Courtship and mating behavior in the Pycnogonida (Chelicerata: Class Pycnogonida): a summary

Summary The few published observations on pycnogonid courtship and mating behavior are widely scattered in the literature and there are no recent summaries available. Consequentially, the exclusively paternal care which is characteristic of this little-known group of marine invertebrates remains understudied by modern behavioral biologists. The current paper provides a comprehensive introduction to pycnogonid morphology with emphasis on the structures required for reproduction and then summarizes all of the available information on courtship and mating behavior in pycnogonids. The summary of reproductive behaviors is divided into categories based on the type of ovigerous leg structure present and the three most common types of ovi-gerous legs (complete ovigerous leg, modified phoxichilid ovigerous leg, modified ammotheid ovigerous leg) are described and named. The role of sexual selection in both the evolution of paternal care within this group and also the evolution of several different kinds of ovigerous legs is discussed and the gradual accumulation of a series of misinterpretations by non-pycnogonid specialists in the recent behavioral literature on paternal care is examined.