Endemic Annelids (Earthworms) of Darjeeling District, West Bengal, India

Earthworms occur in diverse habitats all over the world. However, they rarely survive in deserts, marine environments, areas under constant snow and ice, and areas devoid of soil and vegetation. They possess limited means of active dispersal. High mountain ranges and seas are the effective barriers for extension of their natural distribution. The origin of earthworms is unclear due to absence of any fossil records. Therefore, their phylogeny has been derived by the analysis of distribution, ecology, and comparative anatomy of the extant species.