Holotype. UFPEPOR 1450, Enseada dos Corais Beach (8 ° 19 ' 23 "S, 34 ° 56 ' 57 "W), Cabo de Santo Agostinho Municipality, Pernambuco State, Brazil, 1 m depth, col. U. Pinheiro and G. G. Santos, (26.XI. 2012). Paratype. UFPEPOR 1628, Baía da Traição Municipality (6 ° 41 ' 19 "S, 34 ° 55 ' 60 "W), Paraíba State, Brazil, 1 m depth, col. G. G. Santos, (07.XI. 2013).
Description (Figure 1). Massive shape with tubular projections, partially fused in the base, large apical osculum (1.5–3 mm in diameter). The holotype is 3.4 cm high, 2.8 cm wide. Individual tubes are approximately 6 mm in diameter. Conulose surface, consistency is compressible and fragile. Color in life is sky blue, and after preservation it becomes beige (Fig. 1 A, B). There is no special ectosomal skeleton but a tangential isotropic unispicular reticulation of oxeas forming tracts 38–80 µm in diameter (Fig. 1 C). The choanosomal skeleton is thick, unispicular, interspersed by many choanosomal spaces and reinforced by pauci- to multispicular tracts 24–72 µm in diameter (Fig. 1 D, E). Spongin is scarce, cementing the tracts and the nodes of the isotropic reticulation. Spicules are oxeas (holotype— 67– 74.5 – 80 / 3– 3.9 – 5 Μm; paratype— 62 – 76.0 – 86 / 2 – 4.0 – 5 Μm) sometimes slightly curved, smooth and with sharp tips (Fig. 1 F).
Distribution and ecology. Known from Northeastern of Brazil (Pernambuco and Paraíba States) in shallow water at 1 m depth.
Etymology. Named caelum which means sky in latin.
Remarks: Cladocroce caelum sp. nov. is the first record of the genus from the South Atlantic. This species is allocated to Cladocroce based on the presence of a choanosomal skeleton reinforced by multispicular primary tracts (De Weerdt 2002). The new species differ from others of the genus by possessing the combination of massive-tubular shape, blue color and generally smaller oxeas (see Tab. 1). Among the Atlantic species it differs from C. fibrosa (Topsent, 1890), based on its vase shaped, grey color and larger oxeas (600 / 18 Μm); C. osculosa Topsent, 1927 which is lamellate in growth form and has brown color; C. spathiformis Topsent, 1904 which is tubular and transparent, with larger oxeas (375 / 17 Μm). Furthermore, these three species are from deeper waters (Tab. 1), whereas Cladocroce caelum sp. nov. was found in shallow water which is unusual for this genus. Three other species of Cladocroce are found in shallow water: Cladocroce burapha Putchakarn et al. (2004) from Thailand, C. reina Aguilar-Camacho & Carballo (2010) from Pacific East Mexico, and C. aculeata Pulitzer-Finali (1982) from the Great Barrier Reef. Cladocroce burapha is tubularramose and has two categories of oxeas; C. reina is thinly incrusting and may have a green color; and C. aculeata is tubular, cream color, and shows a great variety of strongyloid oxeas as well as oxeas with mucronate, hastate and asymmetrical tips. Cladocroce tubulosa Pulitzer-Finali (1993) from the Indian Ocean is also a shallow water sponge and has small oxeas within the range of those of C. caelum sp. nov., but is a yellow tubular sponge. Table 1 summarises the basic details of the other eight species of Cladocroce, all of which are from deep waters and have longer oxeas than C. caelum sp. nov.
Cladocroce reina Pacific East Mexico / 3 Green or sky blue Cushion or Oxeas: 130– 151.7 – 175 / Aguilar-Camacho & thinly-encrusting 5– 6.6 – 7.5 Carballo, 2010 9
Cladocroce spathiformis Azores / 1165 Transparent Tubular Oxeas: 375 / 17 Topsent, 1904 10
References: (1) Pulitzer-Finali (1982); (2) Lehnert & Stone (2013); (3) Putchakarn et al. (2004); (4) Topsent (1892); (5) Hentschel (1914); (6) Levi & Levi (1983); (7) Topsent (1927); (8) Lundbeck (1902); (9) Aguilar-Camacho & Carballo (2010); (10) Topsent (1904); (11) Pulitzer-Finali (1993); (12) Fristedt (1887).