From widespread to microendemic: molecular and acoustic analyses show that Ischnocnema guentheri (Amphibia: Brachycephalidae) is endemic to Rio de Janeiro, Brazil
From widespread to microendemic: molecular and acoustic analyses show that Ischnocnema guentheri (Amphibia: Brachycephalidae) is endemic to Rio de Janeiro, Brazil
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DOI：
10.1007/s10592-013-0488-5
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发表时间：
2013-10-01
影响因子：
2.2
通讯作者：
Vences, Miguel
中科院分区：
文献类型：
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作者：
Gehara, Marcelo;Canedo, Clarissa;Vences, Miguel
许多热带两栖动物物种被限制在非常小的范围内，这种微特有现象加上持续的栖息地丧失和对新出现的病原体的敏感性，危及这些物种的长期生存。不完整的分类学和分布知识可能会模糊保护评估，特别是在假定分布广泛的物种中，这些物种通常被认为是红色名单评估中最不受关注的物种，但实际上可能构成部分微型特有物种的复合体。斯坦达克纳的强盗青蛙Ischnocnema guentheri就是这样的例子，它与最近发现的Ischnocnema henselii一起，被认为占据了巴西大西洋森林的大部分。为了测试这些分类群是否可能构成一个范围受限的、因此可能受到威胁的物种复合体，我们分析了160个根氏原虫和/或亨氏原虫的两个分子标记，即16S rRNA(16S)和重组激活基因1(RAG1)。为了验证该复合体的单一性，16S分析还包括了密切相关的物种。来自分子数据和广告呼叫分析的一致证据支持该复合体中存在六个不同的物种：I.guentheri和I.henselii以及四个候选新种。这些谱系在大西洋森林中呈镶嵌分布，在一些地方是共域的，没有混合的迹象。它们的系统地理模式与大西洋森林的古模型部分一致，但也表明在不太稳定的地区存在微型避难所。I.guentheri，以前被认为是广泛分布的，只在它的类型地区被发现，这是里约热内卢市市区的一个保护区。尽管所研究的物种中没有一种受到高度灭绝的威胁，但我们建议在下一次全面更新巴西两栖动物红色名录时重新评估它们的IUCN威胁状态。
Many species of tropical amphibians are restricted to very small ranges, and this microendemism coupled with ongoing habitat loss and susceptibility to emerging pathogens imperils the long-term persistence of these species. Incomplete taxonomic and distributional knowledge may obscure conservation assessment, particularly in putatively widespread species that are typically considered to be of Least Concern in Red List assessments, but that in fact may constitute complexes of partly microendemic species. Such is the case in the Steindachner's Robber Frog, Ischnocnema guentheri which, together with the recently recognized Ischnocnema henselii, is thought to occupy most of the Brazilian Atlantic Forest. To test whether these taxa may constitute a species complex of range-restricted and thus potentially threatened species, we analyzed 160 samples of I. guentheri and/or I. henselii for two molecular markers, 16S rRNA (16S) and recombination activation gene 1 (RAG1). To verify the monophyly of the complex, closely related species were also included in the 16S analysis. Congruent evidence from the molecular data and from analyses of advertisement calls support the existence of six distinct species within the complex: I. guentheri and I. henselii as well as four candidate new species. The lineages are distributed as a mosaic in the Atlantic Forest and are sympatric at some localities without indication of admixture. Their phylogeographical pattern partially agrees with paleo-models for the Atlantic Forest, but also suggests the existence of micro-refugia in less stable areas. I. guentheri, previously considered to be widespread, was found only in its type locality, a reserve within the urban area of Rio de Janeiro city. Although none of the species studied appears highly threatened with extinction, we recommend their IUCN threat status to be re-evaluated carefully for the next comprehensive update of the Red List of Brazil's amphibians.