A groundbreaking discovery has revealed the first giant predatory dinosaur ever unearthed in Kyrgyzstan, a distant cousin of the iconic Tyrannosaurus rex. The fossilized remains, belonging to two individuals, suggest a potential parent and offspring. The larger dinosaur measured an impressive 26 feet (8 meters) long and weighed over 2,700 pounds (1,250 kilograms), despite not reaching full maturity. The smaller individual, likely its offspring, was about 15% to 20% smaller.
The researchers named the dinosaur Alpkarakush kyrgyzicus, drawing inspiration from the giant mythical bird, Alpkarakush, featured in the “Manas” epic poem of Kyrgyz culture. Their study, published in the Zoological Journal of the Linnean Society, places A. kyrgyzicus within the carnosaur family, a group of carnivorous dinosaurs that included T. rex’s lineage and contributed to the larger theropod group which eventually gave rise to modern birds.
Further analysis revealed that A. kyrgyzicus belonged to a specific family called Metriacanthosauridae. These dinosaurs roamed across Asia and Europe during the Jurassic period (201 million to 145 million years ago). This discovery marks the first Jurassic theropod found in Central Asia west of China, significantly expanding our understanding of these ancient creatures.
“Although the affiliation of Alpkarakush with the metriacanthosaurids is not necessarily a surprise, this discovery closes a huge gap in our knowledge of the Jurassic theropods,” stated lead author Oliver Rauhut, a curator at the Bavarian State Collection for Palaeontology and Geology in Germany. “It leads us to important new insights into the evolution and biogeography of these animals.”
The excavation site, located in a mountainous desert region near Tashkumyr in western Kyrgyzstan, yielded the fossilized remains of A. kyrgyzicus. Excavations began in 2006, but the bones were deeply embedded within the steep incline of the slope. It took several expeditions, spanning from 2006 to 2023, to fully retrieve all the fossils.
The larger specimen, remarkably well-preserved, included almost complete hind limbs, skull bones, and vertebrae. These fossils unveiled distinctive features of A. kyrgyzicus, including a prominent orbital brow on the postorbital bone, aptly described as a “distinctive eyebrow.”
To determine the age of the dinosaurs at the time of their demise, researchers meticulously analyzed the internal structures of the bones, particularly growth rings, similar to those found in trees. Their findings indicated that the larger fossil belonged to a subadult, at least 17 years old, while the smaller one represented a considerably younger juvenile. The close proximity of these two individuals led the researchers to conclude that they were likely a parent and offspring.
“This association suggests that juveniles of Alpkarakush travelled together with adults to at least an early subadult stage,” the authors noted in their study.
The discovery of A. kyrgyzicus has significant implications for our understanding of Jurassic theropods in Central Asia. To further advance research, the study authors are sharing 3D models of all the bones, encouraging other researchers to examine them. “These models are now available online and allow researchers worldwide to carry out follow-up studies and make 3D prints,” explained study co-author Oliver Wings, the director of the Bamberg Natural History Museum in Germany. This open access to the digital models will undoubtedly propel further research and shed light on the fascinating world of Jurassic theropods in Central Asia.
