Calthropella Corticellopsis

Van Soest, Rob W. M., Beglinger, Elly J. & De Voogd, Nicole J., 2010, Skeletons in confusion: a review of astrophorid sponges with (dicho-) calthrops as structural megascleres (Porifera, Demospongiae, Astrophorida), ZooKeys 68, pp. 1-88 : 65

Calthropella Corticellopsis Figs 33 A–C

Material examined.

ZMA Por. 10525, Seychelles, Mahé, Cap Maçons & Anse de Forbans, 4.7667°S; 55.5167°E, 0-6 m, NIOP Expedition stat. 612, coll. R.W.M. Van Soest, nr. 612/20, 12 December 1992.

Description.

Cartilaginous crust on a piece of dead coral, surface smooth, size 2 ×1× 0.5 cm. Greyish black alive, pale brown in alcohol.

Skeleton: with low spicular density, predominantly consisting of calthrops.

Spicules: Calthrops, euasters in two categories.

Calthrops (Fig. 33A) small, often with one cladus longer than the other (short shafted triaene), 30 –99.2– 195 × 4 –8.4– 11 µm, cladomes 46 –128.7– 255 µm.

Oxyspherasters (Fig. 33B), multirayed, rare, 9 –12.3– 18 µm.

Small oxyasters (Fig. 33C), approx. 10 rayed, without center, appear faintly tylaster-like, 6 –7.6– 11 µm.

Habitat.

Encrusting dead corals in shallow water.

Distribution.

Known only from a single locality south of Victoria, Mahé.

Remarks.

We refrain from naming this material due to the rarity of its microscleres. By its small sized calthrops this is a distinct species, as no matching descriptions appear in literature dealing with Calthropella s.l. The oxyspherasters were quite rare, and they could not be detected in any of the thick sections, whereas the small oxyasters were only marginally less rare, so there is a possibility that they are not proper to this sponge. The cartilaginous nature and low spicular density of the specimen reminded of Dercitus rather than of Calthropella , but we did not find sanidasters.

Nominal Calthropella species excluded from the genus