When Sifrhippus sandae, the earliest known horse, first appeared in the forests of North America more than 50 million years ago, it would not have been mistaken for a Clydesdale.
It weighed in at around 12 pounds–and it was destined to get much smaller over the ensuing millennia.
Sifrhippus lived during the Paleocene-Eocene Thermal Maximum (PETM), a 175,000-year interval of time some 56 million years ago in which average global temperatures rose by about 10 degrees Fahrenheit. (more…)
AUSTIN, Texas — Atlantic croaker living in the large Gulf of Mexico “Dead Zone” exhibit severe reproductive impairment with potential long-term impacts on the fish’s population abundance, researchers from The University of Texas at Austin’s Marine Science Institute have found.
Males and females were found to produce dramatically fewer sperm and eggs. In addition, females in the hypoxic Dead Zone waters were masculinized — some 20 percent actually produced sperm in their ovaries. The sex ratio was also heavily skewed toward males in the hypoxic area. (more…)
