Skip to main content
Dryad

Supporting data: Eocene origin of anemone carrying in polydectine crabs

Data files

May 28, 2023 version files 811.44 KB

Abstract

Here we study the evolutionary history of an elusive marine invertebrate and the origin of their specialized behavior. The crabs in the sub-family Polydectinae (family Xanthidae) have adapted to a defense behavior in which living invertebrates are used as protection from predators. All polydectine species carry a living invertebrate, usually a sea anemone or nudibranch, in each claw, that is positioned in front of the body and waved to scare off attackers. In an attempt to trace the origin of this behavior, we sequenced the complete mitochondrial genome of 19 crabs using museum samples. The complete mitochondrial genomes were included in a larger data set with previously published sequences and analyzed using maximum likelihood and Bayesian phylogenetic reconstruction. The divergence times of the polydectine crab radiation were estimated using the mitochondrial data set and several fossil calibration points. Our results show that the anemone-carrying polydectine crabs emerged in the late Eocene and consist of at least three deep evolutionary lineages. All three lineages share the unique behavior suggesting that it emerged in the ancestor to Polydectinae nearly 40 million years ago and have persisted in all living species.