Firneno Thomas J, O'Neill Justin R, Itgen Michael W, Kihneman Timothy A, Townsend Josiah H, Fujita Matthew K
Department of Biology University of Texas at Arlington Arlington TX USA.
Department of Biology, Amphibian and Reptile Diversity Research Center University of Texas at Arlington Arlington TX USA.
Ecol Evol. 2021 Aug 11;11(18):12739-12753. doi: 10.1002/ece3.8018. eCollection 2021 Sep.
The delimitation of species is an essential pursuit of biology, and proper taxonomies are crucial for the assessment and conservation management of organismal diversity. However, delimiting species can be hindered by a number of factors including highly conserved morphologies (e.g., cryptic species), differences in criteria of species concepts, lineages being in the early stages of the speciation or divergence process, and discordance between gene topologies (e.g., mitonuclear discordance). Here we use a taxonomically confounded species complex of toads in Central America that exhibits extensive mitonuclear discordance to test delimitation hypotheses. Our investigation integrates mitochondrial sequences, nuclear SNPs, morphology, and macroecological data to determine which taxonomy best explains the divergence and evolutionary relationships among these toads. We found that a three species taxonomy following the distributions of the nuclear SNP haplotypes offers the best explanation of the species in this complex based off of the integrated data types. Due to the taxonomic instability of this group, we also discuss conservation concerns in the face of improper taxonomic delimitation. Our study provides an empirical and integrative hypothesis testing framework to assess species delimitation hypotheses in the face of cryptic morphology and mitonuclear discordance and highlights the importance that a stable taxonomy has over conservation-related actions.
物种的界定是生物学的一项基本追求，恰当的分类法对于生物多样性的评估和保护管理至关重要。然而，物种界定可能会受到多种因素的阻碍，包括高度保守的形态（如隐存种）、物种概念标准的差异、处于物种形成或分化过程早期阶段的谱系，以及基因拓扑结构之间的不一致（如线粒体与核基因的不一致）。在这里，我们利用中美洲一种分类混乱的蟾蜍物种复合体，该复合体表现出广泛的线粒体与核基因不一致，来检验界定假设。我们的研究整合了线粒体序列、核单核苷酸多态性、形态学和宏观生态数据，以确定哪种分类法能最好地解释这些蟾蜍之间的分化和进化关系。我们发现，基于核单核苷酸多态性单倍型的分布，将该复合体分为三个物种的分类法，在综合数据类型的基础上，能最好地解释该复合体中的物种情况。由于该类群分类的不稳定性，我们还讨论了在分类界定不当情况下的保护问题。我们的研究提供了一个实证性和综合性的假设检验框架，以评估在面对隐存形态和线粒体与核基因不一致时的物种界定假设，并强调了稳定的分类法对保护相关行动的重要性。
