Parasphaerasclera kimberleyensis, Bryce, Monika, Poliseno, Angelo, Alderslade, Philip & Vargas, Sergio, 2015

Bryce, Monika, Poliseno, Angelo, Alderslade, Philip & Vargas, Sergio, 2015, Digitate and capitate soft corals (Cnidaria: Octocorallia: Alcyoniidae) from Western Australia with reports on new species and new Australian geographical records, Zootaxa 3963 (2), pp. 160-200 : 166-169

Parasphaerasclera kimberleyensis sp. nov.

( Figs. 2 C–E, 5, 6; Tabs. 1, 2)

Material examined. Holotype: WAM Z59789, Station 44/K10, Long Reef, northern Kimberley, NW Australia, 13.88867° S, 125.74942° E, SCUBA, depth 10 m, coll. M. Bryce, 20 October 2010. Paratype: WAM Z67195, 1 specimen, same data as the holotype.

Description. The holotype is a digitiform colony, with a wide base, which tapers distally towards the rounded apex of the polyparium ( Fig. 2 C–D). It is 15 mm tall, 2 mm in diameter at the apex and 4 mm in diameter across the holdfast. The colony has no real stalk as polyps occur almost to the very base. The polyp-free basal portion occupies less than 20 % of the total colony length. The polyps are rather sparse and evenly distributed. They are monomorphic, large, and when completely retracted, leave a prominent coenenchymal mound on the surface of the polyparium. All polyps are tightly retracted—as they were at the time of collection—and occupy most of the interior of the polyparium.

The majority of the sclerites from the upper part of the polyparium are tuberculate capstans, some slightly club-shaped, 0.05–0.13 mm long ( Fig. 5 ), along with crosses 0.06–0.08 mm diameter and a few rodlets (see Fig. 5 a). An apparent triradiate sclerite (see Fig. 5 b) has been included to point out where errors are possible, as this is actually the broken end of a sclerite with the fracture side down. The authors believe that the sclerites shown in Fig. 24b–f for E. grayi in Versevedt & Bayer (1987), especially d–f, are most probably of this nature.

The sclerites of the coenenchymal mounds of P. kimberlyensis n. sp. are similarly shaped to those of the polyparium. There are no sclerites in the interior of the polyparium.

The base of the colony is densely spiculated with small radiates and tuberculate rods 0.02–0.10 mm long ( Fig. 6 A). Rare clubs 0.08–0.13 mm long are also represented in the base of the colony (see Fig. 6 Aa). The interior of the base is less densely populated with sclerites, and contains mainly spindles, clubs and irregular forms 0.04–0.15 mm long ( Fig. 6 B). Crosses 0.09 mm in diameter are also present in the interior of the base (see Fig. 6 Bb). The tubercles of all sclerites are ornamented with granules that tend to be elongate and arranged in rows or united to form ridges. This is most obvious in the interior stalk sclerites. Polyp sclerites are absent.

Colour. In situ the colonies were uniformly bright yellow-orange with bright red rounded coenenchymal mounds. The polyp-free base was uniformly bright yellow and the polyps were white. The colour did not change on deck or in alcohol. In preserved specimens the surface and internal coenenchymal sclerites are pale-yellow to colourless, the sclerites of the polyp mounds are red, and the interior coenenchyme is white.

Etymology. Named for the type locality, Kimberley, Western Australia.

Habitat. A steep and fractured fore-reef slope with a near vertical wall ascending from 20 metres to a depth of 4 metres. The wall is heavily pocketed with small caves and deep, steep-sided fissures. At 20 metres there are large rocky outcrops forming long reef-gullies, which are almost devoid of life, probably due to the heavy siltation. Sediment between the rocky outcrops is very fine and smothering. The Parasphaerasclera kimberleyensis colonies were found in a small group attached to the wall in an overhang at ten metres depth amongst other scattered soft corals.

Variability. The paratype is very similar to the holotype in shape, colour, arrangement of polyps and sclerite composition, but is smaller. It is also digitiform, with a wider base and tapering distally towards the rounded apex of the polyparium. It is 9 mm tall, 3 mm in diameter at the apex and 4 mm in diameter across the holdfast ( Fig. 2 E).

Remarks. Parasphaerasclera kimberleyensis sp. nov. does not demonstrate a close resemblance to any currently described species within the genus. Morphologically, it is distinguished by the shape of the colony and the shape and colour of the sclerites, and also by the colony colour, the bright yellow colony being offset by the bright red polyp mounds,,but there is some superficial resemblance to P. zanahoria ( Williams, 2000) , which was originally described from Tonga in the South Pacific. More recently P. zanahoria was recorded from the Great Barrier Reef by one of us (Alderslade, unpublished). Like P. kimberleyensis sp. nov., P. zanahoria , which is uniformly orange, is characterised by having some sclerites in the form of large crosses, but in that species the crosses have finely tapered and acutely tipped rays. In comparison P. kimberleyensis sp. nov. has crosses with thorny, rounded rays, and, in addition, all the radiates are distinctly more thorny than those in P. zanahoria .

Figures

FIGURE 5. Parasphaerasclera kimberleyensis sp. nov., holotype WAM Z 59789, sclerites: surface of the polyparium (a = rodlet; b = broken end of a sclerite with the fracture side down).

FIGURE 6. Parasphaerasclera kimberleyensis sp. nov., holotype, WAM Z 59789, sclerites: A, surface of the stalk (a = club); B, interior of the stalk (b = cross).

FIGURE 2. A, B, Parasphaerasclera grayi WAM Z 54774; C – E Parasphaerasclera kimberleyensis sp. nov. C, D, holotype WAM Z 59789; E, paratype WAM Z 67195.