Cinachyrella clavaeformis Fernandez & Rodriguez & Santos & Pinheiro & Muricy 2018, sp. nov.

Cinachyrella clavaeformis sp. nov.

(Figs. 5–7)

Diagnosis. The only species of Cinachyrella with a clavate habit and a disorganized choanosomal skeleton, becoming radial near the surface.

Synonyms. Tetilla sp. 3, Muricy et al. 2006: 139.

Material examined. Holotype MNRJ 5863, REVIZEE Programme sta. Central 5-R42, Espírito Santo State, Southeastern Brazil (20°44’16.8” S, 31°50’01.8” W to 20º44’18” S, 31º50’28.8” W, Columbia Seamount, Vitória- Trindade Seamounts Chain, circa 880 km E off Vitória City), dredging, 80–90 m depth, coll. N.Oc. Astro-Garoupa, 11 July 2001.

Description. Clavate (club-shaped sponge) with a stout base (Fig. 5A); 73 mm high (whole specimen) by 62 mm in diameter (upper region) and 42 mm in diameter (base). Surface strongly hispid, with spicules protruding up to 3 mm high (Fig. 5B). Porocalices, small (up to 4 mm in diameter), hemispherical and randomly scattered on the whole surface (Figs. 5C–E). Color, yellow in vivo, and beige in ethanol. Consistency, hard and almost incompressible.

Skeleton. Radial only near the surface and disorganized in the inner choanosome (Fig. 6A). Tracts of oxeas I and II often perpendicular in upper region, which makes a radial zone of spicules (up to 5000 µm thick); but ectosome not differentiated in a true cortex.

Oxeas protrude up to 3000 µm from the surface. Sand grains and calcareous debris on the surface; with fewer debris in the ectosomal and choanosomal regions. Protriaenes and anatriaenes within the tracts of oxeas in the peripheral radial zone. Choanosome with few small canals (Fig. 6B) up to 250 µm in diameter, and with a few oxeas I and II (most of them broken), microacanthoxeas and sigmaspires scattered throughout the choanosome, (Figs. 6B–D).

Spicules. Megascleres:

Oxeas I (Figs. 7A–B), abundant, relatively stout, slightly fusiform, straight and smooth (slightly curved, strongyloid or styloid forms occur). Extremities, equal and with hastate (more common), telescopic, mucronate or conical tips: 2515–3200–3850/28–37–58 µm.

Oxeas II (Figs. 7C–D), less abundant and thinner than oxeas I, straight and smooth (anisoxea forms less common). Ends, equal or slightly different and with hastate tips: 1085–1780 –2280/ 10–18–20 µm.

Oxeas III (Figs. 7E–F), less abundant than oxeas I and II, thin, curved and smooth. Ends, equal and with acerate tips: 223–253–290/ 6–7–12 µm.

Protriaenes (Figs. 7G–H), common and similar to small plagiotriaenes. Rhabdome, slender (often broken): 1900–2750–3790/ 12–13–14 µm. Cladome, very small, but relatively stout, with short and equal clads. Clads slightly bent, with conical or blunt tips: 19–29–39/ 7–8–12 µm.

Anatriaenes (Figs. 7I –J), common, small (anamonaene forms, rare). Rhabdome, slightly fusiform, slender and flexuous: 3260–5192–7489/ 7–11–14 µm. Cladome, very small, relatively stout, with short and small clads and with blunt or conical tips: 10–15–19 / 5–8–12 µm.

Microscleres:

Microacanthoxeas (Figs. 7K–L), abundant, thin, slightly curved and entirely microspined (many small spines). Ends with bent, mucronate, blunt or conical tips: 100–145–195/2–2.3–3 µm.

Sigmaspires (Fig. 7M), abundant, ‘c’ or ‘s’ shaped and entirely microspined (many small spines): 13–17–28/up to 2 µm.

Ecology and bathymetric distribution. No macrosymbionts were observed in this sponge. The only specimen was collected on a rhodolith bed, at 85 m depth.

Distribution. Known only from the type locality, the Columbia Seamount (Vitória-Trindade Seamounts Chain, off Espírito Santo, Brazil), SW Atlantic (Fig. 1).

Etymology. The species name refers to the clavate habit of the new species (clavae —feminine noun in Latin related to club/stick + formis —noun in Latin related to ‘shaped’).

Remarks. So far, the only known species of Cinachyrella bearing microacanthoxeas in the Atlantic Ocean is Cinachyrella kuekenthali, which is widely distributed in the Tropical Western Atlantic (see our results above; Muricy et al. 2011, and references therein). Cinachyrella clavaeformis sp. nov. also has microacanthoxeas, but it is distinguished from the former species by the clavate habit (vs. semiglobose/subspherical or pear-shaped), the skeleton which is radial at the periphery and disorganized in the choanosome (vs. fully radial skeleton), and by having three categories of smooth oxeas (vs. two categories). The smallest category of smooth oxeas is less than 300 µm in length in the new species, while in Cinachyrella kuekenthali it is larger than 1000 µm in length.

Cinachyrella alloclada, also from the Tropical Western Atlantic has three size categories of smooth oxeas as Cinachyrella clavaeformis sp. nov., but it is devoid of microacanthoxeas and has globular or subspheric/ semiglobular shape (Rützler & Smith 1992; Hajdu et al. 2011).