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[廣告]:

Rockies fossils yield 8 new species

A surprise fossil field at a glacier in B.C.'s Kootenay National Park contains at least eight new species that lived 505 million years ago.

Jean-Bernard Caron, curator of invertebrate paleontology at Toronto's Royal Ontario Museum, said the new arthropods (the group to which crabs and insects belong) and worms were found in an environment where paleontologists previously believed fossils could not be preserved or found.

The discovery means paleontologists might be able to find new fossils in similar environments that they had previously ignored.

"It opens up, I guess, a new terrain to explore," said Caron, who returned Thursday from a followup expedition to similar sites. "I think the chance to find new fossils in the future … will expand dramatically."

Descriptions of the new fossil field and the new species collected two years ago were published in the September issue of the journal Geology.

Fossils were first collected by a hiker walking on a trail near the Stanley Glacier in the park in the 1990s. The hiker contacted the Royal Ontario Museum, which sent researchers to collect fallen rock debris in the park in 1996.

Caron examined the rocks when he began working at the museum in 2006 and noticed that the fossils seemed to appear in a type of Rocky Mountain shale rock that hadn't been known for fossils before.

The rock dates back 505 million years ago, to the Middle Cambrian period — the same one represented by the Burgess Shale, which is located in the Rockies of Yoho National Park and considered one of the most important fossil fields in the world.

The Burgess Shale, located 40 kilometres northwest of the new fossil field, was once at the foot of an undersea cliff in tropical waters. Researchers believed the cliff provided an ideal environment for a diverse community of animals, and its harder rock prevented the fossil in the softer mud of the sea floor from being crushed by geological forces in hundreds of millions of years that followed.

The Stanley Glacier site represents a similar undersea environment, but with no evidence of any cliff nearby. It seems to have been above the Burgess Shale cliff.

Caron led a two-week expedition to the site in 2008, where researchers collected 2,000 specimens. Many of the species were previously known from other sites like the Burgess Shale, although some specimens were better preserved than any known before. However, eight were new, including a primitive arthropod predator that would have grabbed prey with its claws. It was named Stanleycaris after the glacier.

Caron said that's a lot of new species, considering that just 200 species have been discovered among more than 200,000 specimens collected from the Burgess Shale. He suggested the newly discovered animals may have been specifically adapted to that environment.

This August, Caron and his team went to look for similar sites along the same geological formation in the Rockies that yielded the Stanley Glacier site. They didn't find any new fossils this time, but plan to go back in the future.

http://www.cbc.ca/technology/sto ... tanley-glacier.html

2010-9-6 07:08 AM

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[廣告]:

卑诗省现化石宝藏内有未知动物

【大纪元9月4日讯】由加拿大领导的科学家小组，在卑诗南部发现一化石宝藏，。据悉这些化石有助于进一步了解世界著名的伯吉斯页岩（Burgess Shale）的奥秘，同时发现了一种前所未知的掠食动物。
　　
此化石宝藏在卑诗的库特尼国家公园（Kootenay National Park）的史丹利冰川一带，科学家本以为那一带不可能发现伯吉斯型化石，因为地理上缺乏陡峭地势，而5亿年前的伯吉斯型化石只可能存在陡峭的地形里。
　　
由于化石是在寒武纪时代的岩石中被发现，而这类岩石广泛存在加拿大西部，研究人员相信，这次在库特尼的出土化石，可能将掀起一波化石出土潮。
　　
研究人员将史丹利冰川的发现，总结发表在“地质学”9月刊上，“填补了”早期动物进化年代方面的空白。
　　
此次发现的报告书中称：“目前还处在初步的探索阶段，在一个小地理区域，只发现了几个新的物种，我们认为随着探索研究的深入，将来很可能发现更多新物种。”报告的作者中有萨斯喀彻温大学的科学家加布瑞拉‧曼加诺（Gabriela Mangano），与来自美国和瑞典的其他研究人员。
　　
新的掠食者名叫 Stanleycaris hirpex，在史丹利冰川处被发现。他们是当时地球上最大的动物，有的长达2米，这种奇异的动物被认为游泳敏捷，有一口锋利的牙齿。
　　
2009年，加拿大卑诗省南部发现的伯吉斯型页岩（Burgess Shale），是软体动物中化石保存精美度最完美的记录之一，有些保存的肌肉、肠道和神经都清晰可见，时代为中寒武世，是研究寒武纪生物的一重大突破。

2010-9-6 07:09 AM