World’s Oldest Dinosaur Burrow Discovered In Australia
Posted on: Friday, 10 July 2009, 16:20 CDT | Related Video
Paleontologists have discovered the world’s oldest dinosaur burrows in Australia. The 106-million-year-old burrows are the first to be found outside of North America, and were much closer to the South Pole when they were created.
In total, three separate burrows have been discovered, the largest of which was about 6ft. long. Each burrow had a similar design and was just large enough to contain the body of a small dinosaur.
The discovery supports the theory that dinosaurs living in harsh, cold climates burrowed underground to survive.
The only other known dinosaur burrow was discovered in 2005 in Montana, and contained the bones of an adult and two young dinosaurs of a small new species called Oryctodromeus cubicularis. Two years after its discovery, scientists dated the burrow from 95 million years ago.
The older burrows in Australia were found by one of the researchers who made the original Montana discovery.
“Like many discoveries in paleontology, it happened by a combination of serendipity and previous knowledge,” said Anthony Martin of Emory University in Atlanta.
“In May 2006, I hiked into the field site with a group of graduate students with the intention of looking for dinosaur tracks. We did indeed find a few dinosaur tracks that day, but while there I also noted a few intriguing structures,” he told BBC News.
Martin returned to the site, known as Knowledge Creek about 150 miles from Melbourne, to study the structures in July 2007 and again in May of 2009.
He was astonished at what he found.
“I was scanning the outcrop for trace fossils, and was very surprised to see the same type of structure I had seen in Cretaceous rocks of Montana the previous year,” said Martin.
That original structure was the burrow of O. cubicularis.
“So to walk up to the outcrop and see such a strikingly similar structure, in rocks only slightly older, but in another hemisphere, was rather eerie,” Martin said.
Within the rock, which is part of the Otway group of rocks that have produced a large diversity of vertebrate fossils, Martin discovered three separate burrows less than 10 feet apart, two of which formed a semi-helix twisting down into the rock.
The largest and best-preserved burrow turns twice before ending in a larger chamber. Dubbed tunnel A, it is more than 6 feet in length. Martin calculates that an animal weighing around 22 pounds would have created each burrow. Twisting burrows can help keep predators at bay and provide a steady temperature and humidity environment.
Alligators, aardwolves, coyotes, gopher tortoises and striped hyenas are among the modern animals that make such burrows.
Although Martin isn’t sure which species of dinosaur made the burrows, he noted how similar their designs are to the burrow created by O. cubicularis.
A number of small ornithopod dinosaurs, which stood upright on their hind legs and were about the size of a large iguana, were believed to have lived in the area during the same time in the Cretaceous period.
Martin has ruled out a number of other sources that could have created the burrows.
The fact dinosaurs created them makes sense, he said.
Australian researchers first proposed two decades ago that some dinosaurs might have created burrows to survive harsh climates they couldn’t escape from by migrating.
“It gives us yet another example of how dinosaurs evolved certain adaptive behaviors in accordance with their ecosystems,” Martin said.
“Polar dinosaurs in particular must have possessed special adaptations to deal with polar winters, and one of their behavioral options was burrowing. It provides an alternative explanation for how small dinosaurs might have overwintered in polar environments.”
Martin hopes that paleontologists will be on the look out for dinosaur burrows, and for dinosaurs that are physically adapted to burrowing into soil.
The findings were published in the journal Cretaceous Research.
Image 1: Drawing by James Hays, Fernbank Museum
Image 2: Following his Montana discovery of the first trace fossil of a dinosaur burrow, Emory University paleontologist Anthony Martin has found evidence of older, polar dinosaur burrows in Victoria, Australia.
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Paleontologia, scoperte orme fossili nei pressi del lago di Iseo
9 aprile 2009 – Alcune passeggiate fossili di rettili predatori, ritenuti antenati dei dinosauri, sono state rinvenute su una parete di roccia nei pressi del paese di Zone, nei dintorni del lago di Iseo. Le 70 orme, il cui diametro varia dai 12 ai 40 centimetri, a detta del team di paleontologi italiani che le hanno studiate, risalgono al periodo Triassico, approssimativamente a 220 milioni di anni fa. Secondo gli studiosi – che renderanno noti i risultati della loro ricerca, eseguita anche con tecnica laser, il 16 aprile al Museo di Storia naturale di Milano – quelle rinvenute nel Bresciano sono le più grandi, e tra le più antiche, tracce fossili finora scoperte in Italia. I rettili che le hanno lasciate dovrebbero essere dei precursori dei dinosauri e, secondo i paleontologi, per un certo periodo avrebbero coabitato con loro, finendo per trovarsi anche in competizione, fino a esserne soppiantati. La grandezza delle loro orme, dai 12 ai 40 centimetri, potrebbe depistare sulle loro dimensioni, spingendo a ritenerli quasi degli animaletti domestici: in realtà i rettili triassici non appoggiavano a terra tutta la pianta e, dalla distanza tra un passo e un altro, e tra impronte posteriori e anteriori, gli studiosi hanno ricavato l’idea che dovessero raggiungere anche i sei metri di lunghezza. In confronto a rettili contemporanei come i coccodrilli, poi, avevano una maniera di camminare stranamente più evoluta: dalla mancanza della scia di trascinamento della coda, gli studiosi hanno ritenuto che i loro arti erano in posizione verticale sotto il corpo e che quindi camminavano con ventre e coda ben lontani dal terreno. Una tecnica subito imitata dai loro successori, i dinosauri, che li avrebbero poi eliminati. La sfortuna di questi rettili, d’altronde, per gli studiosi, è proprio che “tentarono di diventare dinosauri, senza riuscirci”. E così l’evoluzione li portò all’estinzione. Lo si apprende dall’Ansa. Last Updated ( giovedì, 09 aprile 2009 )
Ancient meat-eating dinosaurs held their arms with palms facing inwards like their bird descendants, a rare set of 198-million-year-old fossilised handprints has revealed. An analysis of the prints, published this week in PLoS One, supports theories that even very early therapods [lit. ‘beast feet’] such as tyrannosaurs and velociraptors had bird-like forelimbs, and walked only on two legs, well before they evolved feathery wings.
The handprints came from a dinosaur that sat down on the edge of a lake in St George, Utah, and extended its arms far enough to leave sediment marks. Six other resting dinosaur traces have been reported before, but they all lack clear hand prints.
This means, reports the Chicago Tribune, that we must banish images of tyrannosaurs holding their forearms like monkeys, with palms facing downwards – a posture that palaeontologists apparently term the “bunny position” – as depicted in Jurassic Park. Instead, we must imagine that dinosaurs were extremely good at holding basketballs.
“What this seems to imply is that, even from fairly early in their history, dinosaurs were entirely bipedal and weren’t using their forearms to support themselves in any way,” paleontologist Tom Holtz of the University of Maryland, says. “Because of that, the hands could specialize as weapons, to grab on to a struggling animal or to fight with other dinosaurs.”
Image: Dilophosaurus wetherilli in bird-like resting pose/Heather Kyoht Luterman
Los Angeles Times – 3-mar-2009
At left, dinosaur tracks with hand prints show bird-like inward-facing palms at Johnson Farm, Utah. At right, an artist’s reconstruction shows the formation …
National Geographic —————————————————————————–
free access article on PlosOne
Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace
Paleontologia: scoperte le più antiche orme umane che rivelano camminata ‘modernà
MILANO – Scoperte in Kenya orme fossili umane risalenti a 1,5 milioni di anni fa: sono le seconde più antiche, ma le prime a rivelare una camminata ‘modernà. Le orme infatti appartengono a un Homo ergaster e rivelano un piede anatomicamente simile al nostro e, appunto, anche una camminata identica a quella dell’uomo moderno. La scoperta è di ricercatori della Rutgers State University of New Jersey e della Bournemouth University in Gran Bretagna, e si è conquistata la copertina di Science. (Agr)
Researchers Uncover 1.5-Million-Year-Old Footprints
Discoverers glean clues about human predecessors from tracks left on an ancient river shore in Kenya
By Katherine Harmon
Freshly discovered trails of ancient footprints, left on what was once the muddy shores of a river near Ileret, Kenya, indicate that some 1.5 million years ago human ancestors walked in a manner similar to that of people today. The international team of researchers who analyzed the prints say that those who left them had feet that looked a lot like ours.
The prints were probably left by Homo ergaster, an earlier, larger version of the widespread Homo erectus, says David Braun, a lecturer in archeology at the University of Cape Town in South Africa and co-author of the study set to be published tomorrow in Science. This discovery “lets us know that they were probably just as efficient at walking upright as we are,” he says.
Previous research has shown that human ancestors were perfectly capable of getting around on their hind legs 3.5 million years ago—and perhaps even earlier. But Braun says these prints reveal, for the first time, a very modern foot with a parallel big toe—unlike an ape’s opposable digit that’s easily curled for grasping tree branches. Homo sapiens proper are said to have emerged about 200,000 years ago.
Footprints can tell scientists a lot about creatures that a skeleton cannot. From them, scientists can learn about the gait, weight distribution and even the approximate size of those who made them. Braun says these prints were apparently made by pedestrians who stood just under five feet (1.5 meters) tall. A modern upright stride can indicate a lot about behavior, as well, says David Raichlen, an assistant professor of anthropology at the University of Arizona in Tucson, who cites long-distance walking and running as possible benefits of this adaptation.
“It really is a snapshot of time,” Braun says. The preserved area also shows a wealth of animal prints, which gives more precise information about what creatures shared the space and time. Exhumed fossils can yield info on general environments; footprints can provide a glimpse into life over days rather than millennia. “With the footprints,” Braun says, “we can almost certainly say these things lived in the same time as each other, which is unique.”
It is much rarer to find footprints than bones, because conditions must be perfect for tracks to be preserved, according to Braun. In this case, the tracks were made during a rainy season near an ancient river just before that river changed course and swept a protective layer of sand over them.
The last major set of footprints, discovered in 1978 in Laetoli, Tanzania, were dated to about 3.6 million years ago. But those revealed a more ancient foot and gait, and it is still debatable whether those who made them had a stride more akin to humans or to chimpanzees, says Raichlen, who has studied the Laetoli prints.
The Ileret tracks were digitally scanned using a laser technique developed by lead study author, Matthew Bennett, a geoarchaeologist at Bournemouth University in Poole, England. Raichlen says the find gives people a rare view of those that have trod before. “It’s important to think about what you’re really getting: a glimpse of behavior in the fossil record that you wouldn’t really get in any other way,” he says. The research reveals “a moment in time when individuals are walking around the landscape. It sort of fleshes out and brings them back to life, in a way.”
ScienceMode – 1 ora fa
The anthropology world is all abuzz with a discovery in Africa that’s knocking scientists off their feet. It’s the finding of 1.5 million-year-old …
Dinosaur footprints, fossils found in central Peru
Lima, February 10, 2009
First Published: 20:00 IST(10/2/2009)
Hundreds of footprints and the fossilised remains of various prehistoric animals, probably dinosaurs that lived 120 million years ago, have been discovered in the Ancash region of central Peru.
The find came when the Antamina mining company, which is owned by BHP Billiton and Xstrata, among other partners, was building a road from its camp at Yanacancha to the Conococha crossroads, in Huari province, some 400 km northeast of Lima.
The company confirmed that a preliminary examination of the site, which is 4,600 metres above sea level, revealed more than 100 footprints made by at least 12 different types of ancient animals, including marine species, demonstrating that in the distant past the site lay at the bottom of an ancient ocean.
According to calculations by the paleontologists in charge of these finds, the site could date back to the Early Cretaceous Period about 120 million years ago.
Some of the fossils discovered there, the daily El Comercio reported, are from large marine reptiles known as sauropterygians, complete skeletons of which were found.
Other fish-like reptiles called ichthyosaurs were also found there, along with extinct species of crocodiles, flying reptiles called pterosaurs, tortoises and fish, not to mention very well-preserved specimens of assorted invertebrates.
The paleontological work in the area dates back to 2006, when construction on the road began and exposed potentially fossil-bearing layers of sediment, according to an analysis conducted by the Ornithology and Biodiversity Centre, known as Corbi.
The excavations performed to date at the site, which is called Cruz Punta, at Kilometer 80 of the highway, revealed a rocky wall-like formation several dozen metres in length on which there were clear indications of fossilised animal tracks, according to the Corbi study.
The footprints of a prehistoric animal are clear to see in a rock layer in Peru
Dinosaurier auf 4600 Metern gefunden
20minuten – 15 ore fa
Dabei stiessen die Strassenbauer auf über hundert fossile Abdrücke und Knochen von Dinosaurier-Arten, die vor etwa 120 Millionen Jahren gelebt haben. Bei den Funden konnten zwölf verschiedene Arten unterschieden werden, darunter fleischfressende …
«Jurassic Park» nell’isola di Wight
Scoperte le tracce fossili di un Velociraptor e di altri dinosauri dove suonò Bob Dylan nel 1969
DAL NOSTRO CORRISPONDENTE – LONDRA – I più giovani, forse, ne hanno sentito parlare di quell’ultimo giorno di agosto del 1969, ben 40 anni fa, quando su un prato dell’Isola di Wight migliaia e migliaia di ragazzi della beat-generation si ritrovarono ballare e cantare con Bob Dylan, vestito di bianco, e la sua «Band». Un concerto-festival entrato nella storia della musica e del costume. Bob Dylan non piacque a molti, ci fu chi scrisse su una pietra: qui giace il grande Bob. Fra la folla c’erano un certo John Lennon e un certo Paul Harrison.
SCAVATE TRE TONNELLATE DI TERRA – Oggi l’isola di Wight, al largo di Southampton nella Manica, fa parlare ancora di sé. Ma per ben altre ragioni. Steve Sweetman, dell’università di Portsmouth, ha ritrovato in quattro anni di ricerca le tracce fossili di un velociraptor, il Predatore Veloce del Cretaceo, di un pterosaurus, di tre sauropodi e di almeno quattro dinosauri erbivori, oltre a tre coccodrilli giganti e 48 specie sconosciute di animali. Il paleontologo ha dragato tre tonnellate mezzo di terra partendo da un minuscolo indizio: la mandibola di una salamandra. Che l’Isola di Wight avesse ospitato cento milioni di anni fa una piccola colonia di dinosauri gli scienziati lo avevano già accertato. Ma la scoperta, annunciata ieri, è sorprendente. Se non altro per la quantità del «tesoro» venuto alla luce. Jurassik Park è davvero esistito.
Dinosaur hunter unearths nearly 50 new species in Britain’s own Jurassic Park
Some 48 new prehistoric species have been unearthed by a British expert from Britain’s own Jurassic Park, including dinosaurs similar to the deadly velociraptor and giant flying pterosaurs.
Partirà da Gravina la puntata di Easy Driver
Gli spettatori di RaiUno alla scoperta della Murgia
Partirà da Gravina la puntata di Easy Driver condotta da Ilaria Moscato e Marcellino Mariucci, che porterà gli spettatori di RaiUno alla scoperta della Murgia.
La registrazione della partenza delle auto di scena è in programma giovedì mattina, in piazza Benedetto XIII dalle ore 8.30 alle ore 12.30.
Le auto di scena di questa puntata di Easy Driver che andrà in onda sabato 7 febbraio alle ore 14, dopo il TG1, sono la Maserati gran turismo S L.13547 e la Renault Twingo RS DS 677 ZP.
Oltre a piazza Benedetto XIII, il regista della trasmissione Marco Speroni e la giornalista Francesca Di Ciccio, lunedì scorso hanno visitato il tratto del torrente “gravina” che parte dal santuario della Madonna della Stella per scegliere i luoghi più belli dell’habitat rupestre da proporre poi nella puntata di Easy Driver che andrà in onda il 7 febbraio.
L’itinerario interesserà anche il territorio di Corato e di Ruvo di Puglia prima di concludersi nella cava dei dinosauri, ad Altamura.
Altamura, dopo 10 anni si aspetta la parola fine per la cava dei dinosauri
|ALTAMURA – Solo qualche mese e sono dieci anni dalla scoperta della cava dei dinosauri. Sarà un anniversario in tono minore perché il giacimento paleontologico è ancora chiuso al pubblico. La questione sarà al centro di un vertice al Comune di Altamura. Il direttore regionale ai beni culturali Ruggiero Martines ed il sindaco Mario Stacca hanno concordato infatti di indire per il 13 gennaio nella sala consiliare di Altamura una conferenza di servizi per la cava dei dinosauri con lo scopo di definire «le opportune soluzioni tecnico-amministrative che possano garantire la pubblica fruibilità del bene».
Oggetto dell’incontro, dunque, è giungere ad una soluzione per cui si possa aprire il sito su cui ricade una pluralità di competenze, pubbliche e private, che rende il nodo più stretto. Sta di fatto che il sito di cava Pontrelli veniva scoperto esattamente dieci anni fa. I geologi Massimo Sarti e Michele Claps, mentre effettuavano dei sondaggi per conto di una compagnia petrolifera, nei primi mesi del 1999 verificarono la presenza della cava che si trova a cinque chilometri da Altamura, sulla strada provinciale per Santeramo.
La cava, in quel momento ferma, in passato era stata utilizzata per estrazione di inerti. I due studiosi furono subito presi dall’interesse per quei numerosi incavi sulla superficie che erano sempre stati considerati solo dei «buchi» dagli operai. L’esperienza del professor Umberto Nicosia, dell’Università La Sapienza, confermò che si trattava di impronte di dinosauri. A giugno del 1999 ci fu l’annuncio ufficiale della scoperta.
L’entusiasmo ed il clamore furono enormi. Per un breve tempo il sito fu anche aperto al pubblico. Poi la chiusura per ragioni di sicurezza. E da quel momento lo stallo perdura. La paleosuperficie è vincolata dallo Stato ma non lo è l’area circostante, ancora di proprietà privata, che bisogna attraversare per giungere al sito. Ci sono intese, protocolli, accordi. Ma niente di definitivo per consentire l’apertura al pubblico del sito. Su cui nel frattempo agiscono anche le intemperie atmosferiche, con il rischio di provocare dei danni ai reperti.
La ricchezza del sito è stata certificata dagli studiosi che stimano la presenza di 30mila orme. Impronte che appartengono a dinosauri erbivori che lasciarono quelle tracce oltre 80 milioni di anni fa. Una pagina di preistoria unica nel mondo. Da riaprire allo studio ed alla conoscenza.
La scoperta di tracce lasciate da un piccolo organismo sul fondo dell’Oceano mette in dubbio l’origine di trace analoghe risalenti al Precambriano. Infatti molte tracce analoghe erano state attribuite ad organismi vermiformi (e quindi evolutivamente molto più complessi) mentre ora tale scoperta fa nascere nuovi interrogativi sull’interpretazione delle tracce fossili del precambriano e sulla diversificazione iniziale dei Bilateralia (wiki link: ENG, GER, ITA).
Tale scoperta ha inoltre spinto gli autori della ricerca a far partire il progetto “deep-sea palaeontology”, ossia la costruzione di una databas di trcce attuali da confrontare poi con quelle fossili
‘Grape’ is key to fossil puzzle
The protist is similar to a grape in size and shape
A single-celled ball about the size of a grape may provide an explanation for one of the mysteries of fossil history.
Writing in Current Biology, researchers say the creature leaves tracks on the seabed which mirror fossilised tracks left up to 1.8 billion years ago.
Many palaeontologists believe only multi-celled organisms could have made these tracks.
This has been difficult to confirm as no multi-cellular fossils of such an age have ever been found.
Covered in mud
The discovery was made by marine biologists monitoring the sea bed in the Bahamas. They noticed a great deal of tracks made by grape-shaped creatures called protists. Dr Mikhail “Misha” Matz from the University of Texas at Austin, US, led the research.
“We were looking for pretty animals that have eyes, are coloured, or glow in the dark; instead, the most interesting find was the organism that was blind, brainless, and completely covered in mud,” he said.
The researchers say the 3cm-wide, single-celled protists propel themselves using tiny protruding legs called pseudopodia. A number of openings all over the body act as mouths and outlets for waste.
The protists move very slowly, taking weeks or even months to make a track of a few centimetres. As the sea bed currents where they were observed are very slight, their tracks are not washed away.
The protist tracks look very similar to fossil tracks found in the pre-Cambrian era more than 500 million years ago.
Perhaps the most famous are the “worm casts” found in the Stirling Ranges in Western Australia. In 2002, these were dated to at least 1.2 billion years old.
The worm casts may not have been made by worms after all
This dating presented a problem for palaeontologists; they assumed multi-cellular organisms with bilateral symmetry, where two halves of their bodies are approximate mirror images of each other, had to be responsible for such tracks, but there is no fossil evidence for the existence of such creatures until several million years later.
Fossil experts believe bilateral symmetry is what gave the organism the ability to make the tracks, with the impressions being produced when the organism moved its weight from one side to another.
Dr Matz believes protists provide an explanation of how the tracks could have been made without the need for organisms with bilateral symmetry.
“We used to think that it takes bilateral symmetry to move in one direction across the seafloor and thereby leave a track,” he explains.
“You had to have a belly and a backside and a front and back end. Now, we show that protists can leave traces of comparable complexity and with a very similar profile.”
Bilateral symmetry appeared in the Cambrian era about about 542 million years ago, early creatures quickly diversified into all of the major animal groups of today. Quite how or why this rapid diversification, known as the Cambrian explosion, occurred is still one of the biggest questions in animal evolution.
Very few fossils exist of organisms that could be the pre-Cambrian ancestors of bilateral animals, and even those are highly controversial. Fossil traces, such as these tracks are the most accepted evidence of the existence of these proto-animals.
Dr Matz says all tracks which predate the rapid evolution of life seen in the Cambrian explosion – could come from protists.
“Pretty much anything within the Precambrian fossil record can in principle be attributed to large protozoans, from the earliest traces and fossils of the Stirling formation,” he says.
The researchers say forms described as “globular or bulbous collapsible bodies” which were found fossilised together with the Stirling formation’s worm trails are probably the remains of creatures very similar to the protists they found at the bottom of the sea.
The tracks resemble those found in prehistoric times
Genetic analysis shows this moving protist from the Bahamas is broadly the same as a stationary type found in the Arabian sea.
The researchers are now beginning a project which they call “deep-sea palaeontology” to create a catalogue of tracks produced by a variety of present-day underwater animals for comparison with the fossil record.
Dr Matz says the giant protists’ bubble-like structure is probably one of the planet’s oldest body designs, and may have existed for 1.8 billion years.
“Our guys may be the ultimate living fossils of the macroscopic world,” he says.
Friday, 21 November 2008
Deep-sea protists may explain trace fossil evidence attributed to ancient animals
Public release date: 20-Nov-2008
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Contact: Cathleen Genova
A new discovery challenges one of the strongest arguments in favor of the idea that animals with bilateral symmetry—those that, like us, have two halves that are roughly mirror images of each other—existed before their obvious appearance in the fossil record during the early Cambrian, some 542 million years ago. In the November 25th issue of Current Biology, a Cell Press publication, researchers report the first evidence that trace fossils interpreted by some as the tracks of ancient bilaterians could have instead been made by giant deep-sea protists, like those that can still be found at the seafloor to this day.
Protists are a diverse group of predominantly microscopic organisms. They are commonly single-celled with a single nucleus, but they may attain larger size by having many nuclei or forming colonies of identical, unspecialized cells. In the new study, the team describes macroscopic groove-like traces produced by living giant protists, known as Gromia sphaerica, which look something like a grape in terms of shape and size. Those grooves bear a remarkable resemblance to the trace fossils from the Precambrian, including ones as much as 1.8 billion years old.
“Our paper gives the precedent of a protozoan that is motile, produces macroscopic traces, and has a large hydrostatically supported body,” said Mikhail Matz of the University of Texas at Austin. “With these possibilities demonstrated, pretty much anything within the Precambrian fossil record can in principle be attributed to large protozoans, from the earliest traces and fossils of the Stirling formation that are 1.8 billion years old to the weird Ediacaran biota with which the Precambrian culminated.”
This new “protozoan option” takes the edge off the most compelling evidence of primitive bilaterians in the Precambrian that is so important for what has been called the “ancient school,” he says. That line of thinking holds that the apparently explosive diversification of multicellular body plans during the Cambrian is an artifact of the fossil record; it suggests that bilaterians actually existed long before the Cambrian and evolved gradually over time. Others think instead that the Cambrian explosion really happened the way it appears that it did and that evolutionary mechanisms must therefore be sought to explain the rapid diversification.
“Previously one could say, ‘There were traces, therefore there must have been bilaterians,’ whereas now it is ‘There were traces, therefore there may have been bilaterians,’ which is, obviously, not nearly as strong a statement,” Matz said.
He calls the findings a “classic case of scientific serendipity.” They stumbled upon the giant protists while working on a project exploring the interaction between light and life in the ocean. “We were looking for pretty animals that have eyes, are colored, or glow in the dark,” Matz said. “Instead, the most interesting find was the organism that was blind, brainless, and completely covered in mud.”
Almost nothing is known about G. sphaerica, he added. His team is now deep sequencing the genes expressed in this giant protist and a few related protozoans to get a better idea about their evolutionary relationships to one another. They also plan to initiate a project on “deep-sea paleontology” to create a catalogue of traces produced by a variety of present-day animals. “There is surprisingly little data on this, so paleontologists have to resort to speculations a lot when interpreting fossil traces,” Matz said.
The researchers include Mikhail V. Matz, University of Texas at Austin, Austin, TX; Tamara M. Frank, Harbor Branch Oceanographic Institute at Florida Atlantic University, Fort Pierce, FL; N. Justin Marshall, The University of Queensland, Brisbane, Queensland, Australia; Edith A. Widder, Ocean Research and Conservation Association, Fort Pierce, FL; and Sonke Johnsen, Duke University, Durham, NC, USA.
Giant Deep-Sea Protist Produces Bilaterian-like Traces
Mikhail V. Matz, Tamara M. Frank, N. Justin Marshall, Edith A. Widder, Sönke Johnsen
Current Biology –
20 November 2008
| Full Text
One of the strongest paleontological arguments in favor of the origin of bilaterally symmetrical animals (Bilateria) prior to their obvious and explosive appearance in the fossil record in the early Cambrian, 542 million years ago, is the occurrence of trace fossils shaped like elongated sinuous grooves or furrows in the Precambrian. Being restricted to the seafloor surface, these traces are relatively rare and of limited diversity, and they do not show any evidence of the use of hard appendages. They are commonly attributed to the activity of the early nonskeletonized bilaterians or, alternatively, large cnidarians such as sea anemones or sea pens. Here we describe macroscopic groove-like traces produced by a living giant protist and show that these traces bear a remarkable resemblance to the Precambrian trace fossils, including those as old as 1.8 billion years. This is the first evidence that organisms other than multicellular animals can produce such traces, and it prompts re-evaluation of the significance of Precambrian trace fossils as evidence of the early diversification of Bilateria. Our observations also render indirect support to the highly controversial interpretation of the enigmatic Ediacaran biota of the late Precambrian as giant protists.