Smenospongia ramosa, Sandes, Joana & Pinheiro, Ulisses, 2014

Sandes, Joana & Pinheiro, Ulisses, 2014, Dictyoceratida (Porifera: Demospongiae) from Tropical Southwestern Atlantic (Northeastern Brazil, Sergipe State) and the description of three new species, Zootaxa 3838 (4), pp. 445-461 : 455-457

Smenospongia ramosa sp. nov.

(Fig. 1–4; Fig. 5; Tab. 3)

Type specimens. Holotype—MNRJ17621, off Pirambu (10º45’36’’S 36º36’08’’W), Sergipe State, Brazil, 20 m depth, coll. Cosme Assis and Damião Assis, July 2003. Paratype: UFPEPOR1627 (same data from holotype) (Fig. 1–4).

Diagnosis. Smenospongia of ramose shape, composed by laminated and uncored primary and secondary fibers 60–70 µm and 20–40 µm wide, respectively.

Description (Fig. 5A–B). Ramose sponge, the holotype is 17 x 1.5 cm (length x width). Conulose surface, with conules 1–3 mm high and 1–3 mm apart from each other. Some depressions on its surface were observed. The oscules are scattered over the surface, less than 1 mm in diameter. The consistency is very soft, spongy, with dark brown color in ethanol.

Skeleton (Fig. 5C–E). The skeleton consists of lamellate and uncored primary and secondary fibers 60–70 µm and 20–40 µm wide, respectively (Fig. 5C). Primary fibers have an axial and granular pith (Fig. 5D). Meshes are oval, circular and polygonal, 50–620 µm in diameter.

Ecology. The specimens were found at 20 m depth.

Geographical distribution. Tropical Southwestern Atlantic, Northeastern of Brazil, Sergipe State.

Etymology. The species name refers to its diagnostic characteristic, the ramose habit.

Remarks. Smenospongia is characterized by the absence of dermal armour, reticulated skeleton of lamellate fibers with distinction between primary and secondary fibers, and surface with honeycomb pattern ( Cook & Bergquist 2002c). This genus consists of seven species, distributed by Caribe, Micronesia and South Africa: Smenospongia aurea ( Hyatt, 1875) ; Smenospongia cerebriformis ( Duchassaing & Michelotti, 1864) ; Smenospongia conulosa Pulitzer-Finali, 1986 ; Smenospongia dysodes (de Laubenfels, 1954); Smenospongia echina (de Lubenfels, 1934); Smenospongia musicalis ( Duchassaing & Michelotti, 1864) and Smenospongia nuda ( Lévi, 1969) (van Soest et al. 2014), of which none are recorded in Tropical Southwestern Atlantic.

Smenospongia has a reticulated skeleton of primary and secondary fibers and very dark color change on death and on exposure to air. These are characteristics of Thorectidae and Aplysinidae , respectively. This debate is widely reported in the literature, since this genus is sometimes included in Aplysinidae (Wiendenmayer 1977, van Soest 1978, Schmitt et al. 2005) and sometimes in Thorectidae ( Bergquist 1980, Cook 2007). Based on morphology, Wiendemayer (1977) and van Soest (1978) described species of Smenospongia including it in Aplysinidae . Bergquist (1980) observed secondary metabolites in Smenospongia that were identical to metabolites of other genera of Thorectidae , but found no brominated compounds in species of Smenospongia . These compounds are shared by all species of the Order Verongida Bergquist, 1978 , although they are also found in other genera outside of this order ( Agelas spp. in van Soest & Braekman 1999 and Jaspis spp. in Kim et al. 1999). However, based on molecular studies, Schmitt et al. (2005) relocated the genus to Aplysinidae , which was contested by Cook (2007), who suggested that Smenospongia should stay in Thorectidae until all species of the genus are reviewed. Here, we prefer to follow the Cook’s proposition ( Cook 2007).

The new species belongs to Smenospongia due to the presence of reticulated skeleton of lamellate primary and secondary fibers, with no foreign debris, and dark brown color when fixed. Smenospongia ramosa sp. nov. is distinguished from all species in this genus by its ramose form. This new species is most similar to S. echina , which differs from S. ramosa sp. nov. due to the presence of cored fibers and black color. The new species resembles S. aurea due to the presence of primary fibers with a dark axial region, without foreign debris, and also differs from S. ramosa by its massive growth form, dark color and large fibers (40–180 µm versus 20–70 µm wide) (Table 3).

F IGURE 5. Smenospongia ramosa sp. nov. (A) Holotype (MNRJ 17621); (B) Paratype (UFPEPOR1627); (C) Reticulated skeleton of isolated spongin fibers; (D) Primary fiber; (E) Secondary fiber. Scale bars: A–B, 1 cm; C, 205 µm; D–E, 21 µm.