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

Clathrina capixaba sp. nov. urn:lsid:zoobank.org:act: A2BA09F3-FABA-44A0-9356-71CA04AD7A13 (Fig 10; Table 7) Etymology: Capixaba is the gentile of who is born in Espírito Santo State. Material examined: Holotype — UFRJPOR 8823, Escalvada Island, 15 m depth, 30.iii.2017, colls. A. Padua and C. Leal. Paratypes — UFRJPOR8810, Escalvada Island, 8 m depth, 29.iii.2017, colls. A. Padua and C. Leal. UFRJPOR 8828, Escalvada Island, 18 m depth, 30.iii.2017, colls. A. Padua and C. Leal. Diagnosis: White Clathrina with regular and tightly anastomosed tubes. Water-collecting tubes present. Two categories of triactines: one with conical actines and sharp tips, while the other category is more abundant and has cylindrical to slightly conical actines and sharp tips. Description: Cormus formed by thin, regular and tightly anastomosed tubes. Water-collecting tubes present. Colour white in vivo and white to beige after fixation (Figs 10A, B). Consistency soft and compressible to the touch. The surface of the tubes is smooth. Aquiferous system asconoid. Skeleton composed of two categories of triactines (Fig 10C). Spicules (Figs 10D–E; Table 7). Triactines I: Regular to subregular. Actines are conical, straight, with sharp tips (Fig 10D). Less abundant than the triactines II. Size: 151.1 (± 15.9)/ 13.7 (± 1.1) µm (N = 20). Triactines II: Regular. Actines cylindrical to slightly conical, straight, with predominantly sharp tips (Fig 10E). More abundant than the triactines I. Size: 101.5 (± 9.3)/ 8.6 (± 1.2) µm (N = 24). Ecology: We have several small specimens attached to octocorals under register numbers UFRJPOR 8823 and 8828. UFRJPOR 8828 was under a rock. Depth range of 8 to 18 m. Distribution: Eastern Brazil ecoregion—Guarapari, Espírito Santo State (type locality; present study). Taxonomic remarks: Four species of Clathrina have only two categories of triactines forming their skeletons and cormus formed by tightly anastomosed tubes as C. capixaba sp. nov.: C. antofagastensis Azevedo, Hajdu, Willenz & Klautau, 2009, C. clara Klautau & Valentine, 2003, C. rotunda Klautau & Valentine, 2003, and C. zelinhae Azevedo, Padua, Moraes, Rossi, Muricy & Klautau, 2017. Differently from C. capixaba sp. nov., C. antofagastensis has no triactines with cylindrical actines. Clathrina clara and C. rotunda also do not present triactines with cylindrical actines, and C. zelinhae has triactines with very different shapes and sizes, the most abundant triactine is cylindrical but much thinner than that of the new species [C. zelinhae: 85.0–95.8 (±5.4)–107.5/ 3.9 (±1.0) µm], while the rare category is conical but much bigger than that of C. capixaba sp. nov. [C. zelinhae: 255.0–271.1 (±13.2)–290.0/ 20.8 (±2.2) µm]. Therefore, we conclude that our specimens represent a new species.