Rhodolith beds are structurally complex biogenic habitats recognized as important reservoirs of marine biodiversity, yet their associated sponge fauna remains poorly documented in the Southwestern Atlantic. Here, two new species of the genus Clathria Schmidt, 1862 (Microcionidae) are described from mesophotic rhodolith beds off the coast of Pernambuco, northeastern Brazil. Clathria (Clathria) crassifibra sp. nov., collected at 56?m depth off Recife, is characterized by a thickly encrusting habit, a reticulate choanosomal skeleton, principal styles with microspined heads, a single category of auxiliary subtylostyles, echinating acanthostyles, rare cleistochelae, palmate isochelae, and wing-shaped toxas. Clathria (Microciona) jaboatonensis sp. nov., collected at 51?m depth off Jaboatão dos Guararapes, is characterized by a thinly encrusting habit, a hymedesmioid to confused skeleton, two categories of echinating acanthostyles and cleistochelae, auxiliary subtylostyles with microspined tyles, palmate isochelae, and wing-shaped toxas. Detailed comparisons with morphologically similar Atlantic congeners are provided in the Remarks sections for each species. The predominance of encrusting morphologies in both species is consistent with previous observations of rhodolith-associated sponge assemblages and may reflect adaptations to these biogenic substrates, although the ecological drivers underlying these growth forms remain poorly understood. The discovery of two new species from a limited sampling effort highlights the potential for additional undocumented sponge diversity associated with mesophotic rhodolith beds and underscores the need for further taxonomic surveys in deeper habitats of the Brazilian continental shelf.