The Caribbean Island of Anguilla in the north-eastern Lesser Antilles is home to one of the last populations of the Critically Endangered Lesser Antillean iguana Iguana delicatissima. This population is highly threatened primarily because of hybridisation with non-native Iguana iguana. This study assesses the degree of hybridisation between Anguilla’s Iguana species firstly using morphological characteristics and then genetic analysis to validate the genetic integrity of morphologically identified I. delicatissima. We also examined the genetic diversity of Anguilla’s I. delicatissima population, and that of a population on the nearby island of Îlet Fourchue, St Barthélemy. Forty-five iguanas were captured in Anguilla and 10 in St Barthélemy, and sequences from 3 nuclear and 1 mtDNA genes were obtained for each. Of the 45 iguanas captured in Anguilla, 22 were morphologically identified as I. delicatissima, 12 as I. iguana and the remainder were identified as hybrids. Morphological assignments were all confirmed by genetic analyses except for one I. iguana and one hybrid individual. These two individuals appeared likely to have originated following ancestral hybridisation events several generations ago. A significant paucity of genetic diversity was found within Anguillan and St Barthélemy I. delicatissima populations, with a single haplotype being identified for each of the three nuclear genes and the mtDNA sequence. This study highlights the urgency for immediate action to conserve Anguilla’s remnant I. delicatissima population. Protection from hybridisation will require translocation to I. iguana-free offshore cays, with supplementary individuals being sourced from neighbouring islands to enhance the genetic diversity of the population.

小安的列斯东北部的加勒比海安圭拉岛是极度濒危的小安的列斯鬣蜥鬣蜥Iguana delicatissima的最后一批居民的家。该种群受到高度威胁，主要是因为与非本地鬣蜥杂交。本研究首先通过形态学特征评估安圭拉鬣蜥物种之间的杂交程度，然后通过遗传分析来验证形态学鉴定的I. delicatissima的遗传完整性。我们还检查了安圭拉I. delicatissima的遗传多样性人口，以及附近的圣巴托洛缪岛ÎletFourchue岛上的人口。在安圭拉捕获了45只鬣蜥，在圣巴托洛缪岛捕获了10只，分别获得了3个核基因和1个mtDNA基因的序列。在安圭拉捕获的45只鬣蜥中，有22只在形态学上被鉴定为I. delicatissima，12只被鉴定为I. iguana，其余被鉴定为杂种。除了一只鬣蜥和一只杂种个体外，所有遗传形态都通过遗传分析得到了证实。这两个人似乎可能是几代人祖传事件之后起源的。在安圭拉和圣巴塞洛缪一世发现了显着的遗传多样性。种群，为三个核基因和mtDNA序列中的每一个鉴定出一个单倍型。这项研究强调了立即采取行动保护安圭拉残余的地衣芽孢杆菌种群的紧迫性。保护免受杂交将需要转移到无鬣蜥的离岸珊瑚礁，并从邻近的岛屿上寻找补充个体，以增强种群的遗传多样性。