Serpula madrigalae

Description. Tube color greenish yellow (Fig. 2 A-B); with five longitudinal ridges, lateral-most ridges larger than middle ones (Figs 1 C-D, 2 A-B); lacking transverse ridges and peristomes; with four rows of alveoli, more evident between dorsal-most longitudinal ridges (Figs 1 C, 2 A-B). Body yellowish-brown, branchial crown and operculum yellow pale (preserved material only, Fig. 2 C). TL = 20 mm; THW = 1.6 mm. Branchial crown with 18 radioles in each lobe; lacking branchial membrane. Peduncle smooth, with well-defined constriction (Fig. 2 D); inserted in left lobe. Club-shaped pseudoperculum present. Operculum with moderately long, shallow, symmetrical funnel; lacking bulbous basal part (Figs 1 A, 2 D-E). OL = 2.3 mm, OD = 1.4 mm. Interradial grooves 1 / 3 of funnel length (Figs 1 A, 2 E). Funnel has 17 radii with rounded tips. Opercular inner surface with irregular tubercles (Figs 1 B, 2 D). Collar thick, with short ventral and dorsal lobes. Thorax consists of seven chaetigers. Collar chaetal fascicles symmetrical with regard to size and composition, unlike in some specimens of Serpula vossae sp. n. Bayonet chaetae with two blunt-elongate teeth, distal blade smooth, lacking proximal rasp (Figs 2 F); hooded (capillary) chaetae present (Fig. 2 G). Thoracic membranes well developed, narrowing toward to last thoracic chaetigers, fused ventrally, forming a short apron. Remaining six thoracic chaetigers with hooded (limbate) chaetae of two sizes; saw-shaped uncini. Anterior part of abdomen lacking distinct achaetous region. Anterior and middle abdominal chaetigers with flat-trumpet chaetae. Posterior chaetigers with ' capillary' chaetae. Anterior and posterior uncini saw-shaped.

Distribution. Only recorded from the vicinity of Caicos Island, Turks and Caicos Islands (Fig. 6).

Etymology. Named after my wife, Dr Socorro Garcia-Madrigal, a specialist on crustaceans, who gave me the necessary encouragement and time to undertake this research.