Aulospongus mandela, Cavalcanti & Santos & Pinheiro, 2014

Cavalcanti, Thaynã, Santos, George Garcia & Pinheiro, Ulisses, 2014, Two new species of Aulospongus Norman, 1878 with a key to the Atlantic species (Poecilosclerida; Demospongiae; Porifera), Zootaxa 3827 (2), pp. 282-292 : 288-290

Aulospongus mandela sp. nov.

( Figures 4–5 , Table 1–2)

Type locality. Brazil, Rio Grande do Norte State, Potiguar Basin .

Type specimens. Holotype. UFPEPOR 1524, Bacia Potiguar (04º 44.8945' S; 036º 25.4571' W), Rio Grande do Norte State, Brazil, depth 108 m, trawl, Bombona 39, col. Petrobras, (23/05/2011) . Paratypes: UFPEPOR 1525, 1526 and MNRJ 17488 (collected together with the holotype); UFPEPOR 1522, Bacia Potiguar (04º 36.7198' S; 036º 46.7554' W), Rio Grande do Norte State, Brazil, depth 140 m, trawl, Bombona 29, col. Petrobras, (22/05/2011); UFPEPOR 1550, Bacia Potiguar (04° 41.2366’ S; 036° 34.9227’ W), Rio Grande do Norte State, Brazil, depth 143 m, trawl, AR53 A, col. Petrobras, (06/12/2009) .

Diagnosis. Aulospongus mandela sp. nov. is the only Aulospongus in the Atlantic with two categories of rhabdostyles, the presence of anisoxeas, and with fan-shaped or vasiform morphology.

External morphology ( Fig. 4A–C ). Fan-shaped or vasiform, 4 x 3 x 0.5 cm (length x height x width), velvety surface ( Fig. 4B–C ) and elastic consistency, not easily torn. The points of the spicules are inside the fibres or protruding externally (as discrete conules) ( Fig. 4C ). Colour in life is unknown and brownish-purple in ethanol. The specimens were collected in the same conditions of Aulospongus trirhabdostylus sp. nov. explained above.

Skeleton ( Fig. 4D ). There is no special ectosomal skeleton. The choanosomal skeleton has fibres and spicule tracts amalgamated into bundles, composed of bulbous spongin fibres cored and echinated by rhabdostyles in plumose tracts, forming individual plumose ascending branches, and terminating as surface lobes.

Spicules ( Fig. 5A–D ). Ectosomal auxiliary anisoxeas (244– 297.9 –366 / 2– 3.4 – 4.8 µm): long, thin, smooth, straight to slightly curved, with distinct ends (one sharply pointed and the other styloid) ( Fig. 5A ); Choanosomal principal rhabdostyles (rhabdostyles I) (146– 186.8 –231 / 5– 10.3 – 15 µm): with a smooth base, microspined (hookshaped spines) from the centre to the apical region, straight to curved and with a slightly curved (rhabd) near the base ( Fig. 5B ); Echinating rhabdostyles (rhabdostyles II) (78– 107.5 –141 / 2– 5.3 – 9 µm): small, usually straight, some spicules are slightly curved near the base (rhabd) and with microspines diffusely distributed, and the basal spines are smaller than others ( Fig. 5C–D ).

Distribution ( Fig. 1 ). Brazil: Northeastern Region: Rio Grande do Norte State: off Bacia Potiguar.

Depth. 108–143 m.

Etymology. This species is named in honor of the Late Nelson Mandela who was a South African antiapartheid revolutionary, politician and President of South Africa.

Remarks. Aulospongus mandela sp. nov. belongs to the genus in having rhabdostyles, and a plumose choanosomal skeleton with fibers ascending to the periphery. Aulospongus mandela sp. nov. differs from other Atlantic species ( A. monticularis , A. phakelloides , A. samariensis , A. spinosus and Aulospongus trirhabdostylus sp. nov.) in the following characters: Aulospongus mandela sp. nov. has two categories of rhabdostyles, while A. trirhabdostylus sp. nov. has three categories. In addition, the former has a fan-shaped or vasiform growth form while the latter has a massive arborescent growth form (see Fig. 3 and 5 ). Aulospongus monticularis has massive to bulbous-encrusting growth form, rhabdostyles I are completely smooth and extra-axial styles are present. Aulospongus phakelloides also has a fan-shaped growth form but lacks anisoxeas. Aulospongus samariensis has a cylindrical or club-shaped growth form, styles, and only one category of echinating rhabdostyles. Aulospongus spinosus has a bulbous shape, raphides, completely smooth rhabdostyles but lacks anisoxeas (see Table 2). The most similar species to Aulospongus mandela sp. nov. is A. involutus ( Kirkpatrick, 1903) from the Indian Ocean, with both species sharing the morphology of rhabdostyles I and vasiform shape. However, the species differ in others aspects: spicules size (see Table 2) and two categories of anisoxeas in A. involutus . Finally, A. involutus is known only from the Indian Ocean, making conspecificity highly improbable.

Figures

FIGURE 1. Location of the studied area, Potiguar Basin, and the collection sites of Aulospongus trirhabdostylus sp. nov. (1) (3) and Aulospongus mandela sp. nov. (1) (2) (3). Collection depths: (1) 108 m; (2) 143 m; (3) 140 m.

FIGURE 3. Spicule composition of Aulospongus trirhabdostylus sp. nov. (UFPEPOR 1517, holotype) in SEM. A, ectosomal auxiliary anisoxea; B, choanosomal principal rhabdostyles; C, echinating rhabdostyles; D, auxiliary rhabdostyles; E–H, details of respectively A–D. Scale bars: A = 40 µm; B = 20 µm; C = 10 µm; D = 20 µm; E–H = 2 µm; E’= 4 µm.

FIGURE 4. Aulospongus mandela sp. nov. (UFPEPOR 1524, holotype). A, preserved specimen; B–C, surface details; D, thick section showing the ectosome and choanosome. Scale bars: A = 1 cm; B = 2 mm; C = 1 mm; D = 500 µm.

FIGURE 5. Spicule composition of Aulospongus mandela sp. nov. (UFPEPOR 1524, holotype) in SEM. A, ectosomal auxiliary anisoxea; B, choanosomal principal rhabdostyles; C, echinating rhabdostyles; D, details of C. Scale bars: A–B = 20 µm; C = 10 µm; D = 5 µm.