The transition zones between and within biogeographic realms are a topical issue. Long ascribed to eastern Palaearctic, Iran was recently proposed as entirely pertaining to its western counterpart (featuring the ´Great Western Palaearctic`). Molecular and phenotypic information from polytypic taxa may help untangle the bioclimatic and environmental dynamics that shaped faunal distributions. In this study, we collected 221 black francolin (Francolinus francolinus Linnaeus, 1766) samples from Cyprus to Bangladesh and compared the spatial genetic structure as inferred from nine microsatellite loci with publically available bioacoustic data. We found striking overlap between the two sources of information, which pointed to the occurrence of a western and an eastern subdivision (FST = 0.435, P < 0.001) with a break across central Iran. When framed within the palaeoclimatic and geomorphological history of this region, we found that high connectivity among local subspecies was facilitated by warmer and more humid conditions preceding the cold-arid climatic phase associated with the last glacial stage. The subsequent temperature increase likely led to the substantial isolation of eastern and western black francolin populations to moist refuges. Overall, these results point to an intra-Palaearctic boundary crossing Iran longitudinally, thus raising prospect of compromise between the two most debated views.

中文翻译：

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分子分类学和古北界内边界：通过微卫星 DNA 对黑弗兰科林 (Francolinus francolinus) 生物地理学的新见解

生物地理领域之间和内部的过渡区是一个热门话题。长期以来，伊朗一直归属于东古北界，最近有人提出，伊朗完全属于其西方对应物（以“大西部古北界”为​​特色）。来自多型分类群的分子和表型信息可能有助于解开影响动物群分布的生物气候和环境动态。在这项研究中，我们收集了从塞浦路斯到孟加拉国的 221 个黑色 francolin (Francolinus francolinus Linnaeus, 1766) 样本，并将从 9 个微卫星位点推断的空间遗传结构与公开的生物声学数据进行了比较。我们发现两个信息来源之间存在惊人的重叠，这表明西部和东部细分（FST = 0.435，P < 0.001）发生在伊朗中部有中断。当以该地区的古气候和地貌历史为框架时，我们发现与末次冰期相关的寒冷干旱气候阶段之前的温暖和潮湿条件促进了当地亚种之间的高度连通性。随后的温度升高可能导致东部和西部黑鹧鸪种群被大量隔离到潮湿的避难所。总体而言，这些结果表明古北界内有一条纵向穿越伊朗的边界，从而提高了两种最具争议的观点之间达成妥协的可能性。随后的温度升高可能导致东部和西部黑鹧鸪种群被大量隔离到潮湿的避难所。总体而言，这些结果表明古北界内有一条纵向穿越伊朗的边界，从而提高了两种最具争议的观点之间达成妥协的可能性。随后的温度升高可能导致东部和西部黑鹧鸪种群被大量隔离到潮湿的避难所。总体而言，这些结果表明古北界内有一条纵向穿越伊朗的边界，从而提高了两种最具争议的观点之间达成妥协的可能性。