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.