The protected area "Meandros do rio Araguaia" encompasses a stretch of the river Araguaia with its complex network of seasonally flooded meanders and tributaries. A survey was undertaken aiming to set the background for a future correlation of the sponge fauna with some of the distinct aquatic habitats and their physical, chemical and productivity characteristics, as well as with the spicule contents in their sediments. The sampling was undertaken at four low (2002-2005) and two high (2004-2005) water periods at 27 GPS referred stations. H. cristalina sp. nov. is described and included in the key for the sponges at the surveyed area.
Amazonian; aquatic habitats; protected area; sponges
