Plakortis angulospiculatus ( Carter, 1882 )

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 : 16

Plakortis angulospiculatus ( Carter, 1882)

Synonymy and references. Plakortis angulospiculatus ( Carter, 1879) : Zea (1987): 222, fig. 81, pl. 13: 6, 7.

Material. USNM 1228898, Carrie Bow Cay, back reef near reef crest, underside of Acropora palmata coral rubble, 0.3 m; K. Ruetzler col. 23 Apr 1974. USNM 1228899, 1228900 Curlew Bank, forereef cave, 20 m; C. Piantoni col. 28 Jun 2007. USNM 1228901, Carrie Bow Cay forereef cave, 26 m; M. C. Diaz col. 8 Sep 2009.

External morphology. Crustose to cushion-shaped (1–12 mm thick), covering up to 120 cm 2 substratum; with a few small (2 mm), elevated oscula. Surface rough, may be completely covered by another sponge; consistency firm but brittle. Color pale orange to grayish brown and medium-dark brown.

Skeleton structure. Reticulate spicule tracts in the ectosome, densely packed spicules without orientation in the choanosome.

Spicules. Straight, bent, and flexuous diods: 38–300 x 1–10 (165 x 6) Μm; triods generally common, many deformed, with one ray smaller than the others or in odd angles (such as Y-shaped): 53–130 (84) Μm.

Ecology. Under coral plates in the back reef and inside forereef caves, 0.3– 26 m. Tends to be overgrown by other sponges, for instance, Xestospongia deweerdtae (see the description there).

Distribution. Gulf of Mexico and throughout the Caribbean.

Comments. The spicule size range in our specimens is larger than that reported by Zea (1987), close to that given by this author for Plakortis halichondroides (Wilson) , but the latter species is black in color and without triactines. However, recent molecular analyses (cox 1, 100% similarity) suggest that these two morphotypes of Plakortis are conspecific ( Ereskovsky et al., 2013). P. zygompha (described below) can be distinguished in the field by greenish-brown color and it has considerably smaller spicules. Three new species of Plakortis recently described from cave habitats in Jamaica ( Ereskovsky et al., 2013; Table 2) differ clearly in color and spicule characteristics and dimensions; none of them occurred in our samples.