Biodiversity of Rotifera in some tropical floodplain lakes of the Brahmaputra river basin, Assam (N.E. India)

Abstract

One hundred and sixteen species of Rotifera are recorded from seven floodplain lakes of the Brahmaputra basin (northeastern India), the highest rotifer biodiversity recorded from these biotopes in the Indian subcontinent to date. The Australasian Brachionus dichotomus reductus and Lecane batillifer; the Oriental Keratella edmondsoni, Lecane blachei and L. acanthinula; the Palaeotropical Lecane braumi, L. lateralis, L. unguitata, Trichocerca tropis, Testudinella greeni and T. brevicaudata; the Pantropical Brachionus donneri and a rather widely distributed Horaella brehmi represent taxa of biogeographical interest. Three species are new additions to the Indian rotifer fauna and eight are new to the N.E. region. Lecanidae > Brachionidae = Colurellidae > Trichocercidae > Testudinellidae comprise the largest fraction (68.0%) of the examined fauna. Comments are made on the general nature and composition of the rotifer taxocoenosis as well as on acidophilic elements, ecology of various taxa and on the species richness of different lakes.

Interesting rotifers (Rotifera: Eurotatoria) from floodplain lakes of lower Brahmaputra river basin of Assam, northeast India

“…Brachionus kostei, described from Australia, is known from Papua Guinea and Thailand while Segers (2007) considered its unpublished report from northeast China as a possible example of introduction. This species is known from India exclusively from Assam state of NEI (Sharma 2004, 2014, Sharma & Sharma 2008, 2014d, 2015b, Sharma et al 2015. Nevertheless, these two Australasian elements affirmed affinity of Rotifera assemblage of Assam state as well as of NEI with the faunas of Southeast Asia and Australia, and thus supported remarks of Sharma (2005) and Sharma and Sharma (2005, 2008, 2014a, 2014c, 2014d (Meas & Sanoamuang 2010, Sor et al 2015.…”

“…Individual collections were screened with a Wild stereoscopic binocular microscope; the rotifer taxa were isolated and mounted in Polyvinyl alcohol-lactophenol, and were observed with Leica (DM 1000) stereoscopic phase contrast microscope fitted with an image analyzer. The different rotifers were identified following the works of Koste (1978), Segers (1995), Sharma (1983Sharma ( , 1987Sharma ( , 1998, Sharma & Sharma (1997, 1999, 2000, 2008, 2015a, 2015b, 2015c …”

“…The rotifer assemblages of these ecotones are poorly documented in India in general except for the floodplain lakes (beels) of the Brahmaputra river basin of Assam state which are known for their rich and interesting rotifer diversity (Sharma & Sharma 2005, 2008, 2014a, 2014b, 2014c, 2015a in the Indian subregion. The present limnological reconnaissance is undertaken to further explore the biodiversity importance of 'managed beels' (for fisheries) of Barpeta district of lower Assam.…”

Rotifers of the upper Paraná River floodplain: additions to the checklist

“…The greatest occurrence of species of the genus Lecane in tropical regions was also mentioned by Koste & Shiel (1983), Bozelli (1992), Bonecker et al (1994), Dussart et al (1984), Dabés (1995), Koste (1999), Sharma & Sharma (2001). This genus and Brachiouns were best represented in Southeast Asia (Segers, 2001).…”

Rich freshwater rotifer fauna of small lentic ecosystems of south Andaman, Andaman Sea, India (Rotifera: Eurotatoria)

“…All samples were screened, the rotifers were isolated and mounted in Polyvinyl alcohol-lactophenol, and observed with Leica (DM 1000) stereoscopic phase contrast microscope fitted with an image analyzer. The works of Koste (1978), Segers (1995), Sharma (1998), Sharma & Sharma (1999, 2000, 2008 were followed for identification of the rotifer taxa. The micro-photographs of some interesting taxa are provided and measurements are indicated in micrometers (µm).…”