That seemingly modifications as of now, with new argon relationship of strata from the Naashoibito Member within the San Juan Basin of present-day New Mexico. Many dinosaur fossils have been obtained from this area, and we all know the location differs from the type of ecosystem discovered at Hell Creek. Nevertheless it was beforehand thought to this point again nearer to 1,000,000 years earlier than the mass extinction. The brand new dates, plus the alignment of magnetic area reversals, inform us that the ecosystem was a recent of the one in Hell Creek, and dates to the previous couple of hundred thousand years previous to the mass extinction.
Various ecosystems
The fossils at Naashoibito have revealed an ecosystem we now label the “Alamo Wash native fauna.” And so they're pretty distinct from those present in Wyoming, regardless of being simply 1,500 kilometers additional south. Analyzing the species current utilizing ecological measures, the researchers discovered that dinosaurs shaped two “bioprovinces” within the late Cretaceous—primarily, there have been distinct ecosystems current within the northern and southern areas.
This doesn't appear to be an artifact of the websites, as mammalian fossils appear to replicate a single group throughout each areas close to the mass extinction, however had distinct ecologies each earlier and after. The researchers suggest that temperature variations have been the important thing drivers of the excellence, one thing that will have had much less of an influence on mammals, that are usually higher at controlling their very own temperatures.
General, the researchers conclude that, relatively than being dominated by a small variety of main species, “dinosaurs have been thriving in New Mexico till the top of the Cretaceous.”
Whereas this speaks on to the concept that restricted variety could have primed the dinosaurs for extinction, it additionally could have implications for the influence of the contemporaneous eruptions within the Deccan Traps. If these have been having a significant international influence, then it's a bit unlikely that dinosaurs can be thriving wherever.
Even with the brand new information, nevertheless, our image remains to be restricted to the ecosystems current on the North American continent. We do have fossils from elsewhere, however they're not precisely dated. There are some indications of dinosaurs within the late Cretaceous in Europe and South America, however we don't have a transparent image of the ecosystems by which they have been discovered. So, whereas these findings assist make clear the variety of dinosaurs within the time main as much as their extinction, there's nonetheless quite a bit left to study.
Science, 2025. DOI: 10.1126/science.adw3282 (About DOIs).
