At the end of the Cretaceous Period, the island of Madagascar was home to a strange collection of creatures found nowhere else on the planet. Welcome to a tour of Madagascar's long-forgotten wonders...
Life in Madagascar was just as strange 70 million years ago as it is today during the Late Cretaceous Period. Some of the unusual species that lived on Madagascar included giant frogs, vegan crocodiles, and cannibal dinosaurs.
Cretaceous Madagascar fossils were discovered in 1895 at the Maevarano geological formation. Maevarano's strange fauna would take nearly a century to be fully realised, beginning with expeditions organised by Canadian palaeontologist David Krause in 1993. Krause's expeditions uncovered many of Maevarano's unique animals, ushering in a new era of palaeontology in Madagascar.
Maevarano's species evolved as a result of Madagascar's isolation. As it is now, Madagascar's island status allowed species to evolve independently from their mainland counterparts, resulting in the development of distinct traits. This article will introduce the strange animals of Maevarano as well as some facts about them. For the sake of clarity, I'll limit myself to the most notable species and list any others at the end. With that, please allow me to be your Cretaceous Madagascar tour guide!
Droughts & Floods: The Climate of Maevarano.
The Maevarano Formation was formed between 70 and 65 million years ago during the Maastrichtian period of the Late Cretaceous Period. Maastrichtian fossil sites are uncommon, making Maevarano one of the best examples of life just before dinosaur extinction. Madagascar had already become an island after breaking away from India 18 million years before.
Cretaceous Madagascar's climate was highly seasonal, with long dry seasons punctuated by intense wet seasons. Droughts were common, as evidenced by arid-forming rocks found throughout Maevarano.
Maevarano was a vast floodplain traversed by numerous rivers. Thirsty animals converged on dried riverbeds in search of water during dry seasons. Occasionally, these animals were unable to find water and died in the ancient riverbeds. When the rains returned, they pushed the animals' bodies downstream, resulting in the formation of mass burial sites. These bonebeds, which frequently contain multiple species buried on top of each other, highlight Maevarano's treacherous Cretaceous climate.
Meet the Species of an Island Nation: Dinosaurs
Majungasaurus crenatissimus was an 8-meter-long theropod whose ferocity made up for its lack of height! Majungasaurus was a well-studied abelisaurid dinosaur with a short and bumpy snout, arms smaller than T-rex, and a small horn atop its skull. Majungasaurus was no peaceful unicorn, make no mistake. Majungasaurus, the top predator of Maevarano, had teeth that shed every few months and ate everything from large sauropods to cannibalising other dinosaurs.
Masiakasaurus knopfleri: Another strange abelisaurid, Masiakasaurus was a small predator named after Dire Straits' lead singer, Mark Knopfler. The two-meter-long carnivore's lower jaw was unusual in that its frontmost teeth protruded from the jaw. It's unclear why Masiakasaurus developed this trait, but it could have helped it catch small, slippery prey like fish and a certain amphibian mentioned later in this article...
Rahonavis ostromi: A dromaeosaurid - or raptor - the size of a pigeon, Rahonavis is one of Madagascar's more unusual dinosaurs. Some palaeontologists believe Rahonavis was capable of flight due to the presence of rudimentary wings, though this is debatable. Rahonavis appears to be a bird in either scenario, demonstrating how little difference there is between some small dinosaurs and prehistoric birds.
Rapetosaurus and Vahiny: The island's largest herbivores were two titanosaurian sauropods, Rapetosaurus and Vahiny. Rapetosaurus was the more common of the two, with specimens ranging in age from 40-day-old babies to a few fragmentary adults. Vahiny was much rarer, with only a handful of bones known, though these are enough to establish the two as separate genera.
Two teeth discovered in 1926 were initially identified as belonging to a subspecies of Stegosaurus, but have since been re-identified as belonging to an ankylosaurid[vii]. Unfortunately, no other dinosaur remains have been discovered. Given the recent discovery of other ankylosaurs from southern continents, I'd be willing to bet that our mystery ankylosaur was a strange little dinosaur.
Birds:
Falcatakely forsterae: One of Maevarano's newest species, Falcatakely was a member of an ancient bird lineage known as the Enantiornithines. While this lineage died out with the dinosaurs at the end of the Cretaceous period, some of Falcatakely's characteristics were similar to those of modern birds, most notably its toucan-shaped beak. Falcatakely is a strange cross between modern and extinct birds, thanks to the presence of a single tooth on its beak.
Crocodiles:
Simosuchus clarki: Simosuchus may be the strangest animal in a land dominated by strange animals. Simosuchus, a meter-long pug-nosed crocodile with a stubby tail, defied its crocodilian ancestors by becoming a vegetarian. Simosuchus was a vegetarian crocodile. Despite popular belief, Simosuchus was not an outlier, as a few other prehistoric crocodiles evolved similar diets.
Mahajangasuchus insignis was the inverse of Simosuchus, a larger, predatory crocodile. Despite having mostly terrestrial ancestors, Mahajangasuchus evolved semiaquatic behaviors. Mahajangasuchus, with its broad skull and blunt teeth, would have been a ferocious predator if you got too close to the water...
Amphibians:
Beelzebufo ampinga: A contender for the strangest animal on Maevarano, Beelzebufo was not your average frog. Beelzebufo was the world's largest frog, measuring 40 centimetres and weighing 9 pounds. The 'devil frog' would have been terrifying to see, especially for the baby dinosaurs Beelzebufo could fit inside its mouth...
Mammals:
Vintana and Adalatherium: For many years, the Gondwanatheres - a mysterious group of Cretaceous and Paleogene mammals - were only known from their teeth. With the discovery of Vintana and Adalatherium, two Gondwanatheres with well-preserved skeletons, that has changed in recent years. These animals were badger-sized vegetarians who may have used nocturnal behaviours to survive in the Cretaceous Madagascar undergrowth.
Other Animals:
Maevarano's rocks are abundant with fish, snakes, and turtles. Madtsoia was the largest snake, reaching lengths of 8 metres and possibly constricting its prey. The fossil material of the turtle Sahonachelys was described in 2021, indicating that it was a suction-feeder of aquatic prey (perhaps like Beelzebufo tadpoles?).
There were crocodiles on land, including the "dog-croc" Araripesuchus. A variety of birds, including the genus Vorona, have also been discovered. Surprisingly, no pterosaurs have been discovered in Maevarano, though future excavations may unearth them.
The animals of the Maevarano Formation offer a unique look at life at the end of the Cretaceous period. Our animals took advantage of their island paradise, evolving into bizarre forms found nowhere else on the planet. When the dinosaurs went extinct 66 million years ago, the strange fauna of Madagascar went extinct with them.
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