Cliona cf. mucronata Sollas, 1878

(Tables 1–2, 6; Figures 9A–F)

Studied material: MNRJ 21505, P.M. M. Recife de Fora (16°24.294′ S, 38°59.143′ W, Porto Seguro, BA, Brazil), intertidal, coll: Hajdu, E. & Avelino, D., 21 st April 2019 .

Description. Encrusting small cavities in a boulder. Only a few rounded spots, up to 1.5 mm in diameter. Color in vivo not recorded, and beige in fixative (Tab. 6; Fig. 9A).

Skeleton. Overall confused and with a low density of spicules, with the notable exception of dense, perioscular, palisade-like arrangements (Figs. 9B–C). Several colored rounded cells throughout the ectosomal (mainly) and choanosomal regions (Fig. 9D).

Spicules. Megascleres only (Tab. 6; Figs. 9E–F): tylostyles I, larger, slender, with pronounced head and sharp apex, 77–135.1–162 x 2.3–5.0–7.6 µm; and tylostyles II, smaller, stouter, with pronounced head and mucronated apex, 60–87.8–112 x 4.5–7.4–12 µm.

Distribution. The type locality is unknown. Previously Indian Ocean (Gulf of Manaar— Thomas 1972, 1975; Madagascar — Vacelet et al. 1976; Mozambique — Thomas 1979), Indonesia (Desqueyroux-Faúndez 1981), Tropical Eastern Pacific (Mexico — Bautista-Guerrero et al. 2006), Caribbean (Belize — Ŗtzler et al. 2014, as C. cf. m.), Pacific Central America (Costa Rica, Panama — Pacheco et al. 2018, as C. aff. m.). New record—Southwestern Atlantic (Costa do Descobrimento, BA, Brazil).

Ecology. Excavating limestone substrate underneath a specimen of Prosuberites laughlini, which has been described in the present study, see above.

Remarks. A detailed study of the boulder excavated by this sponge failed to spot the species on the substrate. Rather, it is visible in cavities in the substrate, analysed under light-microscopy. A few structures similar to oscules were observed (ca. 0.5–1.5 mm diam.), but these only appear in thick sections of the skeleton.

The species had been previously collected in the southwestern Atlantic (Brazil), but had not been formally described (Dr. C.V. Leal, unpubl. res.). The specimen reported upon here presents megascleres matching more closely Indian Ocean (Thomas 1972; Vacelet et al. 1976), Indonesian (Desqueyroux-Faúndez 1981) and Pacific Mexican (Bautista-Guerrero et al. 2006) specimens in dimensions, but the apparent absence of any microscleres is shared only with the latter two. Despite C. mucronata’ s and C. cf. mucronata ’s seemingly discontinuous distributions, similar patterns were already demonstrated for Cliona celata Grant, 1826 (Xavier et al. 2010; de Paula et al. 2012) and C. viridis (Schmidt 1862; in Leal et al. 2016) and are thus not entirely unlikely.