THE FOSSIL RECORD OF SQUAT LOBSTERS: FILLING IN THE GAPS

Galatheoidea, a superfamily of decapod crustaceans more commonly known as squat lobsters, have recently received considerable attention. The number of described fossil species has increased by 60% in the last five years to ~130 species, and two new exclusively fossil families have been erected. Modern galatheoids have also received similarly focused attention, with many higher order revisions occurring, including the designation of a new superfamily and two new families. Nearly 50% of fossil squat lobster species are known from coralgal reefs the Late Jurassic, with 60 unique species described. The study of existing museum material and new collection from Jurassic localities in Europe still yields new taxa: at least two new species from two different families are awaiting formal description. The majority of the new fossil taxa are from the coralgal reefs of the Upper Jurassic, with smaller spikes in the Albian and Miocene.. With over 700 species known in the modern oceans, there is a paucity of fossils found in the Cenozoic.

The fossil record of the Munididae, stretching back into the Jurassic, is incredibly sparse compared to its modern record. Fewer than 20 fossil species of munidids have been described, but there are over 350 modern species. Most of the known munidid species are within the type genus Munida, which has over 250 species. Examinations of some of the established taxa in light of the new revisions, coupled with new specimens discovered in museums, resulted in the discovery of the fossil first occurrences of two genera and at least one new species.

The new taxa and revisions to existing fossil taxa can help update and fine-tune a phylogeny for the squat lobsters. The current accepted phylogeny is at odds with the fossil record, with a supposedly highly derived clade (Porcellanidae) appearing millions of years prior to the basal members (Galatheidae).