Recent collecting and taxonomic studies of dung beetles of the genus Geotrupes Latreille (Coleoptera: Geotrupidae) in the mountains of Oaxaca have evidenced the existence of a vicariant speciation pattern, where one species occupies the northern mountain system and the other one the southern mountain range. A study of this possible vicariant speciation mechanism is presented using a paleobiogeographic mapping analysis of both Geotrupes species distribution during Late Quaternary glaciation events. Based on these paleomaps a possible speciation mechanism (vicariant speciation) is suggested, in which one common ancestor (mother species) lived at the bottom of the Valle de Oaxaca (Oaxaca Valley) during the last local glacial maximum (LLGM, 21-17.5 kyr) and whose possible continuous distribution was broken into two (or more) separated areas on mountaintops as the climate became warmer toward the present. We propose that the fragmentation and isolation of habitats may have promoted genetic differentiation of populations resulting in vicariant speciation, as suggested by a sky-island dynamic process. The example of a possible effect of the Little Ice Age in the mountains of Oaxaca is also discussed. Finally, a projection is made into the XXII century, based on climatic modeling predictions. These last results suggest the possible disappearance of the sky-island dynamic process through the accelerated speed of climatic change.

中文翻译：

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热带山脉过去和未来的天岛动态：墨西哥瓦哈卡的两种土螟（鞘翅目：土螟科）物种的模型

最近对瓦哈卡山区蜣螂属（鞘翅目：蜣螂科）蜣螂的收集和分类学研究证明存在替代物种形成模式，其中一个物种占据北部山脉系统，另一个物种占据南部山脉。使用对晚第四纪冰川事件期间两种 Geotrupes 物种分布的古生物地理绘图分析，提出了对这种可能的替代物种形成机制的研究。根据这些古地图，提出了一种可能的物种形成机制（替代物种形成），其中一个共同祖先（母种）在最后一次局部冰川盛期（LLGM，21-17）期间生活在瓦哈卡河谷（瓦哈卡河谷）底部。5 kyr），随着气候逐渐变暖，其可能的连续分布在山顶上被分成两个（或更多）独立的区域。我们认为栖息地的破碎和隔离可能促进了种群的遗传分化，从而导致了替代物种形成，正如天空岛动态过程所表明的那样。还讨论了瓦哈卡山区小冰河时代可能产生的影响的例子。最后，根据气候模型预测，对 22 世纪进行了预测。这些最后的结果表明，随着气候变化的加速，天岛动力过程可能会消失。我们认为栖息地的破碎和隔离可能促进了种群的遗传分化，从而导致了替代物种形成，正如天空岛动态过程所表明的那样。还讨论了瓦哈卡山区小冰河时代可能产生的影响的例子。最后，根据气候模型预测，对 22 世纪进行了预测。这些最后的结果表明，随着气候变化的加速，天岛动力过程可能会消失。我们认为栖息地的破碎和隔离可能促进了种群的遗传分化，从而导致了替代物种形成，正如天空岛动态过程所表明的那样。还讨论了瓦哈卡山区小冰河时代可能产生的影响的例子。最后，根据气候模型预测，对 22 世纪进行了预测。这些最后的结果表明，随着气候变化的加速，天岛动力过程可能会消失。