The Biodiverse Rotifers (Rotifera: Eurotatoria) of Small Wetlands of the Brahmaputra River Floodplains of Lower and Upper Assam, Northeast India

Bhushan Kumar Sharma,Sumita Sharma

doi:10.17216/limnofish.515981

Abstract

Rotifera assemblages of small floodplain wetlands (dobas or dubies) of lower and upper regions of the Brahmaputra river basin of Assam state of northeast India (NEI) reveal 157 species, belonging to 34 genera and 18 families, and highlight notable speciose constellation of up to 50 species/sample. One species, each is new to the Oriental region and Assam, and species of global and regional biogeographic interest form notable fractions. The biodiverse rotifer fauna and various interesting species are hypothesized to habitat diversity of the sampled dobas or dubies, impact of `the Assam-gateway’- an important biogeographic corridor of India, and location of the study area in the Indo-Burmese biodiversity hot-spot. Lecanidae and Lepadellidae are species-rich families, both of lower and upper Assam wetlands; upper Assam wetlands, in particular, are characterized by a distinct paucity of the Brachionidae and Brachionus spp., the relative paucity of Trichocerca, Keratella and Mytilina species, rare occurrence of Asplanchna and Filinia species, and lack of species of Conochilidae and Hexarthridae. Our results indicate the littoral-periphytic nature and tropical character of the rotifers. Overall, this study is an important contribution to Rotifera biodiversity of small lentic habitats of India, Asia and that of the tropics and subtropics.

Highlights

Small lentic ecosystems form over 90% of the standing water resources of our biosphere and ~ 30% of the global lentic biotopes by surface area and are suggested to be more explicitly considered in analyses of biodiversity, limnology and global processes (Céréghino et al 2014)
Rotifera assemblages of small floodplain wetlands of lower and upper regions of the Brahmaputra river basin of Assam state of northeast India (NEI) reveal 157 species, belonging to 34 genera and 18 families, and highlight notable speciose constellation of up to 50 species/sample
The biodiverse rotifer fauna and various interesting species are hypothesized to habitat diversity of the sampled dobas or dubies, impact ofthe Assam-gateway’- an important biogeographic corridor of India, and location of the study area in the Indo-Burmese biodiversity hot-spot

Summary

Introduction

Small lentic ecosystems form over 90% of the standing water resources of our biosphere and ~ 30% of the global lentic biotopes by surface area and are suggested to be more explicitly considered in analyses of biodiversity, limnology and global processes (Céréghino et al 2014). They are recognized as hotspots both in terms of species composition and biological traits (EPCN 2008) and are often considered as keystone systems for the conservation of biodiversity (Oertli et al 2010; Céréghino et al 2014; Vad et al 2017; Oertli 2018). This study merits biodiversity and biogeographic interest for Rotifera of the floodplains of India, Asia as well as that of the rotifer heterogeneity of the small lentic ecosystems of the Indian sub-region

Material and Methods

Results

Discussion