New Miocene Fossils and the History of Penguins in Australia

Abstract

Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring ‘giant penguins’ after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia.

Mitogenomes Uncover Extinct Penguin Taxa and Reveal Island Formation as a Key Driver of Speciation

“…Palaeosphneiscus, Paraptenodytes, Eretiscus) but no crown penguins. 2) Miocene record of Australia, which has yielded specimens interpreted as being either stem penguins or too incomplete to be assigned to either the stem or crown (Park et al 2016). 3) Miocene-Pliocene record of New Zealand, which has yielded crown species, none of which fall within the Spheniscus-Eudyptula clade.…”

An early Miocene extinction in pelagic sharks

“…Pelagic sharks were not gradually driven to extinction by the evolution of modern pelagic top predator groups. Rather, the abrupt shark extinction appears to have occurred several million years before radiations in tunas and billfish (22), seabirds (23), beaked whales (24), baleen whales (25), and even migratory sharks (26). A gap in whale fossilization that spans the early Miocene shark extinction is associated with a shift in the trajectory of baleen whale evolution and a subsequent appearance of crown filter-feeding whales (27).…”

A Novel Double-Strand DNA Genetic Algorithm for Multi-Objective Optimization

“…The t distribution is often used to estimate the mean of a normal population without known population variance based on a small sample. The approach used by Park et al [42] is used for this part. The distribution of HV is compared with the t distribution on SCH and DEB.…”