Distinguishing coral species is not only crucial for physiological, ecological, and evolutionary studies but also to enable effective management of threatened reef ecosystems. However, traditional hypotheses that delineate coral species based on morphological traits from the coral skeleton are frequently at odds with tree-based molecular approaches. Additionally, a dearth of species-level molecular markers has made species delimitation particularly challenging in species-rich coral genera, leading to the widespread assumption that interspecific hybridization might be responsible for this apparent conundrum. Here, we used three lines of evidence—morphology, breeding trials, and molecular approaches—to identify species boundaries in a group of ecologically important tabular Acropora corals. In contrast to previous studies, our morphological analysis yielded groups that were congruent with experimental crosses as well as with coalescent-based and allele sharing-based multilocus approaches to species delimitation. Our results suggest that species of the genus Acropora are reproductively isolated and independently evolving units that can be distinguished morphologically. These findings not only pave the way for a taxonomic revision of coral species but also outline an approach that can provide a solid basis to address species delimitation and provide conservation support to a wide variety of keystone organisms. [Acropora; coral reefs; hybridization; reproductive isolation; taxonomy.]

中文翻译：

---

解决珊瑚物种划界难题

区分珊瑚物种不仅对生理、生态和进化研究至关重要，而且对于有效管理受威胁的珊瑚礁生态系统也至关重要。然而，根据珊瑚骨架的形态特征来描述珊瑚物种的传统假设经常与基于树的分子方法不一致。此外，缺乏物种水平的分子标记使得物种划界在物种丰富的珊瑚属中特别具有挑战性，导致人们普遍认为种间杂交可能是造成这一明显难题的原因。在这里，我们使用了三类证据——形态学、育种试验和分子方法——来确定一组具有重要生态意义的板状鹿角珊瑚的物种边界。与以往的研究相比，我们的形态学分析产生了与实验杂交以及基于聚结和基于等位基因共享的多位点物种划分方法一致的组。我们的研究结果表明，鹿角珊瑚属的物种是生殖隔离和独立进化的单位，可以在形态上进行区分。这些发现不仅为珊瑚物种的分类修订铺平了道路，而且概述了一种方法，可以为解决物种划界问题提供坚实的基础，并为各种关键生物提供保护支持。[鹿角珊瑚；珊瑚礁; 杂交；生殖隔离；分类。] 我们的研究结果表明，鹿角珊瑚属的物种是生殖隔离和独立进化的单位，可以在形态上进行区分。这些发现不仅为珊瑚物种的分类修订铺平了道路，而且概述了一种方法，可以为解决物种划界问题提供坚实的基础，并为各种关键生物提供保护支持。[鹿角珊瑚；珊瑚礁; 杂交；生殖隔离；分类。] 我们的研究结果表明，鹿角珊瑚属的物种是生殖隔离和独立进化的单位，可以在形态上进行区分。这些发现不仅为珊瑚物种的分类修订铺平了道路，而且概述了一种方法，可以为解决物种划界问题提供坚实的基础，并为各种关键生物提供保护支持。[鹿角珊瑚；珊瑚礁; 杂交；生殖隔离；分类。] [鹿角珊瑚；珊瑚礁; 杂交；生殖隔离；分类。] [鹿角珊瑚；珊瑚礁; 杂交；生殖隔离；分类。]