Ajnabia (AJ-nah-BEE-ah; “Foreign Wanderer”) is a genus of small hadrosaurid, or “duck-billed,” dinosaur that lived during the Late Cretaceous period, about 66 million years ago, in what is now Morocco, North Africa. The name Ajnabia comes from the Arabic word “ajnabi,” meaning “foreigner” or “stranger,” and “Odysseus” refers to the Greek hero known for his long journeys. This name highlights its surprising discovery in Africa, a continent where hadrosaurs were not previously thought to have lived. *Ajnabia* was first described in 2020 by paleontologist Nicholas Longrich and his team based on a partial upper jawbone and teeth.
Description and Classification
Ajnabia was a relatively small dinosaur for a hadrosaurid. Scientists estimate it grew to be about 3 meters (around 10 feet) long. Like other hadrosaurs, Ajnabia was an herbivore, meaning it ate plants. It likely walked mainly on its two hind legs (bipedal) but could also move on all fours (quadrupedal) when needed, perhaps for grazing. A key feature of hadrosaurs, including Ajnabia, was their complex dental batteries – tightly packed rows of hundreds of teeth designed for efficiently grinding tough plant material.
In terms of classification, Ajnabia belongs to the family Hadrosauridae. More specifically, it is placed within the subfamily Lambeosaurinae, a group often characterized by elaborate crests on their heads, though a crest for Ajnabia is unknown due to the limited fossil material. It is considered part of the Arenysaurini tribe, meaning its closest known relatives are hadrosaurs found in Europe, such as Arenysaurus and Pararhabdodon. This relationship suggests a remarkable journey for its ancestors.
Distinguishing Features
Ajnabia can be identified by several key characteristics, especially considering its unusual location:
- Its small size, making it one of the smaller known hadrosaurids.
- Specific features of its maxilla (upper jaw bone) and teeth are distinct from other known African plant-eating dinosaurs of its time but are very similar to those of European lambeosaurine hadrosaurs.
- Its presence in Africa is its most notable feature, as lambeosaurine hadrosaurs were primarily known from North America, Asia, and Europe before its discovery.
Paleoenvironment and Diet
Ajnabia lived at the very end of the Cretaceous period, just before the mass extinction event that wiped out the non-avian dinosaurs. Its fossils were found in phosphate deposits in Morocco, which were marine sediments at the time. This suggests that while Ajnabia lived on land, its remains were likely washed out to sea after death. The environment on land would have been coastal. It shared this ancient world with other dinosaurs, including the predatory abelisaurid Chenanisaurus, large titanosaurian sauropods, and various marine creatures like mosasaurs and plesiosaurs that swam in the nearby seas.
As an herbivore, Ajnabia would have fed on the vegetation available in Late Cretaceous North Africa. Its specialized dental batteries allowed it to eat a variety of tough plants, grinding them down efficiently before swallowing. The exact types of plants it consumed are not known, but it would have been adapted to the local flora of its coastal habitat.
Significance and Ongoing Research
The discovery of Ajnabia is highly significant because it was the first definitive evidence of a hadrosaur in Africa. This finding challenges previous understandings of dinosaur distribution, suggesting that hadrosaurs, specifically lambeosaurines from Europe, were able_to cross significant sea barriers to reach Africa. It implies that marine crossings, perhaps by swimming, drifting on vegetation mats, or “island hopping” over temporary land bridges, were possible for some dinosaurs.
Ongoing research focuses on finding more fossils of Ajnabia and other potential African hadrosaurs to better understand their diversity, anatomy, and how they arrived on the continent. Scientists are also studying the paleogeography of the Late Cretaceous to explore possible dispersal routes between Europe and Africa. The study of Ajnabia helps paint a richer picture of global biodiversity just before the end of the dinosaur age and shows that African dinosaur faunas were more interconnected with other continents than previously realized.