The earliest plants in Earth’s history

Plants cover our planet, providing us with much of the oxygen we breathe, producing fruits and timber, and helping to stabilize and provide the basis for nearly all of the terrestrial environments that we admire across the world. They range from the smallest of the mossess, to the giant sequoias, blanketing so much of our …

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Where did the Mesozoic mammals go?

Based on the fossil record and geological dating methods, we think mammals have been around for a long time. So long, that they appear in the fossil record right around the same time as the dinosaurs, and indeed coexisted alongside them throughout the "Age of the Dinosaurs", the Mesozoic era (252–66 million years ago). But …

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Back when crocs swam the seas

Crocodilians, which include crocodiles, gharials, caimans and alligators, are represented by relatively few species today. Not only are these animals not particularly speciose, they are also quite similar in appearance and habit. Looking at them, they are unmistakably crocodile-esque, with their toothy smiles and elongate bodies embedded with rows of bony scales. Crocodilians are generally ambush predators that hunt in …

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When the hyoliths once roamed

Not all of the extinct groups of animals are large, charismatic, dinosaur-like creatures. Although these may capture our imagination, much of the life that has perished over Earth's history is represented by more minuscule creatures. One such group is known as the hyoliths. Hyolith fossils have been found on all seven continents and appear to have lived from ~541 to 252 million …

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Drepanosaurs: the monkey lizards

If you ever wondered what you get if you crossed a lizard, a monkey, a Velociraptor and a bird (presumably after taking some mind-altering drugs), it would probably look something like a drepanosaur. Drepanosaurs were a group of lizards whose fossils date to between 221.5–201.6 million years ago [1]. They have been found in rocks ranging from Italy and England to …

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The flying relatives of ostriches and emus

As I discussed in my previous two posts, paleognaths are a group of birds that includes large-bodied flightless species such as ostriches, emus, cassowaries, and the extinct moas and elephant birds, as well as the small flightless kiwi and the quail-like tinamous. Molecular phylogenetics suggests that these predominantly flightless birds descended from birds that were …

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Goodbye to the glossopterid forests

Not only have many groups of animals disappeared over earth's history, but entire groups of plants no longer exist. One such example is the glossopterids. Glossopterids were woody seed plants, that were either shrub- or tree-like, something we are still unsure of due to the absence of complete fossil specimens. In the genus Glossopteris alone, more than 70 fossil …

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Sea scorpions: the stuff of nightmares

A recent discovery prompted me to discuss a group of now extinct animals known as the eurypterids or sea scorpions.     These aquatic invertebrates, though not truly scorpions, share similarities with scorpions, as well as spiders and horseshoe crabs. Geological evidence suggests they lived from approximately 460 to 252 million years ago (Ordovician-Permian). Though some were a relatively small, yet respectable, …

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Glyptodonts: the tank armadillos

As my final post on this series on xenarthrans, I'm going to highlight a group of xenarthrans that no longer exists: the glyptodonts. Scientists estimate that glyptodonts lived approximately 23 million to 10,000 years ago, inhabiting the New World, like all xenarthrans. As is clear from the photos, glyptodonts looked much like the offspring of an …

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Ichthyosaurs: the dolphin reptiles

When you think about the large creatures you might see in the ocean, perhaps whales and sharks come to mind. The fossil record suggests that the diversity of large, ocean-dwelling animals in earth's past included many other groups, such as marine reptiles known as ichthyosaurs. Ichthyosaurs lived during the Mesozoic era of earth's history, appearing in the fossil record …

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