers 1-3 (segments 5-7) only with notopodia. Chaetigers 4-15 biramous with noto- and neuropodia; two types of notochaetae, thin and long simple capillary on chaetigers 1-15, and bayonet shaped ones, shorter than first ones, present on chaetigers 4-15, with well-developed median tooth and inner edge of blade dentate. Neuropodia wedge shaped, slightly glandular, torus with numerous uncini, each one with 4-5 rows of small denticles.

Last three posterior segments without notochaetae or neurochaetae, followed by 5 fused segments forming scaphe; segments broad and lobed, with smooth margin, scaphe slightly longer than wide, clearly separated from abdomen; 9 pairs of short, thick scaphal hooks, golden (Fig. 3C). Anal lobe semicircular, with cleft, bearing marginal middle papilla (Fig. 3B).