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This is Scientific American 60 Second Science, I am Christopher Intagliata, got a minute.

Scientists discover new species all the time—on the order of 15,000 a year. One of the latest additions to the tree of life is a new type of leopard¹ frog. Which might sound unremarkable, except for where it was found: New York City.

But how does a frog go unnoticed in the Big Apple? Well even experts have a hard time telling this new species from its northern and southern cousins on looks alone. But the new guy has a different croak², which raised ecologists' suspicions. So they tracked down four leopard frog populations with the unique call—including one within view of the Statue of Liberty—and took DNA³ samples.

As they suspected, the odd croakers weren't southern or northern leopard frogs, or even a mix. They had a genetic⁴ ancestry⁵ of their own—earning them new species status. Those results appear in the journal Molecular⁶ Phylogenetics and Evolution.

The frogs are tough New Yorkers—the center of their range appears to be Yankee Stadium. But the researchers say that the urban amphibians⁷ face threats like pesticides⁸ and infectious diseases. Not to mention real-life games of Frogger.

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1 leopard
n.豹
参考例句：
I saw a man in a leopard skin yesterday.我昨天看见一个穿着豹皮的男人。 The leopard's skin is marked with black spots.豹皮上有黑色斑点。

2 croak
vi.嘎嘎叫，发牢骚
参考例句：
Everyone seemed rather out of sorts and inclined to croak.每个人似乎都有点不对劲，想发发牢骚。 Frogs began to croak with the rainfall.蛙随着雨落开始哇哇叫。

3 DNA
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句：
DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。 Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

4 genetic
adj.遗传的，遗传学的
参考例句：
It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。 Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 ancestry
n.祖先，家世
参考例句：
Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。 He is an American of French ancestry.他是法国血统的美国人。

6 molecular
adj.分子的；克分子的
参考例句：
The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。 For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

7 amphibians
两栖动物( amphibian的名词复数 )；水陆两用车；水旱两生植物；水陆两用飞行器
参考例句：
The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。 Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

8 pesticides
n.杀虫剂( pesticide的名词复数 )；除害药物
参考例句：
vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜 There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。来自《简明英汉词典》