To survive, evolution has developed many and diverse strategies. Among them, there is the production of venom, a toxic substance which is used to defend itself or even paralyze prey. Today, many reptiles have the ability to inject venom, particularly by biting. The poison, secreted by glandsglandscirculate in fine conduits located in the jaw, even in the teeth or hooks.
Few, if any, venomous dinosaurs
Although this mechanism is now well documented for modern species, it is difficult to know what its origins are. In 2009, a study suggested that a small dinosaur, the Sinornithosaurus haoianapossessed venom fangs. An interpretation which has, however, been contested. When Dilophosaurusmade famous in the film Jurassic Parkthere is nothing to suggest that he actually spat venom. If venomous dinosaurs do not seem to have been legion, what about other reptiles of the past?
Small venomous reptiles at the end of the Triassic
In the 1990s, the analysis of small fossilized teeth revealed thatUatchitodona small reptile that lived at the end of the Triassic about 200 million years ago, was almost certainly venomous.
The family tree of species venomousvenomous has, however, recently been completed, with the description of a new species, Microzemiotes sonselaensis. In an article published in the journal Paleontology and Evolutionary Sciencea team details the discovery of a jaw decorated with teeth that belonged to a small reptile measuring around thirty centimeters from the end of the TriasTrias him too. The analysis of fossilfossil reveals the presence of two deep grooves on each tooth, very similar to the venom-conducting grooves of current beaded lizards, or even certain snakes.
This discovery also shows that venom delivery systems have certainly evolved in parallel between different cladesclades. It appears in fact that Microzemiotes sonselaensis is not part of Toxicopheraa clade which nevertheless includes all current venomous reptiles.