Meeting Abstract

7.6  Saturday, Jan. 4 09:15  Origin and evolution of Oceanic pelagic communities SANTINI, F.*; SORENSON, L.; CARNEVALE, G.; Univ. of Torino; Univ. of California, Los Angeles; Univ. of Torino francesco.santini@alumni.utoronto.ca

In order to investigate the origin and evolution of communities of large pelagic predators in today’s Oceans we generated megaphylogenies for three major fish groups (Scombriformes, Istiophoriformes, Clupeiformes) and dated the molecular trees using the rich fossil record of each of these groups. Together with previously available time-calibrated trees of cetaceans, cephalopods and sharks, these new phylogenies reveal for the first time the pattern of origination and diversification of all the major groups of pelagic inhabitants of the world’s major Oceans. Our result show two major bursts of origination and diversification: the first spanning the late Cretaceous/Early Paleogene, in some cases slightly predating the KPg extinction events, and a second one spanning the Late Miocene/Early Pliocene. The first burst of origination and diversification gave origin to many lineages that are currently assigned familial status, while the second episode saw the origin of most of the specific diversity of some of the largest pelagic predators, such as marlins and sailfishes, and tunas. We will discuss what factors may have been responsible for these two separate bursts of diversification in these clades, and how the radiation of these groups led to the present-day diversity of pelagic communities