Anheteromeyenia diamantina sp. nov.

Type locality. Poço Halley, Lençóis, Chapada Diamantina, Bahia State, Brazil.

Material Studied. Holotype. UFPEPOR 2061, Poço Halley, Lençóis, Bahia, Brazil, (12°33’47.9”S 41°23’46.3”W), coll. Calheira, L. 31.xii.2015 . Paratypes. UFPEPOR 2062, coll. L. Calheira, 31.xii.2015; UFPEPOR 2063, 2064, 2065, coll. F. Andrade, 31.xii.2015 (collected together with the holotype).

Diagnosis. One category of megascleres (exclusively smooth oxeas); microscleres absent; acanthoxea and acanthostrongyle gemmuloscleres radially embedded in the gemmular theca, emerging more or less from the inner layer according to their different levels of insertion.

Description of holotype. UFPEPOR 2061 encrusting, less than 10 mm thick. Hispid surface. Oscules inconspicuous. Colour in life green turning creamy white after preservation in ethanol 70%. Consistency soft, compressible and fragile. Spicules. Megascleres oxeas (267–335.1–406 / 10–13.1–16 µm), microscleres absent, gemmuloscleres acanthoxeas (161–172.3–180 / 6–7–10 µm) and acanthostrongyles (100–146–177 / 6–7–10 µm). Gemmules scattered throughout the sponge (567–689.9–867 µm in diameter) (Table 1).

Description. Sponge encrusting to massive. Surface hispid with inconspicuous oscules. Colour green in vivo, creamy white in ethanol 70% (Fig. 2). Consistency soft, compressible and fragile. Spicules. Megascleres oxeas (232–320.3–406 / 8–11.5–16 µm), smooth, straight to slightly curved, gradually pointed (Fig. 3A); microscleres absent; gemmuloscleres acanthoxeas (105–152.2–193 / 5–6.9 –10 µm) (Fig. 3B,D) and acanthostrongyles (77– 123.3–177 / 5–6.6–10 µm), straight shaft, entirely spined with a variable number of spines, usually more abundant and larger at the tips (Fig. 3C,E). Spines straight (predominantly) or curved (rarely), curved ones occur mainly towards the center of the spicule; straight ones in the center of the spicule. Gemmules (533–700.3–867 µm in diameter) abundant, spherical, scattered throughout the sponge body (Fig. 4A, B). Foramen simple, short tube without colar, contained inside a conical concavity of the pneumatic layer (Fig. 4C). Gemmular theca tri-layered: thin inner layer, thick pneumatic layer and inconspicuous outer layer (Fig. 4D). Gemmuloscleres radially embedded in the gemmular theca, emerging from the inner layer according to their different levels of insertion (Fig. 4B).

Ecology. Specimens were collected on rocky substrate in shallow and turbid waters, with depth ranging from 10 cm to 1 m. Gemmules were often abundant.

Etymology. The specific epithet refers to the type locality, at Chapada Diamantina, northeast Brazil.