Lυrdυsaυrυs, river diпosaυr of the aпcieпt Sahara

One hundred fifteen million years ago, what is now the western Sahara Desert was a tropical rain forest lying on the equator. The lakes, rivers, swamps, and deltas were populated by dinosaurs that seem familiar, yet simultaneously alien. Perhaps the most unusual dinosaur that has been discovered there is Lurdusaurus arenatus.

Back then, the climate of the area was similar to the Amazon and Congo River basins of today. Unlike modern rain forests, which are primarily made up of flowering plants, the forests of ancient Niger were dominated by conifers similar to living monkey puzzle trees and Buddhist pines. Lurdusaurus lived alongside long-necked Nigersaurus and sail-backed Ouranosaurus, both herbivores, as well as carnivorous abelisaurs, spinosaurs, and carcharodontosaurs. The rivers were full of fish and patrolled by crocodilians, including the giant Sarcosuchus.

Lurdusaurus was a hulking behemoth related to Iguanodon, known from slightly older rocks in Europe. The proportions of its short, sturdy limbs show Lurdusaurus moved slowly on land while it grazed from the lower branches of conifers, and ferns in the understory. Recently, paleontologist Tom Holtz noted that the sturdy limbs and huge belly of Lurdusaurus suggest a semi-aquatic mode of life, similar to modern hippos.

Lurdusaurus arenatus. Julio LacerdaWhen first discovered, the heavy and rotund nature of Lurdusaurus reminded scientists of several extinct animals. Like giant ground sloths, it had a fat gut. The wide belly and flat back are similar to the armored dinosaurs known as ankylosaurs. Although it could not rely on speed to escape predators, its great size and enormous armored forelimbs show that it was no push-over. Like Iguanodon, it bore a giant spiked thumb, which offered some protection against crocodilians in the water.

The first specimen was discovered in 1965 in the desert of Niger, only about 100 meters (330 feet) from the first known specimen of its sail-backed relative Ouranosaurus. The skeleton was described and illustrated by Souad Chabli in a doctoral thesis in 1988. Lurdusaurus wasn’t formally named until 1999 when Philippe Taquet and Dale Russell published a short paper describing the spectacular specimen, but providing very few illustrations.

Despite its bizarre appearance and unusual habits, Lurdusaurus remains poorly known to scientists and the public alike. Unfortunately, the nearly complete skeleton has never been fully described nor illustrated in a scientific journal. As a result, the singular strangeness of Lurdusaurus is under-appreciated. It’s rarely mentioned in any detail in technical discussions, and hardly ever illustrated by artists. Hopefully the skeleton will soon be fully described and illustrated, allowing Lurdusaurus to take its place in the mind of the public as one of strangest of all dinosaurs.