Plakinastrella onkodes Uliczka, 1929

Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014, Diversity of sponges (Porifera) from cryptic habitats on the Belize barrier reef near Carrie Bow Cay, Zootaxa 3805 (1), pp. 1-129 : 13-15

Plakinastrella onkodes Uliczka, 1929

( Figure 6 )

Synonymy and references. Plakinastrella onkodes Uliczka, 1929 : Zea (1987): 227, fig. 83, pl. 13: 9.

Material. USNM 1228890, Carrie Bow Cay, back reef near reef crest, underside of Acropora palmata coral rubble, 0.3 m; K. Ruetzler col. 23 Apr 1974. USNM 1228891, Carrie Bow Cay reef flat, under Porites porites and Acropora cervicornis coral rubble, 0.5 m; K. Ruetzler col. 29 Jan 1986. USNM 1228892, 1228893 Curlew Bank, forereef cave, 20 m; C. Piantoni col. 29 Jun 2007. USNM 1228894 Curlew Bank, forereef cave, 20 m; C. Piantoni col. 2 Jul 2007. USNM 1228895, Carrie Bow Cay South, back reef, lower surface of rock slab, 1 m; K. Ruetzler col. 13 Mar 0 9. USNM 1228896 Curlew Bank, forereef slope framework cave, 20 m; C. Piantoni & M. Parrish, col. 22 Aug 2012. USNM 1228897 Curlew Bank, forereef slope framework cave, 18 m; C. Piantoni & M. Parrish, col. 23 Aug 2012.

External morphology. Encrusting, 4–20 mm thick, with a few oscula (up to 2 mm diameter) irregularly dispersed, some elevated on cone-shaped lobes. Horizontal spread to about 30 cm 2; parts of the body may be covered by crustose coralline algae. Surface slightly rough to the touch, consistency tough elastic. Color cream, orange, bluish or blackish brown; no dark exudates upon preservation.

Skeleton structure. The ectosome shows a dense reticulation of small diactines (diods), some protruding brush-like from the surface. The choanosome is also very dense with spicules, some in mesh-like formation, many without specific orientation.

Spicules. Diods occur in a great size range, most with the characteristic (for the group) kinks or swellings at or near the center: 20–175 x <1–8 (92 x5) Μm. They are accompanied by delicate triods and more robust calthrops; triods: 35–75 (57) Μm; calthrops: 35–75 (51) Μm. Despite similar overall size and lengths of rays, the bases of rays average 4.8 Μm in triods, 6.2 Μm in calthrops.

Ecology. On the lower surfaces of back-reef coral plates and rubble and inside forereef caves, 0.3– 20 m.

Distribution. Common throughout the Caribbean region.

Figures

FIGURE 6. Plakinastrella onkodes, spicules (SEM): a, diods; b, triods; c, calthrops.