Triassic Mammals and the Story Fossils tell

From KHouse.Org

A boatload of fisherman recently bumped into what appears to be the skull of mesosaur along the Ruta-Ru River in Siberia’s Yamal Peninsula. They photographed the skull and sent it to the Zoological Museum of the Institute of Plant and Animal Ecology in Yekaterinburg, Russia where paleontologists tried to identify the creature. There are a variety of questions about the toothy skull; how it could have been so well-preserved sticking out of the cobbles at the bottom of the river; how it could exist in Yamal, dated to 150 million years, when mesosaurs have been placed at 299–270 million years in age. Whatever this particular specimen turns out to be, fossils are not always as predictable as paleontologists would like.

Triassic Squirrels

Three new species of squirrel-like mammals found in China are causing paleontologists to rewrite their history of when mammals came into the geologic record. The picture we often get is that mammals evolved after the dinosaurs died out at the end of the Cretaceous, but in recent years it’s been recognized that many mammals existed during the age of the dinosaurs. These three new squirrel-like creatures from China are said to have lived between 235 and 201 million years ago, during the Triassic, when crocodiles and giant salamanders reigned.

“What we’re showing here is very convincing that these animals [the three new species] are mammals, and that we need to turn back the clock for mammal divergence,” paleontology museum curator Jin Meng said. “But even more importantly, these new fossils present a new suite of characters that might help us tell many more stories about ancient mammals.”

Mite Backpack

Even creatures that aren’t found at an unexpected “time” can amaze us. A study published recently in the journal Biology Letters describes a mite hooked onto the head of an ant. The two creatures were enveloped in tree sap which fossilized into amber, preserving for us an ancient battle between a blind little arachnid and a social insect. Mites are rare in the fossil record because they generally get eaten quickly when they die, but they apparently haven’t changed much over earth’s history. Nor has their tendency to parasitize ants. The amber-encased mite was determined to belong to a family whose existing species still sponge off ants to this day.

Dolphins and Sharks

Paleontology is a field of puzzle-piecing, and every fossil found offers another clue about earth’s history and the creatures that have lived on the planet. Remarkably, the multitudes of creatures that lived long ago often exist today in varied forms. A desert in southern Peru has recently offered paleontologists the bones of a toothy freshwater dolphin species considered 16 million years old. It has been linked to the river dolphins of the Indus and Ganges rivers. A shark egg case has been discovered in Yorkshire Main Colliery in Edington, an old mine, along with plant remnants and horseshoe crabs. Horseshoe crabs are known for their consistency since ancient times; they’ve hardly changed a lick over the years. Sharks have allegedly been around for 350 million years, yet they exist today. Creatures change over time, but not as much as we’d think.

Archaeopteryx

Even famous missing links are losing their status. Archaeopteryx was a bird-like dinosaur with feathers found in the Solnhofn Limestone of Bavaria more than 150 years ago. For many years it has been considered the evolutionary ancestor of birds, because it contains a variety of dinosaur-like and bird-like characteristics. Within the past few years, however, suggestions have been published that Archaeopteryx was not a bird ancestor at all. A variety of small, feathery dinosaurs have been found over the years, demonstrating that Archaeopteryx was not so special after all. Paleontologist Xing Xu has made the case that this famous creature is more closely related to the Velociraptor and other Deinonychosauria than with birds.

“Archaeopteryx was a bird because it had feathers and nothing else had them. But then other animals started being found that had wishbones, three-fingered hands and feathers. Heck, even T. rex had a wishbone. So one by one we’ve learned Archaeopteryx ’s uniquely avian traits weren’t so unique. The writing was really on the wall,” says Lawrence Witmer, a paleontologist at Ohio University in Athens.

Paleontology is a constantly developing science, yet missing links are rare and hardly unquestionable. As paleontologists continue to unearth the remains of ancient creatures, we find squirrels and dolphins, crabs and dinosaurs. Many creatures have gone extinct, but those alive today can find similar cousins in the fossil record, whether we find them in expected layers or in unexpected layers. We find multitudes of horse species and multitudes of rhinoceros species, but no ancestor that linked the two together. Even transition fossil hopefuls like Archaeopteryx do not hold their position forever.

Telling the story of earth’s history is no easy trick. There are multitudes of animals buried under the top layer of Earth’s skin, and paleontologists will continue to sort through them and develop ideas based on new information. Yet, we believe that in the Beginning, God created the animals, the birds and fish, and then told them to reproduce — each after its own kind (Gen 1:22–25). We don’t have to ignore the fossil record to believe Moses’ account; it’s what we continue to see every time new bones are found.

Related Links

  • Archaeopteryx No Longer First Bird
    — Nature
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