Describing ten new species of Eutyphoeus (Clitellata: Acanthodrilidae) from Manipur, North-East India, together with one new record

A comprehensive investigation into the genus Eutyphoeus (Clitellata: Acanthodrilidae) in Manipur, North-East India, has led to the discovery of ten novel species and the identification of one previously unrecorded species in the region. The study utilized an integrative taxonomic approach, combining both morphological and genetic analyses. Nine of the newly described species – Eutyphoeus morehensis Tiwari & Yadav sp. nov., E. lamdengensis Tiwari & Yadav sp. nov., E. shiroensis Tiwari & Yadav sp. nov., E. kashongensis Tiwari & Yadav sp. nov., E. ukhrulensis Tiwari & Yadav sp. nov., E. lokchaensis Tiwari & Yadav sp. nov., E. baronongini Tiwari & Yadav sp. nov., E. yangoupokpensis Tiwari & Yadav sp. nov. and E. tengnoupalensis Tiwari & Yadav sp. nov. – belong to the E. hastatus group, characterized by holandric male organs, bidiverticulate spermathecae, and annular tumescence around the male porophore. However, E. kwathensis Tiwari & Yadav sp. nov. was found to diverge from E. turaensis, and is diagnosed by metandric male organs, avestibulate and apenile male genital orifices. The study is based on extensive field surveys and the use of DNA barcoding. Each species is accompanied with morphological descriptions that emphasize distinctive features and geographical distribution. In addition, DNA barcodes were analyzed to confirm species identities and determination of genetic distinctiveness. The provided microphotographs of important morphological features complement the taxonomic descriptions. The study significantly enriches the understanding of the diversity of species of Eutyphoeus in Manipur, northeastern region of India, and underscores the importance of integrating molecular techniques in the taxonomy of earthworms and surveys on biodiversity.