Extreme reversed sexual size dimorphism in the extinct New Zealand moa Dinornis
Extreme reversed sexual size dimorphism in the extinct New Zealand moa Dinornis
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DOI：
10.1038/nature01871
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发表时间：
2003-09-11
期刊：
影响因子：
64.8
通讯作者：
Cooper, A
中科院分区：
文献类型：
--
作者：
Bunce, M;Worthy, TH;Cooper, A
平胸恐鸟（Aves;恐鸟形目）是体重可达250公斤的大型重力门浏览者（参考文献1），在新西兰生物群中占主导地位，直到大约500年前灭绝。尽管有广泛的第四纪化石记录，恐鸟分类仍然存在问题（1-4），目前有11个物种被确认。在新西兰发现了三种恐鸟，它们在大小（背高1-2米）和质量（从34公斤到242公斤）上有明显的差异（1）。令人惊讶的是，古代线粒体DNA序列显示，这三个物种在每个岛屿内的遗传上是无法区分的，但形成了独立的北岛和南岛分支。在这里，我们显示，使用第一个性别连锁的核序列从一个灭绝的物种，在每个岛屿上的三个形态形式实际上只代表一个物种，其大小根据性别和栖息地显着变化。在这个性别大小极端颠倒的例子中，最大的雌性大约是最大雄性体重的280%和身高的150%，这在鸟类和陆生哺乳动物中是前所未有的。分子和古生物学数据的结合突出了分析灭绝群体的困难，即使是那些有详细化石记录的群体。
The ratite moa(Aves; Dinornithiformes) were massive graviportal browsers weighing up to 250 kg (ref. 1) that dominated the New Zealand biota until their extinction approximately 500 yr ago. Despite an extensive Quaternary fossil record, moa taxonomy remains problematic(1-4) and currently 11 species are recognized. Three Dinornis species were found throughout New Zealand and differed markedly in size(1-2 m height at back) and mass (from similar to34 to 242 kg)(1). Surprisingly, ancient mitochondrial DNA sequences show that the three species were genetically indistinguishable within each island, but formed separate North and South Island clades. Here we show, using the first sex-linked nuclear sequences from an extinct species, that on each island the three morphological forms actually represent just one species, whose size varied markedly according to sex and habitat. The largest females in this example of extreme reversed sexual size dimorphism were about 280% the weight and 150% the height of the largest males, which is unprecedented among birds and terrestrial mammals. The combination of molecular and palaeontological data highlights the difficulties of analysing extinct groups, even those with detailed fossil records.