Mycale (Aegogropila) phillipensis

Mycale (Aegogropila) aff. phillipensis (Dendy, 1896)

Figs 8 a–f

? Esperella phillipensis Dendy, 1896: 15; Topsent 1897: 463.

? Esperella philippensis (sic); Dawydoff 1952: 50 (listed only).

? Mycale philippensis (sic); Chernyakova 2007: 242 (Southern Vietnam, listed only).

? Mycale (Mycale) phillipensis; Azzini et al. 2007: table 1 and fig. 2C (Vietnam, no description).

? Mycale (Aegogropila) phillipensis; Calcinai et al. 2013: 39, figs 24A–H; Minh–Quang Thai: 114 (listed only).

Not: Esperella philippensis; (sic) Lindgren1898: 302; nec: Mycale phillipensis Pulitzer-Finali 1982b (= M. (Carmia) aff. phyllophila Hentschel, 1911)

Material examined. ZMA Por. 13404, Seychelles, Mahé, NE coast, Anse de Forbans, 4.7667°S 55.5167°E, coastal slope, on coral rubble, depth 0–6 m, coll. R. W.M. van Soest, snorkeling, Netherlands Indian Ocean Expedition stat. 612, 12 December 1992 (color greyish blue).

Description. Small irregular patch (Fig. 8a) of a soft sponge, surface bumpy and clathrous. Size 5 x 5 x 0.5 cm, color greyish blue in life, similar in alcohol, consistency soft, slimy in life, soft in alcohol.

Skeleton (Fig. 8b). Weakly developed, with curved tracts lying at greater distance from each other. The ectosomal tangential reticulation has predominantly thin tracts 15–30 µm in diameter, up to 6 spicules in cross section, following sinuous courses and intersecting at unequal angles. Meshes vary from 150 to 450 µm in width. The choanosomal skeleton has few thick tracts, 50–100 µm in diameter, up to 15 spicules in cross section. These lie at distances of 600–800 µm. They are mostly undivided, but at the periphery they fan out into one or a few spicules carrying the ectosomal reticulation. In between the ectosomal and choanosomal tracts there are numerous anisochelae-rosettes of 60–75 µm in diameter.

Spicules (Figs 8 c–f). Mycalostyles, a single category of anisochelae, sigmas in two size categories.

Mycalostyles (Figs 8c,c 1), approximately equidiametrical over much of the length, but with a slightly constricted neck and prominent elongate head; many have a rather bluntly pointed end, 356– 373.6 –414 x 3– 4.2 – 5 µm.

Anisochelae I (Fig. 8d), they are of a common anisochelae I type with well-developed alae at both ends and the shaft free for approximately 40%, with the upper frontal ala slightly flaring outwards, 36– 39.7 – 44 µm.

Sigmas I (Fig. 8e), common, normal shaped, or rather shallowly curved, intermediate between thin and robust (thickness not exceeding 2 µm), 51– 60.7 – 69 µm.

Sigmas II (Fig. 8f), rare (easily overlooked), strongly curved, 9– 11.4 – 16 µm.

Distribution and ecology. Seychelles (Mahé), under reef rubble at shallow depth; South Australia (type locality). Possibly Indonesia, Vietnam (but see below).

Remarks. Dendy’s (1896) description differs primarily from the above in the absence of the smallest category of sigmas, hence our use of ‘aff.’ Still, the small sigmas were rare in our specimen and easily overlooked. The styles were described by Dendy as having ‘rather abrupt, sharp points’, which differs somewhat from the condition observed in the majority of styles in our specimen. Most other details mentioned by Dendy do conform with the Seychelles material.

The present species name has been used by other authors, Topsent (1897) for a specimen from Ambon, Lindgren (1898), Azzini et al. (2007) and Calcinai et al. (2013) for Vietnamese material, Pulitzer-Finali (1982b) for material from Hong Kong. Topsent reported much smaller anisochelae (21 µm), as did Calcinai et al. (12.5–22.5 µm) and both also had thicker styles. We believe that the difference in size of the anisochelae, and in the case of Azzini et al. and Calcinai et al. also the shape, is too large to make conspecificity with Dendy’s species likely. In any case, it is unlikely that Azzini et al. ’s and Calcinai et al.’s specimens are conspecific with our material as their live specimens were (light) red. Lindgren’s and Pulitzer-Finali’s descriptions of the skeleton of their specimens make it clear that these did not belong to the subgenus Aegogropila, but are likely Mycale (Carmia) phyllophila.

The distant original locality of the type of Dendy (Port Phillip Bay, South East Australia) is possibly a reason that all considered specimens have discrepancies and future work should establish whether the species is as widespread as is suggested by current records. We refrain from giving our specimen separate specific status until a revision has been undertaken.