Latest Fossils: Dinosaurs, Whales and More
Here’s a quick survey of news about fossils, including remains of some monstrous creatures and a tiny one, too.
Hell Creek T. rex: Another big Tyrranosaurus rex was found in the Hell Creek Formation in northern Montana. “The find, which paleontologists estimate to be about 20 percent of the animal, includes vertebrae, ribs, hips and lower jaw bones,” PhysOrg says, not to overlook a fairly complete skull. “Although arguably the most iconic and well-known dinosaur, T. rex fossils are rare,” the article says.
Did Nanotyrranus exist? The BBC News weighs in on the controversy about Nanotyrannus, a supposed miniature version of T. rex. Reporter Alex Riley considers the views of various experts. Most likely, the celebrated type specimen named “Jane” was not a separate species, but a juvenile of the big ones. “Meet Nanotyrannus, the dinosaur that never really existed,” his headline reads.
Duck-bill teeth: How would you like to have 300 teeth that automatically get replaced? Duckbill dinosaur teeth came in on conveyor belts in their mouths, PhysOrg says — a dentist’s dream. Using microscopies, scientists in Canada examined the “unique dental system” of hadrosaurs that apparently worked in juveniles as well as adults. “It’s very elegant – not a single brick of teeth working as a solid unit,” a researcher says. “It’s more like chain mail, providing flexibility as well as strength.”
Footprint national park: A huge dinosaur footprint measuring nearly four feet across has been found in a remote desert in Bolivia. “Bolivia is already known for the region’s Cal Orcko Park, one of the world’s largest beds of fossilized footprints, which has more than 10,000 prints left by nearly 300 species of dinosaur,” PhysOrg says, “But Maragua, where Marquina discovered the giant abelisaurid theropod print, is far more remote.”
Whale of a baleen: In Peru, scientists were delighted to find a fossil whale with its baleen so well preserved they could detect its microstructure. Science Daily teased with “Whales in the desert?” Sure enough, the fossil was found high and dry in the country’s Cerro Colorado desert, hundreds of feet above today’s sea level. The press release from the Geological Society of America omits the question mark after “desert,” stating, “The exceptionality of the finding is that the casts provide details at the submillimetric scale, revealing under the microscope the subtle structure of the baleen bristles.” The full paper is published in Geology. There’s no indication that soft tissue was preserved, but think about how rapidly this whale had to be buried to preserve such details of its baleen:
A rapid formation of the concretion was fundamental for fossilization. We suggest that the whale foundered in a soft sediment chemically favorable to rapid dolomite precipitation, allowing the preservation of delicate structures.
Squirrely lion: Would you believe a lion the size of a squirrel? That’s what National Geographic says about a marsupial lion fossil found in Australia. They’re basing this on one tooth of the only known specimen of a species named Microleo (tiny lion). New Scientist has more information from three specimens of its larger relative Thylacoleo, saying that it was a small but fully-equipped predator. Its “primate-like arms” would have allowed it to “slash at prey with large, retractable thumb claws.” A researcher says, “It probably looked like a cross between a small bear and a wombat.”
Cave bear demise: What killed off the cave bears? Science Daily speculates that it went vegan and couldn’t adapt. Nature says that “longing for home” did them in. Since nobody has seen these extinct bears, you can make up your own version of why they just didn’t get the adaptation game.
Nightmare scenario: Speaking of caves, PhysOrg tells of a fossil cache that could start bad dreams. An opening in the ground in Wyoming drops into a huge bell-shaped cavern, where anything that ventures in falls eight stories to its death. Natural Trap Cave is covered with a grate now, but paleontologists rappelling in with ropes have been looking at the bones of ice age mammals that perished: wolf, bison, lion, cheetah and wolverine. Lions in Wyoming? Cheetahs? Really? The bones provide the evidence such predators used to live in the western United States. Researchers think this cave was a natural trap for thousands of years.
Reinterpreting jaw evolution: “Scientists use the fossil record to make judgments on the physiology and behavior of species,” Science Daily says. “But are those interpretations correct?” A biologist at the University of Notre Dame is asking. Bottom line: diet and eating habits can have a profound effect on jaw shape. A paleontologist might attribute a trait to a species characteristic instead of a life history characteristic. Matthew Ravosa says, “our research offers novel insight into the limitations of functional interpretations of fossils. Because the palaeontological record largely consists of skeletal remains, we show that failure to account for disparities in the responses of hard versus soft tissues may also result in incorrect characterizations of adaptive changes in extinct mammals.”
The hidden half of plants (PNAS): Investigating rhizomes in paleosols (fossil soils), an international team pushed back the origin of tree roots by 20 million years.
The roots and rhizomes of early vascular plants, and their interactions with soils, are poorly documented. Here we report on the complex, belowground rhizome systems of an Early Devonian plant, and their contribution to the formation of the earliest record of rooted red-bed soils in Asia. Our specimens predate the earliest trees with deep roots from the Middle Devonian by 20 million years. We propose that plant rhizomes have long functioned in terrestrial ecosystems, playing important roles in shaping Earth’s environments by reducing soil erosion rates and thereby increasing the stability of land surface and resilience of plant communities.
This is the latest instance of finding complexity further back in the fossil record than expected. It usually doesn’t go the other way. Such findings put pressure on Darwinian processes, making complex systems emerge faster in less time. The Devonian, we all learned in school, was supposed to be the “age of fishes” not of complex vascular plants. Scientists have missed half the picture by just looking above ground. “Such a knowledge gap hinders a deep understanding of the ecology of early plants and their roles in terrestrial environments,” they worry.
The news here is varied. Think about the difference between observation and theory, between gradualism and rapid burial, and between expectation and empirical evidence.