Eurypon clavilectuarium sp. nov.

(Figs 1–3; Table 1)

Type specimens: UFPEPOR 1534 (Holotype), Bacia Potiguar (04º 44.8945' S, 36º 25.4571' W), Rio Grande do Norte State, Brazil, depth 108 m, trawl, Box 37, col. Petrobras, (23.V.2011).

Diagnosis. Eurypon clavilectuarium sp. nov. is the only Eurypon described from the Atlantic with large choanosomal subtylostyles (1200–2000 µm long), and raphidiform styles (440 µm long).

External morphology (Fig. 2 A–B). Encrusting sponge (in calcareous nodules), up to 1 mm thick. Oscules not visible. Surface hispid due to evenly distributed projecting spicules. Consistency is fragile. Color in life is unknown and brownish-purple in ethanol. However, the specimens were collected in the same drag as Aiolochroia crassa (Hyatt, 1875) and stored in the same container. It is possible that the A. crassa pigments stained the Eurypon specimens (as also reported for a specimen of Aulospongus by Cavalcanti et al. 2014).

Skeleton (Fig. 2 C). Skeletal structure is hymedesmioid composed by long subtylostyles, two categories of echinating acanthostyles and raphidiform styles with their bases embedded in basal spongin and points protruding a long way through the surface, forming a dense erect palisade on the basal spongin.

Spicules (Fig. 3 A–G). Choanosomal subtylostyles (Fig. 3 A, E): long, smooth, slender, slightly curved and with bulbous to styloid base (1200–2000 / 8–24 µm); Acanthostyles I (Fig. 3 B, F): varying from straight to slightly curved, with lightly bulbous base, short and curved spines (hook-shaped spines) more concentrated in the middle and apical part of spicules. Spination along the shaft is very sparse (195–600 / 7–17 µm). Acanthostyles II (Fig. 3 C, G): straight, fusiform, base frequently styloid, totally microspined (spines are always recurved and arranged the same as previous category) (72–114 µm); Raphidiform styles (Fig. 3 D): long, smooth, with styloid base, slender, ranging from straight to curved, some sinuous (260–439 / 1.9–3 µm).

Distribution (Fig. 1). Northeastern coast of Brazil, Rio Grande do Norte State, Brazil.

Depth. 108 m.

Etymology. The species is named clavilectuarium (clavus = nail, lectuarius = of a bed), due to the long spicules perpendicular and projecting from the basal spongin on the substate, resembling a bed of nails.

Remarks. The new species belongs to the genus by the presence of choanosomal subtylostyles, echinating acanthostyles, subectosomal raphidiform styles, and an encrusting habit. Eurypon clavilectuarium sp. nov. is the unique species of the genus from Atlantic which has large choanosomal subtylostyles (1200–2000 µm) and raphidiform styles (439 µm). The presence of two categories of acanthostyles in E. clavilectuarium sp. nov. differs the following species from Atlantic: E. cinctum Sarà, 1960; E. clavatella Little, 1963; E. coronula (Bowerbank, 1874); E. fulvum Lévi, 1969; E. lacazei (Topsent, 1891); E. lictor (Topsent, 1904); E. major Sarà & Siribelli, 1960; E. obtusum Vacelet, 1969; E. radiatum (Bowerbank, 1866); E. toureti (Topsent, 1894); E. viride (Topsent, 1889) . Except for E. radiatum, all of these species present tylostyles which are not found in E. clavilectuarium sp. nov. In addition, the following species differ by the presence of oxeas ( E. denisae; E. cinctum; E. fulvum; E. major; E. obtusum); tornotes ( E. lacazei; E. lictor; E. mucronale); isochelae ( E. toureti); and raphides ( E. viride) (see character list in Table 1).