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)

What is it about?

Lots of marine shrimp species from the family Palaemonidae live in symbioses with a wide range of marine invertebrates, including corals, sea urchins, starfish, snails, bivalves, sponges and sea squirts (ascidians). We studied a group of more than 50 bivalve- and ascidian- associated shrimp species, using both DNA and morphological data. Using this data, we could reconstruct a “tree of life” of this group and found that the group had experienced at least six host-switches in its evolutionary history. Host switches from an ascidian to a bivalve host occurred, but also the other way around. Some lineages of closely related shrimp species even switched back and forth in their evolutionary history. In addition, we checked the historical distribution ranges of the ancestors of the species and looked for links between the host-switches and their biogeography. We hypothesize that similar internal habitats, so the insides of bivalves and ascidians, played a major part in the bizarre host switches in the evolution of the shrimp species.

Featured Image