The second species of the endemic Malagasy earthworm genus Howascolex Michaelsen, 1901; Howascolex farafangana sp. n. (Clitellata, Megadrili)

A recent survey of earthworms carried out in South East Madagascar resulted in collecting two species belonging to the endemic Malagasy earthworm genus Howascolex Michaelsen, 1901. One of the species proved to be identical to the generotype Howascolex madagascariensis Michaelsen, 1901. The other species Howascolex farafangana sp. n. represents the second species of the genus. The genus Howascolex was originally classified in the subfamily Octochaetinae Michaelsen, 1900. However, its close morphological similarity with the Malagasy acanthodriline species implies a homoplasious origin of the meroic excretory system of Howascolex and its inclusion in the family Acanthodrilidae Claus, 1880.