Giant dwarfs: discovery of a radiation of large-bodied 'stump-toed frogs' from karstic cave environments of northern Madagascar
Giant dwarfs: discovery of a radiation of large-bodied 'stump-toed frogs' from karstic cave environments of northern Madagascar
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DOI：
10.1111/j.1469-7998.2010.00708.x
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发表时间：
2010-09-01
影响因子：
2
通讯作者：
Glaw, F.
中科院分区：
文献类型：
--
作者：
Koehler, J.;Vences, M.;Glaw, F.
马达加斯加特有的小水螅属（Stumpffia）通常由体小的陆生青蛙组成，它们的口孔长度为16毫米或更短，一些小型化的物种在成年期小至10毫米，只有两个物种的口孔长度超过20毫米。以前的研究已经为马达加斯加的微杂交种提供了平行小型化的证据，以前分配给Stumpffia的几个物种和候选物种可能属于其他尚未描述的属。在这里，相反地，我们报告了在马达加斯加北部发现的四个新物种的微hylids，其中两个比以前已知的所有Stumpffia都要大，但根据分子系统发育关系，它们显然都属于这个属。这四个物种都有完全发育的趾，关系密切，发生在岩溶石灰岩环境中，大多数标本都是在洞穴中收集的，这是一个以前不为人知的栖息地。这个新发现的大型和可能居住在洞穴中的斯坦普菲亚的辐射包括一个来自Nosy Hara的物种，一个来自Ankarana的物种，一个来自Ampombofofo的物种和一个来自Francais山脉的物种。在后一种中，标本可以达到28毫米的鼻口长度。这些新种在16S rRNA基因上存在3.8-8.6%的成对差异，并且在颜色、末端指盘的延伸、相对眼直径和相对头宽方面存在差异。我们讨论了1895年的Stumpffia madagascar Mocquard的现状，并认为它是一个有效的物种，可以参考Montagne d’ambre国家公园发现的两个小体物种之一。此外，我们的研究结果支持了cophyines是高度微地方性的，我们为这里描述的大型物种的小型化祖先提供了支持，从而证明小型化在进化上是可逆的。
The endemic Malagasy microhylid genus Stumpffia usually comprises small-bodied terrestrial frogs with snout-vent lengths of 16 mm or less, with some miniaturized species as small as 10 mm in their adult stage, and only two described species reaching over 20 mm in snout-vent length. Previous studies have provided evidence for parallel miniaturization in Malagasy microhylids, with several species and candidate species previously assigned to Stumpffia probably belonging to other, still undescribed genera. Here, conversely, we report on the discovery of four new species of microhylids from northern Madagascar, of which two are larger than all previously known Stumpffia, but all clearly belong to this genus based on molecular phylogenetic relationships. All four species have fully developed digits, are closely related and occur in karstic limestone environments, with most specimens collected in caves, a habitat formerly unknown for cophylines. This newly discovered radiation of large-bodied and supposedly cave-dwelling Stumpffia contains one species from Nosy Hara, one from Ankarana, one from Ampombofofo and one from Montagne des Francais, respectively. In the latter species, specimens can reach up to 28 mm snout-vent length. These new species are genetically differentiated from each other by 3.8-8.6% pairwise divergence in the 16S rRNA gene and furthermore by differences in coloration, extension of terminal finger discs, relative eye diameter and relative head width. We discuss the status of Stumpffia madagascariensis Mocquard, 1895 and consider it a valid species referable to one of the two small-bodied species identified from Montagne d'Ambre National Park. Furthermore, our results support that cophylines are highly microendemic and we provide support for a miniaturized ancestor of the large-bodied species described here, thus demonstrating that miniaturization is evolutionarily reversible.