瑞典烏普薩拉大學(xué)等機(jī)構(gòu)科學(xué)家最新研究發(fā)現(xiàn)，3.8億年前生活在海里的早期魚類潘氏魚已經(jīng)長有原始腳趾,。
長期以來,，科學(xué)家普遍認(rèn)為,，最先長出簡單腳趾的動物是能夠呼吸空氣的四足動物,，它們在大約3.7億年到3.7億年前從海里爬到陸地上。
不過,，烏普薩拉大學(xué)等機(jī)構(gòu)的研究顯示,，潘氏魚的魚鰭里已經(jīng)出現(xiàn)了原始腳趾。這種魚生活在淺水里,，長約1米,，是一種過渡物種，與四足動物相比更類似于魚類,。
這一發(fā)現(xiàn)已經(jīng)發(fā)表在最新一期英國《自然》（Nature）雜志上,。論文作者之一的烏普薩拉大學(xué)研究人員佩爾·阿爾貝里說：“我們的研究表明,，前肢和后肢在剛變形的鰭骨上就具有雛形，而非完全是從鰭骨上新長出來的,。”（生物谷Bioon.com）
生物谷推薦原始出處：
Nature,，doi:10.1038/nature07339，Catherine A. Boisvert,，Per E. Ahlberg
The pectoral fin of Panderichthys and the origin of digits
atherine A. Boisvert1, Elga Mark-Kurik2 & Per E. Ahlberg1
1 Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Evolutionary Biology Centre, Uppsala University, Norbyv?gen 18A, 752 36 Uppsala, Sweden
2 Institute of Geology at Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
One of the identifying characteristics of tetrapods (limbed vertebrates) is the presence of fingers and toes. Whereas the proximal part of the tetrapod limb skeleton can easily be homologized with the paired fin skeletons of sarcopterygian (lobe-finned) fish, there has been much debate about the origin of digits. Early hypotheses1 interpreted digits as derivatives of fin radials, but during the 1990s the idea gained acceptance that digits are evolutionary novelties without direct equivalents in fish fin skeletons. This was partly based on developmental genetic data2, but also substantially on the pectoral fin skeleton of the elpistostegid (transitional fish/tetrapod)Panderichthys, which appeared to lack distal digit-like radials3. Here we present a CT scan study of an undisturbed pectoral fin of Panderichthysdemonstrating that the plate-like 'ulnare' of previous reconstructions is an artefact and that distal radials are in fact present. This distal portion is more tetrapod-like than that found in Tiktaalik 4 and, in combination with new data about fin development in basal actinopterygians5, sharks6 and lungfish7, makes a strong case for fingers not being a novelty of tetrapods but derived from pre-existing distal radials present in all sarcopterygian fish.
