Anatomical constraints on venom and toxin evolution in centipedes

Centipedes are among the oldest groups of venomous predatory arthropods. They have had similar morphology and life history for many million years and can be compared with centipedes from over 430 Mya. They offer an opportunity to study a homologous venom system, where the lineages have relatively retained similar body plans through their evolutionary history. Previous study on venom evolution commonly tend to focus on drivers with may facilitate the evolution, and less at what may constrain it. This makes centipedes a great research subject as there is observed discrepancies in venom complexity, which is thought to be caused by morphological limitations of its venom glands. The research question in this project was How have differences in structural venom system morphology influenced the venom complexity, its composition, and the compositional changes along the evolutionary history of different centipede lineages? To explore this, we utilized the first database to cover all five taxonomical orders of centipedes. Moreover, I characterized venom composition of extracted venom from 13 new species, where one of these were Henia vesuviana, using the methodology of proteotranscriptomics. Here, I argue that gland complexity is correlated to venom complexity. Strikingly, I discovered 52 new unknown, newly discovered toxin families, where 99 were unique for single orders. My results supported my hypotheses, as all four estimates for the venom complexity had a significant correlation to gland morphometrics. We show consistency with previous studies, and some new advances on the first ever indications of a toxin families identified in all five centipede orders.