About 150 million years back, Opisthiamimus gregori crawled around Jurassic-era THE UNITED STATES, looking for food alongside more famous dinosaurs like Stegosaurus and Allosaurus. It munched on insects and small invertebrates, and, at six inches long, was small enough to match in the palm of today’s adults hand.
This extinct species is one of the same ancient lineage because the present-day tuatara reptile, in accordance with new findings from Smithsonian National Museum of Natural History, University College in London, and the London Natural History Museum. Their study, published on September 15 the Journal of Systematic Paleontology, helps explain a few of the unique differences between this extinct creature in the brand new Zealand critter.
O. gregori is really a rhynchocephalian, a definite group that diverged from lizards through the Triassic Period. The tuatara (its only living relative) is exclusively within present-day New Zealand, looks a bit just like a stout iguana, and is a little bit of an enigma: It appears like a lizard, but isnt a lizard. Lizards participate in an order of reptiles called sqamates, which also contains snakes and worms).
Whats important concerning the tuatara is that it represents this enormous evolutionary story that people are fortunate to catch in what’s likely its closing act, said Matthew Carrano, the National Museum of Natural Historys curator of Dinosauria, in a news release. Though it looks like a comparatively simple lizard, it embodies a whole evolutionary epic heading back a lot more than 200 million years.
A whole and well-preserved O. gregori skeleton was within northern Wyomings Morrison Formation, sitting atop was what once an Allosaurus nest. Through the Jurassic period, rhynchocephalians could possibly be found across the world, came in a variety of sizes and shapes, and were from aquatic fish hunters to bulky plant munchers. It isn’t still understood why, rhynchocephalians all-but disappeared, while snakes and lizards turned out to be the more prevalent and diverse reptiles around the world.
More study of the specimens could reveal why just New Zealands tuatara is surviving today. These animals could have disappeared partly due to competition from lizards but perhaps also because of global shifts in climate and changing habitats, Carrano said. Its fascinating if you have the dominance of 1 group giving solution to another group over evolutionary time, and we still need more evidence to describe just what happened, but fossils such as this one are how exactly we will put it together.
This fossil is nearly entirely complete, and is missing the tail and elements of the hind legs. In accordance with Carrano, this type of complete skeleton is rare for small prehistoric creatures such as this because, their frail bones were often destroyed either before they fossilized or because they emerge from an eroding rock formation in today’s day. Paleontologists typically identify Rhynchocephalians from small fragments of these jaws and teeth.
The team used CT scans to fully capture everything they possibly could concerning the fossil and created a nearly complete 3D reconstruction of the pet. The 3D skull is of particular interest.
This type of complete specimen has huge prospect of making comparisons with fossils collected later on and for identifying or reclassifying specimens already sitting in a museum drawer somewhere, said research associate, David DeMar Jr., in a news release. With the 3D models we’ve, at some time we’re able to also do studies that use software to check out this critters jaw mechanics.