IUCN threat status:

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Comprehensive Description

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General Description

Diagnosis: In live specimens the column is stout and trumpet shaped, with a pale orange to white colour, and covered with a strong blackish cuticle. There are relatively short, tapering, uniformly orange marginal tentacles. The scapus has 24 longitudinal rows of tubercles. The oral disc is lightly concave in live specimens, and is orange to pink in colour. The mesenteries are hexamerously arranged in five cycles, with the fifth cycle present at limbus only. Although all of the larger mesenteries are fertile, only those of the first cycle are perfect.

Oral disc and tentacles: The oral disc is flat with a broad tentacle-free space surrounding a prominent, slit-like mouth that has two prominent siphonoglyphs. In live specimens the oral disc is orange to pink in colour, with a white margin. The siphonoglyphs of preserved specimens are light brown; in live specimens they are orange. The musculature of the oral disc is strong and ectodermal. There are ca, 100 tentacles in six crowded marginal cycles, with the tentacles of the inner and outer cycles ca. equal in length. The tentacles are typically inside the column in contracted specimens. In all examined specimens the distal column covers the oral disc and the base of the tentacles. In contraction the tentacles are blunt and longitudinally furrowed, with a length of ca. 15 mm and are slightly longer than the oral disc radius. In live specimens the tentacles are longer and more sharply tapering, with those of the inner cycle slightly longer than those of the outer cycle. The tentacles of the inner cycles are typically held erect, whilst those of the outer cycle are held out or pointing towards the substrate. In live specimens the tentacles have the same colour as the oral disc, with white markings on the aboral base. The tentacles of preserved specimens are orange to pink in colour, becoming paler at the tips. The ectodermal longitudinal muscles of the tentacles are equally developed on the oral and aboral sides.

Base and column: The column of preserved contracted specimens is stout and cylindrical. The diameter at the base of the column measures 31 - 51 mm, and the column has a height of 25 - 45 mm. In live specimens, the column is cylindrical and flares abruptly at the oral disc. The column is white underneath a dark cuticle in live specimens. The column is differentiated into a cuticle-free distal scapulus and a thick-walled, strongly cuticulate proximal scapus. The scapus bears large, equally developed and regulary arranged tubercles that form 24 longitudinal ridges distally. The mesenterial insertions are more prominent distally because of the ridges and tubercles. The column musculature is concentrated into a strong mesogleal marginal sphincter distally. The sphincter is centred in the mesoglea, and is larger distally, tapering proximally. The pedal disc is adherent, muscular and flat. It has the same colour as the column, and may retain a thin covering of small particles from the substrate. The basilar muscles are poorly developed.

Mesenteries and internal anatomy: The mesenteries are arranged hexamerously in five regular cycles, with the fifth cycle present only at limbus. There are two pairs of directives, each attached to a prominent siphonoglyph. Only the mesenteries of the first cycle are perfect. The mesenteries of the first to third cycles are fertile, whilst those of the fourth and fifth cycles are sterile and without filaments. Acontia are abundant, tightly coiled and present on all of the fertile mesenteries. The longitudinal muscles of the mesenteries are strong. The retractor muscles are strong, diffuse and span half of the distance between the body wall and the filament. They become more restricted closer to the body wall. The parietobasilar muscles are weak and not well differentiated from the mesenterial lamella, and lack a distinct pennon.

Cnidom: Robust and gracile spirocysts, basitrichs, microbasic p-mastigophores.

(Zelnio et al., 2009)

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