The ancient people of Madagascar described strange tales of crocodiles to the first explorers who arrived on the island in the 16th century. In his stories, he developed two types of animals: one slender that preferred to grow in rivers and the other was very strong which had disappeared in recent times along with the rest of the Madagascan megafauna. The former is now recognized as a distinct population of indigo crocodiles (Crocodylus niloticus) While in the second place, baptism Crocodile strong Or horned crocodiles have been in discussion for 150 years. Newer analyzes using DNA extracted from fossilized skulls finally settle this question.
A horned crocodile
Crocodile strong It was distinguished from other crocodiles by the presence of two horns on the posterior part of its skull, which are actually extensions of the squamosal bone present in all vertebrates. It is 5 meters long and can reach more than 150 kg. First described in the 1870s, especially by French naturalists Alfred Grandidier and Lone Valeant, It was considered as a new species crocodile, Or “real crocodiles” that include crocodiles from the Nile, Asia and America. In the early 20th century, scholars characterized them as populations derived from indigo crocodiles and finally, in 2007, another study expelled them outright from the genus. Crocodilus To inspire them between Osteolemus, Dwarf crocodile was found in West Africa.
Hard to decide! Especially since crocodiles have been represented by some 23 species, presenting many morphological similarities. They have been built on a stable body plan for about 150 million years, although at different times in the past they were much more diverse. The only way to properly place a horned crocodile in a phylogenetic tree is to study its DNA. So we should carry this precious molecule genetic code. After several extraction efforts, Evon Hekkala and researchers At the American Museum of Natural History in New York, the two skulls were eventually able to recover mitochondrial DNA from 1300 to 1400 years old.
Close to common ancestor
Results published in the magazine Communication biology, Keep Voay as “A Sister Line” Crocodilus And in fact the animals closest to the common ancestor of these two lineages originated around 25 million years ago. Another conclusion of this study: Real crocodiles are native to Africa and have migrated at least twice, each time, in the past to Madagascar, Australia and Asia, and part of the Caribbean and the Americas.