Questions to be investigated
Since the second half of the 19th century much attention has been paid to the wide spectrum of different morphologies of vertebral centra of Paleozoic and Mesozoic early tetrapods. In stem-tetrapods, temnospondyls, chroniosuchians, and seymouriamorphs the vertebral centrum is multipartite and is composed of inter-and pleurocentrum, whereas lepospondyls are normally characterized by a cylindrical, monospondylous vertebral body that consists of the pleurocentrum. Similarly, the cylindrical centrum is monospondylous in extant lissamphibians and fused to the neural arch. A contrasting pattern of vertebral ossification was described in early tetrapods in which the multipartite centra formed first as cartilaginous elements with subsequent ossification. In contrast, the monospondylous centrum of lepospondyls was formed by direct ossification without a cartilaginous precursor.
In this study, centrum morphogenesis is described for the first time based on bone histology of a wide range of finned stem-tetrapods and early tetrapods and is compared to stained growth series of different extant salamanders. The knowledge of the developmental origin of the tetrapod centrum is important not only for understanding the adaptation of vertebrates to a terrestrial existence, but also for reconstruction of the phylogenetic relationships between different basal tetrapod groups and their affinities with extant lissamphibians, the ancestry of the latter being still one of the most controversially discussed questions in vertebrate palaeontology.
Methodology
- Histological investigation of fossil bones by thin sections.
- Staining of larval salamanders with different staining techniques (Alcian blue & Alizarin red and type II collagen)
Duration
15.10.2012 – 28.02.2017
Funding
German Research Foundation DFG WI 3144/3-1
Selected publications
- Konietzko-Meier, D., Danto, M. and Gadek, K. (2014): “The microstructural variability of the vertebral centra among temnospondyl amphibians.” Biological Journal of the Linnean Society, 112(4), 747-764.
- Danto, M., Witzmann, F., & Fröbisch, NB. (2016): “Vertebral Development in Paleozoic and Mesozoic Tetrapods Revealed by Paleohistological Data.” PloS one, 11(4), e0152586.
- Danto, M., Witzmann, F., Pierce, SE. & Fröbisch NB. (2017): “Intercentrum versus pleurocentrum growth in early tetrapods: a paleohistological approach.” Journal of Morphology.