Pikaia - Wikipedia
Pikaia gracilens is an extinct, primitive chordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Described in 1911 by Charles Doolittle Walcott as an annelid , and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", [ 1 ] or "famously known as the ...
Facts and Figures About Pikaia - ThoughtCo
2019年4月8日 · The slender, lancelet-like Pikaia is one of three early fishlike creatures found preserved from the Cambrian period in the geologic record.
皮卡蟲 - 维基百科，自由的百科全书
皮卡蟲（屬名： Pikaia ，得名自發現地一帶常出沒的鼠兔 Pika），又名皮凱亞蟲或皮克魚，是一種寒武紀的原始脊索動物，其化石在加拿大 不列顛哥倫比亞的伯吉斯頁岩發現。
皮卡虫 - 百度百科
英国剑桥大学的科学家利用最新技术对 加拿大落基山脉 的布尔吉斯页岩发现的114个皮凯虫(Pikaia gracilens)化石标本进行研究后发现，5.05亿年前的皮卡虫是包括人类在内的现代脊椎动物的祖先。
The Middle Cambrian fossil Pikaia and the evolution of chordate ...
2012年7月6日 · Conway Morris and Caron (2012) have recently published an account of virtually all the available information on Pikaia gracilens, a well-known Cambrian fossil and supposed basal chordate, and propose on this basis some new ideas about Pikaia’s anatomy and evolutionary significance.
A new interpretation of Pikaia reveals the origins of the chordate …
2024年7月8日 · Here we reinterpret the morphology of Pikaia, providing evidence for a gut canal and, crucially, a dorsal nerve cord—a robust chordate synapomorphy. The identification of these structures underpins a new anatomical model of Pikaia that shows that this fossil was previously interpreted upside down.
Worm-like fossil a 'distant cousin' of humans | CBC News
2012年3月5日 · But according to a newly released analysis of a fossil unearthed in the Canadian Rockies a century ago, the finger-sized creature — known as Pikaia gracilens — is the oldest known member of the...
The Cambrian fossil Pikaia , and the origin of chordate somites
2024年2月1日 · The Middle Cambrian fossil Pikaia has a regular series of vertical bands that, assuming chordate affinities, can be interpreted as septa positioned between serial myotomes. Whether Pikaia has a notochord and nerve cord is less certain, as the dorsal organ, which has no obvious counterpart in living chordates, is the only clearly defined axial ...
(PDF) The Middle Cambrian fossil Pikaia and the origin
2012年6月13日 · Conway Morris and Caron (2012) have recently published an account of virtually all the available information on Pikaia gracilens, a well-known Cambrian fossil and supposed basal chordate, and...
Human's oldest ancestor found - University of Cambridge
2012年3月6日 · Researchers from the University of Cambridge, University of Toronto and the Royal Ontario Museum (ROM) have confirmed that a 505 million-year-old creature, found only in the Burgess Shale fossil beds in Canada’s Yoho National Park, is the most primitive known vertebrate and therefore the ancestor of all descendant vertebrates, including humans.
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