A venomous reptile from the Triassic period, named
Microzemiotes sonselaensis, reveals unexpected secrets about the evolution of predation strategies.
Discovered in the Chinle Formation of Arizona, this fossil provides valuable insight into ecosystems from 200 million years ago. It represents a vital link between modern reptiles and their ancestors.
Left dentary (partial) of the holotype Microzemiotes sonselaensis DMNH PAL 2018-05-0017.
(A) Photograph of the holotype Microzemiotes sonselaensis DMNH PAL 2018-05-0017,
(B, C) three-dimensional rendering and line drawing of the dentary in lingual view,
(D, E) labial view and (F, G) dorsal view.
The scale bar equals 0.04 inches (1 mm), the arrow points forward. Abbreviations: im, intramandibular; mec, Meckelian canal; fac, facet; f, foramen; sa, surangular; vg, venom groove. The well-preserved fossil presents part of the jaw. The teeth display characteristic grooves, similar to those of modern venomous lizards. These features suggest an efficient method for injecting venom into prey. Before this discovery, evidence of venom use in Upper Triassic reptiles was limited to isolated teeth from another species,
Uatchitodon. Microzemiotes thus becomes the second known venomous reptile from that era.
What is even more intriguing is the size of Microzemiotes' teeth, ten times smaller than those of Uatchitodon. This observation suggests an independent evolution of venom in different reptile lineages.
This discovery broadens our understanding of the ecosystems in which these reptiles lived. By adding Microzemiotes to the list of venomous reptiles, scientists can better comprehend the interactions within these ancient communities. As highlighted by the new data, the evolution of venom may reveal a diversity of adaptations among reptiles. This phenomenon challenges the notion of a single evolutionary path towards venomousness.
Comparing Microzemiotes to modern reptiles, such as rear-fanged snakes and helodermatid lizards, could provide clues about the evolution of venom systems. This offers a new perspective on how these hunting strategies emerged.
This venomous Triassic reptile reshapes our view of prehistoric reptiles. The study, published in the journal
PeerJ Life & Environment, sheds new light on the diversity of ancient life.
Article author: Cédric DEPOND