Rivaling the World's Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar
Rivaling the World's Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar
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DOI：
10.1371/journal.pone.0031314
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发表时间：
2012-02-14
期刊：
影响因子：
3.7
通讯作者：
Vences, Miguel
中科院分区：
文献类型：
--
作者：
Glaw, Frank;Koehler, Joern;Vences, Miguel
背景：马达加斯加树叶变色龙的一个支系，微小布鲁克斯族，已知含有世界上最小的羊膜动物之一的物种。我们报告了这些小型蜥蜴以前未被发现的辐射，包括上文描述的四个新物种。方法论/主要发现：新发现的物种似乎局限于马达加斯加最北部的单一地区，主要是喀斯特地区：Brookesia fikens sp.。N.来自安卡拉那，白纹伊蚊B.deastata sp.N.来自Foret d‘Ambre，B.Micra sp.N.从小岛Nosy Hara和B.tristis sp.来自法国蒙塔涅的联合国。基于微小杆菌组所有命名种的一个线粒体和两个核基因的分子系统发育分析一致地支持这四个新种，以及来自马达加斯加北部蒙塔涅d‘Ambre的结核杆菌，形成了一个强有力的支系。这表明，这些物种在地理上的接近程度在这一小范围内具有多样性。包括新描述的四个新种在内的所有种都具有很深的遗传差异，在ND2基因上有18%-32%，在16S rRNA基因上有6%。尽管这一组中的所有物种表面上都有相似之处，但它们作为独立进化谱系的地位也得到了外部形态上的中等到强烈的差异以及半腱结构上的明显差异的支持。结论/意义：新发现的矮小变色龙物种代表了显著的小型化和微特有现象，表明马达加斯加爬行动物可能存在范围大小与身体大小的关系。新描述的Brookesia Micra雄性口吻最大长度为16毫米，两性总长度不到30毫米，是世界上最小的羊膜脊椎动物之一。由于分布仅限于一个非常小的小岛，本种可能代表岛屿侏儒症的极端情况。
Background: One clade of Malagasy leaf chameleons, the Brookesia minima group, is known to contain species that rank among the smallest amniotes in the world. We report on a previously unrecognized radiation of these miniaturized lizards comprising four new species described herein.Methodology/Principal Findings: The newly discovered species appear to be restricted to single, mostly karstic, localities in extreme northern Madagascar: Brookesia confidens sp. n. from Ankarana, B. desperata sp. n. from Foret d'Ambre, B. micra sp. n. from the islet Nosy Hara, and B. tristis sp. n. from Montagne des Francais. Molecular phylogenetic analyses based on one mitochondrial and two nuclear genes of all nominal species in the B. minima group congruently support that the four new species, together with B. tuberculata from Montagne d'Ambre in northern Madagascar, form a strongly supported clade. This suggests that these species have diversified in geographical proximity in this small area. All species of the B. minima group, including the four newly described ones, are characterized by very deep genetic divergences of 18-32% in the ND2 gene and >6% in the 16S rRNA gene. Despite superficial similarities among all species of this group, their status as separate evolutionary lineages is also supported by moderate to strong differences in external morphology, and by clear differences in hemipenis structure.Conclusion/Significance: The newly discovered dwarf chameleon species represent striking cases of miniaturization and microendemism and suggest the possibility of a range size-body size relationship in Malagasy reptiles. The newly described Brookesia micra reaches a maximum snout-vent length in males of 16 mm, and its total length in both sexes is less than 30 mm, ranking it among the smallest amniote vertebrates in the world. With a distribution limited to a very small islet, this species may represent an extreme case of island dwarfism.