Calliactis tricolor (Le Sueur, 1817)

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 : 89-91

Calliactis tricolor (Le Sueur, 1817) Figure 9, Table 2

Actinia tricolor Le Sueur 1817: 171.

Actinia bicolor Le Sueur 1817: 171.

Cereus bicolor : Milne-Edwards 1857: 273.

Adamsia tricolor : Milne-Edwards 1857: 281.

Adamsia Egletes [sic] Duchassaing and Michelotti 1864: 40.

Adamsia egletes : Duchassaing and Michelotti 1866: 134.

Calliactis bicolor : Verrill 1869: 481.

Adamsia sol McMurrich 1893: 183.

Adamsia bicolor : Andres 1883: 179.

Adamsia tricolor Andres 1883: 180.

Calliactis tricolor : Haddon 1898: 457.

Material examined.

Alacranes reef (22°31'35"N, 89°46'05"W; eight specimens), Serpientes reef (21°26'22"N, 90°28'25"W; five specimens).

Diagnosis.

Fully expanded oral disc and tentacles 9-48 mm in diameter. Oral disc smooth, wider than column, 3-20 mm in diameter, pale-brown translucent, with small white stripes in endocoelic spaces, sometimes forming a white ring; some specimens also with pink flashes (Figure 9A). Mouth bright yellow, orange, or white; often with purple ring around lips (Figure 9A). Tentacles hexamerously arranged in 5-6 cycles (96-192 in number), smooth, thin, short (2.5-15.5 mm), inner ones longer than outer ones, contractile (Figure 9A, B), tapering distally, pale-brown with a longitudinal row of white dots along entire length (Figure 9A, B); some specimens also with bright-pink flashes mainly at tips. Column trumpet-shaped in extended position, dome-shaped when contracted, 5-24.5 mm in diameter and 4-31 mm in height, divided into narrow, smooth capitulum and wrinkled-texture scapus (Figure 9B). Capitulum pale-brown to yellowish, scapus bright to dark orange often with small white stripes or white flashes slightly above limbus (Figure 9B). Pedal disc well-developed, circular to irregular, wider than column, 6-36 mm in diameter, with mesenterial insertions visible, pale-brown and translucent (Figure 9C). One or two rows of cinclides proximally, near limbus; dark-red or brown (Figure 9B). Mesenteries hexamerously arranged in four cycles; same number of mesenteries proximally and distally (to 48 pairs in specimens examined): first cycle perfect, others imperfect; third and fourth cycles poorly developed, without filaments or acontia. Gametogenic tissue not observed in specimens examined. Two pairs of directives each attached to a well-developed siphonoglyph (Figure 9E). Retractor muscles weak and diffuse; parietobasilar muscles poorly developed (Figure 9E, F). Basilar muscles poorly developed (Figure 9H). Marginal sphincter muscle mesogleal, strong, transversally stratified (Figure 9G). Longitudinal muscles of tentacles ectodermal. Acontia numerous, bright orange (Figure 9C), with basitrichs. Zooxanthellae present. Cnidom: basitrichs, microbasic p-mastigophores, and spirocysts (Figure 9 J–Q; see Table 2).

Natural history.

Calliactis tricolor typically dwells on the shells of living hermit crabs often carrying more than one individual (Figure 9D), between 10-30 m. This peculiar symbiotic relationship has been widely studied (reviewed in Gusmão and Daly 2010).

Distribution.

Western Atlantic, from the northern coast of USA to the northern coast of Brazil, along the Caribbean Sea and Gulf of Mexico ( Carlgren and Hedgpeth 1952, Zamponi et al. 1998). This is the first record for the coast of Mexico; found in Serpientes and Alacranes reefs.

Remarks.

Of the 18 valid species currently considered as valid of Calliactis , only two have been reported in the Gulf of Mexico and Caribbean Sea ( Fautin 2013): Calliactis polypus ( Forsskål, 1775) and Calliactis tricolor . These two species differ in the color of the cinclides, white in Calliactis polypus and dark-red in Calliactis tricolor ( Gusmão 2010). In addition, Calliactis tricolor is distributed almost exclusively in the western Atlantic whereas Calliactis polypus has a wide distribution range, being found in the Red Sea, Hawaii, French Polynesia, Australia, South Africa, East Africa, Maldives, Cape Verde Islands, Japan, Galapagos, and Louisiana ( Gusmão 2010, Fautin 2013).