Zyzzya criceta Schonberg 2000

Zyzzya criceta Schönberg, 2000

Synonymy. None known.

Material examined. Zyzzya criceta: KDS-BF-01, slide of discarded sponge kept at VUW, sponge from north of Kaledupa, Wakatobi, Banda Sea, sampled between March and August 2014, 3– 20 m, coll. J. Marlow. KDS-BF-02, slide of discarded sponge kept at VUW, sponge from north of Kaledupa, Wakatobi, Banda Sea, sampled between March and August 2014, 3– 20 m, coll. J. Marlow. K1-BF-01, slide of discarded sponge kept at VUW, sponge from north of Kaledupa, Wakatobi, Banda Sea, sampled between March and August 2014, 3– 20 m, coll. J. Marlow. QM G313370, Zyzzya criceta Schönberg’s (2000) holotype from Orpheus Island, central Great Barrier Reef, Coral Sea, sampled 7. July 1997, 0.5 m, coll. C. Schönberg, examined by use of duplicate spicule slide in CS’s personal collection.

Morphology and erosion. Separate fistules in alpha-morphology. Very dark green, appearing black underwater, choanosomal tissue dark green/grey. Colour of ethanol-preserved specimens dark brown. Fistules 1 mm in diameter, rising 2–7 mm above substrate surface (Fig. 9A). Erosion as numerous small and irregularly sized chambers (crosssectional area 4.2 mm 2 ± 2.3 SD), interconnected, often occupying entire piece of rubble (Fig. 9B).

Skeletal characteristics and presence of Symbiodiniaceae. Fistular tylotes arranged parallel to surface in ectosome, and irregularly distributed in choanosome. Fistular acanthostrongyles rare, irregularly dispersed. Acanthostrongyles far more abundant in erosion chambers and choanosome, outnumbering tylotes, again irregularly dispersed. No evidence for photosymbionts, neither by surface fluorescence, nor through histology.

Spicules. Megascleres—Abundant acanthostrongyles and terminally microspined tylotes of the same length. Acanthostrongyles softly curved, with regularly spaced, but irregularly distributed spines (not in rings), spine tips oriented towards middle of shaft. Variable spine distribution, either covering entire spicule or more concentrated in apical thirds (Fig. 9C). Acanthostrongyle dimensions (min – mean – max and standard deviation): length 181 – 223.5 – 250 µm ± 12.3 SD; and shaft width 8 – 13.1 – 17 µm ± 2.0 SD (means across three Wakatobi specimens, with N = 25 spicules each). Tylotes slender, with microspined tyles (Fig. 9D). Tylote shafts predominantly straight, but occasionally slightly bent (Fig. 9E). Tylote dimensions (min – mean – max and standard deviation): length 171 – 220.2 – 274 µm ± 23.5 SD; shaft width 4 – 5 – 7 µm ± 0.7 SD; and tyle width 4 – 5.5 – 8 µm ± 1.0 SD (means across three Wakatobi specimens). No microscleres found.

Habitat and occurrence in Wakatobi. Very rare; only found in coral rubble at shallow depth (5–7 m) at two low turbidity/high flow sites.

Remarks. The World Porifera Database presently accepts five valid species of Zyzzya (van Soest et al. 2021): Zyzzya coriacea (Lundbeck, 1910), Zyzzya criceta Schönberg, 2000, Zyzzya fuliginosa (Carter, 1879), Zyzzya invemar van Soest et al., 1994b, and Zyzzya papillata (Thomas, 1968). Comparing these to our samples, four species were readily discounted based on their morphology and occurrence, and the Wakatobi material was identified as Zyzzya criceta.

Lundbeck’s North Atlantic Zyzzya coriacea appears to be an endopsammic species.Unlike the Wakatobi material, alcohol-preserved specimens of Zyzzya coriacea are pale-violet, have branching fistules, and the acanthotylotes are longer than the tylotes, strongly size variable and considerably longer than in the Wakatobi samples. Zyzzya papillata is endolithic-fistulate, but yellow, while the Wakatobi specimens were blackish green. In Zyzzya papillata, the acanthostrongyles are only about half as long as the microspined tylotes, while they are of similar length in the Wakatobi samples. Zyzzya invemar is similar to the Wakatobi material in fistule size, however, unlike in the Wakatobi samples the acanthostrongyles have regular rings of spination, and the acanthostrongyles and tylotes are again of a different size. Moreover, Zyzzya invemar has microscleres, none of which have been found in the Wakatobi samples. Zyzzya fuliginosa is often described as being black and could therefore be confused with Zyzzya criceta. However, unlike Zyzzya criceta, but like most other Zyzzya species, it has microspined tylotes that are longer than the acanthostrongyles. Spicule dimensions provided for Zyzzya fuliginosa spicules vary widely in the literature (Carter 1879, Dendy 1922, Hooper & Krasochin 1989, van Soest et al. 1994 b, Schönberg 2000), but the size difference between the two spicule types has been uniformly reported and precludes the identification of Wakatobi sponges as Zyzzya fuliginosa.

Zyzzya criceta is a Pacific sponge, with characteristic dark green (almost black) fistules, which can be bulbous or elongate (Schönberg 2000). To date, Zyzzya criceta is the only Zyzzya species described as having two megasclere types of similar length. This is congruent with the present samples. Unlike the Great Barrier Reef specimens, the Wakatobi sponges were not observed in beta growth, but this can be explained by the small size of the specimens that were found in coral rubble, i.e. in a detached material of limited size. Overall, the match with Zyzzya criceta appears to be very good. The present findings represent a new record and extend the distribution from the central Great Barrier Reef to the Banda Sea, Indonesia.