Reconstruction of the life history traits in the giant salamander Aviturus exsecratus (Caudata, Cryptobranchidae) from the Paleocene of Mongolia using zygapophyseal skeletochronology

ABSTRACT

Here we describe life history traits in the giant cryptobranchid salamander Aviturus exsecratus from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found that Aviturus exsecratus had a similar time of the attainment of sexual maturity and decreasing of juvenile growth (5–8 years) and estimated body size at maturity (50–60% of the maximum size) as modern cryptobranchids. Maximum longevity estimated for A. exsecratus is about 25 years. A. exsecratus had a developmental trajectory similar to that of modern cryptobranchids and is not characterized by extended ontogeny.

Abbreviation

PIN: Paleontological Institute; Russian Academy of Sciences; Moscow; Russia.

KEYWORDS:

• Skeletochronology
• zygapophyses
• Aviturus
• Paleocene
• Mongolia

Acknowledgments

We are grateful to the staff of the Saint Petersburg State University Research Centre for X-ray Diffraction Studies (Saint Petersburg, Russia) for their help with using the Leica 2500P microscope. The authors thank Dorota Konietzko-Meier, Alexandra Houssaye and anonymous reviewer for providing helpful comments that improved the quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data can be accessed here.

Additional information

Funding

The laboratory work of PPS, VVK and EAB was supported by the Russian Scientific Fund project 14-14-00015. VVB, AGS and VKG were funded by RFBR (Russian Foundation for Basic Research) according to the research projects №№ 17-54-10013, 17-04-00410, 16-05-00711, 17-04-01937 and by the subsidy of the Russian Government to support the Program of ‘Competitive Growth of Kazan Federal University among World`s Leading Academic Centers’. EVS was supported by the government theme АААА-А17-117030310017-8