Dinosaurs Declining Before Extinction

Published: 20th Apr 2016

Dinosaurs had been in decline for about 50 millions of years before the mass extinction happened at the end of the Cretaceous according to a new study from Reading University. The new research studied species family trees to reveal that in from 220 million years to 140 million years ago dinosaurs were thriving with many new species evolving. However from about 100 million years ago dinosaurs went into decline and species became extinct faster than they new species evolved.

The study looked at major groups within dinosaurs including theropods, such as Spinosaurus and T rex, ornithiscians, such as Iguandon and Triceratops, and sauropods, such as Argentinosaurus and Diplodocus. It appeared that all dinosaurs experienced a downturn with sauropds being particuklarly hit. The only dinosaurs to buck the trend were the hadrosaurs, such as Corythosaurus, and the ceratopsians, such as Triceratops.

It is thought that environmental changes and competition from emerging mammals were factors in the loss of dinosaur diversity. This consequently meant that when the asteroid impact happened 65 million years ago species diversity was already eakened and hence the dinosaurs as a whole were more vulnerable to the consequent effects. The outcome was extinct for the non-avain dinosaurs.

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