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Comprehensive Description

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General Description

Description: A large stalked sponge ca. 50 cm high, composed of a rhizoid fixation system, a cylindrical stalk ending in an enlarged, ovoid body from which secondary branches radiate in all directions, each ending in an irregular swelling on preserved specimens or a translucent sphere in living specimens. The fixation base was not preserved, but is estimated to be 6 cm long. The stalk is 24.5 cm high and 5-6 mm in diameter and is rigid, smooth near the base and rugose to the fingers near the body. The stalk is made of longitudinally arranged fusiform style and has a coating of rugose tylostyles. The body is ovoid, 30 x 20 mm in size, with a rugose surface from which radiate 13 secondary axes, each 2-4 mm in diameter and with a maximum length of 50 mm. The secondary axes are somewhat curved and end in an irregular bulge, which often coalesces with one or two of the bulges of the nearby extensions, sometimes forming a veil with the axes. The translucent spheres are of variable diameter, estimated to be between 3-5 mm. Apertures are not visible. The sponge has a rigid consistency, but is easily broken. It is coloured yellowish white to clear brown when preserved in alcohol.

Skeleton: The stalk is made of large fusiform styles arranged in a parallel without any twisting, with a thick cover of rugose tylostyles arranged in a dense irregular feltwork. The cover is devoid of microscleres in the most basal part of the stalk, with a few isochelae 1 near the body. The body and secondary branches have a rugose coating of styles smaller than those of the axis, including numerous microscleres. The bulges have a confused skeleton of fusiform styles, smaller than those in the axis, and an outer cover of extremely numerous microscleres, especially isochelae 1.

Spicules: The styles of the fibres of the body and the stalk are straight, strongly fusiform (e.g. a spicule of 4750 um length has a head of 20 um in diameter and a middle of 75 um in diameter), with a head abruptly shrunken to 20 um long and an acerate tip. Size 700-4750 x 15-75 um.

The styles of the terminal swellings are fusiform, similar to those of the stalk and body, but smaller. Size 510-580 x 17-30 um.

The subtylostyles or tylostyles of the outer cover of the stalk and of the swellings are slightly curved or flexuous, often with a marked oval head, rugose with numerous short spines. Size 300-535 x 5-6 um.

The anchorate isochelae 1 are rare or absent from the stalk, but common in the body and very abundant in the swellings, with six alae at each end. The alae are relatively short, lanceolate, sharp with a well-marked hull on the underside. The shaft is curved, with narrow fimbriae. Size 123-140 um, shaft 6-7 um thick, alae 25 um long.

The anchorate isochelae 2 are rare in the stalk, but moderately abundant in the body and the bulges, with six alae. The alae are rather thick, lanceolate with a sharp point. Size 20-32 um, shaft 2 um thick, alae 10-11 um long.

The sigmas are rare in the body and the stalk, but not seen in the bulges. Size 45-120 x 2-3 um, possibly in two size categories, but with numerous intermediary forms.

(Vacelet, 2006)

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