Esponjas (Porifera, Demospongiae) indicadoras ambientais na APA Meandros do Rio Araguaia, Brasil
Abstract
A first survey for freshwater sponges was carried out at the protected Amazonian area of
Meandros do Rio Araguaia , at the Brazilian states of Tocantins, Mato Grosso and Goiás.
The survey aimed to sample the largest number of different freshwater habitats from this
Amazonian clear waters area. It was carried out at different GPS registered sampling stations,
during high and low water periods. Water and sediments were also sampled at the same time
aiming to relate sponge occurrences with the measured habitat parameters. For that purpose,
Canonical Correspondence Analysis (CCA) and Non-metric Multidimensional Scaling
(MDS) analysis were carried out over 12 habitat variables. The taxonomic analysis yielded
the detection of the occurrence in this area of 21 freshwater sponge species, with the
description of Heteromeyenia cristalina n. sp and the revision of the genus Heteromeyenia
Potts, 1881, for South America. Heteromeyenia cristalina, Trochospongilla gregaria, T.
paulula, T. minuta, T. lanzamirandai, T. delicata, T. variabilis, T. pennsylvanica,
Radiospongilla amazonensis, Saturnospongilla carvalhoi, Acalle recurvata and Drulia
browni indicated the seasonally flooded ponds and forest, Spongilla spoliata, Trochospongilla
repens, Oncosclera navicella, O. spinifera and Drulia ctenosclera, indicated the rocky
bottoms dwellers, Corvospongilla seckti and Oncosclera navicella were common to both
habitats. Dissolved oxygen concentration, pH, and organic matter were the variables which
indicated species higher richness at the different habitats. The high water variables appeared
as the most important ones, since they favor sponges distribution and production in this area.