Scientists discover dinosaur species 5x larger than Tyrannosaurus Rex
Ulughbegasaurus, the newly identified dinosaur that dwarfed early T. rex ancestors and reigned as an apex predator 90 million years ago
Researchers have identified Ulughbegasaurus, a massive dinosaur that dominated prehistoric ecosystems before T. rex. (CREDIT: CC BY-SA 4.0)
Scientists have uncovered an apex predator that once ruled the prehistoric world, eclipsing early relatives of the Tyrannosaurus rex (T. rex) in size and dominance.
Named Ulughbegasaurus, this newly identified dinosaur roamed Earth approximately 90 million years ago, long before the iconic T. rex rose to fame. The discovery sheds light on a lesser-known chapter of dinosaur evolution, with significant implications for understanding prehistoric ecosystems.
The identification of Ulughbegasaurus began with a fossilized jawbone, unearthed in the 1980s by a Russian paleontologist in Central Asia, in what is now Uzbekistan.
The fossil had remained largely overlooked in Moscow's Vernadsky State Geological Museum for decades. In 2019, paleontologist Dr. Kohei Tanaka recognized the specimen's significance, setting off a chain of research.
Collaborating with Darla Zelenitsky, an associate professor of paleontology at the University of Calgary, Tanaka used 3D modeling to link the jawbone to fossilized teeth, ultimately confirming a previously unknown dinosaur species.
Ulughbegasaurus was an extraordinary predator, measuring 24 to 26 feet long and weighing over 2,200 pounds. In contrast, the early ancestors of T. rex at the time were far smaller, weighing less than 440 pounds and measuring about 10 feet in length.
Zelenitsky likened the difference to a grizzly bear towering over a coyote. "They likely kept the tyrannosaurus down," she explained. "Ulughbegasaurus was the dominant apex predator of its time."
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The sheer size of Ulughbegasaurus gave it a commanding presence, but its formidable blade-like teeth also set it apart. These teeth enabled slashing bites, a sharp contrast to the bone-crushing jaws of the later T. rex.
According to Zelenitsky, Ulughbegasaurus would have held a significant advantage over its smaller tyrannosaur relatives, not only in hunting prey but also in securing dominance in the food chain.
The disappearance of Ulughbegasaurus approximately 89 million years ago marked a pivotal moment in dinosaur evolution. Its extinction likely allowed tyrannosaurs to grow larger and ascend to the role of apex predators.
Over millions of years, these smaller tyrannosaurs evolved into the giant species we now recognize, including the T. rex, which could reach up to 40 feet in length and weigh over 15,000 pounds.
"The extinction of Ulughbegasaurus may have been driven by changes in prey or environmental conditions," Zelenitsky suggested. The disappearance of large herbivores or shifts in vegetation could have disrupted the predator's food supply. Despite its dominance, the prehistoric landscape eventually reshaped itself in favor of other species.
This discovery fills a critical gap in our understanding of dinosaur ecosystems during the Late Cretaceous period. For years, paleontologists had puzzled over the absence of a large predator in the fossil record from that era.
Zelenitsky emphasized the significance of finally identifying Ulughbegasaurus, stating, "The apex predator was missing from the species, and now here it is. It’s surprising it took this long to identify such a large predator."
Ulughbegasaurus represents not just a remarkable find but also a reminder of the dynamic and competitive nature of evolution. While it dominated its time, its extinction paved the way for the rise of one of history's most famous predators.
Other predatory dinosaurs that were larger than T. Rex
Several predator dinosaurs were larger than Tyrannosaurus rex. Here's a breakdown of some of the notable examples, their timeframes, diets, and relative sizes:
Spinosaurus
- Time Period: Lived approximately 112–93 million years ago during the mid-Cretaceous period. This is earlier than T. rex, which lived about 68–66 million years ago during the late Cretaceous.
- Diet: Primarily piscivorous (fish-eating) but also likely an opportunistic predator/scavenger. Fossil evidence suggests it hunted large fish and possibly other animals near water.
- Relative Size:
- Estimated length: 50–59 feet (15–18 meters), compared to T. rex’s 40–42 feet (12–13 meters).
- Weight: Around 7–10 tons, similar to or slightly heavier than T. rex.
- Unique feature: Its long crocodilian snout and sail-like structure on its back made it a striking predator, distinct from the bulkier T. rex.
Giganotosaurus
- Time Period: Lived around 98–97 million years ago during the late Cretaceous, also earlier than T. rex.
- Diet: Likely preyed on large sauropods, including Argentinosaurus. Its teeth were adapted for slicing through meat, and it may have hunted in packs.
- Relative Size:
- Estimated length: 40–46 feet (12–14 meters).
- Weight: 8–10 tons, comparable to T. rex but with a more elongated body and smaller arms.
- Distinction: It had a longer but less robust skull than T. rex, making it a specialized predator.
Carcharodontosaurus
- Time Period: Lived approximately 100–93 million years ago during the mid-Cretaceous, predating T. rex.
- Diet: Likely preyed on large herbivorous dinosaurs such as Paralititan and Ouranosaurus.
- Relative Size:
- Estimated length: 39–45 feet (12–14 meters).
- Weight: 6–9 tons.
- Distinction: It had serrated teeth resembling those of sharks (hence its name, "shark-toothed lizard") and a slender body.
Mapusaurus
- Time Period: Lived approximately 97–93 million years ago during the late Cretaceous, around the same time as Giganotosaurus and before T. rex.
- Diet: Likely specialized in hunting giant sauropods in South America. Evidence suggests it may have lived and hunted in groups.
- Relative Size:
- Estimated length: 40–44 feet (12–13.5 meters).
- Weight: Around 6–8 tons.
- Distinction: Similar in size to Giganotosaurus but slightly lighter.
These larger predators were generally less robust than T. rex, whose powerful bite and muscular build made it a formidable predator despite its smaller size. Many of these larger theropods also lived earlier, meaning they likely never encountered T. rex in the wild.
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