HENDRICKX, C., ABDALA, F., CHOINIERE, J. 2016. Postcanine microstructure in Cricodon metabolus, a Middle Triassic gomphodont cynodont from south‐eastern Africa. Palaeontology, 59, 6, 851-861. DOI: 10.1111/pala.12263
Christophe Hendrickx, Fernando Abdala, and Jonah Choiniere- Christophe Hendrickx - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa (Email: christophendrickx@gmail.com)
- Fernando Abdala - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa (Email: nestor.abdala@wits.ac.za)
- Jonah Choiniere - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa (Email: jonah.choiniere@wits.ac.za)
- Manuscript Accepted: 31 August 2016
- Manuscript Received: 09 March 2016
Cricodon metabolus is a trirachodontid cynodont from the Anisian (Middle Triassic) of eastern and southern Africa. It has labiolingually expanded (gomphodont) postcanines but also a sectorial tooth in the last postcanine locus. In this paper, we examine the crown microstructure of isolated sectorial and gomphodont postcanines belonging to the holotype specimen of this taxon using scanning electron microscopy. The enamel of both teeth is prismless and composed of discontinuous columnar divergence units, supporting the consistent presence of synapsid columnar enamel in cynognathians. Abundant tubules and numerous irregularly spaced incremental lines are also visible in the enamel and dentine layers in each tooth. This study reveals that the enamel thickness varies along the tooth row in Cricodon as the enamel layer of the gomphodont postcanines is 11.5 times thicker than that of the sectorial crown. It is likely that this difference reflects occlusal stresses and fewer replacements in gomphodont postcanines relative to sectorial teeth. Approximately 100 incremental growth lines of von Ebner are present in the dentine layer, indicating that the deposition of the dentine by odontoblasts occurred for three months before the animal's death.
Data for this study are available in the Dryad Digital Repository http://dx.doi.org/10.5061/dryad.8d1t2 Wiley Online Library