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Scientists Unveil Mystery Surrounding 500 Million-Year-Old Critter Without Anus_我的网站

A |     Researchers from China and the UK have solved the mystery surrounding Saccorhytus coronaries – a millimeter-long spiny creature that was found in 2017 and believed to have inhabited oceans 500 million years ago. The veil of mystery over the critter persisted for years, as the scientists could not locate the creature’s anus. Turns out – they should not have even tried.,The critter was originally determined to be a member of a deuterostomes group of animals - the ancestors to the modern vertebrates (including humans). However, scientists' latest research suggests that it actually belongs to another group called ecdysozoans – the predecessors of the modern spiders and various insects. As it turned out, the whole mishap happened over the creature's anus – or rather lack thereof.,Ecdysozoans normally have an anus and hence the critter was initially ruled not to belong to them. But, upon closer discovery using x-rays, scientists saw it resembles ecdysozoans internally more than the ancestors of the vertebrates.,Like them, Saccorhytus has a large mouth and also features tiny holes around it that served as bases for spines that kept the critter anchored in one place. Those holes also served as a source of confusion as they were originally believed to be gills – another mark of the proto-vertebrates.,'Ugliest I've Ever Seen': Fisherman Shares Pic of Mysterious Creature He Found in Australia29 June, 13:17 GMT,As to Saccorhytus' absence of anus, scientists are yet to find out what happened to it. One theory suggests that there was an even earlier representative of ecdysozoans that has not been discovered, but did not have an anus.,Another theory goes that Saccorhytus did not actually need one.,"It could be that it lost it during its own evolution - perhaps it didn't need one because it could just sit in one spot with one opening for everything," Emily Carlisle, one of the researchers, said.。    亚马逊将从现有合作伙伴美国航空运输服务集团(ATSG)租赁这10架飞机。此前，亚马逊已在2016年从ATSG租赁了20架波音767货运飞机。今年11月，亚马逊接收了第40架波音767货运飞机，使得正在使用的货运飞机已达40家。这10架新飞机将在未来两年加入亚马逊机队。届时，亚马逊的机队规模将增至50架。

B | 亚马逊还将于2019年在沃思堡机场开设一个新的地区航空枢纽，然后在2021年在辛辛那提/北肯塔基国际机场再开设一个航空枢纽。之前有报道称，ATSG将在未来三年收购20架从美国航空公司退役的二手波音767。

C | 这种客机可以改装为货运飞机，而且亚马逊很可能是主要客户。不过，ATSG在消息传出时拒绝点出亚马逊就是其客户。就在几天前，联邦快递淡化了亚马逊的威胁。联邦快递CEO史密斯对投资者表示：“目前，我们并未把他们视为同业竞争对手。

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