Although chrysophyte stomatocysts have a fossil record that likely extends to the lower Cretaceous, to date neither scales nor bristles of the scaled chrysophyte genera older than Holocene have been reported. This leaves the origin of this important group of freshwater algae a mystery. We discovered abundant and diverse scaled chrysophyte microfossils in ca. 47 Ma sediments (Middle Eocene, Lute...

In this research, biostratigraphy related to the carbonate succession of the Shahbazan Formation at the southeastern flank of Chenar anticline, Lurestan Basin, is discussed. A study of large benthic foraminifera from the 294 mthick Shahbazan Formation led to the identification of two Middle Eocene biozones: Somalina sp. Zone, Nummulites-Alveolina Assemblage Zone. The age of the Shahbazan Format...

The late Middle Jurassic–early Eocene (;120 m.y.) sediment-accumulation history of the Cordilleran foreland basin in northern Utah exhibits a sigmoidal pattern on a rate vs. time plot, with moderate rates of accumulation during late Middle Jurassic, very low net rates during Late Jurassic–earliest Cretaceous, increasingly rapid rates during Earlymiddle Cretaceous, and low rates during Late Cret...

[1] Previous workers identified a magnetically anomalous clay layer deposited on the northern United States Atlantic Coastal Plain during the Paleocene-Eocene thermal maximum (PETM). The finding inspired the highly controversial hypothesis that a cometary impact triggered the PETM. Here we present ferromagnetic resonance (FMR), isothermal and anhysteretic remanent magnetization, first-order rev...

BACKGROUND As Earth warms, temperate and subpolar marine species will increasingly shift their geographic ranges poleward. The endemic shelf fauna of Antarctica is especially vulnerable to climate-mediated biological invasions because cold temperatures currently exclude the durophagous (shell-breaking) predators that structure shallow-benthic communities elsewhere. METHODOLOGY/PRINCIPAL FINDI...

摇 A new myodont rodent is reported from the lower part of the Arshanto Formation in Nuhe鄄 tingboerhe of Nei Mongol, which represents one of the earliest and most primitive myodont rodents in Asia. The new species is characterized by several primitive features, such as M1 and M2 subequal in size, anterior cingulum( id) pronounced and having weak or no connection with the protocone and protoconid...

Oxygen isotope records of planktonic foraminifera indicate that Late Eocene and Oligocene tropical sea surface temperatures were as much as 88C lower than present at a time when high latitude sea surface temperatures were higher than present. Using a numerical model which describes oxygen isotope exchange during burial and recrystallization of deep sea carbonate, the effects of diagenesis on bu...

Continuity is important for tracing evolutionary lineages through geological time. Modern Odontoceti and Mysticeti can be traced backward in time to Eocene Archaeoceti, and before them to mesonychian Condylarthra. Within this shared continuum, the origin of Archaeoceti and the origin of Cetacea is marked by the first indication of a derived evolutionary transition-in-grade from terrestrial to a...