Navigation Links
Colossal new predatory dino terrorized early tyrannosaurs

A new species of carnivorous dinosaur one of the three largest ever discovered in North America lived alongside and competed with small-bodied tyrannosaurs 98 million years ago. This newly discovered species, Siats meekerorum, (pronounced see-atch) was the apex predator of its time, and kept tyrannosaurs from assuming top predator roles for millions of years.

Named after a cannibalistic man-eating monster from Ute tribal legend, Siats is a species of carcharodontosaur, a group of giant meat-eaters that includes some of the largest predatory dinosaurs ever discovered. The only other carcharodontosaur known from North America is Acrocanthosaurus, which roamed eastern North America more than 10 million years earlier. Siats is only the second carcharodontosaur ever discovered in North America; Acrocanthosaurus, discovered in 1950, was the first.

"It's been 63 years since a predator of this size has been named from North America," says Lindsay Zanno, a North Carolina State University paleontologist with a joint appointment at the North Carolina Museum of Natural Sciences, and lead author of a Nature Communications paper describing the find. "You can't imagine how thrilled we were to see the bones of this behemoth poking out of the hillside."

Zanno and colleague Peter Makovicky, from Chicago's Field Museum of Natural History, discovered the partial skeleton of the new predator in Utah's Cedar Mountain Formation in 2008. The species name acknowledges the Meeker family for its support of early career paleontologists at the Field Museum, including Zanno.

The recovered specimen belonged to an individual that would have been more than 30 feet long and weighed at least four tons. Despite its giant size, these bones are from a juvenile. Zanno and Makovicky theorize that an adult Siats might have reached the size of Acrocanthosaurus, meaning the two species vie for the second largest predator ever discovered in North America. Tyrannosaurus rex, which holds first place, came along 30 million years later and weighed in at more than twice that amount.

Although Siats and Acrocanthosaurus are both carcharodontosaurs, they belong to different sub-groups. Siats is a member of Neovenatoridae, a more slender-bodied group of carcharodontosaurs. Neovenatorids have been found in Europe, South America, China, Japan and Australia. However, this is the first time a neovenatorid has ever been found in North America.

Siats terrorized what is now Utah during the Late Cretaceous period (100 million years ago to 66 million years ago). It was previously unknown who the top meat-eater was in North America during this period. "Carcharodontosaurs reigned for much longer in North America than we expected," says Zanno. In fact, Siats fills a gap of more than 30 million years in the fossil record, during which time the top predator role changed hands from carcharodontosaurs in the Early Cretaceous to tyrannosaurs in the Late Cretaceous.

The lack of fossils left paleontologists unsure about when this change happened and if tyrannosaurs outcompeted carcharodontosaurs, or were simply able to assume apex predator roles following carcharodontosaur extinction. It is now clear that Siats' large size would have prevented smaller tyrannosaurs from taking their place atop the food chain.

"The huge size difference certainly suggests that tyrannosaurs were held in check by carcharodontosaurs, and only evolved into enormous apex predators after the carcharodontosaurs disappeared," says Makovicky. Zanno adds, "Contemporary tyrannosaurs would have been no more than a nuisance to Siats, like jackals at a lion kill. It wasn't until carcharodontosaurs bowed out that the stage could be set for the evolution of T. rex."

At the time Siats reigned, the landscape was lush, with abundant vegetation and water supporting a variety of plant-eating dinosaurs, turtles, crocodiles, and giant lungfish. Other predators inhabited this ecosystem, including early tyrannosaurs and several species of other feathered dinosaurs that have yet to be described by the team. "We have made more exciting discoveries including two new species of dinosaur," Makovicky says.

"Stay tuned," adds Zanno. "There are a lot more cool critters where Siats came from."


Contact: Tracey Peake
North Carolina State University

Related biology news :

1. Predators vs. alien: European shrimps win predatory battles with an American invader
2. Predatory beetles eavesdrop on ants chemical conversations to find best egg-laying sites
3. Early-career investigator discovers current volcanic activity under West Antarctica
4. Biometric-Mobile Wallet Technology Takes Aims at a Target Market Of Nearly $1Billion Potential
5. Oxygen, phosphorous and early life on Earth
6. Fast-mutating DNA sequences shape early development; guided evolution of uniquely human traits
7. Hypersensitivity to pain produced by early life stress is worsened by later stress exposure
8. Mutations in novel tumor suppressor gene associated with early onset breast cancer
9. Early-life exposure of frogs to herbicide increases mortality from fungal disease
10. IRICoR and Université de Montréal license a novel program for early-onset morbid obesity to Pfizer
11. UT Dallas researchers find early success in new treatment for stroke recovery
Post Your Comments:
Related Image:
Colossal new predatory dino terrorized early tyrannosaurs
(Date:10/29/2015)...   MedNet Solutions , an innovative SaaS-based eClinical ... research, is pleased to announce that it has been ... one of only three finalists for a 2015 ... Growing" category. The Tekne Awards honor Minnesota ... innovation and leadership. iMedNet™ eClinical ...
(Date:10/29/2015)... , Oct. 29, 2015 Daon, a ... that it has released a new version of its ... in North America have already ... v4.0 also includes a FIDO UAF certified server ... already preparing to activate FIDO features. These customers include ...
(Date:10/29/2015)... , Oct. 29, 2015  Connected health pioneer, ... the explosion of technology-enabled health and wellness, and the ... book, The Internet of Healthy Things ... or smartphones even existed, Dr. Kvedar, vice president, Connected ... health care delivery, moving care from the hospital or ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... Jose, CA (PRWEB) , ... ... ... Content Intelligence Company, today announced tighter software integration with MarkLogic, the Enterprise ... where organizations maximize information to drive change. , Smartlogic’s Content Intelligence capabilities ...
(Date:11/27/2015)... ... November 27, 2015 , ... Pittcon is pleased to announce ... offered in symposia, oral sessions, workshops, awards, and posters. The core of ... applications such as, but not limited to, biotechnology, biomedical, drug discovery, environmental, food ...
(Date:11/25/2015)... 26, 2015 --> ... 2016 - 2020 report analyzes that automating biobanking ... quality in long-term samples, minimizing manual errors, improving ... minimizes manual errors such as mislabeling or inaccurate ... it plays a vital role in blood fractionation, ...
(Date:11/25/2015)... Mass. , Nov. 25, 2015 Harvard ... biotechnology company developing bioengineered organ implants for life-threatening conditions, ... present at the LD Micro "Main Event" investor conference ... The presentation will be webcast live and posted for ... be available at the conference for one-on-one meetings on ...
Breaking Biology Technology: