Corvospongilla seckti BONETTO AND EZCURRA DE DRAGO (1966)

Tavares-Frigo, Maria da Conceição, Volkmer-Ribeiro, Cecília, Oliveira, Ana Elenice Zanini de & Machado, Vanessa de Souza, 2015, Freshwater sponges from the Pampa Biome, Brazil, with description of a new species of Oncosclera, Neotropical Biology and Conservation 10 (3), pp. 110-122 : 113-114

Corvospongilla seckti BONETTO AND EZCURRA DE DRAGO (1966)

( Figures 2B ; 3B )

Corvospongilla seckti Bonetto and Ezcurra De Drago (1966):133; (1967) ; De Rosa-Barbosa 1988:116- 122; Ezcurra de Drago and Bonetto (1969):366; Tavares et al. 2003:177.

Examined material: BRAZIL, Rio Grande do Sul: Alegrete, EPA of Ibirapuitã, Ibirapuitã River, Estância Sá Brito , 23.III.2011, M.C. Tavares-Frigo and M. Pairet Jr. leg., MCN-POR 8847 ; 27.III.2012, MCN- POR 8912 ; 05.VI.2012, MCN-POR 8931; 20.XI.2012, MCN-POR 8940; 22.I.2013, M.C. Tavares-Frigo, A.E.Z. Oliveira and M. Pairet Jr. leg., MCN- POR 8944 .

The sponge only occurred in one station ( Table 1), situated at the point furthest downstream in the EPA and in deeper locations with no access by foot. It formed crusts on loose stones lying on the flat rocky bottom of the Ibirapuitã River, as well as in rocky pans almost 1m deep, which were sheltered from the current. Due to the greater depth both of the bed and the craters, the sponge occurred in shaded environments. The crusts have a smooth and delicate but compact consistency, with irregular shapes and variable thickness, not exceeding a few centimetres, with brownish to slightly yellowish colouring ( Figure 2B ). Gemmules were present but not conspicuous. The findings indicate occurrence regardless of seasonality. The spicule set corresponds to the original description of the species (Bonetto and Ezcurra de Drago, 1966) ( Figure 3B ).

Remarks: The records of C. seckti represent a continuous distribution from the North (Volkmer-Ribeiro and Tavares, 1993) to the South of Brazil and Argentine waters. The record of C. seckti in the Ibirapuitã River is the second for the Uruguay basin in the State of Rio Grande do Sul, the first being made by De Rosa-Barbosa ( 1984, 1988) in the Ibicuí Mirim River. In Rio Grande do Sul State, the species is abundant in the Jacuí River Basin (De Rosa-Barbosa, 1984).

Figures

Figure 2. Photographs of the living sponge species detected in the Environmental Protection Area (EPA) of Ibirapuitã, southern Brazil. A, Heteromeyenia insignis WELTNER (1895); B, Corvospongilla seckti BONETTO and EZCURRA DE DRAGO (1966); C, Corvoheteromeyenia australis (BONETTO and EZCURRA DE DRAGO, 1966); D, Oncosclera navicella (CARTER, 1881); E, Oncosclera schubarti (BONETTO and EZCURRA DE DRAGO, 1967); F, Oncosclera rosariae n.sp. Bar = 3 cm.

Figure 3. Camera lucida drawings of the spicular sets of sponge species sampled in the Environmental Protection Area (EPA) of Ibirapuitã, southern Brazil. A, Heteromeyenia insignis WELTNER (1895); B, Corvospongilla seckti BONETTO AND EZCURRA DE DRAGO (1966); C, Corvoheteromeyenia australis (BONETTO AND EZCURRA DE DRAGO, 1966); D, Oncosclera navicella (CARTER, 1881); E, Oncosclera schubarti (BONETTO AND EZCURRA DE DRAGO, 1967); F, Oncosclera rosariae n.sp. meg: megascleres; gem: gemmoscleres; gem-1: short gemmoscleres; gem-2: long gemmoscleres; mic: microscleres; mic-1: chaela microsclere; mic- 2: birotulated microsclere). Bar = 50 micrometers.