據(jù)2月5日的《科學(xué)》雜志報(bào)道說(shuō),，新的研究也許能夠解釋蟾蜍為什么能夠在僅僅5500萬(wàn)年之中就能夠在大部分的陸地生根繁殖。 蟾蜍科中已知的品種有500個(gè)左右,，它們?cè)谌澜缯紦?jù)著多種不同的棲息地,。 有些蟾蜍（如五彩蟾蜍）存在于小面積的地區(qū)，它們非常脆弱,；另外有些蟾蜍（如甘蔗蟾蜍）則以它們的適應(yīng)能力及一種 異?？斓乃俣葋?lái)擴(kuò)大其活動(dòng)范圍而著稱。
Ines Van Bocxlaer及其一個(gè)國(guó)際性團(tuán)隊(duì)的同僚對(duì)與蟾蜍地理分布范圍有關(guān)的不同特性的進(jìn)化史進(jìn)行了重構(gòu),，并發(fā)現(xiàn)了7種可能使蟾蜍能夠擴(kuò)大其活動(dòng)范圍的特性,。 文章的作者報(bào)告說(shuō)，比如,，那些無(wú)需依賴永久的有水環(huán)境或潮濕空氣的成年蟾蜍會(huì)有較大的分布范圍,。 那些能夠在不同的水體中產(chǎn)卵的蟾蜍,，那些幼體能夠從環(huán)境中而非從其母體攝取食物的蟾蜍，以及那些產(chǎn)卵數(shù)較多的蟾蜍都可能會(huì)有較為廣泛的分布,。
文章的作者提出,，大多數(shù)的原種蟾蜍都累積有這些特性，從而建立了一種可使該群體擴(kuò)大和發(fā)散的“分布區(qū)擴(kuò)大的表型”,。 除了能夠解釋這些物種在遠(yuǎn)古時(shí)期的發(fā)散之外,，這一研究的框架可幫助解釋當(dāng)代的擴(kuò)散性物種（如甘蔗蟾蜍）的進(jìn)化背景。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 5 February 2010: DOI: 10.1126/science.1181707
Gradual Adaptation Toward a Range-Expansion Phenotype Initiated the Global Radiation of Toads
Ines Van Bocxlaer,1 Simon P. Loader,2 Kim Roelants,1 S. D. Biju,3 Michele Menegon,4 Franky Bossuyt1,*
Recent studies have identified range expansion as a potential driver of speciation. Yet it remains poorly understood how, under identical extrinsic settings, differential tendencies for geographic movement of taxa originate and subsequently affect diversification. We identified multiple traits that predict large distributional ranges in extant species of toads (Bufonidae) and used statistical methods to define and phylogenetically reconstruct an optimal range-expansion phenotype. Our results indicate that lineage-specific range-shifting abilities increased through an accumulation of adaptive traits that culminated in such a phenotype. This initiated the episode of global colonization and triggered the major radiation of toads. Evolution toward a range-expansion phenotype might be crucial to understanding both ancient widespread radiations and the evolutionary background of contemporary invasive species such as the cane toad.
1 Biology Department, Amphibian Evolution Lab, Unit of Ecology and Systematics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
2 Department of Environmental Sciences, Section of Biogeography, University of Basel, 4056 Basel, Switzerland.
3 Systematics Lab, Centre for Environmental Management of Degraded Ecosystems (CEMDE), School of Environmental Studies, University of Delhi, Delhi 110 007, India.
4 Sezione di Zoologia dei Vertebrati, Museo Tridentino di Scienze Naturali, Via Calepina 14, I–38100 Trento, Italy.
