Too hot to nest? In a hot summer the Tortoise Chersina Angulata can switch from nesting to facultative viviparity

In a captive colony of Chersina angulata in Cape Town, South Africa, we observed in 2015/16 retention of the last egg clutch inside the female until the hatching stage was reached, conforming to the generally accepted definition of viviparity. Retrospective climatic analysis indicates egg retention until the hatching stage co-occurred with unusually hot summer weather: the average air temperatures in December 2015 and January and February 2016 were higher than during the preceding five and the following 5 years when facultative viviparity could not be observed. Late December and January appears to be the critical period for females to either deposit their last clutch of the nesting season into a nest, or to retain the last clutch for embryonic development inside the female. Over the 28 December to 24 January period the minimum, average and maximum air temperatures in 2015–16 were about 3◦C higher than in the five following years

A population genetic analysis of the Critically Endangered Madagascar big-headed turtle, Erymnochelys madagascariensis across captive and wild populations

Erymnochelys madagascariensis is a Critically Endangered turtle endemic to Madagascar. Anthropogenic activity has depleted the wild population by 70% in the last century, and effective conservation management is essential to ensuring its persistence. Captive breeding was implemented to augment depleted populations in the southern part of Ankarafantsika National Park (ANP), when no genetic data were available for E. madagascariensis. It is unknown how much of the natural population’s diversity is encapsulated in captivity. We used eight microsatellite loci and fragments of two mitochondrial genes to identify the genetic structure of E. madagascariensis in the wild. Captive bred turtles were compared with wild populations in order to assess the representativeness of this ex situ conservation strategy for ANP. Six microsatellite clusters, ten cytochrome b, and nine COI haplotypes were identified across wild populations, with high genetic divergence found between populations in two groups of watersheds. Captive bred individuals represent three out of six sampled microsatellite clusters found in the wild and just one mitochondrial haplotype, possibly due to genetic drift. To improve genetic representation, the strategy of frequent interchange between captive and wild breeders within ANP should be revitalised and, as originally planned, hatchlings or juveniles should not be released beyond ANP

GONADAL CYCLES OF THE WESTERN AUSTRALIAN LONG-NECKED TURTLES CHELODINA OBLONGA AND CHELODINA STEINDACHNERI (CHELONIA CHELIDAE)

Volume: 14Start Page: 189End Page: 19

Chelonian vocal communication

Recently it was discovered that freshwater turtles communicate underwater by sound. The vocal repertoire of the Western Australian longneck turtle Chelodina colliei includes complex and percussive calls which are harmonically structured and frequency modulated, with dominant frequencies below 1 kHz and a range from around 100 to 3.5 kHz. Sounds with similar characteristics are used by the females of the South American river turtle Podocnemis expansa when migrating to nesting beaches and during communal nesting. Near term embryos inside eggs vocalize, and hatchlings emerging from nests and scampering across the beach and into the river continue to vocalize. In the water the adult females respond and the hatchlings then migrate with the females down the river, presumably to the flooded forests where they feed. Many unexplained aspects of aquatic turtles social behavior may eventually be explained when their vocalizations have been studied. © 2014 Springer Science+Business Media Dordrecht. All rights are reserved