Macroevolutionary patterns in the diversification of parrots: effects of climate change, geological events and key innovations
Macroevolutionary patterns in the diversification of parrots: effects of climate change, geological events and key innovations
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DOI：
10.1111/j.1365-2699.2011.02555.x
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发表时间：
2011-11-01
影响因子：
3.9
通讯作者：
Hertwig, Stefan T.
中科院分区：
文献类型：
--
作者：
Schweizer, Manuel;Seehausen, Ole;Hertwig, Stefan T.
目的鹦鹉被认为起源于白垩纪的冈瓦那。树冠群鹦鹉最初的分裂将新西兰的分类群与现存物种分开，并被认为与新西兰从冈瓦那82-85 Ma的分离相吻合，假设鹦鹉的多样化主要是由替代形成的。然而，几个现存鹦鹉种群的分布模式不能不引用跨洋扩散来解释，这对这一假设提出了挑战。为了评估过去气候变化、板块构造和生态机会的影响的相对重要性，我们以外部鸟类化石为校准点，提出了鹦鹉多样性的时空框架。定位于澳大拉西亚、非洲、印度支那和新热带地区。使用贝叶斯松弛分子钟方法估计了发散日期和可信区间。考虑到区域间的时间连通性，对生物地理模式进行了评估。我们测试了鹦鹉的物种多样性是否随着时间的推移保持不变，以及一些鹦鹉种群是否比预期的物种丰富。结果鹦鹉冠群多样性开始的时间仅为58 Ma左右，发生在古近纪，明显晚于之前的想法。澳大拉西亚的狐猴，可能还有新热带的阿里尼，都被发现出人意料地物种丰富。在始新世/渐新世边界和中新世中期，在以全球冷却为特征的两个重大全球气候异常时期，鹦鹉的多样性可能会增加。主要结论鹦鹉的多样性是由气候和地质事件以及关键的创新所塑造的。由大陆解体引起的初始变化事件之后是跨洋扩散和局部辐射。气候变化和造山作用造成的生境变化可能通过提供新的生态机会和挑战，以及由于生境碎片化而造成的孤立，而成为多样性的催化剂。狐猴构成了唯一高度食蜜的鹦鹉分支，它们与形态创新相关的饮食变化可能是进化中的关键创新，使它们能够探索未被充分利用的生态位，促进它们的多样化。
Aim Parrots are thought to have originated on Gondwana during the Cretaceous. The initial split within crown group parrots separated the New Zealand taxa from the remaining extant species and was considered to coincide with the separation of New Zealand from Gondwana 82-85 Ma, assuming that the diversification of parrots was mainly shaped by vicariance. However, the distribution patterns of several extant parrot groups cannot be explained without invoking transoceanic dispersal, challenging this assumption. Here, we present a temporal and spatial framework for the diversification of parrots using external avian fossils as calibration points in order to evaluate the relative importance of the influences of past climate change, plate tectonics and ecological opportunity.Location Australasian, African, Indo-Malayan and Neotropical regions.Methods Phylogenetic relationships were investigated using partial sequences of the nuclear genes c-mos, RAG-1 and Zenk of 75 parrot and 21 other avian taxa. Divergence dates and confidence intervals were estimated using a Bayesian relaxed molecular clock approach. Biogeographic patterns were evaluated taking temporal connectivity between areas into account. We tested whether diversification remained constant over time and if some parrot groups were more species-rich than expected given their age.Results Crown group diversification of parrots started only about 58 Ma, in the Palaeogene, significantly later than previously thought. The Australasian lories and possibly also the Neotropical Arini were found to be unexpectedly species-rich. Diversification rates probably increased around the Eocene/Oligocene boundary and in the middle Miocene, during two periods of major global climatic aberrations characterized by global cooling.Main conclusions The diversification of parrots was shaped by climatic and geological events as well as by key innovations. Initial vicariance events caused by continental break-up were followed by transoceanic dispersal and local radiations. Habitat shifts caused by climate change and mountain orogenesis may have acted as a catalyst to the diversification by providing new ecological opportunities and challenges as well as by causing isolation as a result of habitat fragmentation. The lories constitute the only highly nectarivorous parrot clade, and their diet shift, associated with morphological innovation, may have acted as an evolutionary key innovation, allowing them to explore underutilized niches and promoting their diversification.