What Triturus newts can tell us about diversification and evolution within hybrid zone?
2019
Document Type:
Conference object (Published version)
,
© 2019 by the University of Milan, the University of Pavia, the Natural History Museum of Milan and the University of Milano-Bicocca
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Show full item recordAbstract:
The natural hybrid zone of Triturus ivanbureschi and T. macedonicus in the central Balkan Peninsula with
a specific species displacement scenario provides an excellent background for evolutionary studies. We set up a
common garden experiment for breeding and reciprocal crossing of these two species from populations out of the
hybrid zone. We collected data on life-history and morphological diversification throughout ontogeny. Our results
showed that there are no pre- or postzygotic reproductive barriers, with proven fecundity of F1 generation in all
crossings. Reproductive characteristics and survival rates were similar for both species and their hybrids.
Hybridization significantly affects morphological variation, with hybrids showing distinct tail and head
morphology compared to parental species. The head shape ontogeny from hatchling to metamorphosed stage was
used to explore postembryonic ontogenetic trajectories and to test whether metamorphosis acts as developmental
constraint. Differences in the developmental rate of the two species were found. Hybrids had intermediate values
relative to parental species. Also, obtained results revealed that metamorphosis cannot be regarded as a
developmental constraint for salamander head shape. Overall, results obtained from the common garden
experiment provided an insight into evolutionary mechanisms that lead to divergence from the common ancestral
developmental program and evolution of ontogenies in the hybrid zone.
In:
- XX European Congress of Herpetology. Program & Abstracts; 2019 Sep 2-6; Milan, Italy. Milan, Italy: University of Milan, the University of Pavia, the Natural History Museum of Milan and the University of Milano-Bicocca; 2019. p. 166.