Fake Italian dragon, pterosaur or dog?


Engravings from Meyer's book of the fake Italian dragon

From World Science:

Killed twice in 1600s, hoax “dragon” slain again—in creationism dispute

May 8, 2013
Special to World Science

A “drag­on” thought to have turned up out­side Rome in the 1600s was killed once, or even twice, in the lo­cal lo­re of its day.

It then lay for­got­ten for three cen­turies—be­fore tak­ing on yet a new life, in the minds of some crea­t­ion­ists who saw in the tale com­pel­ling ev­i­dence for their be­liefs.

Two bi­ol­o­gists from Fay­ette­ville State Uni­vers­ity in North Car­o­li­na have now de­cid­ed to slay the beast once and for all, by do­ing some sleuthing to con­firm what many Ital­ians al­ready sus­pected way back then.

The drag­on was a hoax, they con­clude. Such ex­ist­ence as it had, they add, was based on a forgery com­posed of var­i­ous an­i­mal bones. In that sense it was not too un­like the fa­mous Pilt­down Man, a fake “early hu­man” con­sist­ing of the low­er jaw­bone of an orang­u­tan com­bined with a hu­man skull. That scheme was ex­posed in 1953.

The drag­on sto­ry as trans­mit­ted through old doc­u­ments has de­light­ed some crea­t­ion­ists be­cause they cite the mon­ster—en­grav­ings from the time in­clude a de­tailed skele­tal view—as proof that con­tra­ry to main­stream sci­ence, a fly­ing, rep­til­i­an cous­in of the di­no­saurs lived just re­cent­ly.

But the tale cap­ti­vat­ed Ital­ians long be­fore ar­gu­ments over ev­o­lu­tion. The sto­ry brings us back to about the time when the great sculp­tor-ar­chi­tect Gian Lo­ren­zo Ber­ni­ni re­built the fa­mous square in front of St. Pe­ter’s Ba­sil­i­ca in Rome, erect­ing its cel­e­brat­ed col­on­nade.

A cou­ple of dec­ades af­ter that proj­ect, ru­mors of the drag­on cropped up in con­nec­tion with an­oth­er, less fa­mous con­struc­tion near­by.

Ac­tu­al­ly, one pub­lished ver­sion of the drag­on tale ac­tu­ally dat­ed its “death” to the mid­dle of the St. Pe­ter’s Square proj­ect, in 1660. Yet ma­te­ri­al in an­oth­er book sug­gests that ru­mors of its sight­ing cir­cu­lat­ed about 1691, in the swamps out­side Rome where a di­ke was un­der con­struc­tion. Which­ev­er ver­sion might ac­cu­rately re­flect the “real” ru­mor, the lat­ter book is the one with the en­grav­ings.

This book, by an en­gi­neer in­volved with the di­ke, states that the drag­on was killed and pro­vides three de­light­ful en­graved il­lustra­t­ions. But it says lit­tle else on the sub­ject, ex­cept to men­tion that the beast was “was reco­vered in the hands of the en­gi­neer” him­self, one Cor­ne­li­us Mey­er. The book is mostly about di­ke con­struc­tion proj­ects around Rome.

De­tails on the bi­zarre rep­til­i­an tale are thus fog­gy. But the two bi­ol­o­gists, Pon­danesa D. Wil­kins and Phil Sen­ter, spec­u­late, based on the doc­u­ments, that a drag­on ru­mor be­came an ob­sta­cle to a di­ke con­struc­tion in 1691. Lo­cals or work­ers might have balked at the proj­ect, be­liev­ing a drag­on was on the loose in the ar­ea, per­haps one that was an­gry over the dis­turb­ance of its home. The beast was per­haps viewed as a res­ur­rec­tion of the same mon­ster writ­ten else­where to have died in 1660, al­so in the Rome ar­ea.

In any case, the bi­ol­o­gists pro­pose that Mey­er’s pub­lished “ev­i­dence” of the death in­clud­ing the en­grav­ings might have been part of an effort to fi­nally quell the ru­mors and keep the proj­ect afloat. A pa­per with their findings ap­pears in the May-August is­sue of the on­line re­search jour­nal Pa­lae­on­tolo­gia Elec­tron­ica.

The explanation for the engravings is that “Meyer chose not to invite op­position by ex­press­ing skepticism about the lo­cal rumor,” they argue. “In­stead, he wisely chose to avoid re­sist­ance by hu­moring the lo­cals… em­bracing the lo­cal rumor and pro­viding vi­sual evid­ence that their source of con­cern had been van­quished.”

Wil­kins and Sen­ter ar­gue that some­one likely cob­bled to­geth­er a fake skel­e­ton. This nat­u­rally found its way in­to some of those closely ob­served de­pic­tions for which Ital­ians had such a flair. In one of these en­grav­ings, the ske­l­e­ton ap­pears, prop­erly perched on a charm­ing ba­roque ped­es­tal.

All that re­mained was for Wil­kins and Sen­ter to fig­ure out just what went in­to this “skel­e­ton.” In­ter­est­ingly “the en­grav­ing is de­tailed enough to test” the view that it’s a real pter­o­saur, the re­search­ers wrote.

The con­clu­sions from their analysis are cut­ting.

“The skull of Mey­er’s drag­on is that of a do­mes­tic dog,” they write. “The man­di­ble is that of a sec­ond, smaller do­mes­tic dog. The ‘hindlimb’ is the fore­limb of a bear. The ribs are from a large fish. Os­ten­si­ble skin hides the junc­tions be­tween the parts of dif­fer­ent an­i­mals. The tail is a sculpted fake. The wings are fake and lack di­ag­nos­tic traits of bat wings and pter­o­saur wings. No part of the ske­l­e­ton re­sem­bles its coun­ter­part in pter­o­saurs.”

“This piece of young-Earth crea­t­ion­ist ‘ev­i­dence’ there­fore now joins the ranks of oth­er dis­cred­ited ‘ev­i­dence’ for hu­man-pter­o­saur coex­ist­ence and against the ex­ist­ence of the pas­sage of mil­lions of years,” Wil­kins and Sen­ter add. “Also, a three-century-old hoax is fi­nally un­veiled, the mys­tery of its con­struc­tion is solved, and an in­ter­est­ing and bi­zarre ep­i­sode in Ren­ais­sance Ital­ian histo­ry is elucidat­ed.”

Skep­ti­cism over the drag­on yarn is far from new. The con­tem­po­rary Ger­man au­thor George Kirch­meyer re­counts that the “fly­ing ser­pent” was sup­posedly “killed by a hunt­er af­ter a se­vere and dan­ger­ous strug­gle”; but “this sto­ry, which ap­peared more like some fa­ble than real truth, was a sub­ject of dis­cus­sion among the learn­ed. The cir­cum­stance was de­nied by many, be­lieved by oth­ers, and left in doubt by sev­er­al.”

Two crea­t­ion­ists who have cho­sen to join the be­liev­ers are the au­thors John Go­ertzen and Da­vid Woet­zel, who penned 1998 and 2006 pa­pers on the sub­ject, re­spec­tive­ly.

“This study helps to es­tab­lish the re­cent ex­ist­ence of rham­phorhyn­choid pter­o­saurs; an­i­mals that main­stream sci­ence be­lieves be­came ex­tinct about 140 mil­lion years ago,” Go­ertzen wrote in his pa­per, which ap­peared in the Pro­ceed­ings of the Fourth In­terna­t­ional Con­fer­ence on Crea­t­ion.

Crea­t­ion­ists claim that the Bi­ble proves Earth is only a few thou­sand years old. Thus things like di­no­saurs, which died out 65 mil­lion years ago, pose a prob­lem for crea­t­ion­ists.

Woet­zel did not re­spond to an e­mail sent through his web­site re­quest­ing com­ment.

Go­ertzen could not be lo­cat­ed via e­mail or tel­e­phone, with none of his sev­er­al pa­pers on­line pro­vid­ing con­tact in­forma­t­ion. How­ev­er, his 1998 pa­per on the drag­on ar­gued that the Ital­ian drag­on tale was not the only piece of ev­i­dence for its re­cent ex­ist­ence.

“The re­mark­a­ble thing about this an­i­mal is that it was de­picted in sev­er­al cul­tures of an­ti­qu­ity. Ar­ti­facts iden­ti­fied with this in­ter­est­ing pter­o­saur spe­cies in­clude Roman-Alex­and­rian coins, an Ara­bia-Phil­istia coin, a French wood carv­ing, a Ger­man stat­ue and coin, sev­er­al Mid­dle Ages pic­ture maps, and an en­light­en­ing sketch of a mount­ed an­i­mal in Rome.”

See also here.

Ancient fossil named after Johnny Depp


Kooteninchela deppi

From Biology News Net:

Actor Johnny Depp immortalized in ancient fossil find

May 16, 2013 04:57 PM

A scientist has discovered an ancient extinct creature with ‘scissor hand-like’ claws in fossil records and has named it in honour of his favourite movie star.

The 505 million year old fossil called Kooteninchela deppi (pronounced Koo-ten-ee-che-la depp-eye), which is a distant ancestor of lobsters and scorpions, was named after the actor Johnny Depp for his starring role as Edward Scissorhands – a movie about an artificial man named Edward, an unfinished creation, who has scissors for hands.

Kooteninchela deppi is helping researchers to piece together more information about life on Earth during the Cambrian period when nearly all modern animal types emerged.

David Legg, who carried out the research as part of his PhD in the Department of Earth Science and Engineering at Imperial College London, says:

“When I first saw the pair of isolated claws in the fossil records of this species I could not help but think of Edward Scissorhands. Even the genus name, Kootenichela, includes the reference to this film as ‘chela’ is Latin for claws or scissors. In truth, I am also a bit of a Depp fan and so what better way to honour the man than to immortalise him as an ancient creature that once roamed the sea?”

Kooteninchela deppi lived in very shallow seas, similar to modern coastal environments, off the cost of British Columbia in Canada, which was situated much closer to the equator 500 million years ago. The sea temperature would have been much hotter than it is today and although coral reefs had not yet been established, Kooteninchela deppi would have lived in a similar environment consisting of sponges.

The researcher believes that Kooteninchela deppi would have been a hunter or scavenger. Its large Edward Scissorhands-like claws with their elongated spines may have been used to capture prey, or they could have helped it to probe the sea floor looking for sea creatures hiding in sediment.

Kooteninchela deppi was approximately four centimetres long with an elongated trunk for a body and millipede-like legs, which it used to scuttle along the sea floor with the occasional short swim.

It also had large eyes composed of many lenses like the compound eyes of a fly. They were positioned on top of movable stalks called peduncles to help it more easily search for food and look out for predators.

The researcher discovered that Kooteninchela deppi belongs to a group known as the ‘great-appendage’ arthropods, or megacheirans, which refers to the enlarged pincer-like frontal claws that they share. The ‘great-appendage’ arthropods are an early relation of arthropods, which includes spiders, scorpions, centipedes, millipedes, insects and crabs.

David Legg adds: “Just imagine it: the prawns covered in mayonnaise in your sandwich, the spider climbing up your wall and even the fly that has been banging into your window and annoyingly flying into your face are all descendants of Kooteninchela deppi. Current estimates indicate that there are more than one million known insects and potentially 10 million more yet to be categorised, which potentially means that Kooteninchela Deppi has a huge family tree.”

In the future, David Legg intends to further his research and study fossilised creatures from the Ordovician, the geological period that saw the largest increase in diversity of species on the planet. He hopes to understand why this happened in order to learn more about the current diversity of species on Earth.

Ape, monkey evolution discoveries in Tanzania


Artist’s impression of the newly discovered Rukwapithecus, front, and Nsungwepithecus, right (Mauricio Anton)

From Big News Network (ANI):

Oldest evidence of split between Old World monkeys and apes uncovered

Thursday 16th May, 2013

Discovery of two fossils from the East African Rift has provided new information about the evolution of primates, according to a study.

The team’s findings document the oldest fossils of two major groups of primates: the group that today includes apes and humans (hominoids), and the group that includes Old World monkeys such as baboons and macaques (cercopithecoids).

Geological analyses of the study site indicate that the finds are 25 million years old, significantly older than fossils previously documented for either of the two groups.

Both primates are new to science, and were collected from a single fossil site in the Rukwa Rift Basin of Tanzania.

Rukwapithecus fleaglei is an early hominoid represented by a mandible preserving several teeth. Nsungwepithecus gunnelli is an early cercopithecoid represented by a tooth and jaw fragment.

The primates lived during the Oligocene epoch, which lasted from 34 to 23 million years ago. For the first time, the study documents that the two lineages were already evolving separately during this geological period.

“The late Oligocene is among the least sampled intervals in primate evolutionary history, and the Rukwa field area provides a first glimpse of the animals that were alive at that time from Africa south of the equator,” said Nancy Stevens, an associate professor of paleontology in Ohio University’s Heritage College of Osteopathic Medicine who leads the paleontological team.

Prior to these finds, the oldest fossil representatives of the hominoid and cercopithecoid lineages were recorded from the early Miocene, at sites dating millions of years younger.

The new discoveries are particularly important for helping to reconcile a long-standing disagreement between divergence time estimates derived from analyses of DNA sequences from living primates and those suggested by the primate fossil record, Stevens said.

Studies of clock-like mutations in primate DNA have indicated that the split between apes and Old World monkeys occurred between 30 million and 25 million years ago.

“Fossils from the Rukwa Rift Basin in southwestern Tanzania provide the first real test of the hypothesis that these groups diverged so early, by revealing a novel glimpse into this late Oligocene terrestrial ecosystem,” Stevens said.

The new fossils are the first primate discoveries from this precise location within the Rukwa deposits, and two of only a handful of known primate species from the entire late Oligocene, globally.

The scientists scanned the specimens in the Ohio University’s MicroCT scanner, allowing them to create detailed 3-dimensional reconstructions of the ancient specimens that were used for comparisons with other fossils.

“This is another great example that underscores how modern imaging and computational approaches allow us to address more refined questions about vertebrate evolutionary history,” said Patrick O’Connor, co-author and professor of anatomy in Ohio University’s Heritage College of Osteopathic Medicine.

The study was published online in Nature this week led by Ohio University scientists.

See also here. And here. And here.

How animals learned to eat plants


Right lateral aspect of the skull of a juvenile specimen of Orobates pabsti. Credit: Dr Amy Henrici, Carnegie Museum, Pittsburgh; Photo permission: Dr Thomas Martens, Stiftung Schloss Friedenstein Gotha, Germany

From the University of Lincoln in England:

Land animals kept fish-like jaws for millions of years

09 May 2013 University of Lincoln

Research has confirmed how early land vertebrates, which evolved from fish, developed weight-bearing limbs and other adaptations long before their feeding systems adjusted to a vegetation-based diet.

Now, for the first time, fossil jaw measurements have demonstrated this gap in evolutionary development.

Scientists from the University of Lincoln (UK), the University of Massachusetts, Amherst, and the University of Oxford (UK), examined the lower jaws of 89 fossils of early tetrapods (four-footed animals) and their fish-like predecessors.

The fossils ranged in age from about 300 to 400 million years old and the team were interested in how the mechanical properties of the jaws of these animals differed through time.

They used 10 biomechanical metrics to describe jaw differences. One of these, called mechanical advantage, measured how much force an animal can transfer to its bite.

Dr Marcello Ruta, from the School of Life Sciences, University of Lincoln, said: “Our study is the first of its kind to address changes in biomechanical properties of the lower jaw across the transition from fish to land vertebrates using a diverse range of extinct species. This work paves the way to in-depth analyses of the rates of evolutionary transformation in other anatomical structures during this major episode in vertebrate history. It also lays the foundations for integrative research that explores themes as diverse as the origin of the first terrestrial food webs, the impact of acquisition of new structures on the diversification of major animal groups, and patterns and processes of functional change.”

So it turns out that just moving into a new environment is not always enough to trigger functional adaptations.

The team discovered that the mechanical properties of tetrapod jaws did not show significant changes in patterns of terrestrial feeding until some 40 to 80 million years after the four-legged creatures initially came out of the water. Until then, tetrapod jaws were still very fish-like, even though their owners had weight-bearing limbs and the ability to walk on land.

In the paper, which has been published in an early online edition of the journal Integrative and Comparative Biology, the authors say the results may be explained by an earlier hypothesis: a shift from gilled to lung breathing in later four-footed animals was necessary before they could adapt their jaw structure to eating plants.

This finding suggests tetrapods may have shown a limited variety of feeding strategies in the early phases of their evolution on land.

Lead author Dr Phil Anderson, from the University of Massachusetts, said: “The basic result was that it took a while for these animals to adapt their jaws for a land-based diet. They stayed essentially fish-like for a long time.”

Dr Matt Friedman, lecturer in palaeobiology at the University of Oxford, said: “The thing that is really interesting is that the diversity of jaw function didn’t really take off until around the origin of amniotes – creatures that lay hard-shelled eggs on land rather than being tied to water for reproduction like fishes and amphibians. It is in amniotes and their closest relatives that we see the first evidence for dedicated herbivory – until that point tetrapods had basically been carnivores. So this means it took at least 50 million years of evolution after the origin of features like limbs, fingers and toes before tetrapods achieved dietary diversity that began to resemble what we see today.”

The statistical methods developed in this work could be used in future studies of more subtle biomechanical patterns in fossil animals that may not be initially clear.

Pachycephalosaur discovery in Canada


Researchers think Acrotholus audeti looked much like this. Image Courtesy: Julius Csotonyi

From Science Fare Media:

New dog-sized pachycephalosaur unearthed in southern Alberta

Small size hints that more similar-sized dinosaurs are still probably waiting to be discovered

Lee Flohr

May 7, 2013

When Roy Audet let researchers scour his ranch for creatures that roamed there roughly 85 million years ago, he didn’t expect them to find the fossil of a new dinosaur with features that he’ll jokingly admit they might share – he didn’t expect it to be named after him either.

But, a team of researchers from Canada and the United States did just that when they found a skull cap belonging to a new species of pachycephalosaur on his southern Alberta ranch in 2008.

“I get lots of jokes because I am a bit hard headed you know,” Audet told SciFare.com.

Formally named Acrotholus audeti, it’s the oldest pachycephalosaur dome found in North America – maybe even the world – it’s roughly two inches thick and sat on the head of a dinosaur that’s about as big as a large dog, but stretched roughly six feet long from tip-to-tip.

“It has a very well developed dome for its geological age,” David Evans, study co-author and curator of vertebrate paleontology at the Royal Ontario Museum in Toronto, told SciFare.com. “The vast majority of dome-headed dinosaurs in the fossil record are basically based on isolated skull caps.”

Fortunately for researchers, they found a less complete dome sitting on their shelf after it was recovered from the same region, more than 50 years ago.

“Even though I had recognized it as being something distinct, it wasn’t until Caleb found the really good specimen in 2008 that we really clinched it,” Evans said. “It’s very well preserved, has a lot of detail and shows how a lot of characteristics of pachycephalosaurs that we thought appeared later in the fossil record, actually occurred earlier.

In order to look dome’s internal structure, researchers used a CT-scanner and found that by the time the dinosaur started walking into the fossil record it had already evolved into one complete unit.

“So, the acquisition of a very tall dome had occurred, at least, by the time of Acrotholus, 85 million years ago,” he added.

The CT-scan also allowed them to determine the dinosaur’s life stage without destroying it – traditional methods require them to slice the bone and dye it – and weighing roughly 100 pounds, it was entirely possible that it belonged to a juvenile.

“We can tell by the density how mature the individuals are,” Evans said. “In this case the dome’s extremely dense and that’s something we only see in the most mature adults.”

Turns out their thick skulls actually have profound consequences for the entire fossil record – their unique head gear may be the only reason we know them at all.

By dinosaur standards, Acrotholus is small. The researchers say that if a mature, small bodied pachycephalosaur exists, small bodied versions of other dinosaurs should exist too – but they don’t.

“Their bones are very small and susceptible to weathering and destruction by predators,” Evans said. “Something about the size of a small dog would be one bite for a predator, and all of those bones would be gone.”

So, if they didn’t end up as hors d’oeuvres, their skeletons were certainly ground up by the sands of time – the planet looked a lot different 85 million years ago.

When the researchers added the new find to the pachycephalosaur family tree, they found Acrotholus’ dome was closely related to a pachycephalosaur from Mongolia, known as Prenocephale.

Fortunately, its skeleton is more complete and researchers were able to use it to generate the image of Acrotholus’ – the turtle in the picture was also found on Audet’s ranch and described by a team that included Evans in 2012.

Eric Snively studies how pachycephalosaurs might have used their thick skulls – he wasn’t part of this discovery though. He told SciFare.com the research is interesting because it shows much there’s still left learn about this time period – known technically as the Santonian – and pachycephalosaur evolution during it.

“They would have split off from their sister group, which are horned dinosaurs like Triceratops and their relatives, many millions of years before we find the first good pachycephalosaur fossils,” Snively, who’s currently a post-doctoral researcher at Ohio University, told SciFare.com.

“There are still a lot of gaps to fill in, but we know that by the time this animal was around they were pretty standard looking pachycephalosaurs,” he added.

He’s also intrigued by the idea that many other small-sized dinosaurs are likely waiting to be discovered – if their existence hasn’t been ground out of the fossil record.

“It’s showing us more evidence that there’s greater diversity of small dinosaurs than we thought,” Snively said.

Evans said his team’s gearing up to head back to Audet’s ranch later this spring so they can hunt for more new and cool fossils. For Audet, it’s just another chance to learn something cool about the creatures that once dominated his ranch, 85-million years ago.

“It’s always fun for me when someone comes along from the scientific community because I can always learn something,” Audet said. “It’s not difficult for me to help ‘em across the river with a canoe or let ‘em park in the yard.”

The new dinosaur was described in the journal, Nature Communications.

Fossil elephant tusk discovery


This video says about itself:

Extinct Elephant Survived Late In North China

Dec 19, 2012

Wild elephants living in North China 3,000 years ago belonged to the extinct genus Palaeoloxodon, scientists say.

They had previously been identified as Elephas maximus, the Asian elephant that still inhabits southern China.

The findings suggest that Palaeloxodon survived a further 7,000 years than was thought.

The team from China examined fossilised elephant teeth and ancient elephant-shaped bronzes for the study.

The research, published in Quaternary International was carried out by a group of scientists from Shaanxi Normal University and Northwest University in Xi’an and The Institute of Geographic Sciences and Natural Resources Research, Beijing.No wild elephants live in North China today, but historical documents indicate that they roamed freely 3,000 years ago.

For decades experts believed that the ancient elephants were E. maximus – a species adapted to a tropical climate and that is still found in China’s southerly Yunnan province.

From Xinhua news agency:

Ancient elephant tusk found in east China

2013-5-6 19:49:18

A fossilized elephant tusk that can be dated back at least 10,000 years has been discovered in east China’s Anhui Province, local cultural heritage authorities said Monday.

A villager spotted the fossil tooth, more than three meters in length, on Thursday while working on his farmland in the township of Gucheng, Huaiyuan County in Bengbu City, said Chen Liding, director of the county’s institute of cultural heritage management.

Experts with the institute identified the tusk as belonging to an adult elephant of the extinct genus Palaeoloxodon after unearthing the fossil buried over two meters underground, Chen said.

The tusk was fragile as a result of calcification, he added.

The species is believed to inhabit Anhui and Henan provinces of the Huaihe River basin between 120,000 and 10,000 years ago.

In 2007, a fossil tooth of a Palaeoloxodon elephant was found several kilometers from the township of Gucheng, Chen said.

Tyrannosaurus rex excavation update


This video from 1 May 2013 is about the Tyrannosaurus rex excavation by the Dutch Naturalis museum in Wyoming, USA.

On 30 April, fossil parts of the feet bones of the extinct Cretaceous dinosaur were discovered.

The team keeps digging, hoping to find more.

This video about the dig is from 30 April.

Blog, in Dutch, about this expedition: here.

Coelacanth DNA and tetrapod evolution


This video says about itself:

DNA From Fish May Explain How Feet Evolved From Fins

18 April 2013

Decoding the coelacanth fish genome has put scientists closer to reconstructing how animal ancestors crawled out of the sea 400 million years ago.

By Philip Guelpa:

Genome sequencing of “living fossil” fish sheds light on the evolution of land animals

30 April 2013

In a newly published article in the scientific journal Nature (496, 311–316), scientists report a significant step in the understanding of the evolutionary process that led certain ancient fish to develop limbs and emerge onto dry land, becoming the ancestors of all amphibians, reptiles, birds, and mammals. This transition is one of the most important in the development of life on earth.

The new research is based on the decoding of the genome of a so-called “living fossil” fish, the “coelacanth” (pronounced SEE-luh-canth). This group of fishes, known from fossils dating as far back as 400 million years ago, was long thought to have gone extinct 70 million years ago, in the Late Cretaceous Era. However, the discovery of a living specimen in the West Indian Ocean off of South Africa in 1938 demonstrated that a reclusive population still survived. More recently, a second species of living coelacanth, both belonging to the genus Latimeria, was discovered in Indonesia.

Coelacanths have been colloquially known as living fossils because of their close resemblance, at least outwardly, to fossil specimens dating back tens and even hundreds of millions of years. But perhaps the most interesting aspect of these fish is their apparent close evolutionary relationship to the first land vertebrates.

It has long been thought, based on paleontological and anatomical evidence, that all tetrapods (four-limbed, vertebrate animals—amphibians, reptiles, birds, and mammals) evolved, somewhere in the neighborhood of 400 million years ago, from fish closely resembling the now mostly extinct group of lobe-finned fish belonging to the class Sarcopterygia.

Lobe-finned fish have a well-developed bony skeleton inside their fins, in contrast to the common ray-finned (teleost) fish. Living representatives of this lineage include lungfish, which are actually able to breathe air with lungs that are homologous (have the same genetic origin) as those of tetrapods, and the coelacanth.

Basic anatomical similarities between the skeletal structures in the fins of lobe-finned fish and the limbs of tetrapods strongly suggested an evolutionary link. However, the details of the mechanism for the transformation of fins into limbs had yet to be understood. The newly reported research begins to fill in that gap.

The technique of DNA sequencing, which in recent years has permitted the decoding of the human genome and those of a growing number of other species, has now been used to document the coelacanth’s DNA sequence. Among the resulting discoveries is a genetic mechanism that controls the growth of both the lobe-shaped fins in the coelacanth and of limbs in tetrapods.

Scientists have long wondered whether lungfish or coelacanths were more closely related to tetrapods. In other words, which group is closer to the common ancestor of the earliest vertebrate animals to walk on land? Genetic sequencing holds the potential to answer such questions. Unfortunately, lungfish have an incredibly large genome, which cannot be effectively sequenced by existing methods. It should be noted that the size of a species’ genome has no necessary correlation with the complexity of the organism, due to duplications of DNA sequences and other “baggage” accumulated during the course of evolution, which is not a particularly neat process.

Despite this, the scientific team whose research was published in Nature was able to decode segments of the lungfish genome and compare it to their newly completed full coelacanth sequence as well as to those from a sample of tetrapods. This permitted the conclusion that lungfish are more closely related to tetrapods than are coelacanths. Nevertheless, since the two groups of lobe-finned fish are closely related to each other, knowledge of the coelacanth genome is revealing much regarding the evolution of the first land-dwelling vertebrates.

The first and highly necessary step for the investigators was to determine whether the living coelacanth had evolved only very slowly from its ancestors millions of years ago, as suggested by its ancient outward appearance. This was critically important because the relevance of further analysis would depend on whether the genetic patterns observed in the modern coelacanth could be expected to resemble those of the common ancestor of lobe-finned fish and tetrapods.

The results of this analysis indicate that coelacanths have evolved very slowly as opposed to a number of other species to which they were compared. Many factors influence the rate of evolution in any given lineage of organisms. Evolution is a dialectical interaction between a species and all the elements of its environment. A stable environment means that there is little selective pressure that would prompt adaptive changes. The relatively static environment in which the surviving coelacanths live, and a lack of predators, are likely to have been factors in their slow evolution.

With that understanding, the researchers focused on studying genes that control the expression of structural genes (i.e., genes that build body parts). Such control genes regulate such factors as the degree, rate, and timing of expression of the structural genes.

Among the categories of regulatory genes identified as being newly evolved in tetrapods (that did not exist in the ancestral lobe-finned fish) were ones associated with sensing of chemicals, through taste and smell, driven by the need to more fully perceive the complex terrestrial environment.

Other categories of new control genes include those related to radial pattern formation (body form), hind limb development, kidney development, and the immune system. Again, all of these would have been important in evolutionary adaptation to the new constraints and opportunities of terrestrial existence.

In all, the team identified over 44,000 control genes that evolved after the appearance of tetrapods.

The researchers paid particular attention to the genetic control of the development of hands and feet by comparing genes of teleost (ray-finned) fishes, coelacanths, and tetrapods. They found a specific gene sequence that is common to the latter two, but not found in the former. This sequence was identified as affecting limb development. Experimental insertion of the coelacanth genes into mouse embryos demonstrated that they could provide much of the regulation needed to produce tetrapod limbs, thus demonstrating that this gene complex existed in lobe-finned fishes and was repurposed in the evolution of land animals.

Also identified was a gene in coelacanths that appears later to have become important in the development of the mammalian placenta. Coelacanths give birth to live young which develop inside the mother’s body, but don’t receive direct nourishment from the mother during gestation, as is the case with placental mammals.

The research reported by this team demonstrates the great power and potential of genetic sequencing in helping to elucidate the patterns and mechanisms of biological evolution, complimenting evidence from the fossil record. In a broader sense, this work shows that biological evolution is a process that can be objectively studied and understood as part of the development of the material world.

Microraptor dinosaurs ate fish


This video is called Flying MicroraptorPlanet Dinosaur – Episode 2 – BBC One.

And now, from a very big carnivorous dinosaur, to a very small carnivorous dinosaur.

From Wired:

Microraptor: A 4-Winged, Fish-Eating Dinosaur

By Nadia Drake

04.22.13

7:12 PM

Fossilized guts reveal that Microraptor — a four-winged, flying dinosaur — had an unusual taste for fish. Located near the fossil’s ribs, a mass of fish bones bearing the mark of strong digestive acids suggests the crow-sized reptile’s prey veered from the arboreal to the aquatic.

“There are only two other good examples of dinosaurs with a taste for sushi: the giant, crocodile-like spinosaurs and the tiny compsognathids,” said Scott Persons, from the University of Alberta. “So, no. Fish are not usually considered as staples of a dino’s diet.”

Previous analyses of Microraptor specimens pointed toward prey retrieved from trees: small mammals and birds. But a new analysis, reported Apr. 19 by Persons and colleagues in the journal Evolution, suggests the dinosaur feasted on fish as well. The team based its conclusions on specimen QM V1002, retrieved from northeastern China in an area thought to have been a forested, freshwater lake environment 120 million years ago. Nearly complete, though with a badly crushed skull, the fossil bears traces of the long, dark feathers that have come to distinguish Microraptor. Among the preserved bones and feathers is a lump of bony fish bits that includes fin rays, ribs, vertebrae, and bits of acid-etched fish skull.

Yum.

Persons and colleagues also suggest the dinosaur’s teeth made it particularly good at impaling fish. Its small teeth are angled forward, as is commonly seen in other fish-eating animals such as crocodiles. And they’re only serrated on one edge, which would prevent prey from being ripped apart while struggling.

The team isn’t sure yet whether the dinosaur caught its own fish, or scavenged on leftovers. And, whether the glossy, flying dino behaved more like an eagle or an egret is also still unclear.

“It does not have the long legs of wading bird (like a heron or stork), and we don’t think it had the opposable talons of a modern raptor (like an osprey or fish eagle),” Persons said in an email. “It may have swooped down on fish like a kingfisher, but there is a lot of debate over how agile of a flyer Microraptor was.”

Dutch Tyrannosaurus rex excavation in Wyoming


This video is called Tyrannosaurus REX (Extreme Survivor).

Translated from Naturalis museum in the Netherlands:

T. rex expedition 2013

From 29 April / May 18, 2013 Naturalis will excavate a Tyrannosaurus rex. This they will do in Wyoming, USA, in co-operation with the Black Hills Institute. Follow the excavation in this news blog and enjoy this exciting adventure!

Translated from Corine Knoester in the Netherlands:

While searching for a T. rex Naturalis came in contact with T. rex expert Pete Larson of the Black Hills Institute. He pointed out to them a place in Wyoming where a few fragmented but beautiful fossilized bones of the left foot were found. It is usually the small bones that get lost the first and the fact that some of these bones have been found together is one of the promising bits of evidence that the rest of the skeleton is also present.