Cover letter

Dear chief-editors,
We are delighted to submit our manuscript entitled “Clasp and dance: Mating mode promotes variable sexual size and shape dimorphism trajectories in crocodile newts (Caudata: Salamandridae) ” toEcology and Evolution , exclusively.
The knowledge about the evolutionary processes leading to dimorphic sexes is still somehow cryptic and not fully understood especially in cold-blooded animal groups which often express only subtle shape differences between males and females. The enigmatic crocodile newts of the genera Tylototriton and Echinotriton are on the one hand morphologically conservative, but on the other hand polymorphic in their reproductive behaviour and hence, represent a well-suited model system to investigate evolutionary forces leading to different patterns of sexual dimorphisms. We carried out a comparative approach on several species exhibiting different mating behaviours, by applying 3D geometric morphometrics to the cranium and humerus. Especially, the humerus is of interest as it plays a major role between the different mating modes. Our study reveals how the ecology of a species interacts with the expressed patterns of sexual shape dimorphism in these newts and add another important piece to the puzzle in understanding the evolution of sexual dimorphisms.
We are sure our work and the approach used herein is of interest to a broader audience of evolutionary biologists, ecologists and morphologists.
We look forward to hearing from you in the near future.
Yours sincerely,
Peter Pogoda, Marcus Zuber, Tilo Baumbach and Alexander Kupfer