現代的動物可能起源自三角洲

 原文網址：https://www.exeter.ac.uk/research/news/articles/modernanimallifecouldhave.html

新研究提出今日存活的許多動物的祖先，可能曾經生活在中國的一座三角洲。

節肢動物(娜羅蟲)的化石。圖片來源：Xiaoya Ma博士

動物出現的第一道跡象也許是具海綿化石

原文網址：https://phys.org/news/2021-07-oldest-fossils-animals-canada.html

by Christina Larson

根據星期三發表在期刊《自然》(Nature)的研究報告，一位加拿大的地質學家也許發現了地球上最早的動物化石紀錄。

這張沒有日期的照片由加拿大勞倫森大學的Elizabeth Turner提供，顯示了她在加拿大西北領地的野外考察地點之一。根據2021年7月28日星期三發表在期刊《自然》的研究報告，這位加拿大的地質學家也許在這片區域發現了地球上最早的動物化石紀錄。圖片來源：Elizabeth Turner

現今加拿大西北方一處遍布崇山峻嶺的區域，大約在十億年前是片史前海洋，該篇論文表示當時沉積下來的礦物裡面也許保存了原始海綿的遺骸。

地質學家Elizabeth Turner在加拿大西北領地唯有靠直升機才能到達的偏遠區域發現了這些岩石，她從1980年代開始就在此地挖掘化石。從岩石薄片可以看到其中含有與現今的海綿骨骼類似的立體構造。

「我相信它們確實是古代的海綿，只有這類生物才擁有這種由絲狀有機物形成的網狀結構，」德國哥廷根大學的地質生物學家與海綿專家Joachim Reitner,表示。他並未參與此研究。

鄰近岩層的定年結果指出這些樣品的年代大約為8.9億年，相較於之前發現最古老、確定為海綿的化石，它們的年代還要早了3.5億年。

「這項發現最令人驚訝的部分是年代，」瑞典烏普薩拉大學的海綿專家Paco Cardenas表示。他也未參與此研究。「發現將進九億年前的海綿化石，勢必會大幅增進我們對於動物早期演化過程的認知。」

許多科學家相信最初的動物類型包括了柔軟的海綿或是類似海綿的動物，雖然它們缺乏肌肉與神經，但是已經擁有其他簡單的動物特徵，像是功能分異的細胞與精子。

可以肯定的是，任何年代為距今十億年前的事物都很難在科學界取得共識或肯定，因此其他研究人員未來可能會繼續審視並討論Turner的發現。

「我認為她的理由很有說服力，這確實十分值得發表――將證據呈現出來讓其他人可以加以檢視，」南加州大學的古生物學家David Bottjer表示。他並未參與這項研究。

科學家相信地球的生命大約出現在37億年前，而最早的動物則要過了許久才出現，但是確切的時間仍有許多爭議。

目前為止，最早可以確定為海綿化石的年代大約是在5.4億年前，稱作寒武紀的時代。

但是科學家利用另外一條線索「分子時鐘」――分析兩物種的基因突變速率來回推牠們分家的時間――得出的現有證據指出海綿的出現時間要來得更早，大概是在十億年前。

然而，目前為止卻還沒有發現任何實體證據來支持。

「這是首次發現比寒武紀更加古老的海綿化石，而且不只是比較早，還早了非常多，這真的讓人非常興奮，」烏普薩拉大學的Cardenas說。他繼而表示研究似乎也確認了分子時鐘的估計結果。

動物在寒武紀才首次演化出堅硬的骨骼、外骨骼以及外殼這些比較容易保存下來的部位，因此在寒武紀之前的化石紀錄十分稀少。

「這類化石屬於比較複雜的動物――明顯的，在這之前勢必得有一段歷史屬於更加簡單的動物，像是最早出現的海綿，」論文作者Turner表示。她任職於加拿大安大略省的勞倫森大學。

距今8.9億年前這個時間非常重要，因為如果可以確定這些化石為海綿的話，就證實了最初的動物演化出來的時候，大氣和海洋的氧氣還沒有上升到科學家曾經以為要讓動物出現必須到達的濃度。雖然最近的研究已經顯示某些海綿可以在氧氣很少的情況下生存。

「地球上的所有生物都有個祖先。我們總是預測動物出現的第一道證據會相當微小而隱晦，不過是條十分細微的線索，」麻省理工學院的地質生物學家Roger Summons表示。他並未參與此研究。

 

First sign of animal life on Earth may be a sponge fossil

A Canadian geologist may have found the earliest fossil record of animal life on Earth, according to a report published Wednesday in the journal Nature.

Around a billion years ago, a region of northwest Canada now defined by steep mountains was a prehistoric marine environment where the remains of ancient sponges may be preserved in mineral sediment, the paper says.

Geologist Elizabeth Turner discovered the rocks in a remote region of the Northwest Territories accessible only by helicopter, where she has been excavating since the 1980s. Thin sections of rock contain three-dimensional structures that resemble modern sponge skeletons.

"I believe these are ancient sponges—only this type of organism has this type of network of organic filaments," said Joachim Reitner, a geobiologist and expert in sponges at Germany's University of Gottingen, who was not involved in the research.

The dating of adjacent rock layers indicates the samples are about 890 million years old, which would make them about 350 million years older than the oldest undisputed sponge fossils previously found.

"What's most stunning is the timing," said Paco Cardenas, an expert on sponges at Sweden's Uppsala University, who was not involved in the research. "To have discovered sponge fossils from close to 900 million years ago will greatly improve our understanding of early animal evolution."

Many scientists believe the first animal groups included soft sponges or sponge-like creatures that lack muscles and nerves but have other features of simple animals, including cells with differentiated functions and sperm.

To be sure, there's very little scientific consensus or certainty about anything dating back a billion years ago, so other researchers will likely continue to vet and debate Turner's findings.

"I think she's got a pretty strong case. I think this is very worthy of publishing—it puts the evidence out there for other people to consider," said David Bottjer, a paleobiologist at University of Southern California, who was not involved in the research.

Scientists believe life on Earth emerged around 3.7 billion years ago. The earliest animals appeared much later, but exactly when is still debated.

Until now, the oldest undisputed fossil sponges date to around 540 million years ago, an era called the Cambrian period.

But scientists using a line of reasoning called the molecular clock —where they analyze the rate of genetic mutations to backdate when two species likely diverged—say that available evidence points to sponges emerging much earlier, around a billion years ago.

Yet no supporting physical evidence has yet been found until now.

"This would be the first time that a sponge fossil has been found from before the Cambrian, and not only before, but way before—that's what's most exciting," said Uppsala University's Cardenas, adding that the research seems to confirm the molecular clock estimates.

Fossil evidence is scant before the Cambrian period when animals first developed hard skeletons, exoskeletons and shells, which are more likely to be preserved.

"Those kinds of fossils belong to more complicated animals—obviously there has to be a back history" of simpler animals like sponges emerging first, said the paper's author Turner, who is based at Laurentian University in Ontario.

The dating of 890 million years ago is significant because, if the sponge's identification is confirmed, it shows that the first animals evolved before a time when oxygen in the atmosphere and ocean reached a level scientists once thought was necessary for animal life. Yet recent research shows that some sponges can survive with very little oxygen.

"Everything on Earth has an ancestor. It's always been predicted that the first evidence of animal life would be small and cryptic, a very subtle clue," said Roger Summons, an MIT geobiologist who was not involved in the research.

原始論文：Elizabeth C. Turner. Possible poriferan body fossils in early Neoproterozoic microbial reefs. Nature, 2021. DOI:10.1038/s41586-021-03773-z

顯示動物存在的最古老證據

原文網址：https://news.ucr.edu/articles/2018/10/15/oldest-evidence-animals-found-ucr-researchers

顯示動物存在的最古老證據

分子化石證據指出在寒武紀一億年前的古代海床上就已經有海綿了

Sarah Nightingale

加州大學河濱分校的研究人員發現目前為止顯示動物存在的最古老證據，年代可以追溯至著名的寒武紀大爆發(動物化石突然大量出現的事件)的一億年前。

在遠古岩石中發現的26-mes也能由現生的尋常海綿Rhabdastrella globostellata製造出來。圖片來源：Paco Cárdenas

研究人員找到古生物學的聖杯：5.58億年前的脂質揭露出已知最古老的動物身分

原文網址：https://anu.prezly.com/researchers-find-holy-grail-of-palaeontology-558-million-year-old-fat-reveals-earliest-known-animal

研究人員找到古生物學的聖杯：5.58億年前的脂質揭露出已知最古老的動物身分

澳洲國立大學和其他國家的科學家在一具年代久遠的化石中發現脂質分子，從而得出地質紀錄中有證據顯示其為動物的化石最早存活於5.58億年前。

一具狄更遜水母的化石。圖片來源：澳洲國立大學

研究解開地球第一批動物如何出現的謎團

原文網址：http://www.anu.edu.au/news/all-news/anu-led-study-solves-mystery-of-how-first-animals-appeared-on-earth

研究解開地球第一批動物如何出現的謎團

由澳洲國立大學(ANU)進行的研究解開了地球第一批動物如何出現的謎團，若地球沒有發生這齣重大事件則人類也不會存在。

動物演化史：在火熱的開始之後是一陣寒冬

原文網址：www.sciencedaily.com/releases/2017/06/170615084556.htm

動物演化史：在火熱的開始之後是一陣寒冬

動物演化的最初階段進行速度比迄今認為得還要快：新的分析結果提出首批動物門以很快的速度接連出現，時間點為7億年前全球陷入冰河期之前。

化石證據顯示現存的所有動物門幾乎都是在5.4億年前，地球歷史剛進入寒武紀時就已經出現了。人類所知最早的動物化石已經呈現出相當複雜的型態，意謂動物必定早在寒武紀開始之前就出現了。然而，可以確切分類的化石中，只有極少數能確定它們的年代是在前寒武紀時期。為了確定動物演化樹的根源看起來是何種樣貌，生物學家需要對最古老的動物類群――海綿、腔腸動物、櫛水母和絲盤蟲做出更加可信的定年資訊。慕尼黑路德維希-馬克西米利安大學地球和環境科學系，古生物和地質生物學門的Martin Dohrmann博士和Gert Wörheide教授，運用了以分子時鐘為基礎的新策略，來研究早期動物演化的年代順序，並對最古老動物類群的出現時間做出新的預測。他們的結果刊登於期刊《科學報告》(Scientific Reports)。

分子時鐘的原理是基於所有生物體內的基因體，都會隨著時間經過而累積突變。因此，兩條生物譜系之間的基因差異程度，應該會跟它們從共同祖先分歧出來已經過了多久有關。Dohrmann解釋：「我們研究的基礎結合了現存生物的基因數據，加上從定年良好的化石中取得的資訊。然後再藉助複雜的電腦演算來分析。」為了進行研究，研究人員利用了一個龐大的資料庫，其中含有55個物種身上128種蛋白質的定序結果。這些物種包括了所有動物類群中的代表性物種。研究人員特別聚焦於那些非常久以前就跟其他物種分道揚鑣的生物。

分析證實了一篇前人研究得出的結論，他們將動物的起源定在從10億年前持續至5.4億年前的新元古代(Neoproterozoic Era)。然而，令他們大感驚訝的是，分析結果也呈現出最早的動物門和所有兩側對稱動物的祖先，都是在短短5000萬年中(以地質角度來說)接連出現。Dohrmann表示：「此外，這段發生在演化史早期的多樣化階段，似乎是在讓地球進入雪球地球的極端氣候變遷之前。在7.2億年前至6.35億年前，整個地球都陷入一段極為漫長的冰河期，稱為雪球地球。」為了評估這項新發現的可信程度，研究人員接下來的計畫是利用包含層面更廣的資料庫和改良後的統計方法進行更深入的分析。Wörheide表示：「要得到從最初動物的型態和生態角度來看都相當穩固的結論，我們還需要更加瞭解新元古代時普遍的環境狀態，以及更多可以確切歸屬至特定分類族群的化石。」

Animal evolution: Hot start, followed by cold shock

The initial phases of animal evolution proceeded faster than hitherto supposed: New analyses suggest that the first animal phyla emerged in rapid succession -- prior to the global Ice Age that set in around 700 million years ago.

The fossil record reveals that almost all of the animal phyla known today had come into existence by the beginning of the Cambrian Period some 540 million years ago. The earliest known animal fossils already exhibit complex morphologies, which implies that animals must have originated long before the onset of the Cambrian. However, taxonomically assignable fossils that can be confidently dated to pre-Cambrian times are very rare. In order to determine what the root of their family tree looked like, biologists need reliable dating information for the most ancient animal subgroups -- the sponges, cnidarians, comb jellies and placozoans. Dr. Martin Dohrmann and Professor Gert Wörheide of the Division of Palaeontology and Geobiology in the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich have now used a new strategy based on the so-called molecular-clock to investigate the chronology of early animal evolution and produce a new estimate for the ages of the oldest animal groups. Their findings appear in the journal Scientific Reports.

The molecular clock approach is based on the principle that mutations accumulate in the genomes of all organisms over the course of time. The extent of the genetic difference between two lineages should therefore depend on the time elapsed since they diverged from their last common ancestor. "Our study is based on a combination of genetic data from contemporary animals and information derived from well dated fossils, which we analyzed with the help of complex computer algorithms," Dohrmann explains. For the study, the researchers used an unusually large dataset made up of the sequences of 128 proteins from 55 species, including representatives of all the major animal groups, focusing in particular on those that diverged very early.

The analysis confirms the conclusion reached in an earlier study, which dated the origin of animals to the Neoproterozoic Era, which lasted from 1000 to 540 million years ago. However, much to their surprise, the results also suggested that the earliest phyla, and the ancestors of all bilateral animal species (the so-called Bilateria), originated within the -- geologically speaking -- short time-span of 50 million years. "In addition, this early phase of evolutionary divergence appears to have preceded the extreme climate changes that led to Snowball Earth, a period marked by severe long-term global glaciation that lasted from about 720 to 635 million years ago," Dohrmann says. In order to assess the plausibility of the new findings, the researchers plan to carry out further analyses using more extensive datasets and improved statistical methods." To arrive at well-founded conclusions with respect to the morphology and ecology of the earliest animals, we also need to know more about the environmental conditions that prevailed during the Neoproterozoic, and we need more fossils that can be confidently assigned to specific taxonomic groups," Wörheide says.

原始論文：Martin Dohrmann, Gert Wörheide. Dating early animal evolution using phylogenomic data. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-03791-w

引用自：Ludwig-Maximilians-Universität München. "Animal evolution: Hot start, followed by cold shock." ScienceDaily. ScienceDaily, 15 June 2017.

有關世上最古老動物化石的新觀點

原文網址：http://www.geologypage.com/2017/05/worlds-oldest-animal-fossils.html

有關世上最古老動物化石的新觀點

由布里斯托大學領導的研究團隊，發現之前被認為是世上最古老動物遺骸的案例的某些遠古化石，實際上可能隸屬於別的類群，像是藻類。

古生物學家找到了神祕的古代錐形海洋生物的分類地位

原始網址：www.sciencedaily.com/releases/2017/01/170111132815.htm

古生物學家找到了神祕的古代錐形海洋生物的分類地位

演化樹上的一根分枝在今天變得更加擁擠了一些。由多倫多大學20歲的學生Joseph Moysiuk領導的科學家團隊，終於確認了一種已經滅絕的奇特錐形動物族群的真實身分。

被稱為軟舌螺(hyolith)的這種海洋生物大約是在5.3億年前的寒武紀期間演化出來，牠們也是已知會形成礦物質外骨骼的首批動物之一。

雖然長久以來牠們被認為跟蝸牛、烏賊和其他軟體動物所屬同一家族，今日在科學期刊《自然》上刊登的一篇論文卻證實軟舌螺與腕足動物的關係更為密切。儘管腕足動物門存活至今的現生物種相當稀少，但牠們卻留下了相當豐碩的化石紀錄。

腕足動物擁有被上下外殼包覆的柔軟本體，這跟雙殼軟體動物的外殼呈現左右排列有所不同。腕足動物在攝食時會從前端打開牠們的外殼，其餘時刻則緊緊閉闔以保護他們的攝食構造以及身體的其他部分。

雖然化石紀錄中軟舌螺的骨骸為數眾多，但含有牠們軟組織構造中重要特徵的化石至今為止仍然付之闕如。

「我們最重要也最驚人的發現是找到了軟舌螺的攝食構造。這是一排從口部伸出的柔軟觸手，位在錐狀的下殼與蓋子般的上殼之間。」Moysiuk表示。「在現生動物當中只有一群動物擁有被雙殼包覆的類似攝食構造，那就是腕足動物。此發現顯示跟軟舌螺關係最密切的現存動物是腕足動物而非軟體動物。」

Moysiuk說：「這表示軟舌螺跟現今的腕足動物一樣以懸浮在水中的有機物質維生，牠們會利用牠們的觸手將食物掃進嘴裡。」

於多倫多大學主修地球科學和生態及演化生物學的Moysiuk完成的這項專題為該校研究機會培育計畫的一部份。此計畫為多倫多大學文理學院專門為大學生設立。

過往試著分類軟舌螺時都對牠們獨特的外型和構造相當棘手。所有軟舌螺都有著細長且兩側對稱的錐狀外殼，在開口處則有一小塊蓋狀甲殼(口蓋，operculum)可以將其封住。有些種類還有一雙堅硬的弧狀尖刺(海倫體，helens)從錐狀外殼和口蓋之間延伸出來。在其他動物族群當中完全沒有跟海倫體同樣的構造。

仔細檢查從伯吉斯頁岩中找到的不同軟舌螺樣品的海倫體延伸方向，研究人員認為這些尖刺可能是這些動物將牠們的身體從沉積物中撐高時所用的支架，牠們以此舉起攝食器官來增加捕食效率。

Moysiuk以及共同作者英國杜倫大學的Martin Smith，和多倫多大學與皇家安大略博物館的Jean-Bernard Caron，主要是依據從英屬哥倫比亞著名的伯吉斯頁岩中最新發現的化石來完成他們的論述。

「伯吉斯頁岩之所以獨一無二是因為它保存了在正常情況下通常難以留存下來的軟組織。」Moysiuk的指導教授Caron表示。Caron是皇家安大略博物館無脊椎古生物學的高級研究員，同時也是多倫多大學地球科學、生態學和演化生物學系的副教授。

「雖然有些論文的作者提出牠們跟軟體動物的親緣較為接近，但這些假說的依據仍然不夠充足。軟舌螺成為演化樹上無家可歸的一道分枝，成為古生物學家難以啟齒的存在。在第一次對軟舌螺做出記述約莫175年之後，我們終於從最新的野外研究成果中找到了破解牠們故事的關鍵。」

近期由Caron領導對伯吉斯頁岩進行的野外研究成果中，找到了許多成為此研究基礎的樣品。這些關鍵樣品發現於庫特尼國家公園中，史丹利冰河和大理石峽谷附近最新發現到的沉積物。該地點位於幽鶴國家公園最初的伯吉斯頁岩場址東南方40公里處。

要研究於5.42億年前開始的寒武紀，動物如何誕生及早期的演化過程時，伯吉斯頁岩是最重要的化石庫之一。在寒武紀大爆發誕生的生物群中，軟舌螺僅是眾多動物族群裡最具代表性的其中一類。牠們成為全球海洋生態系中一個成員眾多的家族長達2.8億年，卻在首批恐龍演化出現以前的2..52億年前步入滅絕。

「寒武紀大爆發是化石紀錄中最主要的動物族群迅速演化而成的時期，解開有關軟舌螺分類地位上的爭議有助於讓我們對這段時期有更多的理解。」Smith表示。他在牛津大學時開始這項研究，現在則為杜倫大學的古生物學講師。「對於要闡釋那些我們仍所知甚少的生物的演化史來說，我們的研究再次重申了伯吉斯頁岩類型的沉積物中保存的軟組織有多麼重要。」

從數個地點發現的這些樣品皆來自伯吉斯頁岩，其為加拿大洛磯山脈世界遺產的一部分。在研究於5.42億年前左右開始發生的寒武紀大爆發期間，動物的起源和早期演化過程時，伯吉斯頁岩是最重要的化石庫之一。

加拿大公園管理局保護這處享譽全球的場所，並且贊助同儕審核的科學研究以持續增進我們對這座豐富的古生物寶庫的認識。加拿大公園管理局出版的指南每年跟眾多遊客熱心分享這些早期動物演化的精采故事，而這項發現又為此更添一筆。

本研究的主要資金來源為皇家安大略博物館，以及加拿大自然科學暨工程研究委員會授予Caron的經費。

Paleontologists classify mysterious ancient cone-shaped sea creatures

One branch on the tree of life is a bit more crowded today. A team of scientists led by 20-year-old University of Toronto (U of T) undergraduate student Joseph Moysiuk has finally determined what a bizarre group of extinct cone-shaped animals actually are.

Known as hyoliths, these marine creatures evolved over 530 million years ago during the Cambrian period and are among the first animals known to have produced mineralized external skeletons.

Long believed to belong to the same family as snails, squid and other molluscs, a study published today in the scientific journal Nature shows that hyoliths are instead more closely related to brachiopods -- a group of animals which has a rich fossil record, although few living species remain today.

Brachiopods have a soft body enclosed between upper and lower shells (valves), unlike the left and right arrangement of valves in bivalve molluscs. Brachiopods open their valves at the front when feeding, but otherwise keep them closed to protect their feeding apparatus and other body parts.

Although the skeletal remains of hyoliths are abundant in the fossil record, key diagnostic aspects of their soft-anatomy remained critically absent until now.

"Our most important and surprising discovery is the hyolith feeding structure, which is a row of flexible tentacles extending away from the mouth, contained within the cavity between the lower conical shell and upper cap-like shell," said Moysiuk. "Only one group of living animals -- the brachiopods -- has a comparable feeding structure enclosed by a pair of valves. This finding demonstrates that brachiopods, and not molluscs, are the closest surviving relatives of hyoliths.

"It suggests that these hyoliths fed on organic material suspended in water as living brachiopods do today, sweeping food into their mouths with their tentacles," Moysiuk said.

Moysiuk, who studies Earth sciences and ecology & evolutionary biology, completed this project as part of the Research Opportunity Program at U of T, a special undergraduate research program in the Faculty of Arts & Science.

The distinctive appearance and structure of the hyolith skeleton has obstructed previous attempts to classify these animals. All hyoliths had an elongated, bilaterally symmetrical cone-shaped shell and a smaller cap-like shell which covered the opening of the conical shell (known as an operculum). Some species also bore a pair of rigid, curved spines (known as helens) that protruded from between the conical shell and operculum -- structures with no equivalents in any other group of animals.

Examination of the orientation of the helens in multiple hyolith specimens from the Burgess Shale suggests that these spines may have been used like stilts to lift the body of the animal above the sediment, elevating the feeding apparatus to enhance feeding.

Moysiuk and coauthors Martin Smith at Durham University in the United Kingdom, and Jean-Bernard Caron at the Royal Ontario Museum (ROM) and U of T were able to complete the descriptions based mainly on newly discovered fossils from the renowned Cambrian Burgess Shale in British Columbia.

"Burgess Shale fossils are exceptional because they show preservation of soft tissues which are not usually preserved in normal conditions," said Caron, Moysiuk's research supervisor, who is the senior curator of invertebrate palaeontology at the ROM and an associate professor in U of T's Departments of Earth Sciences and Ecology & Evolutionary Biology.

"Although a molluscan affinity was proposed by some authors, this hypothesis remained based on insufficient evidence. Hyoliths became an orphaned branch on the tree of life, an embarrassment to paleontologists. Our most recent field discoveries were key in finally cracking their story, around 175 years after the first description of a hyolith."

Caron led recent fieldwork activities to the Burgess Shale which resulted in the discovery of many specimens that form the basis of this study. The key specimens came from recently discovered deposits near Stanley Glacier and Marble Canyon in Kootenay National Park, about 40 kilometres southeast of the original Burgess Shale site in Yoho National Park.

The Burgess Shale is one of the most important fossil deposits for studying the origin and early evolution of animals that took place during the Cambrian period, starting about 542 million years ago. Hyoliths are just one of the profusion of animal groups that characterize the fauna of the 'Cambrian Explosion'. They became a diverse component of marine ecosystems around the globe for more than 280 million years, only to go extinct 252 million years ago, prior to the evolution of the first dinosaurs.

"Resolving the debate over the hyoliths adds to our understanding of the Cambrian Explosion, the period of rapid evolutionary development when most major animal groups emerge in the fossil record," said Smith, who started this research at the University of Cambridge and who is now a lecturer in paleontology at Durham University. "Our study reiterates the importance of soft tissue preservation from Burgess Shale-type deposits in illuminating the evolutionary history of creatures about which we still know very little."

The Burgess Shale, from which the specimens were recovered from several locations, is part of the Canadian Rocky Mountain Parks World Heritage Site. It is one of the most important fossil deposits for understanding the origin and early evolution of animals that took place during the Cambrian Explosion starting about 542 million years ago.

Parks Canada protects this globally significant site, and supports peer-reviewed scientific research that continues to enhance our understanding of these rich paleontological deposits. This discovery adds another element to the dramatic story of early animal evolution that Parks Canada guides share enthusiastically with hundreds of park visitors every year.

Funding for the research was provided primarily by the Royal Ontario Museum and a Natural Sciences and Engineering Research Council of Canada Discovery Grant to Caron.

原始論文：Joseph Moysiuk, Martin R. Smith, Jean-Bernard Caron. Hyoliths are Palaeozoic lophophorates. Nature, 2017; DOI: 10.1038/nature20804

引用自：University of Toronto. "Paleontologists classify mysterious ancient cone-shaped sea creatures." ScienceDaily. ScienceDaily, 11 January 2017.