An animation from a Smithsonian Channel documentary shows a dyrosaur being constricted by the "monster snake" Titanoboa.
Killer-jaw crocodiles, known for their unusually fast and powerful bites, lived from the Middle Jurassic to the Early Cretaceous. Recently discovered
--- meaning "savage swimmer" -- was one such croc. These and others of the time are collectively known as metriorhynchids.
lived about 157 million years ago and grew to be close to 15 feet long, reports a new study in the latest issue of the Zoological Journal of the Linnean Society. This croc chomped down on prey in Britain's shallow seas at the time, says lead author Mark Young of the University of Southampton's National Oceanography Centre and the University of Edinburgh's School of Biological Sciences.
This was a smaller-bodied dino-era croc that grew to about 6.5 feet in length. “Based on the shape and length of the snout, and the lack of cutting edges on the teeth," Young told Discovery News, "this species was most likely specialized to impale small-bodied prey, such as fish and squid.”
During the Late Jurassic, staggeringly large plant-eating dinosaurs and armored dinosaurs that looked like living tanks roamed around. Co-existing with these massive creatures was
, which, like
, lived approximately 152 million years ago.
“is exceptionally unusual as it had tooth-tooth contact, a bullet-shaped skull, which is very wide and deep, with very large serrated teeth,” Young said.
Yet another croc from 152 million years ago was
. Though relatively small compared to these other ancient crocs, it was quite a hunter in waters off of what is now Germany. “This species had triangular, blade-like teeth which were finely serrated," Young said. "The upper-jaw teeth contacted the lower-jaw teeth in a scissor-like arrangement analogous to living great barracudas.”
Waters off of France were home to huge prehistoric crocs too.
lived there, as well as in waters off of what is now England, 165 million years ago. This croc grew to a length of about 15.5 feet.
The largest-known metriorhynchid was
. It grew to 22.3 feet long and lived 157 million years ago. To match its impressive body size, it possessed the largest known jaw gape for this type of animal and had huge serrated teeth. “Based on its size -- and that all known teeth lack evidence of biological wear -- this species may have been analogous to living killer whale populations that specialize on fleshy-prey (such as dolphins),” Young said. “
may have been a specialist in feeding on other marine reptiles.”
lived approximately 153 million years ago in waters off of what is now England. It grew to about 15.5 feet in length. “This species has a peculiar jaw-closing muscle arrangement,” Young said. “It is still poorly known, but seems to be adapted to rapidly close its jaws and apply considerable pressure on its prey.”
was like an odd mishmash of living animals. Its body was like that of a dolphin. It possessed a shark-like tail fin. Despite these features, it was all croc. This one lived 165 million years ago and measured about 13.5 feet. Its home was off the waters of England, France and Poland. “This species had an odd occlusion mechanism: In the back half of the jaws, the upper and lower jaw teeth interlock vertically -- think of how two cogs interlock,” Young said. “As their teeth were serrated and relatively large, this tooth arrangement may have aided in cutting prey items into smaller pieces.”
It was 16 feet (4.8 meters) long and tipped the scales at 900 lbs. (408 kilograms). With a blunt snout and powerful bite, it ate turtles and battled monster snakes. Now this extinct dyrosaur, a type of crocodilian, which roamed an ancient rainforest a few million years after the dinosaurs died, has a scientific name.
It's called Anthracosuchus balrogus after the fiery Balrog that lurked deep in the Middle-Earth mines of Moria in J.R.R. Tolkien's novel "The Lord of the Rings."
"Much like that giant beast, Anthracosuchus balrogus was from deep within a mine after 60 million years trapped within the rocks of tropical South America," study researcher Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History, told Live Science in an email. [Image Gallery: 25 Amazing Ancient Beasts]
Four specimens of the new species were unearthed in a layer of rock in the fossil-rich Cerrejón coal mine of northern Colombia, where scientists previously have found huge turtles with shells as thick as high-school textbooks and skeletons of the world's largest snake, Titanoboa, a 48-foot-long (14.6 m) beast that recently starred in a Smithsonian Channel documentary.
A. balrogus is the third new species of ancient crocodilian found at Cerrejón, scientists say. (Another, Acherontisuchus guajiraensis, was described in the journal Palaeontology in 2011.) The newly named croc belonged to an intrepid family known as the dyrosaurids.
These creatures arose in Africa, paddled across the Atlantic Ocean to South America about 75 million years ago and remarkably survived the mass extinction that wiped out the dinosaurs about 65 million years ago, scientists say. Some dyrosaurid species, such as A. balrogus, adapted to freshwater ecosystems like the rainforest of Cerrejón, which was much warmer and swampier 60 million years ago than it is today.
"This group offers clues as to how animals survive extinctions and other catastrophes," Alex Hastings, a postdoctoral researcher at Martin Luther Universität Halle-Wittenberg and former graduate student at the Florida Museum of Natural History, said in a statement. "As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejón adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome."
Hastings and colleagues described the new species last month in the journal Historical Biology. Compared with its cousins, A. balrogus has an unusually short, blunt snout. Paired with the large jaw muscles that are characteristic of dyrosaurids, this feature would give A. balrogus an incredibly powerful bite, Hastings explained.
"It quickly became clear that the four fossil specimens were unlike any dyrosaur species ever found," Hastings said. "Everyone thinks that crocodiles are living fossils that have remained virtually unchanged for the last 250 million years. But what we're finding in the fossil record tells a very different story."
Original article on Live Science.
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