Actinella species (Bacillariophyta) from an Amazon black water floodplain lake (Amazonas - Brazil)

Abstract

The genus Actinella Lewis was studied using planktonic samples from a black water floodplain lake in entral Amazon region. For species identification the taxa were morphological and morphometricaly nalyzed on base in light microscope (LM) and scanning electronic microscope (SEM). Five species were registered: ctinella brasiliensis Grunow, A. guianensis Grunow, A. gracile Kociolek, A. mirabilis (Eulenstein ex runow) Grunow and A. robusta Hustedt. A. gracile is reported for the first time for Amazon State and black ater systems and it is firstly documented with SEM. In addition, a review of geographic distribution of ctinella species in Brazilian Amazon region is given.