Paedomorphosis in newts in Belgium The life cycle of newts of the genera Mesotriton, Lissotriton and Triturus is characterised by an aquatic larval stage, followed by a succession of transitions between aquatic and terrestrial habitats. However, in some cases the terrestrial component is eliminated; the larvae acquire sexual maturity before metamorphosis, retaining their gills and gill slits. This alternative path of development is known as paedomorphosis (in Dutch ‘neotenie’). In most cases, only a small part of the population follow the paedomorphic ontogenetic pathway, while the majority metamorphoses normally. This article describes all cases of paedomorphosis in Belgium known hitherto. Prior to this article, in 1932, only one case of paedomorphosis has been published in Belgium.