Clathrina albata Lopes, Padua, Azevedo & Klautau, 2025, sp. nov.

Clathrina albata sp. nov. urn:lsid:zoobank.org:act: 67D256C9-BBE5-4CCE-A465-87FFEEDEB9AE (Fig 9; Table 6) Etymology: From the Latin albatus (= “clothed in white”), because of the bright white colour of this species. Material examined: Holotype — UFRJPOR 8808, Escalvada Island, 8.3 m depth, 08.iv.2017, colls. A. Padua and C. Leal. Diagnosis: White Clathrina with regular and tightly anastomosed tubes. Water-collecting tubes absent. Skeleton composed of tripods and two categories of triactines. Spicules always with sharp tips. Description: Cormus encrusting, formed by thin, regular and tightly anastomosed tubes. Colour white when alive and after fixation (Figs 9A, B). Oscula spread on the surface, without water-collecting tubes. Consistency friable and uncompressible to the touch. Surface of the tubes smooth. Aquiferous system asconoid. Skeleton composed of tripods and two different categories of triactines (Fig 9C). *From Fonseca et al. (2023). Spicules (Figs 9D–F; Table 6). Tripods: Regular. Actines strongly conical, stout, straight, with sharp tips (Fig 9D). Rare. Size: 186.1 (± 55.7)/ 31.0 (± 7.2) µm (N = 14). Triactines I: Regular. Actines cylindrical to slightly conical, straight, with sharp tips (Fig 9E). Most abundant category. Size: 105.7 (± 15.4)/ 9.9 (± 1.2) µm (N = 20). Triactines II: Regular. Actines conical, straight, with sharp tips (Fig 9F). Very small in size, resembling young triactines. However, they are common; hence, we considered them as a different category. Size: 46.6 (± 8.5)/ 5.4 (± 1.3) µm (N = 20). Ecology: The specimen inhabited cryptic and shaded environments, colonized mostly by algae, hydrozoans, and other sponges. Distribution: Eastern Brazil ecoregion—Guarapari, Espírito Santo State (type locality; present study). Taxonomic remarks: Three species of Clathrina have tripods in the skeleton: Clathrina clara Klautau & Valentine, 2003, Clathrina robusta Fonseca, Cóndor-Luján & Cavalcanti, 2023, and Clathrina rotunda Klautau & Valentine, 2003. Besides the tripods, C. clara and C. rotunda have one category of triactines, whereas C. albata sp. nov. has two categories differing in shape and size. Moreover, C. clara and C. rotunda have water-collecting tubes, while the new species does not, and the triactines I of C. clara and C. rotunda are conical, while in C. albata sp. nov. it is cylindrical to slightly conical. Morphologically, Clathrina robusta is the most similar species to C. albata sp. nov. with only subtle differences. The tips of the spicules are blunt to sharp, while in our new species they are always sharp. Besides, although in the original description it was said that C. robusta did not present water-collecting tubes, it is possible to recognise them on the picture (Fonseca et al. 2023). This is another difference, as the new species does not have water-collecting tubes. Considering molecular data, they are also distinct species. Clathrina albata sp. nov. and C. robusta were present in separate clades in our C-LSU tree (we do not have ITS sequences for the new species). The new species was sister of C. capixaba sp. nov., and C. robusta was sister of C. helveola + C. wistariensis (Fig 2). Hence, the p-distance between C. albata sp. nov. and C. robusta was 3.3%.