Actinoporus elegans

Diagnosis. Fully expanded oral disc and tentacles up to 52 mm in diameter. Central part of oral disc smooth, narrow, to 16 mm diameter, beige; mouth oval with a well-developed conchula (Figure 8 C). Tentacles small, vesicle-like, arranged in double radial rows covering almost entire oral disc, on endocoelic and exocoelic spaces, 24 - 26 tentacles per double row; reddish or pinkish rows of tentacles alternating with pale brown rows (Figure 8 A-D). Deep fosse (Figure 8 G). Column elongated, funnel-shaped, to 60 mm in height, wider distally than proximally; column diameter: distally 38 mm, mid-column 27 mm, proximally 13 mm (Figure 8 E). Column with longitudinal rows of vesicles (6 - 8 vesicles per row) distally (Figure 8 B, E). Pedal disc well-developed, narrow, 19 mm in diameter. Column and pedal disc white to pale-brown; mesenterial insertions visible distally (Figure 8 E). Mesenteries irregularly arranged in three cycles (28 pairs in specimen examined): first cycle perfect, others imperfect. Gametogenic tissue not observed in specimen examined. Two pairs of directives, only one pair attached to a single well-developed siphonoglyph. Retractor muscles strong, circumscribed, with main muscle lamella divided in two parts; parietobasilar muscles strong with thick mesogleal pennon (Figure 8 F). Basilar muscles well-developed (Figure 8 H). Marginal sphincter muscle endodermal, strong and circumscribed, pinnate (Figure 8 G). Longitudinal muscles of the tentacles ectodermal (Figure 8 I). Zooxanthellae absent. Cnidom: basitrichs, microbasic p-mastigophores, and spirocysts (Figure 8 J-P, Table 2).

Distribution. Western Atlantic, from the northern coast of Brazil to Guadeloupe, Jamaica, and Curacao (Correa 1973), and Cape Verde Islands (Wirtz 2009). This is the first record for the coast of Mexico; found in the VRS.