Actinoporus elegans Duchassaing, 1850

Gonzalez-Munoz, Ricardo, Simoes, Nuno, Tello-Musi, Jose Luis & Rodriguez, Estefania, 2013, Sea anemones (Cnidaria, Anthozoa, Actiniaria) from coral reefs in the southern Gulf of Mexico, ZooKeys 341, pp. 77-106 : 87-88

Actinoporus elegans Duchassaing, 1850 Figure 8, Table 2

Actinoporus elegans Duchassaing 1850: 10.

Actinoporus Elegans [sic]: Duchassaing 1870: 21.

Aureliana elegans : Andres 1883: 289.

Material examined.

La Gallega reef (19°13'20"N, 96°07'39"W; one specimen).

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 8C). 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 8G). 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 8E). Column with longitudinal rows of vesicles (6-8 vesicles per row) distally (Figure 8B, E). Pedal disc well-developed, narrow, 19 mm in diameter. Column and pedal disc white to pale-brown; mesenterial insertions visible distally (Figure 8E). 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 8F). Basilar muscles well-developed (Figure 8H). Marginal sphincter muscle endodermal, strong and circumscribed, pinnate (Figure 8G). Longitudinal muscles of the tentacles ectodermal (Figure 8I). Zooxanthellae absent. Cnidom: basitrichs, microbasic p-mastigophores, and spirocysts (Figure 8 J–P, Table 2).

Natural history.

Actinoporus elegans inhabits sandy bottoms, at 1-2 m; the column is burrowed in the sand but the pedal disc is strongly attached to rocks. When disturbed, it contracts the oral disc suddenly, completely burrowing the entire body.

Distribution.

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

Remarks.

Currently there are two valid species of Actinoporus : Actinoporus elegans and Actinoporus elongatus Carlgren, 1900 ( Fautin 2013). Actinoporus elongatus is reported for India, Mozambique and Australia ( Carlgren 1900, Menon 1927, Clayton and Collins 1992), and it lacks the longitudinal rows of vesicles in the distal column of Actinoporus elegans ( Carlgren 1900, Corrêa 1973). Additional color patterns observed for Actinoporus elegans in coral reefs off the coast of Venezuela include tentacles and oral disc almost completely white with dark-brown stripes, or completely bright orange (unpublished data).