Galatheoid decapod crustaceans consist of ~1250 species today, but their evolutionary history and origin are poorly known. We studied the largest known fossil galatheoid assemblage, from the Late Jurassic of Ernstbrunn, Austria. This coral-associated assemblage yielded 2348 specimens, arranged in 53 species, 22 genera and six families. Rarefaction analyses show that nearly all taxa have been collected. In addition to abundant Munidopsidae, this assemblage also contains the oldest members of four of the six galatheoid families, including Galatheidae, Munididae, Paragalatheidae and Porcellanidae. We describe the oldest Porcellanidae and Galatheidae to date, and a catillogalatheid: Vibrissalana jurassica gen. et sp. nov., ?Galathea genesis sp. nov. and Galatheites britmelanarum sp. nov. Our re-examination of the oldest claimed porcellanid, Jurellana tithonia, from Ernstbrunn, indicates that it represents a homolodromioid brachyuran, ascribed to Jurellanidae fam. nov. along with Ovalopus gen. nov. The second-oldest claimed porcellanid, Early Cretaceous Petrolisthes albianicus, is transferred to the catillogalatheid Hispanigalathea. We further document that 10.4% of Ernstbrunn galatheoid specimens were parasitized by epicaridean isopods, as shown by swellings in the gill region. Statistical analyses indicate that infestation is near non-random, varying from 0 to 33% for common species. Thus, Late Jurassic coral-associated habitats were key ecosystems in the evolution of galatheoids and their parasites.

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We present a systematic study of late Paleocene macrofauna from methane seep carbonates and associated driftwood in the shallow marine Basilika Formation, Spitsbergen, Svalbard. The fauna is composed of 22 taxa, comprising one brachiopod, 14 bivalves, three gastropods, three crustaceans, and one bony fish. The reported fish remains are among the first vertebrate body fossils from the Paleogene of Spitsbergen. One genus is new: the munidid decapod Valamunida Klompmaker and Robins gen. nov. Four new species are described: the terebratulide brachiopod Neoliothyrina nakremi Bitner sp. nov., the protobranch bivalve Yoldiella spitsbergensis Amano sp. nov., the xylophagain bivalve Xylophagella littlei Hryniewicz sp. nov., and the munidid decapod Valamunida haeggi Klompmaker and Robins gen. et sp. nov. New combinations are provided for the mytilid bivalve Inoperna plenicostata, the thyasirid bivalve Rhacothyas spitzbergensis, the ampullinid gastropod Globularia isfjordensis, and the munidid decapod Protomunida spitzbergica. Thirteen taxa are left in open nomenclature. The fauna contains a few last occurrences of Cretaceous survivors into the Paleocene, as well as first occurrences of Cenozoic taxa. It is composed of chemosymbiotic thyasirid bivalves and background species common in the northern Atlantic and Arctic during the Paleocene. Our results provide no evidence for a Paleocene origin of vesicomyid and bathymodiolin bivalves typical for Eocene and younger seep environments; instead, the Paleo cene seeps of the Basilika Formation are more similar to their Late Cretaceous equi valents rich in thyasirids.

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