Giant tortoises have been found from the Plio-Pleistocene sediments of Tha Chang sandpits, Nakhon Ratchasima Province, Thailand. These tortoises are represented by several individuals and are described based on carapace, plastron, limb bones, and isolated plates. Three different morphotypes of epiplastral projection are recognized, pertaining to different sexes or different ontogenetic stages. Based on their large size, thick shell, single supracaudal, well-developed epiplastral projection, gulars covering anterior part of the entoplastron or in contact with the latter, and humeropectoral sulcus posterior to entoplastron, these Thai giant tortoises are assigned to the genus Megalochelys. Thai specimens show strong similarities with large tortoises from India as well as those from Flores and Timor, and are therefore very close morphologically to Melgalochelys atlas. Our study provides new evidence about polymorphism and additional information about distribution of Plio-Pleistocene fossil giant tortoises in South and Southeast Asia.

在泰国那空叻差玛省Tha Chang沙坑的上新世沉积物中发现了巨龟。这些乌龟由几个人代表，并根据甲壳，腹甲，肢骨和隔离板进行了描述。识别出三种不同形态的表皮质突，分别属于不同性别或不同个体发育阶段。基于它们的大尺寸，厚壳，单个supracaudal，发达epiplastral投影，gulars覆盖entoplastron的或与后者接触前部，和humeropectoral沟后方entoplastron，这些泰巨龟被分配给属Megalochelys。泰国标本与印度以及弗洛雷斯和帝汶的大型乌龟表现出强烈的相似性，因此在形态上与梅加洛奇利斯地图集非常相似。我们的研究提供了有关多态性的新证据，以及有关南亚和东南亚上新世更新世化石巨龟分布的更多信息。