Tuesday, January 26, 2021

[Herpetology • 2021] Discovery of the first Mascarene Giant Tortoise (Testudinidae: Cylindraspis) Nesting Site on Rodrigues Island, Indian Ocean


 Rodrigues giant tortoises on the Plaine Corail, 
based on a unique stuffed Saddleback Tortoise Cylindraspis vosmaeri male (MNHN 1883.558; centre left) and a complete carapace of Domed Tortoise C. peltastes (MNHN 7831; front). The Rodrigues rail Erythromachus leguati, a predator of tortoise eggs and young, forages amongst the tortoises. 
in Hume, Griffiths, ... et Bour, 2021. 
Illustration: Julian Pender Hume

Abstract
Five species of giant tortoise (genus Cylindraspis) once occurred in huge abundance on the Mascarene Islands of Mauritius, Réunion, and Rodrigues. They disappeared after colonisation of the island by humans in the 17th and 18th centuries, primarily due to over-hunting and predation of eggs and young by introduced pigs and cats. So rapid was their extinction that virtually nothing is known about their life history, especially nesting and egg-laying behaviour. Here we report the discovery on Rodrigues of the first Mascarene tortoise-nesting site, which contained intact nesting chambers, complete egg clutches and fossil remains of a known native predator of tortoise eggs. We further compare the nesting behaviour with the giant tortoises of Aldabra Atoll in the Seychelles and the Galapagos Archipelago in Ecuador and provide details of the decline and extinction of Mascarene tortoises, most notably those of Rodrigues, for which good historical records exist. 

Keywords: Mauritius, Réunion, Aldabrachelys giganteaChelonoidis, egg chamber, clutches, extinction 

A complete clutch of Cylindraspis vosmaeri eggs removed intact from PB4 on Rodrigues Island. The clutch contains 13 eggs. 
Scale bar = 100 mm.


A reconstruction of Rodrigues giant tortoises on the Plaine Corail, based on a unique stuffed Saddleback Tortoise Cylindraspis vosmaeri male (MNHN 1883.558; centre left) and a complete carapace of Domed Tortoise C. peltastes (MNHN 7831; front) (see Bour et al. 2014a). The Rodrigues rail Erythromachus leguati, a predator of tortoise eggs and young, forages amongst the tortoises. 
Illustration by Julian Pender Hume.

Two species of extinct giant tortoises, Cylindraspis vosmaeri (larger, saddlebacked) and C. peltastes (smaller, domed) in their native habitat on Rodrigues Island in the late 1600s when accounts indicate the herds of tortoises were so large and dense that it was possible to walk for long distances on their backs without touching the ground (Leguat 1707). 
Painting by Julian Pender Hume (from Griffiths et al. 2013).


Julian Pender Hume, Owen Griffiths, Aurèle Anquetil Andre, Arnaud Meunier and Roger Bour. 2021. Discovery of the first Mascarene Giant Tortoise Nesting Site on Rodrigues Island, Indian Ocean (Testudinidae: Cylindraspis). Herpetology Notes. 14; 103-116. biotaxa.org/HN/article/view/62722/64867