Naturwissenschaften

, Volume 97, Issue 12, pp 1117–1121

Grooves to tubes: evolution of the venom delivery system in a Late Triassic “reptile”

  • Jonathan S. Mitchell
  • Andrew B. Heckert
  • Hans-Dieter Sues
Short Communication

DOI: 10.1007/s00114-010-0729-0

Cite this article as:
Mitchell, J.S., Heckert, A.B. & Sues, H. Naturwissenschaften (2010) 97: 1117. doi:10.1007/s00114-010-0729-0

Abstract

Venom delivery systems occur in a wide range of extant and fossil vertebrates and are primarily based on oral adaptations. Teeth range from unmodified (Komodo dragons) to highly specialized fangs similar to hypodermic needles (protero- and solenoglyphous snakes). Developmental biologists have documented evidence for an infolding pathway of fang evolution, where the groove folds over to create the more derived condition. However, the oldest known members of venomous clades retain the same condition as their extant relatives, resulting in no fossil evidence for the transition. Based on a comparison of previously known specimens with newly discovered teeth from North Carolina, we describe a new species of the Late Triassic archosauriform Uatchitodon and provide detailed analyses that provide evidence for both venom conduction and document a complete structural series from shallow grooves to fully enclosed tubular canals. While known only from teeth, Uatchitodon is highly diagnostic in possessing compound serrations and for having two venom canals on each tooth in the dentition. Further, although not a snake, Uatchitodon sheds light on the evolutionary trajectory of venom delivery systems in amniotes and provide solid evidence for venom conduction in archosaur-line diapsids.

Keywords

VenomUatchitodonUatchitodon schneideriEvolutionary trajectoryTriassic

Supplementary material

114_2010_729_MOESM1_ESM.doc (53 kb)
ESM 1(DOC 53 kb)
114_2010_729_Fig3_ESM.jpg (1.2 mb)
Figure S1

Measurements taken from the Moncure Uatchitodon specimens. The mesial carina is at top, and the lingual surface is to the right. See Table S1 for results. (JPEG 1209 kb)

114_2010_729_Fig4_ESM.jpg (1.3 mb)
Figure S1

Measurements taken from the Moncure Uatchitodon specimens. The mesial carina is at top, and the lingual surface is to the right. See Table S1 for results. (JPEG 1209 kb)

114_2010_729_Fig5_ESM.jpg (1.7 mb)
Figure S1

Measurements taken from the Moncure Uatchitodon specimens. The mesial carina is at top, and the lingual surface is to the right. See Table S1 for results. (JPEG 1209 kb)

114_2010_729_MOESM2_ESM.pdf (3 kb)
Figure S4aGraphs showing the Uatchitodon lateral compression data (a, b) and size-related data (c, d). Lateral compression of aU. schneideri and bU. kroehleri. c Plot of the ln of the distance from the tip as a function of the ln of tooth width (least-squares regression yields an R2-ad = 0.97, p < 0.001) and d canal shape as a function of the fore-aft length and distance from the tip. (PDF 3 kb)
114_2010_729_MOESM3_ESM.pdf (3 kb)
Figure S4b(PDF 2 kb)
114_2010_729_MOESM4_ESM.pdf (10 kb)
Figure S4c(PDF 10 kb)
114_2010_729_Fig6_ESM.jpg (76 kb)
Figure S1

Measurements taken from the Moncure Uatchitodon specimens. The mesial carina is at top, and the lingual surface is to the right. See Table S1 for results. (JPEG 1209 kb)

114_2010_729_MOESM5_ESM.xls (36 kb)
Table S3(XLS 36 kb)

Copyright information

© Springer-Verlag (outside the USA) 2010

Authors and Affiliations

  • Jonathan S. Mitchell
    • 1
    • 2
  • Andrew B. Heckert
    • 2
  • Hans-Dieter Sues
    • 3
  1. 1.Committee on Evolutionary BiologyThe University of ChicagoChicagoUSA
  2. 2.Department of GeologyASU Appalachian State UniversityBooneUSA
  3. 3.Department of PaleobiologyNational Museum of Natural HistoryWashingtonUSA