The region with the highest marine biodiversity on our planet is known as the Coral Triangle or Indo-Australian Archipelago (IAA)^1,2. Its enormous biodiversity has long attracted the interest of biologists; however, the detailed evolutionary history of the IAA biodiversity hotspot remains poorly understood³. Here we present a high-resolution reconstruction of the Cenozoic diversity history of the IAA by inferring speciation–extinction dynamics using a comprehensive fossil dataset. We found that the IAA has exhibited a unidirectional diversification trend since about 25 million years ago, following a roughly logistic increase until a diversity plateau beginning about 2.6 million years ago. The growth of diversity was primarily controlled by diversity dependency and habitat size, and also facilitated by the alleviation of thermal stress after 13.9 million years ago. Distinct net diversification peaks were recorded at about 25, 20, 16, 12 and 5 million years ago, which were probably related to major tectonic events in addition to climate transitions. Key biogeographic processes had far-reaching effects on the IAA diversity as shown by the long-term waning of the Tethyan descendants versus the waxing of cosmopolitan and IAA taxa. Finally, it seems that the absence of major extinctions and the Cenozoic cooling have been essential in making the IAA the richest marine biodiversity hotspot on Earth.

我们星球上海洋生物多样性最高的地区被称为珊瑚三角区或印度-澳大利亚群岛 (IAA) ^1,2 。其巨大的生物多样性长期以来引起了生物学家的兴趣；然而，人们对 IAA 生物多样性热点的详细进化历史仍然知之甚少 ³ 。在这里，我们通过使用综合化石数据集推断物种形成-灭绝动力学，对 IAA 新生代多样性历史进行了高分辨率重建。我们发现，自大约 2500 万年前以来，IAA 就表现出单向多样化趋势，随后大致逻辑增长，直到大约 260 万年前开始多样性稳定期。多样性的增长主要受多样性依赖性和栖息地大小的控制，也受到1390万年前后热应力缓解的促进。大约25、20、16、12和500万年前记录了明显的净多样化峰值，这可能与气候转变之外的重大构造事件有关。关键的生物地理过程对 IAA 多样性产生了深远的影响，特提斯后裔的长期衰退与世界性和 IAA 类群的增加就表明了这一点。最后，没有发生重大灭绝事件和新生代变冷对于使 IAA 成为地球上最丰富的海洋生物多样性热点至关重要。