Tetilla rodriguesi, Fernandez, Julio C. C., Peixinho, Solange, Pinheiro, Ulisses S. & Menegola, Carla, 2011

Fernandez, Julio C. C., Peixinho, Solange, Pinheiro, Ulisses S. & Menegola, Carla, 2011, Three new species of Tetilla Schmidt, 1868 (Tetillidae, Spirophorida, Demospongiae) from Bahia, northeastern Brazil, Zootaxa 2978, pp. 51-67 : 63-65

Tetilla rodriguesi sp. nov.

( Figs 6 , 7 ; Table 3)

Holotype. UFBA 2046-POR, Goi Island, Camamu Bay, Mara, south of Bahia State, Brazil, (13o56’01.5”S – 38o59’31.6”W), <5 m depth, viii.2004, coll. W. Andrade.

Diagnosis. Tetilla rodriguesi sp. nov. is devoid of microscleres, has three categories of oxeas, two of trichoidal protriaenes and one of rhizoidal anatriaenes.

Description. The sponge is pear-shaped, 4 mm in diameter and 9 mm in height. At the posterior end there is a rhizoid for attachment of the sponge ( Fig. 6 A). This structure is long and slender, with a length of 13 mm and diameter of 0.5 mm. The consistency of the sponge body is quite soft. Its surface is slightly hispid, except the region near the rhizoids. There are small pores arranged on the side of the sponge, with an average diameter of 150 μm. No oscule was observed. The color of the species was not registered in vivo; and is dark brown after preservation in ethanol.

Spicules. Megascleres, Oxeas I ( Fig. 7 A), straight, smooth, fusiform, with thin ends, larger and thicker than the oxeas II, 648– 1097 –2016 μm / 4.7–8.8–10.8 μm. Oxeas II ( Fig. 7 B), straight and smooth, with one end slightly conical and the other long and quite thin, the latter is flexuous, 294–452–672 μm / 3–3.5–4 μm. Oxeas III ( Fig. 7 C), isoactinal, slight to moderately curved in the middle portion, 130–417–560 μm / 1.8–5.0–7.2 μm. Trichoidal protriaenes I ( Fig. 7 D), larger and thicker than the second category, long rhabdomes tapering gradually from the insertion point of the cladome, 1000–1860–2520 μm / 3.6–4.0–5.5 μm; cladi with similar dimensions, sharp and thinner than rhabdomes, 50–78.8–105 μm / 1.5–1.8–2.0 μm. Trichoidal protriaenes II ( Fig. 7 E), rhabdomes tapering gradually to their points, 154–279–532 μm / 0.5–0.7–1.0 μm; cladomes with thin cladi of similar or different lengths (larger up to 2 x the length of the smaller, sometimes three different lengths); cladi, when these are of equal dimensions, 14.5–36.5–90 μm / 0.4–0.5–0.7 μm. Anatriaenes ( Fig. 7 F), exclusively rhizoidal; rhabdome relatively thin and long, over 6000 μm, provided with three main diameters; the largest one immediately under the insertion of the cladome, 4 μm on average; about 60 μm further along its extension, it quickly thins out to 1.7 μm on average; then reexpanding back to about 3.5 μm; wherefrom it tapers gradually to the point; stout cladome, often strongly curved, cladi with very fine tips, 25–30– 45 μm / 3.0–3.5 – 5.5 μm.

Skeleton. The skeleton is composed of main radial tracts of oxeas I, starting from the center of the sponge toward the ectosome, and often reaching the surface, piercing it 150–200 μm on average ( Fig. 6 B). Oxeas II are intermingled with these bundles close to the ectosome, thus rendering this area denser ( Fig. 6 C). Protriaenes I and II are mixed with the main tracts in the ectosome, usually with their cladomes piercing the surface slightly. Oxeas III occur in the portion between the choanosome and the subectosomal region, do not have a visible arrangement being interspersed in a criss-cross manner with the radial bundles. The choanosome is crossed by canals with a diameter of 100–200 μm. Some foreign particles, such as sand grains, may be found in the choanosome. Microscleres of any kind are absent both in the body and in the rhizoids of the sponge.

Ecology. Tetilla rodriguesi sp. nov. was collected at the northwest side of Goi Island, southwest of Campinho Island, Mara Peninsula. This area is a typical mangrove with muddy substrate, but sandy bottoms are also present in the area. The waters around Goi Island are exposed to large amounts of nutrients as well as a considerable fluctuation of salinity, as a consequence of their proximity to river Mara and other smaller rivers in the area. Although the salinity in this collection point has not been measured, the new species appears to be euryhaline.

Etymology. The name of the new species is a tribute to Professor Sergio de Almeida Rodrigues, who contributed significantly to the science of marine biology in Brazil.

Remarks. Tetilla rodriguesi sp. nov. is devoid of sigmaspires, similar to Tetilla muricyi sp. nov. and the seven other species of the genus mentioned before. This new species shares with Tetilla muricyi sp. nov. the mangrove habitat, but can be distinguished through a series of morphologic traits: the possession by the former of three categories of oxeas, only one of anatriaenes and a strictly radial skeleton. Tetilla muricyi sp. nov. has two categories of oxeas and of anatriaenes, a single category of prodiaenes and a criss-crossed secondary skeleton. The new species differs from Tetilla pentatriaena sp. nov. by presenting a single category of anatriaenes, and by its lack of sigmaspires. Regarding the species that are devoid of microscleres ( Tetilla euplocamos , T. globosa , T. radiata , T. truncata , T. enoi , T. pedifera and T. schulzei ) Tetilla rodriguesi sp. nov. presents a distinct spiculation, the main differences being its three categories of oxeas and mangrove habitat.

Figures

FIGURE 6. Tetilla rodriguesi sp. nov.; A. Holotype; preserved specimen (UFBA 2046 - POR), displaying pear-shaped body and a rhizoid at the base. Scale = 2 mm. B. transverse section (from center to surface) showing the radial skeleton. Scale = 500 µm. C. detail of the ectosome. Scale = 500 µm.

FIGURE 7. Spicules of the holotype of Tetilla rodriguesi sp. nov.; A. Oxea I, B. Oxea II, C. Oxea III, D. Protriaene I, E. Protriaene II and F. Anatriaene. Scale: A – G = 50 µm.