These are not the Paleogene Penguins you are Looking for

New late Eocene and Oligocene remains of the flightless, penguin-like plotopterids (Aves, Plotopteridae) from western Washington State, U.S.A.

Authors:

Mayr et al

Abstract:

We describe new plotopterids (Aves, Plotopteridae) from late Eocene and Oligocene strata in western Washington State, U.S.A. The specimens belong to four new species of these flightless, wing-propelled seabirds, three of which are named and assigned to two new supraspecific taxa, Olympidytes, gen. nov., and Klallamornis, gen. nov. We confirm previous observations on a high diversity of plotopterids in the Paleogene of North America, but because the fossils are from different formations, it remains elusive how many of the six currently recognized species from western Washington actually coexisted. Tonsala, the only previously described plotopterid taxon from the Olympic Peninsula, is likely to occupy a more basal phylogenetic position than the other plotopterids of this geographic area. Olympidytes and Klallamornis may be successive sister taxa of Copepteryx and Hokkaidornis from the late Oligocene of Japan, but a determination of the exact affinities of the new taxa requires the discovery of further fossils. Notably, the geochronologically youngest plotopterid, the early Miocene Plotopterum, differs from earlier taxa in plesiomorphic features and is here considered to be among the phylogenetically most basal plotopterids. The late Eocene basal Phocavis likewise temporally overlaps with more derived plotopterid taxa. The coexistence of basal and more derived plotopterids in the late Eocene may indicate a rapid evolution of plotopterids towards the late Eocene. The factors that allowed the persistence of basal taxa into the Miocene remain, however, elusive, and so are those that triggered the evolution of wing-propelled diving in these highly specialized birds.

Evidence From Washington Direct Impacts of Volcanic Eruptions Insufficient to Cause Mass Extinctions

Extrinsic forcing of plant ecosystems in a large igneous province: The Columbia River flood basalt province, Washington State, USA

Authors:

Ebinghaus et al

Abstract:

Volcanism associated with large igneous provinces (LIPs) has been implicated in both global climate and environmental change. To determine the impact of LIP volcanism on plant ecology we have examined plant community succession in sedimentary interbeds of the Columbia River flood basalt province (CRBP; northwest United States). Interbasaltic vegetation is characterized by primary succession communities that inhabit fresh lava surfaces until terminated by the next eruptive event, and it is assumed that longer volcanic hiatuses should lead to more mature plant communities. This expected succession trajectory is contradicted by palynological data that show that seral succession declines during the phase of waning CRPB volcanism and prolonged interbed intervals. Frequent volcanic activity and increased deposition of Snake River Plain hotspot ashes during this phase resulted in ecological disturbance of intralava field vegetation. Together with geochemical proxies from interbed sediments, this suggests that CRBP flora was largely driven by extrinsic forcing, and implies that LIP volcanism of similar scale and magnitude to that of the CRBP had a limited environmental impact. This study supports the theory that past biotic extinctions were triggered by numerous factors rather than a single geological event.