英發現世界最小化石 長度不到五分之一毫米

Scientists at the University of Manchester have discovered what is believed to be the smallest fossil ever found.

A 50-million-year-old parasite - hitching a ride on a not-much-bigger spider - was discovered during a scan of Baltic amber.

Published in the Royal Society's Biology Letters, the find was made using a computed toMography (CT) scan, which builds up a 3-D image from multiple flat scans.

Biologist Dr David Penney wrote in the paper that the arthropod fossil was extremely small - less than two tenths of a millimetre long - and “extremely rare”.

Dr Penney wrote that the Faculty of Life Sciences teams would not have been able to identify the mite without the CT scan.

He told the BBC: “CT allowed us to digitally dissect the mite off the spider in order to reveal the important features on the underside required for identification.”

“The specimen, which is extremely rare in the fossil record, is potentially the oldest record of the living family Histiostomatidae. “

“Most amber fossils consist of individual insects or several insects together, but without unequivocal demonstrable evidence of direct interaction. “

Fellow biologist Dr Richard Prezoisi added that the team could now date how long species such as the mite had been using larger organisms for transportation.

He said it would give “important clues as to how far back in geological time such behaviours evolved”.據英國《每日郵報》11月11日報道，英國曼徹斯特大學的科學家發現了被認爲是迄今爲止最小的化石。

這隻5000萬年前的寄生蟲是在科學家掃描一隻波羅的海琥珀時發現的，它正附着在一隻比它大不了多少的蜘蛛身上。

這一發現發表在了英國皇家學會的《生物學通訊》上，是科學家利用計算機斷層掃描技術發現的。該技術能將多個平面斷層掃描圖像合成一張3D圖像。

生物學家大衛-彭尼在論文中寫道：這隻節肢動物的化石極其微小——還不到五分之一毫米長，並且“極爲罕見”。

彭尼博士寫道，如果沒有計算機斷層掃描技術，(曼徹斯特大學)生命科學院的研究小組就不會發現這隻蟎蟲。

他告訴BBC的記者說：“計算機斷層掃描技術使我們把這隻蟎蟲從蜘蛛身上分離下來，以便展示能識別其身份的身體底部的重要特徵。”

“這隻蟎蟲標本在化石記錄中極爲罕見，它有可能是現存薄口蟎科動物家族中最爲古老的一種。”

“大多數的琥珀化石內含一隻或多隻昆蟲，但是沒有直接的證據證明它們之間存在着直接的相互作用。

他的同事理查德-普雷佐伊斯補充道，現在研究小組可以確定從多久之前象這隻蟎蟲一樣的物種就開始利用大型的生物做交通工具。

他說這將爲研究“這種行爲是在多遠古的地質時期逐漸形成的提供重要的線索。”