Histriobdellidae, the so-called Charlie Chaplin worms, is an enigmatic group of microscopic commensal annelids associated with crustaceans. They crawl by alternately attaching their adhesive anterior appendages and left and right huge lateral ‘feet’, and bear a complex jaw apparatus in the ventral muscular pharynx. Although histriobdellids were always thought to be a part of the jaw-bearing clade Eunicida, their exact placemen...

Tomopteridae are transparent, predatory Annelida inhabiting pelagic ocean zones. Despite being well-known for their fast metachronal swimming and species-specific bioluminescence, our knowledge of morphological adaptations in these fascinating holopelagic worms remains extremely limited. In particular, the evolutionary scenarios and adaptive changes related to the transition from putative benthic ancestors to recent free-swimm...

Chaetopteridae — the parchment worms — comprise a group of early branching annelids with a scarcely investigated neuroanatomy and neurogenesis. Due to their phylogenetic position in the annelid tree, studying them is nevertheless inevitable for our understanding of character evolution in segmented worms. Therefore, we investigated several adult und larval chaetopterids using a broad set of morphological methods — including ser...