Tetilla pentatriaena, 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 : 53-57

Tetilla pentatriaena sp. nov.

( Figs 2 , 3 ; Tables 1, 3)

Holotype. UFBA 2048-POR, Camaçari, north of Bahia State, Brazil (12o45’41.61”S – 38o06’12.77”W), 26 m depth, ii.1999, coll. Walter Andrade.

Paratypes. (1) Camaçari, north littoral of Bahia State, Brazil (1247’05.0”S 3806’38.4”W), (same collector and depth as holotype), UFBA 2049-POR, vii.2003; UFBA 2051-POR, UFBA 2052-POR, UFBA 2053-POR, UFBA 2054-POR and UFBA 2055-POR, vii.2005; UFBA 2057-POR, UFBA 2058-POR, UFBA 2059-POR and UFBA 2060-POR, ii.2006; UFBA 2373-POR, UFBA 2374-POR, UFBA 2375-POR, UFBA 2376-POR and UFBA 2377- POR, vii.2007; UFBA 3272-POR, i.2010. Camaçari, north littoral of Bahia State, Brazil (1244’59.7”S 3804’05.5”W), UFBA 2050-POR, 28 m depth, ii.2004, coll. (same collector as holotype). Camaçari, north littoral of Bahia State, Brazil (1247’05.0”S 3807’58.1”W), UFBA 2056-POR, 23 m depth, ii.2006, coll. (same collector as holotype). (2) Salvador, Bahia State, Brasil (12o58’50.6”S 38o22’44.3”W), UFBA 2904-POR, 35 m depth, i.2009, coll. (same collector as holotype). (3) Todos os Santos Bay, Salvador, Bahia State, Brazil (1256’46”S 3830’38”W), UFBA 3877-POR, 19 m depth, iii.2010, coll. (same collector as holotype). Todos os Santos Bay, Salvador, Bahia State, Brazil (1257’12”S 3830’26”W), UFBA 3878-POR, 10 m depth, iii.2010, coll. (same as holotype). Todos os Santos Bay, Salvador, Bahia State, Brazil (1257’43”S 3830’34”W), UFBA 3879-POR (12 specimens), 12 m depth, iii.2010, coll. (same as holotype). (4) Ilha Grande, Camamu Bay, Mara, south of Bahia (13o55’08.8”S 38o59’59.3”W), UFBA 2112-POR and UFBA 2400-POR, 16 m depth, viii.2004, coll. (same as holotype).

Diagnosis. Tetilla pentatriaena sp. nov. is the only species possessing five categories of triaenes, two of choanosomal protriaenes, two of choanosomal anatriaenes, and one of exclusively rhizoidal and quite long anatriaenes (average of 7000 µm).

Description. The shape can vary from spherical to oval, with a single oscule on the apical side of the sponge ( Figs 2 A and C). The body height varies from 3 to 6 mm and the diameter from 1 to 6 mm. On the underside there is a slender rhizoid, generally longer than the sponge body. This structure consists of long spicules surrounded by spongin-like fibres. The consistency of the body is hard, but compressible. The entire surface is quite hispid, with bundles of spicules protruding about 2 mm above, arranged radially and slightly spirally. They feature a light beige color in 80% ethanol. Their color in vivo is unknown.

Spicules. Megascleres: Oxeas I ( Fig. 3A ), abundant, smooth, straight, fusiform, with both ends slender and gradually pointed: 700–1400–2100 μm / 10–16.0–28 μm. Oxeas II ( Fig. 3B ), usually smaller than oxeas I, and sometimes a little thicker. Smooth, slightly curved near the middle region; commonly slightly aniso: 235–650–940 μm / 12–15.0–25 μm. Oxeas III ( Fig. 3C ), smooth, straight, with unequal ends, one slightly conical and the other very thin: 350–590–900 μm / 3.5–6.0–10.6 μm. Protriaenes I ( Fig. 3D ), large, also as prodiaenes. Rhabdome: 1080–1435.5–2880 μm / 6.5–8.0–11.5 μm. Cladi are stout, gradually pointed, with equal lengths: 37– 70.5–151 μm / 1.8 4.6 –10.8 μm. Protriaenes II ( Fig. 3E ), also as prodiaenes. Thin rhabdome: 168–390–560 μm / 0.5–2.5–5.0 μm. Cladi are small, pointed, slender and generally with equally long ends, but sometimes one clade may be larger than the others (usually 1.5 x the smaller ones): 10–20–38 μm / 0.5–1.0–2.5 μm. Anatriaenes I ( Fig. 3F and J), are choanosomal, long rhabdome: 1260–2108 –3528 μm, with variable thicknesses along it: in the insertion point of the cladome, 5.5–8.5–10.8 μm; 70 μm distant from the cladome, 1.5–3.2–7.2 μm; and a third measure further down the rhabdome, 3.0–4.5–7.2 μm. Cladi are stout, pointed, forming an angle of 45–60 with the rhabdome: 11–34.5–54 μm / 3.6–8.0–11 μm. Anatriaenes II ( Fig. 3G and J), are choanosomal, smaller than anatriaenes I, with slender rhabdomes, becoming gradually thinner from the point of insertion of the cladome: 280–526.5–1300 μm / 3.0–4.0– 7.2 μm. Cladi are also more slender in relation to the first category, forming an angle of nearly 90° with the rhabdome, but with their apices bent further down: 11–14.5–36 μm / 1.5–3.5–7.2 μm. Anatriaenes III (Fig. H), are exclusively rhizoidal, presenting cladomes with similar size and morphology as the anatriaenes I, but differing from those by the length of the rhabdome which is over 7000 μm long. Microscleres: small and distorted sigmaspires with microspined surface (Fig. I): 7–10–16 μm.

Skeleton. The skeleton is composed of main tracts of radially and slightly spirally oriented spicules, which develop from the center of the sponge body and reach the ectosome, usually piercing it ( Fig. 2 B). These tracts are spaced by about 40 μm on the inner portion of the choanosome, becoming denser and more closely spaced toward the center of the choanosome and surface, due to a slight expansion in their width. These main tracts are composed mainly by oxeas I and also by anatriaenes I. The latter are abundant and well attached to the tracts. The cladomes of anatriaenes I are clearly seen one above the other, arranged from the inner portion of the choanosome to the surface of the sponge ( Fig. 2 D), with their rhabdomes pointing inward. Anatriaenes II exhibit a similar arrangement as the first category, but are located from the center of the sponge until only the middle portion of the choanosome. Closer to the surface protriaenes I mix up with the main tracts, which are usually abundant and may protrude their cladomes 500 μm beyond the surface. Protriaenes II are abundant and visible on the surface, interspersed to the main tracts. Oxeas II and III are located in the subectosomal region, scattered without an apparent arrangement and located also between the main tracts in the choanosomal region ( Fig 2 E). Sigmaspires are abundant and distributed throughout the sponge body. It is common to find foreign material adhered to the surface, like sand-grains. Also common is the presence of foreign material in the choanosome, but in smaller quantities. The rhizoids are formed mostly by anatriaenes III, with their cladomes in the sediment, thus anchoring the sponge in the soft substrate. The rhabdome of the anatriaenes may be coiled inside the choanosome. There are also small amounts of oxeas I, II and III reinforcing the rhizoids.

Ecology. The collection points on the north coast of Bahia, as well as one located off Salvador, outside Todos os Santos Bay, are in the proximity of sewage outfalls that release organic effluents. In addition to these, another outfall throws inorganic acids and heavy metals nearby; i.e. Millenium submarine out fall. All samples of Tetilla pentatriaena sp. nov. obtained on the north coast originated from the area under the influence of organic waste. The absence of this species in the stretch under the influence of inorganic effluents could not be explained by the nature of substrate, as it is quite similar in both areas, composed by a mix of biodetritic debris with gravel and sand.

In contrast, the collection point in Camamu Bay was located in an estuary, with a considerable supply of freshwater from nearby rivers. However, due to its depth of 16 m, and location near the exit of the bay, it is likely that salt water predominates. Substrate in this area was a mixture of mud and sand. The substrate at Todos os Santos Bay was where found this species similar to that of the north coast.

Etymology. The name pentatriaena refers to the characteristic and unique presence of five categories of triaenes.

Remarks. Tetilla pentatriaena sp. nov. is the only species of Tetilla with five categories of triaenes, two choanosomal protriaenes, two choanosomal anatriaenes, and one exclusively rhizoidal anatriaenes. No species of Tetilla occurring in the Atlantic has more than two categories of oxeas together with two categories of protriaenes or anatriaenes, and one category of sigmaspires. Two of these are Tetilla bonaventura Kirkpatrick, 1902 and T. capillosa Levi, 1967 , both possessing two categories of oxeas and two of protriaenes, but with only one category of anatriaenes. Tetilla nimia ( Topsent, 1927) , also recorded in the Atlantic Ocean, has two categories of oxeas and two of anatriaenes, but only one category of protriaenes. Tetilla euplocamos and T. radiata are recorded from southeastern Brazil, but are both devoid of sigmaspires and therefore differ from Tetilla pentatriaena sp. nov. in this important aspect. Besides this difference, the new species can be distinguished from T. euplocamos and T. radiata by its possession of three categories of oxeas, two of protriaenes and three of anatriaenes, compared to only one category in each spicule type in both previously known species. In comparison with other species of Tetilla in the world, the new species is closer to Tetilla disigmata Levi, 1964 , reported from Indonesia, by sharing three categories of oxeas and two of protriaenes, but it can still be easily distinguished in having three categories of anatriaenes and only one of sigmaspires, in contrast to one category of anatriaenes and two of sigmaspires in the Indonesian species.

Figures

FIGURE 2. Tetilla pentatriaena sp. nov.; A. Holotype, preserved specimen (UFBA 2048 - POR), body with an oval shape and rhizoids at the base. Scale = 1 mm. B. transverse section (from center to surface) showing the radial skeleton. Scale = 500 µm C. the same specimen with a view from another angle; arrow showing contracted apical oscule. Scale = 0.5 mm. D. detail of one of the principal skeletal tracts showing the arrangement of anatriaenes I. Scale = 50 µm. E. detail of the ectosome. Scale = 100 µm.

FIGURE 3. A – H. Spicules of the holotype of Tetilla pentatriaena sp. nov. A. Oxea I, B. Oxea II, C. Oxea III, D. Protriaene I, E. Protriaene II, F. Anatriaene I, G. Anatriaene II, H. Anatriaene III, I. sigmaspire and J. anatriaenes I and II of the choanosome. Scales: A – H = 5 µm, I = 2 µm and G = 10 µm.