Diversity of features of the female reproductive system and other morphological characters in leeches (Citellata, Hirudinida) in phylogenetic conception

Abstract

An epistemological-evolutionary conception of leeches (Hirudinida) based on features of the female reproductive system in combination with other morphological characters is presented in the spirit of the cladistic school of taxonomy. Characters relating to the structure of the ovary and the course of oogenesis in leeches were interpreted in this manner, for the first time. Each study was conducted on type species of higher taxonomic groups of true leeches. Results of analyses using features of the reproductive system only as well as in combination with other morphological characters show Piscicolidae and Glossiphoniidae as sister clades making Rhynchobdellida a monophyletic group. Also, Hirudiniformes and Erpobdelliformes appeared to be sister clades within Arhynchobdellida. The relationship between the outgroup specimens and leeches remained unresolved, because both Acanthobdella peledina and branchiobdellidans appeared to be in an equivocal relationship to hirudinidans. Characters concerning the structure of the female reproductive system and course of oogenesis thus appeared to be useful, although conservative, for reconstruction of leech phylogeny, and they well reflect phylogenetic relationships of Hirudinida at the family level.