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论谱系地理和景观对花背蟾蜍Strauchbufo raddei释放叫声结构的影响

一项新的横跨东北亚的合作研究!在演化史和释放叫声的结构之间没有强相关性,释放叫声必须保守,如此才能作为有效的性识别和反捕食警报。与此前的发现相反,这里我们使用了广泛分布在东亚的花背蟾蜍Strauchbufo raddei作为研究模型,提供了景观屏障和过去冰川作用对谱系地理格局和释放叫声变异影响的证据。

这里,我们使用了化石校正的松散分子钟来估计分化的时间格局,并重建整个东亚的S. raddei线粒体谱系地理(图1)。此外,我们还推断了末次冰期蒙古-俄罗斯分支(N 类群=147)的种群动态,并比较了亨廷山山脉两侧、外贝加尔地区和阿穆尔河流域分支释放叫声的地理变化因素。分子钟显示,两个谱系之间存在基本分裂:东北和南部起源于S. raddei约15.00至9.00 个百万年前。祖先范围估测阐明了,南部谱系,通过散布作用,起源于大约6.80个百万年前,并支持了南部范围向中亚草原扩展,北部范围向今天的外贝加尔地区扩展,约2.60 个百万年前(图1)。

图1.根据893 bp 的CR片段推断的Strauchbufo raddei(N=288)的分化时间估算校准树。分支的颜色和范围的起源也采用类似的颜色编码。每个分支(N=6)的特定景观嵌入在时间树的相应节点旁边。

我们的研究结果还支持,隔离的西北亨廷分支和广泛分布在黑龙江流域的东部亨廷分支之间的释放叫声的显著差异(图2)。很可能,释放叫声的变化归因于北部分支中的一个近期的种群扩张,适用了冰川后北部避难所的模式,该模式仅限于亨廷山脉的西边缘,南部谱系的外贝加尔地区(图2)。因此,我们阐明了花背蟾蜍的释放叫声反映了分支内的谱系地理结构。

图2:Strauchbufo raddei的两个不同分支的波形图、时间树和释放叫声特征。柱状图显示了两个谱系的叫声之间的地理差异:分别位于蒙古和俄罗斯的东北分支(橙色)和南部起源分支(蓝色)。地图上的颜色与柱状图的颜色相匹配。波形图中描述了两个分支之间显著不同的释放叫声特征(叫声持续时间、上升阶段和下降阶段)。

Othman S. N., Choe M., Chuang M.-F., Purevdorj Z., Maslova I., Schepina N., Jang Y. & Borzée A. (2022). Across the Gobi Desert, impact of landscape features on the biogeography and phylogeographically-structured release calls of the Mongolian Toad Strauchbufo raddei in East Asia. Evolutionary Ecology. In press. DOI: 10.1007/s10682-022-10206-4

Impact of phylogeography and landscapes on the structure of release calls in the Mongolian toads, Strauchbufo raddei

New collaborative study from across northeast Asia! Also explained on YouTube! There is no strong relation between evolutionary history and the structures of release calls as release calls must be conserved to be effective as sex recognition and anti-predator alarms. Contrary to earlier findings, here we provide evidence on the effect of landscape barrier and past glaciations on the patterns of phylogeography and release call variability, using the widespread Mongolian toad Strauchbufo raddei distributed across East Asia as study model.

Here, we enforced a fossil-calibrated relaxed clock to estimate the temporal pattern of divergence and to reconstruct the mitochondrial phylogeography of S. raddei across East Asia (Figure 1). Additionally, we inferred the population dynamic of the Mongolian-Russian clades (N taxa = 147) over the last glacial periods, and we compared the geographic variations in the release calls for the clades occurring in either side of the Hentiyn mountains range, the Transbaikal area and the Amur River basin. Molecular dating suggested a basal split between two lineages: the northeastern- and southern-originated of S. raddei c. 15.00 to 9.00 Mya. Ancestral range estimation elucidated the emergence of southern-originated lineage c. 6.80 Mya by dispersals, and supported a southern range expansion towards the central Asian steppes and a northern expansion towards present-day Transbaikal area c. 2.60 Mya (Figure 1).

Figure 1. Calibrated tree with estimated divergence for Strauchbufo raddei (N = 288) inferred from 893 bp of the CR fragment. The colour for the clades and the origins of ranges are similarly colour coded. The specific landscape for each clade (N = 6) is embedded next to the corresponding node of the timetree.

Our findings also supported significant differences in the release calls between the isolated north-western Hentiyn clade and the eastern Hentiyn clade distributed widely across the Amur River Basin (Figure 2). Likely, the variation in the release calls attributes to the recent population expansion for one of the northern clades supported the pattern of post-glacial northern refugia restricted to the west margin of Hentiyn Mountains, and Transbaikal area for the southern lineage (Figure 2). Therefore, we clarified that release calls of the Mongolian toad reflect the phylogeographic structures within the clades.

Figure 2: Oscillogram, tree time and release call characteristics of Strauchbufo raddei from two divergent clades. The bar chart shows the geographic variations between the calls of the two lineages: the northeastern clade (orange) and the southern originated clade (blue) in Mongolia and Russia. The colours on the map match with the colours of the bar charts. The release call characteristics that significantly differed between the two clades (call duration, rise time and fall time) are described in the oscillogram.

Othman S. N., Choe M., Chuang M.-F., Purevdorj Z., Maslova I., Schepina N., Jang Y. & Borzée A. (2022). Across the Gobi Desert, impact of landscape features on the biogeography and phylogeographically-structured release calls of the Mongolian Toad Strauchbufo raddei in East Asia. Evolutionary Ecology. In press. DOI: 10.1007/s10682-022-10206-4

从野外到我们的餐桌:运用多种手段解译东北亚林蛙贸易的隐蔽性

实验室新发表的关于东北亚林蛙(Rana sp.)贸易的论文,论文阐明了隐种的划定,以及用于物种识别的形态学方法,以避免对鉴定有误的个体开展交易。

两栖动物的国际贸易增加了全世界和东北亚的物种入侵风险。为了解该地区的两栖动物贸易状况,我们首先开发了物种精准鉴定方法及工作流程,以指导大规模的物种鉴别,分析物种贸易路径;进而,利用进口到韩国的隐种林蛙检测我们的工作流程有效性。

在校准的时间树上确定OTUs的比较物种划界和匹配的比较形态计量学。

该工作流程结合了形态计量学、系统发育特征、物种鉴定模型和系统地理学,从进口到韩国的171个标本中成功鉴定出三种非本地物种:中国林蛙、黑龙江林蛙和高原林蛙。

使用机器学习法和贝叶斯因子定界法评估四种常用的物种鉴定、分类模型(BLAST、ABGD、sGMYC和bPTP),并从171个个体中分离出12个分类单元(OTU)。然后,我们将来自12个OTU的信息进行组合,建立16S系统发育树,包括交易标本和对照标本(n=230)。

中新世以来东北亚部分选定林蛙趾蹼的表型演化。

基于模型的OTUs和系统发育揭示了贸易的林蛙个体可能广泛来源于野生环境,它们养殖场循环,然后融入合法贸易。除了遗传因素外,我们的形态计量学结果还表明,韩国特有物种,特别是桓仁林蛙和贸易中涉及的林蛙之间具有极高的表型隐蔽性。

然而,性状进化结果也点明了过去12.0 Mya中,林蛙趾蹼的独立进化模式,这很可能是整个东北亚林蛙物种鉴别的一个非常有用的关键特征。基于本文开发的大规模物种鉴别工作流程,我们建议东北亚地区制定林蛙物种贸易监测机制,并制定相关法律。

Othman S. N., Shin Y., Kim H.-T., Chuang M.-F., Bae Y., Hoti J., Zhang Y., Jang Y. & Borzée A. (2022).Evaluating the efficiency of popular species identification analytical methods, and integrative workflow using morphometry and barcoding bioinformatics for taxonomy and origin of traded cryptic brown frogs.Global Ecology and Conservation. 38:e02253. DOI: 10.1016/j.gecco.2022.e02253

朝鲜半岛一极危、狭域分布爪鲵属Onychodactylus新种

通过多项合作包括描述,发布的新出版物 Onychodactylus sillanus 即新罗爪鲵!

即新罗爪鲵(Onychodactylus sillanus) 的一生

尚未被学界正式描述的物种往往都难以得到有效的保护,不论它们的受威胁等级有多高。尽管韩国境内的栖息地质量近年来持续衰退,但其国内两栖动物分类学和保护生物学的研究仍处于较滞后的状态。

例如,尽管已有研究表明爪鲵属Onychodactylus在朝鲜半岛最南端存在一个独立演化支系,与其姐妹种韩国爪鲵Onychodactylus koreanus分化时间已达6.82百万年,且该独立演化支系受到严重的人为活动干扰威胁,但至今该支系依旧未得到妥善的法律保护。该研究结合形态、分子和模型模拟,确定了韩国爪鲵属这一独立演化支系的分类地位,将其描述为一新种,即新罗爪鲵Onychodactylus sillanus sp. nov. 

即新罗爪鲵(Onychodactylus sillanus) 的分布范围、适宜生境和系统发育关系。

此外,依据IUCN标准和不同温室气体的典型浓度路径(Representative Concentration Pathways, RCPs),研究评估了新种的生存威胁、栖息地破坏程度和灭绝可能性。依据多个不同的气候变化模型,研究结果预测在新种未来三代的时间内其适宜栖息地将会缩减87.6%–97.3%,而依据IUCN标准A3,这样的种群变化趋势应被评为极危CR。研究结果可以为将来开展针对性保护行动提供理论支撑

未来气候变化对即新罗爪鲵(Onychodactylus sillanus) 适宜生境的潜在影响

Borzée A., Shin Y., Poyarkov N. A., Jeon J. Y., Baek H. J., Lee C. H., An J., Hong Y. J., Min M-S. (2022).  Dwindling in the mountains: description of a critically endangered and microendemic Onychodactylus species (Amphibia, Hynobiidae) from the Korean Peninsula. Zoological Research. 43(5):750-755. DOI: 10.24272/j.issn.2095-8137.2022.048

Attendance to the Graduate Summer Course in Bioacoustics (Denmark)

Vishal Kumar Prasad presented a poster/graphical summary about his recent publication “Vocal behaviour of Balloon frogs” at the Southern Denmark University in Odense, Denmark on 7 August 2022. The poster presentation was one of the programs of the biennial international Ph.D. course on bioacoustics he is participating in.

Vishal Kumar Prasad with  Prof. Jakob Christensen-Dalsgaard (course director) and other participants.