A Smithsonianmag.com writer is trying to make the ordinary extraordinary by claiming, “The Rise of Meat-Eating Dinosaurs Is More Complicated Than We Thought. “
Writer Riley Black (formerly Brian Switek)
writing in smithsonianmag.com declares: “The earliest dinosaurs arose about 235 million years ago during the Middle Triassic. They didn’t look much like modern favorites Triceratops or Spinosaurus. Instead, these lanky creatures didn’t get much bigger than a German shepherd. The current spate of evidence suggests they were omnivorous.”
Black also provides this image (Fig. 1) of middle Triassic Herrerasaurus, the basalmost dinosaur in the large reptile tree (LRT, 1688+ taxa) and this is no omnivore. This taxon is 3 meters or 16 feet long, not the size of a German shepherd.
“Up until now, paleontologists thought theropods remained generally small and on the ecological sidelines from about 235 through 201 million years ago. It was only after a mass extinction at the end of the Triassic, at the 201 million-year mark, that carnivorous dinosaurs started to get big. But that view is starting to change thanks to a new reading of the bone trail by scientists who think large meat-eaters may have appeared much earlier. Virginia Tech paleontologist Christopher Griffin says a key player in this story is Herrerasaurus.”
Confused? So am I. This brings us back to where the LRT starts, regarding dinosaurs. Everyone in paleo knows Herrerasaurus is a Middle Triassic carnivorous dinosaur. The little German shepherd-sized dinos are either made up or never existed. In either case, Black doesn’t list or illustrate them.
“The known carnivorous dinosaurs during the later part of the Triassic appeared to be smaller and less imposing than the crocodile relatives they lived alongside (such as Postosuchus from the southwestern United States). Thanks to a better understanding of dinosaur growth, however, paleontologists have found that some of those little theropods were hiding a secret.”
Postosuchus is not a crocodile relative in the LRT. Herrerasaurus is closer to crocodiles in the LRT because only crocodylomorphs and dinosaurs make up the clade Archosauria.
“The few remains we’ve found of larger Triassic theropods come exclusively from immature animals that are still growing rapidly,” Griffin says. These young carnivores would have grown to lengths exceeding 18 feet in adulthood. That’s a little less than half a full-grown T. rex, but enough to make you want to avoid meeting such a carnivore face-to-face.”
A few Late Triassic theropod lengths: Tawa is 2m long. Coelophysis is 3m long. Both are represented by adult skeletons. Again, where are these imaginary few remains?
Black finally raises the curtain on her main attraction:
“Late last year, Ludwig-Maximilian University of Munich paleontologist Oliver Rauhut and colleague Diego Pol named an exceptional skeleton of a Middle Jurassic carnivore they called Asfaltovenator. This was a large animal, more than 25 feet long, that approached the average size of the later Allosaurus and bears more a passing resemblance to the later dinosaur.”
This is no big deal. Between the Late Triassic and the Late Jurassic we expect to find theropod dinosaurs bigger than their ancestors and smaller than their descendants with transitional morphologies.
Black concludes with a quote:
“There is much more to be learned about theropod evolution during this time,” Rauhut says, with finds like Asfaltovenator hinting at what remains to be uncovered.”
Again, no big deal. There is always ‘much more to be learned’ about all taxa ‘during this time.’ Some people complain because I was a journalism major. Sometimes that degree comes in handy.
Black R 2020. The Rise of Meat-Eating Dinosaurs Is More Complicated Than We Thought. online here.