The British Herpetological Society

The Herpetological Journal is the Society's prestigious quarterly scientific journal. Articles are listed in Biological Abstracts, Current Awareness in Biological Sciences,Current Contents, Science Citation Index, and Zoological Record.

The 2017/18  impact factor of The Herpetological Journal is 1.268

ISSN 0268-0130


pdf 06. A latitudinal cline of dark plastral pigmentation in the tortoise Testudo hermanni in Greece

323 downloads

Open Access

pp.125-132

Authors: Ronald E. Willemsen And Adrian Hailey

Abstract: The area of dark pigmentation on the plastron of the tortoise Testudo hermanni shows a latitudinal cline over about 400 km in Greece, with populations in the south being darker. The carapace did not show the clinal trend, and pigmentation was not significantly related to longitude or altitude. We examined several possible explanations for the cline, including an effect of incubation temperature, random genetic variation, and adaptation to several environmental variables. The most likely explanation is selection for thermoregulation, with decreased dark pigmentation in the north reducing heat loss to the substrate by infra red radiation during activity. This hypothesis was supported by data on body (Tb) and substrate (T, ) temperatures in populations from northern, central and southern Greece. Tb was generally above T, , showing that heat would generally be lost rather than gained through the plastron, and the mean difference Tb -T, was greatest in the north: +6.6 °C, compared to +2.4 °C in the south. Mean Tb was lowest in the south (26.9°C, compared to 29.3°C in the north) and the slope of Tb on T, was about I (compared to 0.5 in the north). Thermoregulation in southern Greece is similar to that of tropical tortoises, with avoidance of overheating being the major problem, rather than elevation of Tb for activity.

Keywords: cline, pigmentation, Testudo, thermoregulation, tortoise

Download Access:

The latest 8 issues can be downloaded when logged in with a Herpetological Journal subscription membership.

Individual articles can be purchased for download.

Older issues and occasional Open Access articles are available for public download

Submissions:

For further information and submission guidelines please see our Journal Instructions to Authors

pdfBHS Ethics Policy

IMPORTANT NOTE - JUNE 2020

Please note that as from Volume 31 Number 1 (January 2021) on, the Herpetological Journal will be available as an online publication only - the last print edition will be Volume 30 Number 4.   

Aligning with this change, it is now no longer possible to purchase a subscription that includes a print copy of the HJ.  All members who have existing HJ print subscriptions that remain active as at end June 2020 will receive the full four 2020 print editions.  New subscribers or renewals after this time will only have option to subscribe to the online only subscription package.  Subscription pricing has been amended to reflect the content changes.