Sentences with phrase «modern mammal groups»

A large mammal ancestor that ultimately gave rise to all modern mammal groups, including the rodents, might simply have failed to fossilise.

Several modern mammal groups such as rodents emerged after the dinosaur extinction, and the fossils show their first members were small.

The classic story is that all modern mammal groups started to develop no more than 65 million years ago, after the end of the Cretaceous Period, when a probable meteorite impact led to a major extinction in which all the dinosaurs died.

Not exact matches

«Fossil records have long indicated that the ancestors of many modern placental mammal groups can be traced back to the period immediately following the dinosaur extinction.

«In particular, we found a group called Laurasiatheria quickly increased their body size and ecological diversity, setting them on a path that would result in a modern group containing mammals as diverse as bats, cats, rhinos, whales, cows, pangolins, shrews and hedgehogs.»

The standard explanation is that the evolution of the modern groups of mammals and birds didn't get under way until after that.

Dunne continued: «We now know that the rainiforest collapse was crucial in paving the way for amniotes, the group which ultimately gave rise to modern mammals, reptiles and birds, to become the dominant group of land vertebrates during the Permian period and beyond.»

Yet two ancient anklebones from Pakistan indicate that whales are descended from artiodactyls, a group of even - toed hoofed mammals that includes modern sheep, cows, pigs, and camels — along with hippos, which appear to be whales» closest living relatives.

What's more, the new tree indicates that these mammals very quickly diversified into the modern groups, close to the downfall of the dinosaurs, Wible and colleagues report in the 21 June issue of Nature.

The species name xenarthrosus refers to the odd way the creature's spinal vertebrae interlock and stiffen the back, similar to modern - day armadillos, anteaters, and other mammals in a group called xenarthrans.

The team discovered that the genes responsible for the regulation of NRL became more refined in the placental mammals as the modern retina evolved and were lost in several non-mammalian groups.

As no other taxonomic group contains terrestrial animals in the size classes of the large modern mammals, the functional loss of large mammals can rarely be compensated, leading to permanent ecosystem changes [49].

Was Antarctica a site of the origins of certain modern bird and mammal groups?

Discovered in Inner Mongolia, China, Megaconus is one of the best - preserved fossils of the mammaliaform groups, which are long - extinct relatives to modern mammals.

Applying these strictures to modern animals is fairly straightforward, since these two characteristics are restricted only to members of the clade Ruminantia, which is the subgroup of even - toed hoofed mammals that includes the cattle, goats, sheep, antelopes, deer, pronghorn, mouse deer, giraffe (Zivotofsky 2000) and okapi (a clade is a taxonomic group whose members share a common ancestry; in this case it does not have a formal associated Linnaean level, such as family or order).