Mycale (Mycale) grandis Gray, 1867

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 : 33-35

Mycale (Mycale) grandis Gray, 1867

( Fig. 21 A–L) ( Tab. 9 )

Examined material. Sample HK 9: Hawai’i, O’ahu Island, Hawai’i Kai, depth between 0.5–3 m, 31 May 2007.

Description. The sponge, about 1 cm thick, grew around the basal portion of a colony of Carijoa riisei ( Fig. 21 A). The examined fragment is a small portion of the colony, 3 cm long ( Fig. 12 B). Consistency is compact, but compressible. The surface is smooth with rare, small, scattered oscules (<1mm). In situ the sponge is vivid red ( Fig. 21 A), grey-beige in formalin ( Fig. 21 B).

Skeleton. Ectosomal skeleton consisting of tangential, intersecting megascleres and scattered microscleres ( Fig. 21 C). Choanosomal skeleton plumoreticulate of multispicular ascending tracts of mycalostyles, opening upon reaching the sponge surface; scarce spongin and scattered microscleres in between ( Fig. 21 D, E).

Spicules. Mycalostyles straight 445 – (537.2 ± 77.8) – 650 x 5 – (11.9 ± 6.9) – 20 µm, slightly curved or sinuous ( Fig. 21 F) without the typical subterminal constriction and sharp pointed extremities. Anisochelae in three size classes. Anisochelae I ( Fig. 21 G), with very long and straight shaft and different extremities, 140 – (146 ± 4.7) – 155 x 10 – (12.2 ± 0.9) – 13.7 µm. The upper alae are arcuate with three teeth (two lateral longer than the frontal); at the other end, only one frontal ala is well developed, while the lateral alae are reduced. Anisochelae II palmate ( Fig. 21 H) with long upper alae and short shaft, 22.5 – (30.1 ± 5.3) – 45 x 2.5 – (2.6 ± 0.8) – 5 µm. Anisochelae III palmate ( Fig. 21 I) with reduced basal alae and a spur, 15 – (18.4 ± 1.5) – 20 µm. Sigmas in two size classes; sigmas I “C” and “S” shaped ( Fig. 21 J), 42.5 – (52.7 ± 5.4) – 62.5 µm; sigmas II “C” shaped ( Fig. 21 K), 7.5 – (16.5 ± 3.2) – 22.5 µm. Raphides in trichodragmas ( Fig. 21 L), 27.5 – (56.3 ± 13.1) – 72.5 µm.

Distribution and remarks. Red Sea, Indian Ocean (van Soest et al. 2011) and Hawai’i ( Coles et al. 1999).

Because of the brevity of the original description, numerous authors considered M. grandis a senior synonym of M. armata Thiele, 1903 (see van Soest et al. 2011). Thiele (1903) did not describe raphides and anisochelae III with the typical spur ( Tab. 9 ); in contrast, our specimen and previous records of M. grandis possess these features. For example Hentschel (1912) described a specimen of M. grandis from Aru Islands ( Indonesia) with a third category of anisochelae, bearing a characteristic spur, that he defined as anisochelae of Iophon ( Tab. 9 ). Pulitzer- Finali (1993) described M. grandis from Kenya with the same spicule complement that was comparable in size to that of the present specimen ( Tab. 9 ).

Anisochelae Sigmas Raphides

Mycalostyles

I II III I II This species was probably introduced to Hawai’i, where it was discovered in 1996 in Pearl Harbor ( Coles et al. 1999). Later it was recorded in other localities of Hawai’i (as Mycale armata, Coles et al. 2006 ); recently Coles & Bolick (2007) noted it is able to aggressively overgrow and smother native Hawaiian corals.

Figures

FIGURE 12. Hymedesmia (Hymedesmia) spinata n. sp. A, Sponge covering a colony of Carijoa riisei in situ (holotype); B, Holotype encrusting several fragments of C. riisei; C, Close up of the sponge showing the octocoral completely encrusted with only polyp openings free; D, Dermal membrane with scattered tornotes and chelae; E, Choanosomal skeleton hymedesmioid with acanthostyle heads on the substrate and scattered tornotes and chelae; F, Isotornote with close up of the acerate tip; G, Strongly spined acanthostyle and detail of the head and the spined tip; H, Acanthostyle with smooth extremity; I, Arcuate chela I; J, Arcuate chela II. (F – J, paratype).

FIGURE 21. Mycale (Mycale) grandis Gray, 1867. A, Specimen on Carijoa riisei; B, Examined specimen; C, Ectosome; D – E, Choanosomal skeleton of multispicular ascending tracts; F, Mycalostyle; G, Anisochela I with close up of the basal extremity; H, Anisochela II; I, Anisochela III; J, Sigmas I; K, Sigma II; L, Raphides in trichodragma.