Cinachyrella strongylophora sp. nov.

(Figs. 8–10, Tab. 2)

Diagnosis. The only species of Cinachyrella with true strongyles.

Synonyms. Cinachyrella aff. kuekenthali, Muricy et al. 2006: 115; Hajdu & Lopes 2007: 354; Muricy et al. 2011: 187 (in part, only specimens from Almirante Saldanha Seamount).

Cinachyrella kuekenthali, Muricy et al. 2006: 115; Hajdu & Lopes 2007: 354; Muricy et al. 2011: 169 (in part, only specimens from Almirante Saldanha Seamount).

Material examined. Holotype MNRJ 6015, REVIZEE Programme sta. Central 6-Y2, Rio de Janeiro State, Southeastern Brazil (22°22’56” S, 37°35’15” W, Almirante Saldanha Seamount, circa 358 km E off Cabo de São Tomé), dredging, 270 m depth, coll. N.Oc. Astro-Garoupa team, 12 June 2002. Paratypes MNRJ 6598, 11976, 11978, 20959, 20960, same collection data as holotype .

Description. Globular sponge (Figs. 8A–G); holotype 35 mm high by 25 mm in diameter; largest paratype, 34 mm high by 33 mm in diameter; smallest paratype, 2 mm high by 1.4 mm in diameter. Surface smooth to slightly hispid, with some calcareous debris. Porocalices small (0.5–5.0 mm in diameter), hemispherical and scattered on the surface. Color orange in vivo, and light beige or brown in ethanol. Consistency very hard and incompressible.

Skeleton. Radial, with main bundles of oxeas I and II reinforced by protriaenes and anatriaenes; radiate tracts from the center to the surface (Fig. 9A); ectosome does not differentiated in a cortex. Oxeas I and triaenes frequently pierce the surface, reaching up to 500 µm in height. Strongyles in tracts or scattered in the ectosome and choanosome (Figs. 9B–C). Microacanthoxeas, sigmaspires and spherules scattered throughout the choanosome and ectosome. Detritus (sand grains and calcareous debris) adhered to the surface and in choanosome.

Spicules. Megascleres (Tab. 2):

Oxeas I (Figs. 10A–B), abundant, stout, fusiform, straight to slightly curved and smooth. Extremities, equal, with telescopic, mucronate, hastate or conical tips (malformations common): 1430–2535 –3375/15–32–55 µm.

Oxeas II (Figs. 10C–D), less abundant, smaller and thinner than oxeas I, fusiform, straight to slightly curved, and smooth. Extremities, equal and with hastate tips: 920– 1370–2025 / 5–10–15 µm.

Strongyles (Figs. 10E–F), less abundant than the oxeas I and II, curved or slightly flexuous and smooth.

Extremities, equal, blunt: 280–385–525/ 5–10–15 µm. Protriaenes (Figs. 10G–H), common, often modified to prodiaenes (more frequently) or promonaenes (less frequently). Rhabdome, thin and flexuous: 1250–2400–4420/2.5–4.5–8 µm. Cladome, small and with short sinuous clads: 10–22–25 /2.5–4–7 µm.

Anatriaenes (Figs. 10I –J), common, often modified to anamonaenes or irregular forms. Rhabdome, slender: 1300–3470–3950/3–5–8 µm. Cladome, small, with thin clads making an angle of approximately 60º with the rhabdome: 8–22–30 /3–4–5 µm.

Microscleres (Tab. 2):

Microacanthoxeas (Figs. 10K–L), abundant, thin, straight, flexuous or angulate, and entirely microspined (many small spines); extremities, gradually pointed and with hastate or acerate tips: 55–83–115/1–2–3.5 µm.

Sigmaspires (Fig. 10M), abundant, thin, ‘s’ or ‘c’ shaped and entirely microspined (many small spines): 10– 15–23 /up to 1.5 µm.

Calcareous spherules (Fig. 9D), abundant, small and irregular: 22–30 µm in diameter.

Ecology and bathymetric distribution. No macrosymbionts were observed. The specimens were collected on soft bottom with rhodolith beds, at 270 m depth.

Distribution. Known only from the type locality, the Almirante Saldanha Seamount, off Rio de Janeiro State, SE Brazil, SW Atlantic (Fig. 1).

Etymology. The name ‘strongylophora’ refers to the presence of strongyles, which is characteristic of the new species.

Remarks. Cinachyrella strongylophora sp. nov. is the third Atlantic species of Cinachyrella with microacanthoxeas. It differs from Cinachyrella clavaeformis sp. nov. and Cinachyrella kuekenthali in the possession of true strongyles, which are unique among members of Cinachyrella as well as Tetillidae . These spicules were previously considered to be simply modifications of oxeas, leading to the erroneous identification of the specimens from Almirante Saldanha Seamount as Cinachyrella kuekenthali and Cinachyrella aff. kuekenthali, (Muricy et al. 2006) . Our revision has shown, however, that the strongyles consistently form a distinct category of spicules, which is characteristic of this species.

Calcareous spherules and nodules have been previously reported in other tetillids: Cinachyrella alloclada, C. arenosa van Soest & Stentoft 1988 (Rützler & Smith 1992), and Levantiniella levantinensis (Vacelet, Bitar, Carteron, Zibrowius & Pérez 2007) . However, their taxonomic value within the Tetillidae still needs to be evaluated.