Schematic arrangement of the ventral plates in all members of the weglarskae group (species are arranged in order of the increasing reduction of the ventral armature). Known cases of ontogenetic variability and sexual dimorphism are depicted. Following species taken from Kaczmarek et al. (2012): B. aaseae, B. iohannis, B. parvuspolaris, B. sinensis and B. weglarskae; Gąsiorek et al. (2017a): B. maculatus; Gąsiorek & Degma (2018): B. instabilis.