Megascolecidae sensu Gates 1972

Megascolecidae sensu Gates 1972

With regard to previous classifications of the Megascolecidae the following conclusions can be drawn from the present molecular analyses. The widely used system for internal classification of the Megascolecidae of Gates (1959, 1972) cannot be sustained, as already argued by Lee (1959, 1970) and Jamieson (1971a-c). Diagnosis of Megascolecidae in the restricted sense of Gates (1972) by the possession of racemose prostates (with holo- or meronephridia) is not supported in any MP trees, with multiple evolution of racemose and tubular prostates implied by the molecular phylogenies ( Figs 3 View FIG ; 4 View FIG ). However, bootstrap values are low in the relevant section of the trees and, as no species with tubular prostates has a high bootstrap linkage with a species with racemose prostates [notwithstanding the Terrisswalkerius athertonensis-Didymogaster clade]. Likelihood ratio tests are equivocal on this but we suggest this is more a reflection on the SH test as overly conservative.