A Note on the Freshwater Bryozoa of West Bengal Wetlands

Abstract

Bryozoa or Ectoprocta are small benthic, sessile and aquatic invertebrates growing as colonies of connected zooids on submerged substrates. They feed on suspended organic particles which they captured by the whorls of ciliated tentacles (lophophore). Of the estimated 8000 extant species of bryozoans (Ryland, 2005), only a small number are found in freshwater habitats. Till now 94 bryozoan species are found in freshwater consisting of 24 genera and 10 families (Massard and Geimer, 2008). Most of these species belong to the exclusively freshwater inhabiting class Phylactolaemata and reproduce asexually by means of statoblasts (buoyant floatoblasts and fixed sessoblasts), which are very important in identification of species. Freshwater bryozoan colony adheres to the surface of any substratum inside the water bodies, i.e., aquatic weeds, logs, stones, bricks or any other artificial substratum in the ponds, lakes, water reservoirs, streams, and rivers.