110 MILLION YEAR RECORD OF CATSHARK EGG CAPSULES FROM METHANE SEEPS

Elasmobranch egg capsules are rare in the fossil record. They include Palaeozoic and Mesozoic spirally coiled capsules of the Palaeoxyris group found mainly in freshwater deposits, occasional occurrences of chimaeroid egg capsules (Chimaerotheca) ranging back to the Triassic, and rare skate egg capsule specimens (Rajitheca) from the Oligocene of central Europe. All these records represent internal or external molds, many are flattened, and a capsule wall has never been reported. Here we report newly discovered catshark egg capsules from deep-water methane seeps from the modern Eastern Mediterranean, the Miocene of New Zealand, Late Eocene of Washington State, USA (Scyliorhinotheca goederti) and poorly preserved specimens from the Albian of California. All the specimens are closely associated with tube worm bushes, suggesting that cold-seep ecosystems have served as nurseries for predatory elasmobranch fishes for at least 110 million years. The fossil capsules are preserved three−dimensionally and some show mineralized remnants of capsule walls, now replaced by carbonates resulting from the anaerobic oxidation of methane biogeochemical process.