Redescription, phylogenetic placement, and taxonomic reassignment of Mesobdella lineata (Sciacchitano, 1959) (Hirudinida : Arhynchobdellida)

Abstract

Mesobdella lineata, a small terrestrial species of leech from southern Africa, originally placed in the family Haemadipsidae, is redescribed based on internal and external morphological characters of the holotype and of additional material collected in 1975. The placement of this species in the South American genus Mesobdella on the basis of seemingly triannulate midbody somites is found to be erroneous as midbody somites are five-annulate. Mesobdella lineata has neither the midventral nephridial pore, a synapomorphy of Xerobdellidae, nor the posteriolateral auricles of Haemadipsidae. With a caudal sucker that is wider than the four most posterior somites of the body, eight teeth per jaw, micromorphic median reproductive structures, and no postanal annuli, this species is placed in the mammalophilic family Praobdellidae. A morphological matrix of 32 characters was analyzed with parsimony and implied weighting. The new genus Parapraobdella is warranted to accommodate the unique combination of characters of the species that is morphologically similar to Neotropical representatives of the family.