(Figs 2,3; Table 1)
Type locality: Brazil, Maranhão State, Tutóia Municipality, Tutóia beach, Brazil.
Type specimen: Holotype: UFPEPOR 2351, Tutóia beach (02º45’13.000” S, 42º17’16.977” W), Tutóia Municipality, Maranhão State, Brazil, coll. B. Annunziata, R. A. Silva, L. H. O. Souza, 24 July 2017.
Diagnosis. Bush sponge with flattened branches emerging at encrusting base, styles (167–522 / 3–10 µm), subtylostyles (171–488 / 3–10 µm), and palmate isochelae (10–19 µm); toxa absent.
External morphology. Bush sponge emerging at encrusting base, with flattened branches measuring 6.25 x 0.53 cm (7.0– 5.5 cm x 0.8– 0.3 cm) (Fig. 2A). Oscula inconspicuous, hispid surface and soft consistency. Orange color in life, and dark gray in 80% ethanol (Fig. 2B).
Skeleton (Fig. 2C). Choanosomal skeleton with differentiated axial and extra-axial regions: axial skeleton compressed and ascending, extra-axial skeleton plumo-reticulate or confused. Ectosomal skeleton produced by spicules from the extra-axial skeleton forming discrete bouquets of subtylostyles. Styles placed at the axial skeleton and subtylostyles protruding into extra-axial skeleton at acute angles. Palmate isochelae dispersed within choanosome.
Spicules. Megascleres: Styles (167– 396.4 –522 / 3– 7 – 10 µm): smooth, slender straight to slightly curved, with rounded base (Fig. 3A,C); Subtylostyles (171– 354.9 –488 / 3– 5.5 – 10 µm): straight with microspined base, and pointed or mucronate points (Fig. 3B,D); Microscleres: palmate isochelae (10– 15.1 – 19 µm): normal shaft to slightly curved “V”-shaped shaft and short alae (Fig. 3E).
Distribution and ecology. The specimen was found in Tutóia Channel, about 9.5 km from the shore and was collected dragged by fishing nets, in Tutóia beach, Tutóia municipality, Maranhão State, Brazil.
Etymology. From Latin “ aurantius ” referring to its vivid orange color in life.
Remarks. Clathria (Axosuberites) aurantia n. sp. as well as C. (A.) papillata Van Soest, Beglinger & De Voogd, 2013, and C. (A.) riosae Van Soest, 2017 differ from other C. (Axosuberites) species by the absence of toxas. However, the new species has smooth styles and one category of subtylostyles versus microspined styles in C. (A.) papillata and two size categories of subtylostyles in C. (A.) riosae (see Table 1). The main difference between C. (Axosuberites) aurantia n. sp. and C. (A.) pachyaxia (Lévi, 1960) and C. (A.) georgiaensis Hooper, 1996 is the presence of toxas. In addition, there are some differences in the categories of their spicule arrangements and geographic distributions making specificity unlikely (see Table 1). Species of Axosuberites that have more than two categories of megascleres are: C. (A.) benguelaensis Samaai & Gibbons, 2005, Clathria (A.) canaliculata (Whitelegge, 1906), C. (A.) cylindrica (Ridley & Dendy, 1886), C. (A.) flabellata (Topsent, 1916), C. (A.) nidificata (Kirkpatrick, 1907), C. (A.) patula (Hooper, 1996), and C. (A.) thetidis (Hallmann, 1920). Species with much larger isochelae and stout styles are C. (A.) fromontae Hooper, 1996, C. (A.) macrotoxa (Bergquist & Fromont, 1988), C. (A.) marplatensis (Cuartas, 1992) and C. (A.) multitoxaformis (Bergquist & Fromont, 1988). Furthermore, two species show larger megascleres when compared to Clathria (Axosuberites) aurantia n. sp.: Clathria (A.) ramea (Koltun, 1964) and C. (A.) rosita Goodwin, Brewin & Brickle, 2012.