Abstract

Four economically important species of earthworm were cultured and the external and internal characters of adult clitellate earthworms were studied. Partial sequences for ribosomal 16S rDNA and subunit one for mitochondrial cytochrome c oxidase (COI) of four earthworm species were obtained. The result of sequence analysis combined with taxonomic characters could distinguish the different species of earthworm. Morphology and nucleotide sequence of two genes for the red worm (Pheretima peguana) were distinct from Eudrilus eugeniae but were similar to the blue worm (Perionyx excavatus) and Lao worm (P. excavates) and therefore, it was classified as a new species, Perionyx sp. 1. Moreover, Eudrilus eugeniae was evidently defined as the same genus and species. Interestingly, the blue worm and Lao worm were morphologically similar to Perionyx sp. However, the molecular data of 16S rDNA could not differentiate in taxa of those two species. COI nucleotide sequence analyses showed the presence of divergent lineages between two species, suggesting the blue worm and Lao worm could be described as Perionyx sp. 2 and Perionyx sp. 3, respectively. © 2011 Friends Science Publishers.