Plicidentine and the repeated origins of snake venom fangs

August 14, 2021

Alessandro Palc (1,2), Aaron R. H. LeBlanc (3,5), Olga Panagiotopoulou (6), Silke G. C. Cleuren (7), Hyab Mehari Abraha (6), Mark N. Hutchinson (1,2), Alistair R. Evans (7,8), Michael W. Caldwell (3,4), Michael S. Y. Lee (1,2)
Proceedings of the Royal Society B, 288, Issue 1956, August 2021. DOI: 10.1098/rspb.2021.1391


Serpentes; Ophidia; Colubroidea; fangs; venom groove; development


Snake fangs are an iconic exemplar of a complex adaptation, but despite striking developmental and morphological similarities, they probably evolved independently in several lineages of venomous snakes. How snakes could, uniquely among vertebrates, repeatedly evolve their complex venom delivery apparatus is an intriguing question. Here we shed light on the repeated evolution of snake venom fangs using histology, high-resolution computed tomography (microCT) and biomechanical modelling. Our examination of venomous and non-venomous species reveals that most snakes have dentine infoldings at the bases of their teeth, known as plicidentine, and that in venomous species, one of these infoldings was repurposed to form a longitudinal groove for venom delivery. Like plicidentine, venom grooves originate from infoldings of the developing dental epithelium prior to the formation of the tooth hard tissues. Derivation of the venom groove from a large plicidentine fold that develops early in tooth ontogeny reveals how snake venom fangs could originate repeatedly through the co-option of a pre-existing dental feature even without close association to a venom duct. We also show that, contrary to previous assumptions, dentine infoldings do not improve compression or bending resistance of snake teeth during biting; plicidentine may instead have a role in tooth attachment.

How Our Software Was Used

Dragonfly was used to perform 3D visualization, imaging and segmentation.

Author Affiliation

(1) College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia.
(2) South Australian Museum, North Terrace, Adelaide, SA 5000, Australia.
(3) Department of Biological Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9.
(4) Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9.
(5) Faculty of Dentistry, Oral and Craniofacial Sciences, Guy’s Campus, King’s College London, London WC2R 2LS, UK.
(6) Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC 3800, Australia.
(7) School of Biological Sciences, Monash University, VIC 3800, Australia.
(8) Geosciences, Museums Victoria, Melbourne, VIC 3001, Australia.