Dercitus Stoeba

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 : 30-31

Dercitus Stoeba

Dercitus sp. Kobluk and Van Soest 1989: 1211.

Material examined.

ZMA Por. 08985, Netherlands Antilles, Bonaire, W coast, near Kralendijk, in reef caves, 12-43 m, 12.15°N; 68.278°W, 1984, coll. D.R. Kobluk.

Description.

Insinuating in coral crevices, in reef caves between 10 and 40 m depth. The available sponge material has been 'used up’ entirely for the initial slides from which the genus identification (as Dercitus ) was made. Properties of the sponge and structure of the skeleton cannot be accurately described. The skeleton is a confused, dense mass of calthrops megascleres on the outside covered by a layer of microscleres. These are also common throughout the sponge body. Spicules are simple calthrops and sanidasters.

Calthrops regular, with four equal cladi, which may occasionally be curved; endings occasionally bifid or irregularly terminally knobbed, but no true dichotriaene nor triactine modifications are present; sizes highly variable, cladi 39 –102.3– 186 × 4 –9.8– 16 µm, cladomes ranging 58 –159.7– 288 µm.

Sanidasters, thin, 12 –14.8– 18 × 0.5 –0.76– 1.5 µm.

Habitat.

In reef caves at the deeper parts of fringing reefs.

Remarks.

Kobluk and Van Soest (1989) reported a few oxeas of 600 µm length, which are here considered foreign, and 'dichotriaene-like variations’ by which they meant the calthrops with bifid cladi, not to be confused with true dichocalthrops. Since no proper specimen was left, no SEM observations of the spicules of this species could be made. It is likely that it is an undescribed species. It differs from Central West Atlantic Dercitus (Stoeba) latex (Moraes & Muricy, 2007) in habit (encrusting in latex), and spicule size (calthrops cladi larger, up to 212 × 25 µm, and sanidasters smaller, up to 15 × 1 µm). Dercitus (Stoeba) bahamensis sp. n. likewise is encrusting and it has dichocalthrops and thicker sanidasters (see above).