Biemna fistulosa ( Topsent, 1897 )

Calcinai, Barbara, Bavestrello, Giorgio, Bertolino, Marco, Pica, Daniela, Wagner, Daniel & Cerrano, Carlo, 2013, Sponges associated with octocorals in the Indo-Pacific, with the description of four new species, Zootaxa 3617 (1), pp. 1-61 : 30

Biemna fistulosa ( Topsent, 1897)

( Fig. 19 A–I) ( Tab. 8 )

Examined material. Sample HK 11: Hawai’i, O’ahu Island, Hawai’i Kai, depth between 0.5–3 m, 31 May 2007; sample HK 12: Hawai’i, O’ahu Island, Hawai’i Kay, depth not stated, 31 May 2007; sample HK 13: Hawai’i, O’ahu Island, Hawai’i Kai, depth not stated, 31 May 2007.

Description. The HK 11 specimens grew in massive forms around the axis of seven small portions of Carijoa riisei , up to 5 cm long. Specimen HK 13 consists of a small fragment that is very badly preserved, covering a colony of C. riisei . Specimen HK 12 produced long fistules, encrusting the axis of the coral ( Fig. 19 A, B). Only a small portion of this specimen was examined. It covers a small colony of C. riisei about 7 cm long, with a small portion of a fistula. The fistula has a thin wall and smooth surface. The sponge is fragile and breaks easily. In situ the sponge is yellow ( Fig. 19 A), pale yellowish when preserved.

Skeleton. Ectosomal skeleton absent, only a thin membrane with detritus and pigmented cells. Choanosomal skeleton plumoreticulate with multispicular tracts running towards the surface ( Fig. 19 C); groups of raphides are visible scattered in the choanosome. Specimen HK 11 has a more regular reticulum.

Spicules. Styles, with a slight curve in the basal part of the axis, and with regular head ( Fig. 19 D), 295 – 370 x 5 – 12.5 μm. Microxeas in two categories: microxeas I smooth and with different extremities ( Fig. 19 E), 82.5 – 117.5 x 2.5 μm; microxeas II with one smooth extremity and the other microspined ( Fig. 19 F), 20–43.7 μm. Raphides with spines oriented towards one extremity ( Fig. 19 G), 87.5–125 μm. Sigmas “C” and “S” shaped with spined extremities and in a single category ( Fig. 19 H), 12.5–50 μm. Commas rare, sinuous and microspined, with spines directed towards the larger extremity ( Fig. 19 I), 22.5–37.5 μm. Refer to Tab. 8 for complete measurements. Distribution and remarks. Ambon ( Topsent 1897; Desqueyroux-Faúndez 1981), Hong Kong ( Pulitzer-Finali 1982), East Africa ( Pulitzer-Finali 1993) and Hawai’i ( Coles et al. 1999).

This species is well characterised by its spicule complement with commas and two kinds of microxeas. The specimen recorded from Hawai’i agrees with the previous records of this species in the size and the shape of spicules. Topsent (1897) described B. fistulosa as a fragile sponge with reticulate skeleton; spicules are styles, more or less curved, especially in the apical part (300 – 330 x 8 μm), sigmas very numerous, in two sizes (58 x 2 μm and 15 x 1 μm), two kinds of microxeas (33 x 1 μm and 105 x 3 μm) and raphides (110 μm). Commas were not originally described, but later recorded by the same author (Topsent 1913) in the type material.

Figures

FIGURE 19. Biemna fistulosa (Topsent, 1897). A, Sponge growing on Carijoa riisei in situ; B, specimen HK 12 encrusting the axis of the coral; C, Choanosomal skeleton; D, Style; E, Microxea I; F, Microxea II with magnified microspined tip; G, Raphide with magnified tips; H, Sigma with magnified microspined extremity; I, Comma with magnified larger, microspined extremity.

Tables

TABLE 8. Spicule dimensions in µm of Biemna fistulosa (Topsent, 1897).

	Styles	Raphides	Microxeas I II	Sigmas	Commas
HK11	295 – (335.9 ± 19.3) – 355 x 7.5 – (10.2 ± 2.3) – 12.5	100 – (106.5 ± 4.6) – 112.5	87.5 – (103.6 20 – (29.8 ± ± 8.4) – 122.5 5.9) – 40	15 – (31.5 ± 9.6) – 45	30 – (32.5 ± 3.5) – 37.5
HK12	315 – (339.7 ± 14.6) – 370 x 10	102.5 – (109.8 ± 5.1) – 117.5	90 – (109.8 ± 22.5 – (32.3 10.1) – 125 ± 4.9) – 37.5	12.5 – (27.2 ± 10.5) – 50	27.5 – (30.8 ± 4.1) – 37.5
HK13	270 – (325 ± 24.8) – 355 x 5 – (9.5 ± 2.7) – 12.5	90 – (109.8 ± 9.6) – 120	100 – (105.7 ± 25 – (30 ± 5.5) – 115 3.4) – 35	12.5 – (29.6 ± 11.3) – 45	ca. 30