{"id":113985,"date":"2025-10-31T11:30:09","date_gmt":"2025-10-31T11:30:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/113985\/"},"modified":"2025-10-31T11:30:09","modified_gmt":"2025-10-31T11:30:09","slug":"new-fossils-show-dinosaurs-were-thriving-until-the-final-asteroid-strike","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/113985\/","title":{"rendered":"New Fossils Show Dinosaurs Were Thriving Until the Final Asteroid Strike"},"content":{"rendered":"

\"Alamosaurus <\/a>Alamosaurus fossils show southern dinosaurs differed from same-age northern species in Montana and Wyoming. Credit: Natalia Jagielska<\/p>\n

A new study is challenging a long-standing view of the final days of the dinosaurs. For decades, many palaeontologists believed that non-avian dinosaurs were already in decline before the asteroid impact 66 million years ago. The assumption was that dinosaurs were collapsing, and the space rock<\/a> was merely the coup de gr\u00e2ce. But research recently published in Science<\/a> suggests a very different story: these animals were still thriving when the catastrophe hit.<\/p>\n

\u201cThey\u2019re doing great, they\u2019re thriving, and the asteroid impact<\/a> seems to knock them out,\u201d said Andrew Flynn, a geologist at New Mexico State University and lead author of the study.<\/p>\n

This new evidence, discovered in the Naashoibito Member of the Kirtland Formation<\/a>, paints a far more vibrant picture of the dinosaurs\u2019 final days and complicates the long-standing narrative that they were already doomed.<\/p>\n

The Right Time Placement<\/p>\n

The story begins in the San Juan Basin<\/a> of New Mexico. In it, there\u2019s a geological formation<\/a> called the Naashoibito Member. This formation has numerous interesting fossils, but its age is very uncertain. Earlier estimates placed it millions of years before the asteroid impact. But this new study says otherwise. Using two high-precision techniques (radioisotopic dating of volcanic crystals and magnetostratigraphy based on Earth\u2019s shifting magnetic poles<\/a>) Flynn and colleagues pinpointed its place in time.<\/p>\n

They found that the dinosaur-bearing layers of the Naashoibito Member were deposited between 66.87 and 66.38 million years ago\u2014no more than 400,000 years before the Chicxulub <\/a>asteroid slammed into the planet.<\/p>\n

\"\" <\/a>A restoration of the environment, featuring Dineobellator (center front), Ojoceratops (right), Tyrannosaurus (far left), and Alamosaurus (center back), taxa all known from the formation. Image via Wiki Commons.<\/p>\n

This means the fossil assemblage in this region is nearly contemporaneous with the famous Hell Creek Formation<\/a> (home to Triceratops<\/a> and Edmontosaurus<\/a>). But here in New Mexico the fauna includes a variety of other species, including crested lambeosaurids and large sauropods which could reach ~30 metres in length (comparable to a Boeing 737).<\/p>\n

The dinosaur fauna is so varied that it suggests dinosaurs were doing just fine before the asteroid.<\/p>\n

\u201cThere is no sign that these dinosaurs were in any trouble, or that anything unusual was happening to them, or that they were in any type of long-term decline,\u201d Brusatte told The Guardian<\/a>.<\/p>\n

Regional Diversity<\/p>\n

For years, paleontologists debated whether dinosaur ecosystems had become homogenous by the end of the Cretaceous<\/a>, a possible sign of fragility before collapse. The idea was that biodiversity had thinned out, leaving species more vulnerable to environmental upheaval.<\/p>\n

But this new research contradicts that view.<\/p>\n

Flynn and his colleagues ran advanced ecological modeling on fossil communities from across western North America<\/a>. What emerged were distinct \u201cbioprovinces\u201d\u2014regional ecological zones defined not by simple geography, but by temperature gradients. Dinosaurs in the north lived in cooler, more temperate climates. Those in the south, like New Mexico, thrived in warmer habitats.<\/p>\n

\"\" <\/a>Depiction of what a Lambeosaurus may have looked like. Image via Wikipedia.<\/p>\n

\u201cWe recognize the final ~1 million years of dinosaur evolution as a time of biogeographic diversity and partitioning,\u201d the authors wrote.<\/p>\n

That diversity held true for early mammals<\/a> as well. After the asteroid impact, mammals rapidly diversified. Within 300,000 years, mammals had developed new body sizes, diets, and ecological roles. Yet even in this rebound, the north and south bioprovinces remained intact.<\/p>\n

\u201cThe surviving mammals still retain the same north and south bioprovinces,\u201d Flynn said. \u201cWhich is different than other mass extinctions<\/a> where it seems to be much more uniform.\u201d<\/p>\n

In other words, ecosystems didn\u2019t become uniform after the extinction. They stayed regional and shaped by climate\u2014similar to how they are today.<\/p>\n

Lessons for Today<\/p>\n

This finding doesn\u2019t just help us understand dinosaurs better, it also helps us understand our current times because unfortunately, we\u2019re also living in a time of extinctions.<\/p>\n

\"The <\/a>The impact. Credit: Donald E. Davis\/Wikimedia Commons.<\/p>\n

The question of how dinosaurs disappeared speaks to how life on Earth responds to sudden, massive change. As ecologist Lindsay Zanno puts it<\/a>, \u201cA view of life\u2019s fragility that is limited to the present is myopic. It requires empirical insight derived from Earth\u2019s deep-time fossil archive.\u201d<\/p>\n

The new findings come at a time when scientists are raising alarms about today\u2019s rapid loss of biodiversity. Many species are struggling as habitats shrink and the climate shifts. Looking at how life recovered after past extinctions could help scientists understand what can be done today.<\/p>\n

The asteroid impact was sudden and devastating. But the world it struck wasn\u2019t already falling apart. Dinosaurs were still going strong\u2014until, very abruptly, they weren\u2019t. <\/p>\n","protected":false},"excerpt":{"rendered":"Alamosaurus fossils show southern dinosaurs differed from same-age northern species in Montana and Wyoming. Credit: Natalia Jagielska A…\n","protected":false},"author":2,"featured_media":113986,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[9154,13650,61,60,68899,4726,82],"class_list":{"0":"post-113985","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-cretaceous","9":"tag-dinosaur","10":"tag-ie","11":"tag-ireland","12":"tag-mesozoic","13":"tag-paleontology","14":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/113985","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=113985"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/113985\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/113986"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=113985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=113985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=113985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}