January 20, 2023 | David F. Coppedge

Rethinking Dinosaurs

Dinosaurs have come along way from the horror films of decades ago.
Their image is evolving.

 

Velociraptors probably didn’t use their ‘wicked’ claws for slashing, surprising new study suggests (Live Science, 19 Jan 2023). It may spoil your memories of the first Jurassic Park movie, but velociraptors were about the size of turkeys, Stephanie Pappas says. And they didn’t use their “wicked claws” for disemboweling their victims. Pappas points to a living bird called a seriema that uses its curved claw to hold down an object of interest while it looks at it. In the photo, it holds down a keychain.

Who knows; maybe early farmers might have raised these notorious theropods for meat and eggs, like we do with barnyard fowl today. Roast velociraptor for Thanksgiving, anyone?

Unlike the velociraptors made famous by the “Jurassic Park” franchise, actual velociraptors were turkey-size. Deinonychus or Utahraptor are closer in size to the dinos that stalked Dr. Grant in the movie. (In fact, the velociraptors in Jurassic Park are actually based on Deinonychus.) Jurassic Park also popularized the notion that these dinosaurs used their curved claws to slash at prey as big or larger than themselves, but paleontologists have long been skeptical of that idea. As it turns out, dromaeosaurid claws don’t resist side-to-side force well, said James Napoli (opens in new tab), a paleontologist and postdoctoral researcher at the North Carolina Museum of Natural Sciences and North Carolina State University who was not involved in the new study. Nor do they make great knives. 

The curved claw may have functioned as a clasp, not as a scimitar. How the larger raptors like Utahraptor or Deinonychus behaved, no one knows. Large birds like cassowaries are very dangerous with their claws, so one cannot rule out the risk of encountering a beast like a big raptor dinosaur. But neither can they prove they were the terrors of Hollywood movies. If we only had the fossils of German shepherds or pit bulls, could we conclude they were vicious hunters incapable of domestication or of being good pets?

Fossils Reveal Dinosaurs of Prehistoric Patagonia (University of Texas Geosciences, 11 Jan 2023). What? Modern birds living alongside big raptor dinosaurs with big claws? What did we just learn about those claws?

The fossils represent the first record of theropods — a dinosaur group that includes both modern birds and their closest non-avian dinosaur relatives — from the Chilean portion of Patagonia. The researchers’ finds include giant megaraptors with large sickle-like claws and birds from the group that also includes today’s modern species.

The artist conception, for whatever scientific value it has, shows birds that look somewhat like ducks, sparrows and geese. The theropods in the picture were obviously not beginning a long evolutionary climb into the domain of powered flight; they were already well equipped. The dinosaurs had imaginary feathers:

Reaching over 25 feet long, megaraptors were among the larger theropod dinosaurs in South America during the Late Cretaceous. The unenlagiines — a group with members that ranged from chicken-sized to over 10 feet tall — were probably covered with feathers, just like their close relative the velociraptor. The unenlagiinae fossils described in the study are the southernmost known instance of this dinosaur group.

Feathers were not found on Velociraptor fossils. CMI reminds its readers that feathers were inferred from the presence of small pits on the bones of the creature, presumed to be quill knobs. So from this indirect inference, the writer of this press release leaps into the presumption that the group of dinosaurs “probably” had feathers – imaginary ones.

Caption from the University of Texas article: “A time averaged artist’s interpretation of Patagonia during the Late Cretaceous, about 66-78 million years ago. The animals pictured include non-avian dinosaurs, birds and other vertebrates that have been discovered in the fossil record of the region. Their specific identifications are as follows: ornithurine birds (flying and walking on the ground), Stegouros (armored dinosaur), Orretherium (mammal), Yaminuechelys (turtle), a megaraptorid (large carnivore), unenlagiines (pair of carnivores), and enantiornithine birds (in foreground). Credit: Mauricio Alvarez and Gabriel Diaz.”

Treasure trove of fossil eggs hints titanosaurs nested in colonies (New Scientist, 18 Jan 2023). This is one of several popular-level articles about a paper from PLoS One about a discovery of 250 round rocks (assumed to be titanosaur eggs) from India, assumed to represent 92 nesting sites.

A treasure trove of fossil nests uncovered in India hints at an array of as-yet-undiscovered dinosaurs belonging to the titanosaur group, and gives clues to how these animals reproduced.

The story was also echoed in a press release from PLoS One published by Science Daily on 18 Jan 2023. Before titillating the public’s imagination about a nursery ward for clucking titanosaur mothers, though, scientists should exercise more caution about identifying what these stones mean. Not everything about the word picture of eggs sitting on nesting sites fits the taphonomy of the fossils. Does burial of so many eggs occur today for animals laying eggs on the ground? Don’t think that the scientists found nice, neat nests scattered about in the area, each with a clutch of eggs inside. Most of the word-picture is inferred from assumptions. The facts are more complex:

Resorption craters are found in some of the eggshells (Fig 5H), and are very less in number as compared to the clutches showing evidences of hatching. The lack of such resorption craters may indicate either infertile eggs or death of embryo prior to ossification either because of environmental or biological reasons. Additionally, high levels of diagenetic alteration in the form of silicification and recrystallization observed in the extracted eggshells may have obliterated resorption craters. In most of the cases, the extracted eggshells were thoroughly embedded in the rock matrix which may have resulted in the removal of these craters upon diagenesis. However, in clutches of Padlya, where many clutches show intact circular egg outlines and spherical complete eggs, the absence of resorption craters may indicate that these eggs were either biologically infertile, buried too deep causing embryo asphyxiation or affected by environmental events such as flash floods that could have suffocated the embryo much before ossification.

Aha; so flood waters could have buried these eggs. Many questions come to mind. Why were they entombed in rock? Why were so many of them infertile or suffocated? What kind of diagenetic alterations occurred, and how?

Another problem with the narrative is that the authors identified six different egg-species (oospecies), suggesting a higher diversity of titanosaurs than is represented by skeletal remains from this region.” The paper uses escape hatch words like “could have” or “may have” or “possibly” dozens of times. Surely more is uncertain about this site than can be stated with confidence.

Tweety Rex

We end with a hilarious headline from Live Science 11 Jan 2023 by Harry Baker to make your day: “Ancient bird with T. rex-like skull discovered in China.” TGIF!

About 120 million years ago, a fearsome bird with a skull that looked eerily similar to that of a Tyrannosaurus rex flew the early Cretaceous skies, hunting for a meaty meal to gobble down, a new study finds. A newly described specimen of this previously unknown species provides clues about how birds began to finalize their evolutionary divergence from the rest of the dinosaurs.

It’s just like the Babylon Bee! Our satire came true! Believe it or not.

Oh, that scientists would just report the facts and let people debate and discuss what it means. How often are they later proved wrong! How often their deep-time Darwinian worldview pollutes what they observe and what they describe. How often do they imagine things that are not supported by evidence. Back to epistemic modesty, please!

Recommended resource: Dr Carl Werner has a good DVD about Living Fossils that describes his quest to find out if modern animals lived alongside extinct ones, which would disprove evolution. He gives many examples of so-called extinct animals in every category from insects to mammals that look identical or nearly so with modern counterparts, but were given different scientific names. He also shows that museums either typically hide these fossils from the public, or else display them apart from the dinosaurs, when in reality the fossils were found together.

 

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Categories: Birds, Dinosaurs, Fossils

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