Early development of the centipede Geophilus serbicus (Chilopoda: Geophilomorpha: Geophilidae) from the Balkan Peninsula

The first detailed description of early development of the recently described European geophilid Geophilus serbicus is presented. Based on specimens from a natural population from the Balkan Peninsula, new insight was gained into the reproductive and developmental biology of the group. Changes in the morphology of brooded specimens allow 15 early developmental stages obligatorily dependent on prolonged maternal care, arranged in three phases (embryonic, embryoid, and adolescent) to be distinguished. The embryonic phase includes eight stages, followed by an intermediate stage of hatching, followed in turn by five embryoid stages and one adolescens stage. Detailed morphological descriptions of all stages are provided. Adolescens I is recognized as the first stage at which species and sex identification are possible. Besides the description of the earliest stages, we provide notes on reproductive behaviour and ecological features of the species.