Revision of Promonotus Beklemischev, 1927 (Platyhelminthes : Proseriata), with description of two new species from the Mediterranean

Abstract

Two new species of Promonotus Beklemischev, 1927 from the Mediterranean (P. sphaerobursa n. sp. and P. spinosissimus n. sp.) are described, and the whole genus is revised. The monophyly of the genus, characterized by the absence of a vagina externa, is questioned. Based on the morphology of the copulatory organ, the existence of apomorphies shared by most of the species currently attributed to the genus can be demostrated. This group of species is hypothesized to constitute a monophyletic group. Lack of a vagina externa in the other species is considered as a homoplasous feature; their generic placement is unresolved at present.