The rise to dominance of lanternfishes (Teleostei, Myctophidae) in the oceanic ecosystems: a paleontological perspective

Lanternfishes currently represent one of the dominant groups of mesopelagic fishes in terms of abundance, biomass and diversity. Their otolith record dominates pelagic sediments below 200 m in dredges, especially during the entire Neogene. Here we provide an analysis of their diversity and rise to dominance primarily based on their otolith record. The earliest unambiguous fossil myctophids are known based on otoliths from the late Paleocene and early Eocene. During their early evolutionary history myctophids were likely not adapted to a high oceanic lifestyle, but occurred over shelf and upper slope regions where they were locally abundant during the middle Eocene. A distinct up-scaling in otolith size is observed in the early Oligocozoicne, which also marks their earliest occurrence in bathyal sediments. We interpret this transition to be related to the change from a halothermal deep ocean circulation (HTC) to a thermohaline regime (THC), and the associated cooling of the deep ocean an...