Coming out of your shell or crawling back in: multiple interphylum host switching events within a clade of bivalve- and ascidian-associated shrimps (Caridea: Palaemonidae)

Bijdragen tot de Dierkunde, vol. 91, pp. 166–198

Abstract

Abstract Marine symbiotic Palaemonidae, comprising over 600 species, live in association with marine invertebrates of different phyla, like Cnidaria, Echinodermata, Mollusca, Porifera, and Tunicata. A phylogenetic study is performed on a clade of bivalve- and ascidian-associated endosymbiotic shrimp species (Caridea: Palaemonidae), using morphological and molecular data. A Total Evidence approach is used in order to include all currently known ingroup species in an evolutionary framework. Ancestral state reconstruction analyses are performed to identify host-switching events and ancestral ranges. The clade, including Ascidonia, Conchodytes, Dactylonia, Odontonia, and Pontonia, and various smaller genera, is recovered as monophyletic, with an ascidian-associated ancestral host state. At least six interphylum host switches are tentatively identified, with members of Odontonia and Notopontonia switching back to an ascidian host affiliation after the ancestral host switch of the clade including Conchodytes, Odontonia and related genera, from an ascidian- to a bivalve host. The clade including Ascidonia and Pontonia was recovered to have an ancestor with an East Pacific/Atlantic distribution. The other studied genera remained in the original ancestral Indo-West Pacific range. We hypothesize that similar internal environments of shrimp hosts from different phyla will function as hot spots for interphylum host switching in various lineages of symbionts.

Authors 3

1. Werner de Gier corresponding Aachen Naturalis Biodiversity Center

   University of Groningen · Naturalis Biodiversity Center

   Affiliation as printed

   Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands, werner.degier@naturalis.nl

   Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands

2. Mike Groenhof corresponding Aachen Institute of Biology Leiden Naturalis Biodiversity Center

   Leiden University · Naturalis Biodiversity Center

   Affiliation as printed

   Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300, RA Leiden, The Netherlands

   Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands

3. Charles H. J. M. Fransen corresponding Aachen Naturalis Biodiversity Center

   Naturalis Biodiversity Center

   Affiliation as printed

   Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands