摩洛哥出土的驚人化石改寫了演化時間線

原文網址：www.sciencedaily.com/releases/2015/07/150707213241.htm

Spectacular Moroccan fossils redefine evolutionary timelines

摩洛哥出土的驚人化石改寫了演化時間線

Some of the oldest marine animals on the planet, including armoured worm-like forms and giant, lobster like sea creatures, survived millions of years longer than previously thought, according to a spectacularly preserved fossil formation from southeastern Morocco.

位於摩洛哥東南，保存狀況驚人地良好的化石層顯示某些地球上最古老的海洋生物，包括一些覆有甲殼的蟲以及巨大、狀似龍蝦的海洋生物，存活的時間可能比之前所認為的還要長了數百萬年。

The Lower Fezouata formation has been revealing exciting discoveries about life in the Ordovician -- around 485 -- 444 million years ago -- since its discovery just five years ago.

自短短五年前發現下Fezouata層後，科學家便一直從中得到跟奧陶紀(Ordovician，4億8500年前至4億4400萬年前)生物有關的驚人發現。

'The Fezouata is extraordinarily significant' says Professor Derek Briggs of Yale University, co-author of a study published today in the Journal of the Geological Society. 'Animals typical of the Cambrian are still present in rocks 20 million years younger, which means there must be a cryptic record in between, which is not preserved.'

「Fezouata的重要性不言而喻，」耶魯大學的Derek Briggs教授說，他是本篇今日發表在《地質學會雜誌》(Journal of the Geological Society)上的論文的共同作者。「在寒武紀(Cambrian)過後2000萬年的岩石中仍能發現典型的寒武紀生物，代表說這之間一定有紀錄未被保存下來。」

Over 160 genera have already been documented from the Fezouata, with much more expected to be found. They include animals which would have looked perfectly at home during the Cambrian: armoured lobopodians -- worm like creatures with spines on their backs and short, stubby legs, and anomalocaridids -- huge segmented animals with remarkable feeding limbs, which are some of the largest marine creatures of the time.

從Fezouata出土的化石中，已經紀錄到超過160屬，未來預期還會發現更多。其中包括某些在寒武紀過得很自在的生物：有甲殼的葉足動物(lobopodian)，其背上有尖刺、足部粗短、看起來像蠕蟲；以及奇蝦(anomalocaridid)，為巨大的多節動物，擁有用來捕食的顯著前肢，其中有些種類為當時最大型的海洋生物之一。

As well as demonstrating the longevity of fauna thought to have been extinct millions of years previously, the Fezouata proves that other creatures evolved far earlier than previously thought.

Fezouata除了顯示過往認為已經消失數百萬年的動物可能更為長壽之外，也證實了某些生物較之前認為的還要早演化出來。

'Horseshoe crabs, for example, turn out to be at least 20 million years older than we thought. The formation demonstrates how important exceptionally preserved fossils are to our understanding of major evolutionary events in deep time' says Peter Van Roy, also of Yale, who first recognised the scientific importance of the Fezouata fauna and is lead author of the study, part of a project funded by the National Science Foundation.

「舉例來說，馬蹄蟹的出現時間至少比我們過去所認為的還要早了2000萬年。這個地層顯示了保存狀態格外良好的化石對我們瞭解過去的大型演化事件有多麼重要。」此篇研究的第一作者，同為耶魯大學的Peter Van Roy說，他是首先體認到Fezouata生物群在科學上的重要性的人。本研究部分由國家科學基金贊助。

The spectacular preservation, which includes detailed soft parts and organisms over 2 metres in length, is thanks to the fine grained, muddy sediments in which the organisms were preserved.

這些保存狀態良好的化石中包括某些細緻的軟組織以及超過2公尺長的生物，而這得歸功於保存這些生物的細粒泥質沉積物。

'These are special rocks' says Professor Briggs. 'Some of the organisms are enormous -- several metres in length. With such exceptional preservation, in a fully marine exposure, we can develop a reasonably full picture of what marine life looked like in the Ordovician.'

「這些岩石相當特殊，」Briggs教授說。「這些生物有些可以長到非常巨大，達數公尺這麼長。有了這些完整體現當時的海洋環境且保存相當良好的化石，我們可以合理描繪出在奧陶紀時的海洋生命的完整樣貌。」

The discoveries suggest the 'Great Ordovician Biodiversification Event' -- an explosion in diversity throughout the earlier part of the Ordovician period -- may have been a continuation of the Cambrian explosion.

這些發現顯示「奧陶紀生物大輻射」(Great Ordovician Biodiversification Event)--在奧陶紀早期時發生的生物多樣性大爆發事件—可能為寒武紀大爆發(Cambrian explosion)的接續事件。

'There is much more to learn from the Fezouata' says Professor Briggs. 'Why do we not see more assemblages like this in the Ordovician? What ecological changes happened at the Cambro-Ordovician interval? Are the Cambrian Explosion and the Great Ordovician Biodiversification Event separate, or phases of the same event?'

「我們還能從Fezouata中學到許多事物」Briggs教授說。「為什麼我們沒有在其他的奧陶系地層發現更多這種類型的生物組成？在寒武紀與奧陶紀交界時生態環境發生了什麼樣的變化？寒武紀大爆發與奧陶紀生物大輻射究竟是獨立的事件，亦或是同一事件的不同階段？」

The paper, published online today, marks the start of a themed series of 'Review focus' articles for the Journal of the Geological Society, centring on sites of exceptional fossil preservation spanning Earth's history. All papers in the series will be available for free download, and further 'Review focus' themes are planned.

此篇刊登在線上的論文，為《地質學會雜誌》上主題式「重點回顧」文章系列的開頭，此系列聚焦在地質歷史各時期中保有特別完整的化石的遺址。此系列的所有論文皆可以免費下載，而更多的主題式「重點回顧」文章系列正在規劃中。

'The purpose of these articles is to present a distilled, forward looking review of a topic', says the series editor Professor Philip Donoghue. 'We decided to start with a thematic series on fossil Lagerstätten since these deposits are fundamental archives of evolutionary history.'

「這些文章的目的在呈現對此主體的精簡未來展望。」本系列的編輯，Philip Donoghue教授說。「我們決定以關於化石庫(fossil Lagerstätten)的主題系列作為開端，這是因為這些沉積物為構築演化史的基石。」

'By making the papers freely available, it is hoped they will interest a wide range of readers, from undergraduates, to specialists in the field, to members of the public.'

「藉由讓這些文章可以被免費下載，我們希望它們能夠激起各個領域的讀者的興趣，從研究生至本領域的專家至普羅大眾。」

引用自：Geological Society of London. "Spectacular Moroccan fossils redefine evolutionary timelines." ScienceDaily. ScienceDaily, 7 July 2015.