Rhinconichthys : New fossil fish species with giant mouth

Researchers have discovered two new fossil fish species that could swing the jaws open extra wide, like a parachute, from the Cretaceous Period, about 92 million years ago, when dinosaurs roamed the planet.These fossil fish species of the genus called Rhinconichthys were estimated to be more than 6.5 feet long and fed on plankton.

Rhinconichthys are exceptionally rare, known previously by only one species from England, said one of the study authors Kenshu Shimada, paleobiologist at DePaul University in Chicago, US.

Rhinconichthys purgatoirensis

Rhinconichthys purgatoirensis

But a new skull discovered in Colorado, US, along with the re-examination of another skull from Japan have tripled the number of species in the genus with a greatly expanded geographical range.

These new species have been named R. purgatoirensis and R. uyenoi, respectively.

“Based on our new study, we now have three different species of Rhinconichthys from three separate regions of the globe, each represented by a single skull,” Shimada noted.

The findings will appear in the forthcoming issue of the journal Cretaceous Research.

Rhinconichthys belongs to an extinct bony fish group called pachycormids, which contains the largest bony fish ever to have lived. The new study specifically focuses on highly elusive forms of this fish group that ate plankton.

Rhinconichthys had a highly unusual specialization for bony fish.

One pair of bones called hyomandibulae formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth, similar to the way many sharks open their mouth, Shimada said.

Courtesy: India today.

Key: WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil society

Rusingoryx atopocranion : An ancient wildebeest

By poring over the fossilized skulls of ancient wildebeest-like animals (Rusingoryx atopocranion) unearthed on Kenya’s Rusinga Island, researchers have discovered that the little-known hoofed mammals had a very unusual, trumpet-like nasal passage similar only to the nasal crests of lambeosaurine hadrosaur dinosaurs. The findings reported in the Cell Press journal Current Biology on February 4 offer “a spectacular example” of convergent evolution between two very distantly related taxa and across tens of millions of years, the researchers say.

“The nasal dome is a completely new structure for mammals– it doesn’t look like anything you could see in an animal that’s alive today,” says Haley O’Brien of Ohio University, Athens. “The closest example would be hadrosaur dinosaurs with half-circle shaped crests that enclose the nasal passages themselves.”

This evolutionary convergence may be explained by similarities in the wayRusingoryx and hadrosaurs lived. In fact, hadrosaurs are sometimes referred to as the “cows of the Cretaceous.”

An artist's interpretation of Rusingoryx atopocranion on the Late Pleistocene plains of what is now Rusinga Island, Lake Victoria. Scientists have found many links between Rusingoryx and hadrosaur dinosaurs -- particularly the large, hollow dome that makes a crest on top of the animal's skull. Credit: Todd S. Marshall (http://www.marshalls-art.com)

An artist’s interpretation of Rusingoryx atopocranion on the Late Pleistocene plains of what is now Rusinga Island, Lake Victoria. Scientists have found many links between Rusingoryx and hadrosaur dinosaurs — particularly the large, hollow dome that makes a crest on top of the animal’s skull.
                                                                                        Credit: Todd S. Marshall (http://www.marshalls-art.com)

For Tyler Faith of the University of Queensland, one of the study’s corresponding authors, it all started in 2009. He and his colleagues were working on a field program in the Lake Victoria region when other scientists directed them to a site they called Bovid Hill. The hill had been so named because of an abundance of fossil Bovidae, the group including antelopes and buffaloes, eroding from its surface.

“After several years of collecting fossils from Bovid Hill, it became very clear that most of the fossils belonged to the poorly known species Rusingoryx atopocranion, described from the same site in 1983, and that we may be dealing with an entire herd that was somehow wiped out and buried at the site,” Faith says.

The researchers also uncovered stone tools and butchered bone, raising the possibility that early modern humans had something to do with the peculiar concentration of Rusingoryx skeletons. In 2011, study co-author Kirsten Jenkins of the University of Minnesota took charge of excavations, hoping to find more complete fossils and to establish why so many skeletons had ended up in that spot. Along the way, she found several intact skulls.

“I was astonished to see that [the skulls] looked unlike any antelope that I had ever seen–the only thing more surprising would have been fossil zebras with horns growing from their heads!” Faith says. “The anatomy was clearly remarkable.”

Faith and O’Brien later decided to explore the anatomy further in six skulls representing Rusingoryx juveniles and adults. The similarity to hadrosaurs was immediately clear to the researchers when they opened CT scan files revealing the inner structures of those bones.

“We were expecting the inside of the dome to have something closer to normal mammalian anatomy, but once we took a look at the CT scans, we were pretty shocked,” O’Brien says.

At first, the researchers thought the hollow nasal dome might have had something to do with thermoregulation. Now, based on their anatomical investigations together with acoustical modeling, they think the trumpet-like nasal tube may have allowed Rusingoryx to deepen its normal vocal calls. In fact, their calculations suggest that the animals might have been able to call at levels very close to infrasound, such that other animals may not have been able to hear individuals in the herd calling back and forth to each other.

Both Rusingoryx and hadrosaur dinosaurs are thought to have been highly social, O’Brien explains. They might have communicated with each other across fairly large distances.

“Vocalizations can alert predators, and moving their calls into a new frequency could have made communication safer,” she says. “On top of this, we know that [both] Rusingoryx and hadrosaurs were consummate herbivores, each having their own highly specialized teeth. Their respective, remarkable dental specializations may have initiated changes in the lower jaw and cheek bones that ultimately led to the type of modification we see in the derived, crest-bearing forms.”

The researchers say they will continue to explore the developmental shifts required to produce the animals’ bizarre morphology. They’d also like to understand what ultimately led the once-thriving Rusingoryx to disappear.

Funding was provided by the National Geographic Society, R. Potts and the Human Origins Program at the Smithsonian Institution, the National Science Foundation, the Australian Research Council, the L.S.B. Leakey Foundation, the Paleontological Society, the American Society of Mammalogists, the Geological Society of America, the Society for Integrative and Comparative Biology, the American Museum of Natural History, Baylor University, Harvard University, New York University, Ohio University, City University of New York, the American School for Prehistoric Research, and the University of Wollongong.

Citation: Cell Press. “Ancient wildebeest-like animal shared ‘bizarre’ feature with dinosaur.” ScienceDaily. ScienceDaily, 4 February 2016. <www.sciencedaily.com/releases/2016/02/160204150559.htm

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Oregramma illecebrosa: Discovery of ‘Jurassic butterflies’

IU paleobotanist David Dilcher is a co-author on a study out today in the Proceedings of the Royal Society: B that identifies a Jurassic age insect whose behavior and appearance closely mimic a butterfly — but whose emergence on Earth predates the butterfly by about 40 million years.

Dilcher — who made international headlines last year for his role in discovering the mythical “first flower” — said these proverbial “first butterflies” survived in a similar manner as their modern sister insects by visiting plants with “flower-like” reproductive organs producing nectar and pollen.

The butterfly-like insects, which went on to evolve into a different form of insect from the modern butterfly, is an extinct “lacewing” of the genus kalligrammatid called Oregramma illecebrosa. Another genus of this insect — of the order Neuroptera — survives into our modern era, and are commonly known as fishflies, owlflies or snakeflies.

Kalligrammatid structural diversity. Specimens are from the late-Middle Jurassic Jiulongshan Fm. (JIU), China; Late Jurassic Karabastau Fm. (KAR), Kazakhstan; and mid-Early Cretaceous Yixian Fm. (YIX), China (electronic supplementary material, tables S2 and S3). At (a–i) are nine species showing general habitus [11]. Arrows indicate proboscis tips. (a) Kalligramma circularia (JIU); (b) Affinigramma myrioneura (JIU); (c) A. myrioneura (JIU); (d) Kallihemerobius feroculus (JIU); (e) Oregramma aureolusa (YIX); (f) Ithigramma multinervia (YIX); (g) Abrigramma calophleba (JIU); (h) Kalligramma brachyrhyncha (JIU); and (i) Oregramma illecebrosa (YIX). (i–k) Lateral views of ovipositor structure in O. illecebrosa above: (i) intact specimen; (j) complete ovipositor and posteriormost abdominal segments; and (k) lateral valve pairs. (l–q): five kalligrammatid wing eyespot and spot types detailed in figures 2 and 3; electronic supplementary material, figure S1. (l) Type 1 wing eyespot with two outer rings and ca 15 contiguous ocules surrounding a central pigmented disc (O. illecebrosa, YIX); (m) Type 2 wing eyespot with a single outer ring, light-hued inner area, and uninterrupted, pigmented central disc with surrounding, non-contiguous ocules (Kallihemerobius almacellus, JIU); (n) Type 2 eyespot similar to (M) (Kallihemerobius feroculus, JIU); (o) Type 3 wing eyespot with a light-hued circular area and a few, variably sized ocules in a darkly pigmented central disc (Ithigramma multinervia, YIX); (p) Type 4 wing eyespot contains a few ocules and others surrounding a pigmented central disc, a light-hued inner area and surrounding, dark outermost ring (K. circularia, JIU); and (q) Type 5 wing spot of a circular, pigmented central disc (Kallihemerobius aciedentatus, JIU). Scale bars: solid, 10 mm; striped, 1 mm.

Kalligrammatid structural diversity. Specimens are from the late-Middle Jurassic Jiulongshan Fm. (JIU), China; Late Jurassic Karabastau Fm. (KAR), Kazakhstan; and mid-Early Cretaceous Yixian Fm. (YIX), China (electronic supplementary material, tables S2 and S3). At (a–i) are nine species showing general habitus [11]. Arrows indicate proboscis tips. (a) Kalligramma circularia (JIU); (b) Affinigramma myrioneura (JIU); (c) A. myrioneura (JIU); (d) Kallihemerobius feroculus (JIU); (e) Oregramma aureolusa (YIX); (f) Ithigramma multinervia (YIX); (g) Abrigramma calophleba (JIU); (h) Kalligramma brachyrhyncha (JIU); and (i) Oregramma illecebrosa (YIX). (i–k) Lateral views of ovipositor structure in O. illecebrosa above: (i) intact specimen; (j) complete ovipositor and posteriormost abdominal segments; and (k) lateral valve pairs. (l–q): five kalligrammatid wing eyespot and spot types detailed in figures 2 and 3; electronic supplementary material, figure S1. (l) Type 1 wing eyespot with two outer rings and ca 15 contiguous ocules surrounding a central pigmented disc (O. illecebrosa, YIX); (m) Type 2 wing eyespot with a single outer ring, light-hued inner area, and uninterrupted, pigmented central disc with surrounding, non-contiguous ocules (Kallihemerobius almacellus, JIU); (n) Type 2 eyespot similar to (M) (Kallihemerobius feroculus, JIU); (o) Type 3 wing eyespot with a light-hued circular area and a few, variably sized ocules in a darkly pigmented central disc (Ithigramma multinervia, YIX); (p) Type 4 wing eyespot contains a few ocules and others surrounding a pigmented central disc, a light-hued inner area and surrounding, dark outermost ring (K. circularia, JIU); and (q) Type 5 wing spot of a circular, pigmented central disc (Kallihemerobius aciedentatus, JIU). Scale bars: solid, 10 mm; striped, 1 mm.

The discovery of the insect was made possible by the examination of well-preserved fossils recently recovered from ancient lake deposits in northeastern China and eastern Kazakhstan. The study was led by Conrad Labandeira, a curator at the Smithsonian Institution’s National Museum of Natural History, and Dong Ren of Capital Normal University in Beijing, China, where the fossils are housed.”Poor preservation of lacewing fossils had always stymied attempts to conduct a detailed morphological and ecological examination of the kalligrammatid,” Dilcher said. “Upon examining these new fossils, however, we’ve unraveled a surprisingly wide array of physical and ecological similarities between the fossil species and modern butterflies, which shared a common ancestor 320 million years ago. ”

Phylogenetic context of wing spots and eyespots in mid-Mesozoic kalligrammatids, with comparisons to modern lepidopterans (electronic supplementary material, text S3). The best preserved fossil material was used for this analysis. (a) Most parsimonious tree of Kalligrammatidae phylogeny [11] (electronic supplementary material, table S2), with right forewing eyespot/spot condition mapped onto terminal clades and likely wing spot and eyespot origins. Wing eyespot and spot type symbols are at upper-left; crosses are eyespot/spot absences. (b–g) Examples of right forewings with wing eyespots or spots from mid-Mesozoic Kalligrammatidae (b–f), and modern Psychopsidae (g). These taxa correspond to a Type 1 eyespot (b), Type 2 eyespot (c), Type 3 eyespot (d), Type 4 eyespot (e) and two Type 5 double spots (f) matched by two spots in modern psychopsid (red arrows) in (g). Kalligrammatid wing eyespots and spots are compared to modern Lepidoptera in (h–k), of butterfly species with Type 6 eyespots (h) and multiple Type 5 spots (i); moth lacking wing spots or eyespots (j); and modern owl butterfly eyespot (k), showing pigmentation similar to Type 2 and 3 eyespots (b), indicated by arrow pointing to an ocule series and longitudinal wing vein. Scale bars: solid, 10 mm; striped, 1 mm.

Phylogenetic context of wing spots and eyespots in mid-Mesozoic kalligrammatids, with comparisons to modern lepidopterans (electronic supplementary material, text S3). The best preserved fossil material was used for this analysis. (a) Most parsimonious tree of Kalligrammatidae phylogeny [11] (electronic supplementary material, table S2), with right forewing eyespot/spot condition mapped onto terminal clades and likely wing spot and eyespot origins. Wing eyespot and spot type symbols are at upper-left; crosses are eyespot/spot absences. (b–g) Examples of right forewings with wing eyespots or spots from mid-Mesozoic Kalligrammatidae (b–f), and modern Psychopsidae (g). These taxa correspond to a Type 1 eyespot (b), Type 2 eyespot (c), Type 3 eyespot (d), Type 4 eyespot (e) and two Type 5 double spots (f) matched by two spots in modern psychopsid (red arrows) in (g). Kalligrammatid wing eyespots and spots are compared to modern Lepidoptera in (h–k), of butterfly species with Type 6 eyespots (h) and multiple Type 5 spots (i); moth lacking wing spots or eyespots (j); and modern owl butterfly eyespot (k), showing pigmentation similar to Type 2 and 3 eyespots (b), indicated by arrow pointing to an ocule series and longitudinal wing vein. Scale bars: solid, 10 mm; striped, 1 mm.

The species are an example of convergent evolution, Dilcher explains, where two distantly related animals develop similar characteristics independently.As a paleobotanist, Dilcher contributed to the study by describing these ecological similarities, including the insect’s relationship to a type of fossilized plant found in the same region of China as the insect fossils. An extinct order of seed plants called bennettitales, these plants first appeared about 250 million years ago during the Triassic period, surviving for nearly 200 million years until the end of the late Cretaceous period.

Based on their examination, which drew in part upon microscopically small clues such as the fossilized remains of food and pollen trapped in the mouthparts of the insects, Dilcher and colleagues concluded kalligrammatid fed upon bennettitales using a long tongue to probe nectar deep within the plant. The insects also possessed hairy legs that allowed for carrying pollen from the male flower-like reproductive organs of one plant to the flower-like female reproductive organs of another.

Microstructure of three kalligrammatid forewing eyespot types and their cuticular scales. (a) Kalligrammatid ellipsoidal wing-scale socket retains a broken scale base in cross-section of four lower (bottom arrows) and three upper (top arrows) ribs, enlarged from upper-right of (j). This socket type receives distinctive flat scales on major veins present elsewhere on the wing, depicted as an overlay drawing in (b), showing four longitudinal ribs basally and eight ribs terminally on Kalligramma sp. (JIU). For comparison of (b), at (c) and (d) is a foreleg scale of the modern neuropteran Lomomyia squamosa (Berothidae) (electronic supplementary material, text S2), in a SEM at left (c) and overlay drawing at right (d). (e–h) A Type 4 eyespot of Kalligramma circularia (JIU). (e) Light photograph showing eyespot pigmentation pattern, with epifluorescence microscopy revealing a differently pigmented ocule (f), and three additional ocules (g), each in a wing compartment surrounded by minor veins bearing flattened, four-ribbed scales, four shown in the SEM at (h). (i) Light photograph of a Type 2 eyespot of Kallihemerobius almacellus (JIU), showing seven whitish hued ocules surrounding a central pigmented disc, the boundary (template) shows smaller empty scale sockets in interveinal areas and occasional larger scale sockets on veins in the SEM at (j). Large wing-scale socket at upper-right enlarged at (a). (k–n) and (p) A light photograph of a Type 1 eyespot (k) from Oregramma illecebrosa (YIX), with dark pigmented central disc surrounded by whitish ocules and two dark outer rings. (l) SEM detail of four curved scales, each socketed on a longitudinal vein; black arrows indicate alternating sockets that lack scales. (m) Nearby scales. (n) Field of clumped scales on a wing region lacking veins and eyespots and a fascicle of eight, large, detached scales in (p), each displaying a ridged structure. Eyespot ocule at (o), from Kallihemerobius aciedentatus (JIU), shows a regular array of interveinal scale sockets, structurally distinct from central-disc pigmented regions, bearing scales socketed on major veins. See electronic supplementary material, table S2 for specimen data; scale bars: solid, 10 mm; striped, 1 mm; dotted, 10 µm.

Microstructure of three kalligrammatid forewing eyespot types and their cuticular scales. (a) Kalligrammatid ellipsoidal wing-scale socket retains a broken scale base in cross-section of four lower (bottom arrows) and three upper (top arrows) ribs, enlarged from upper-right of (j). This socket type receives distinctive flat scales on major veins present elsewhere on the wing, depicted as an overlay drawing in (b), showing four longitudinal ribs basally and eight ribs terminally on Kalligramma sp. (JIU). For comparison of (b), at (c) and (d) is a foreleg scale of the modern neuropteran Lomomyia squamosa (Berothidae) (electronic supplementary material, text S2), in a SEM at left (c) and overlay drawing at right (d). (e–h) A Type 4 eyespot of Kalligramma circularia (JIU). (e) Light photograph showing eyespot pigmentation pattern, with epifluorescence microscopy revealing a differently pigmented ocule (f), and three additional ocules (g), each in a wing compartment surrounded by minor veins bearing flattened, four-ribbed scales, four shown in the SEM at (h). (i) Light photograph of a Type 2 eyespot of Kallihemerobius almacellus (JIU), showing seven whitish hued ocules surrounding a central pigmented disc, the boundary (template) shows smaller empty scale sockets in interveinal areas and occasional larger scale sockets on veins in the SEM at (j). Large wing-scale socket at upper-right enlarged at (a). (k–n) and (p) A light photograph of a Type 1 eyespot (k) from Oregramma illecebrosa (YIX), with dark pigmented central disc surrounded by whitish ocules and two dark outer rings. (l) SEM detail of four curved scales, each socketed on a longitudinal vein; black arrows indicate alternating sockets that lack scales. (m) Nearby scales. (n) Field of clumped scales on a wing region lacking veins and eyespots and a fascicle of eight, large, detached scales in (p), each displaying a ridged structure. Eyespot ocule at (o), from Kallihemerobius aciedentatus (JIU), shows a regular array of interveinal scale sockets, structurally distinct from central-disc pigmented regions, bearing scales socketed on major veins. See electronic supplementary material, table S2 for specimen data; scale bars: solid, 10 mm; striped, 1 mm; dotted, 10 µm.

Eventually, this system of pollination by long-tongued lacewings traveling between plants with exposed reproductive parts — called gymnosperms — gave way to more familiar system of insect pollinators and modern flowers, or angiosperms, in which the reproductive parts of the plants are contained with a protective seed.

However, another evolutionary innovation found in the ancient lacewing fossils’ wings remained remarkably unchanged over the course of millennia: so-called “eye spots.”

This is an artist's rendering of Oregramma illecebrosa consuming pollen drops from bennettitales, an extinct order of plant from the Triassic period.

This is an artist’s rendering of Oregramma illecebrosa consuming pollen drops from bennettitales, an extinct order of plant from the Triassic period.   Credit: Vichai Malikul

This unique pattern on the wings, arising over 200 million years ago, is nearly identical to markings on the modern owl butterfly. To this day, owl butterflies use these circular marks as a defense mechanism against predators, which mistake the spots as the eyes of a larger, more threatening animal.

Evolution is a great innovator, Dilcher said. But at the same time: “if it worked once, why not try it again.”

This work was supported in part by the National Basic Research Program of China, National Science Foundation of China, National Institutes of Health and Swedish National Space Board.

Courtesy: Indiana University. “Discovery of ‘Jurassic butterflies’.” ScienceDaily. ScienceDaily, 3 February 2016. <www.sciencedaily.com/releases/2016/02/160203134942.htm

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Rocks of Tetons formed by continental collisions

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University of Wyoming scientists have found evidence of continental collisions in Wyoming’s Teton Range, similar to those in the Himalayas, dating to as early as 2.68 billion years ago.The research, published Jan. 22 in the journal Geochimica et Cosmochimica Acta, shows that plate tectonics were operating in what is now western Wyoming long before the collisions that created the Himalayas starting 40 million years ago.

In fact, the remnants of tectonic activity in old rocks exposed in the Tetons point to the world’s earliest known continent-continent collision, says Professor Carol Frost of UW’s Department of Geology and Geophysics, lead author of the paper. “While the Himalayas are the prime example of continent-continent collisions that take place due to plate tectonic motion today, our work suggests plate tectonics operated far, far back into the geologic past,” Frost says.
Rolling Thunder Mountain near Talus Lake is part of the Teton Range. The orange rock in the foreground is Webb Canyon gneiss, granite formed by decompression melting more than 2.6 billion years ago.

Rolling Thunder Mountain near Talus Lake is part of the Teton Range. The orange rock in the foreground is Webb Canyon gneiss, granite formed by decompression melting more than 2.6 billion years ago.   Credit: Carol Frost

The paper’s co-authors include fellow UW Department of Geology and Geophysics faculty members Susan Swapp and Ron Frost. The researchers reached their conclusions by analyzing ancient, exposed granite in the northern Teton Range and comparing it to similar rock in the Himalayas. The rocks were formed from magma produced by what is known as decompression melting, a process that commonly occurs when two continental tectonic plates collide. The dramatically thickened crust extends under gravitational forces, and melting results when deeper crust rises closer to the surface. While the Tetons are a relatively young mountain range, formed by an uplift along the Teton Fault less than 9 million years ago, the rocks exposed there are some of the oldest found in North America.The UW scientists found that the mechanisms that formed the granites of the Tetons and the Himalayas are comparable, but that there are significant differences between the rocks of the two regions. That is due to differences in the composition of the continental crust in Wyoming 2.68 billion years ago compared to crustal plates observed today. Specifically, the ancient crust that melted in the Tetons contained less potassium than the more recently melted crust found in the Himalayas. Citation: University of Wyoming. “Ancient rocks of Tetons formed by continental collisions.” ScienceDaily. ScienceDaily, 29 January 2016. <www.sciencedaily.com/releases/2016/01/160129170502.htm  

Genyornis newtoni: Extinction points to humans

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The first direct evidence that humans played a substantial role in the extinction of the huge, wondrous beasts inhabiting Australia some 50,000 years ago — in this case a 500-pound bird — has been discovered by a University of Colorado Boulder-led team.

The flightless bird, known as Genyornis newtoni, was nearly 7 feet tall and appears to have lived in much of Australia prior to the establishment of humans on the continent 50,000 years ago, said CU-Boulder Professor Gifford Miller. The evidence consists of diagnostic burn patterns on Genyornis eggshell fragments that indicate humans were collecting and cooking its eggs, thereby reducing the birds’ reproductive success.

An illustration of a giant flightless bird known as Genyornis newtoni, surprised on her nest by a 1 ton, predatory lizard named Megalania prisca in Australia roughly 50,000 thousand years ago.

An illustration of a giant flightless bird known as Genyornis newtoni, surprised on her nest by a 1 ton, predatory lizard named Megalania prisca in Australia roughly 50,000 thousand years ago.   Credit: Illustration by Peter Trusler, Monash University

“We consider this the first and only secure evidence that humans were directly preying on now-extinct Australian megafauna,” said Miller, associate director of CU-Boulder’s Institute of Arctic and Alpine Research. “We have documented these characteristically burned Genyornis eggshells at more than 200 sites across the continent.”

A paper on the subject appears online Jan. 29, in Nature Communications.

In analyzing unburned Genyornis eggshells from more than 2,000 localities across Australia, primarily from sand dunes where the ancient birds nested, several dating methods helped researchers determine that none were younger than about 45,000 years old. Burned eggshell fragments from more than 200 of those sites, some only partially blackened, suggest pieces were exposed to a wide range of temperatures, said Miller, a professor in CU-Boulder’s Department of Geological Sciences.

Optically stimulated luminescence dating, a method used to determine when quartz grains enclosing the eggshells were last exposed to sunlight, limits the time range of burned Genyornis eggshell to between 54,000 and 44,000 years ago. Radiocarbon dating indicated the burnt eggshell was no younger than about 47,000 years old.

The blackened fragments were likely burned in transient, human fires — presumably to cook the eggs — rather than in wildfires, he said.

Amino acids — the building blocks of proteins -decompose in a predictable fashion inside eggshells over time. In eggshell fragments burned at one end but not the other, there is a tell-tale “gradient” from total amino acid decomposition to minimal amino acid decomposition, he said. Such a gradient could only be produced by a localized heat source, likely an ember, and not from the sustained high heat produced regularly by wildfires on the continent both in the distant past and today.

Miller also said the researchers found many of the burnt Genyornis eggshell fragments in tight clusters less than 10 feet in diameter, with no other eggshell fragments nearby. Some individual fragments from the same clusters had heat gradient differences of nearly 1,000 degrees Fahrenheit, conditions virtually impossible to reproduce with natural wildfires there, he said.

“We can’t come up with a scenario that a wildfire could produce those tremendous gradients in heat,” Miller said. “We instead argue that the conditions are consistent with early humans harvesting Genyornis eggs, cooking them over fires, and then randomly discarding the eggshell fragments in and around their cooking fires.”

Another line of evidence for early human predation on Genyornis eggs is the presence of ancient, burned eggshells of emus — flightless birds weighing only about 100 pounds and which still exist in Australia today — in the sand dunes. Emu eggshells exhibiting burn patterns similar to Genyornis eggshells first appear on the landscape about 50,000 years ago, signaling they most likely were scorched after humans arrived in Australia, and are found fairly consistently to modern times, Miller said.

The Genyornis eggs are thought to have been roughly the size of a cantaloupe and weighed about 3.5 pounds, Miller said.

Genyornis roamed the Australian outback with an astonishing menagerie of other now-extinct megafauna that included a 1,000-pound kangaroo, a 2-ton wombat, a 25-foot-long-lizard, a 300-pound marsupial lion and a Volkswagen-sized tortoise. More than 85 percent of Australia’s mammals, birds and reptiles weighing over 100 pounds went extinct shortly after the arrival of the first humans.

The demise of the ancient megafauna in Australia (and on other continents, including North America) has been hotly debated for more than a century, swaying between human predation, climate change and a combination of both, said Miller. While some still hold fast to the climate change scenario — specifically the continental drying in Australia from about 60,000 to 40,000 years ago — neither the rate nor magnitude of that change was as severe as earlier climate shifts in Australia during the Pleistocene epoch, which lacked the punch required to knock off the megafauna, said Miller.

Miller and others suspect Australia’s first inhabitants traveled to the northern coast of the continent on rafts launched from Indonesian islands several hundred miles away. “We will never know the exact time window humans arrived on the continent,” he said. “But there is reliable evidence they were widely dispersed across the continent before 47,000 years ago.”

 

Evidence of Australia megafauna hunting is very difficult to find, in part because the megafauna there are so much older than New World megafauna and in part because fossil bones are easily destroyed by the chemistry of Australian soils. said Miller.

“In the Americas, early human predation on the giant animals in clear — stone spear heads are found embedded in mammoth bones, for example,” said Miller. “The lack of clear evidence regarding human predation on the Australia megafauna had, until now, been used to suggest no human-megafauna interactions occurred, despite evidence that most of the giant animals still roamed Australia when humans colonized the continent.”

Courtesy: University of Colorado at Boulder. “Ancient extinction of giant Australian bird points to humans: First reliable evidence humans were preying on now-extinct Australian Megafauna.” ScienceDaily. ScienceDaily, 29 January 2016. <www.sciencedaily.com/releases/2016/01/160129090057

Ptilocercus kylin:Treeshrew fossil found in China

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 Treeshrews are widely considered a “living model” of an ancestral primate, and have long been called”living fossils”. Actual fossils of treeshrews, however, are extremely rare. In a paper published 14 January in Scientific Reports (6), Drs. LI Qiang and NI Xijun, Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP), Chinese Academy of Sciences, reported a new fossil species of Ptilocercus treeshrew from the early Oligocene (over 34 million years ago) of China that represents the oldest definitive fossil record of the crown group of treeshrews and nearly doubles the temporal length of their fossil record.
Upper and lower dentition (in color) of Ptilocercus kylin, compared with P. lowii (in gray-scale). Credit: NI Xijun

Upper and lower dentition (in color) of Ptilocercus kylin, compared with P. lowii (in gray-scale). Credit: NI Xijun

These new treeshrew fossils were discovered at the Lijiawa mammalian locality near Qujing City in Yunnan Province, China. Among the numerous fossil mammal specimens recovered from this fossil site are those belonging to a large form of Gigantamynodon giganteus, an unnamed species of Cricetops, and a primitive Eucricetodon comparable with Eucricetodon caducus from the earliest Oligocene of Xinjiang, China. Those species all indicate an early Oligocene age for this fauna.

The fossil species is strikingly similar to the extant pen-tailed treeshrew (Ptilocercus lowii), a generally recognized as the most primitive extant treeshrew. It demonstrates that Ptilocercus treeshrews have undergone little evolutionary change in their morphology since the early Oligocene.

Morphological comparisons and phylogenetic analysis support the long-standing idea that Ptilocercus treeshrews are morphologically conservative and have probably retained many characters present in the common stock that gave rise to archontans, which include primates, flying lemurs, plesiadapiforms and treeshrews.

Reconstruction of Ptilocercus kylin. Credit: NI Xijun

Reconstruction of Ptilocercus kylin.           Credit: NI Xijun

“This discovery provides an exceptional example of slow morphological evolution in a mammalian group over a period of 34 million years, and it supports the suggestion that the extant P. lowii gives us a living glimpse of the first ancestor of the Archonta, our own superordinal group”, said lead author NI Xijun of the IVPP, “The persistent and stable tropical environment in Southeast Asia through the Cenozoic likely played a critical role in the survival of such a morphologically conservative lineage”.

This project was supported by the Strategic Priority Research Program of Chinese Academy of Sciences, the National Basic Research Program of China, the CAS 100-talent Program, and the National Natural Science Foundation of China.

Ref: Qiang Li et al. An early Oligocene fossil demonstrates treeshrews are slowly evolving “living fossils”, Scientific Reports (2016). DOI: 10.1038/srep18627 and Phy.Org.

Key: WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil Society

Explosive underwater volcanoes of ‘Snowball Earth’

WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil Society,Explosive underwater volcanoes of ‘Snowball Earth’

Around 720-640 million years ago, much of the Earth’s surface was covered in ice during a glaciation that lasted millions of years. Explosive underwater volcanoes were a major feature of this ‘Snowball Earth’, according to new research led by the University of Southampton.

Many aspects of this extreme glaciation remain uncertain, but it is widely thought that the breakup of the supercontinent Rodinia resulted in increased river discharge into the ocean. This changed ocean chemistry and reduced atmospheric CO2 levels, which increased global ice coverage and propelled Earth into severe icehouse conditions.

Extensive underwater volcanism during ridge spreading led to rapid alteration of volcanic deposits and major changes in ocean chemistry.

Extensive underwater volcanism during ridge spreading led to rapid alteration of volcanic deposits and major changes in ocean chemistry.   Credit: Gary Hincks

Because the land surface was then largely covered in ice, continental weathering effectively ceased. This locked the planet into a ‘Snowball Earth’ state until carbon dioxide released from ongoing volcanic activity warmed the atmosphere sufficiently to rapidly melt the ice cover. This model does not, however, explain one of the most puzzling features of this rapid deglaciation; namely the global formation of hundreds of metres thick deposits known as ‘cap carbonates’, in warm waters after Snowball Earth events.

The Southampton-led research, published in Nature Geoscience, now offers an explanation for these major changes in ocean chemistry.

Lead author of the study Dr Tom Gernon, Lecturer in Earth Science at the University of Southampton, said: “When volcanic material is deposited in the oceans it undergoes very rapid and profound chemical alteration that impacts the biogeochemistry of the oceans. We find that many geological and geochemical phenomena associated with Snowball Earth are consistent with extensive submarine volcanism along shallow mid-ocean ridges.”

During the breakup of Rodinia, tens of thousands of kilometres of mid-ocean ridge were formed over tens of millions of years. The lava erupted explosively in shallow waters producing large volumes of a glassy pyroclastic rock called hyaloclastite. As these deposits piled up on the sea floor, rapid chemical changes released massive amounts of calcium, magnesium and phosphorus into the ocean.

Dr Gernon explained: “We calculated that, over the course of a Snowball glaciation, this chemical build-up is sufficient to explain the thick cap carbonates formed at the end of the Snowball event.

“This process also helps explain the unusually high oceanic phosphorus levels, thought to be the catalyst for the origin of animal life on Earth.”

Courtesy: University of Southampton. “Explosive underwater volcanoes were a major feature of ‘Snowball Earth’.” ScienceDaily. ScienceDaily, 18 January 2016. <www.sciencedaily.com/releases/2016/01/160118134449.htm

Key: WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil Society

 

world’s oldest Jurassic dinosaur fossil?

It could be the long-lost ancestor of the dinosaurs from Jurassic Park. A fossil discovered in the UK is thought to be the oldest Jurassic dinosaur ever found and is one of the most complete specimens from the time period.The well-preserved remains of a juvenile dinosaur were found at Lavernock Point near Cardiff, Wales, a location that exposes rocks spanning from the late Triassic to the early Jurassic.The fossil came from rocks that lie right in between these two eras, but subsequent analysis showed the specimen was from the early Jurassic.

Amgueddfa Cymru/National Museum of Wales

Amgueddfa Cymru/National Museum of Wales

“Only a few handfuls of specimens worldwide come from this time and most of them are only fragments,” says Steven Vidovic from the University of Portsmouth in the UK, a member of the team that investigated the fossil.

The early Jurassic is a critical time in the evolutionary history of dinosaurs. An extinction event in the late Triassic wiped out many plants and animals, but not dinosaurs.The species that crossed over into the Jurassic are thought to hold clues as to how they diversified into the many species that existed in the middle Jurassic, some of which are the ancestors of birds.

Robert Nicholls/National Museum of Wales

Robert Nicholls/National Museum of Wales

Peculiar features

The specimen classifies as a new genus and species of neotheropod. It has been named Dracoraptor hanigani, its genus name referring to the national symbol of Wales – the dragon.

It has peculiar features, like short arms but hands as big as its forearms, and is estimated to have been about two metres long, although the specimen might have been a juvenile. Its teeth suggest that it was a carnivore.

Vidovic thinks the fact it has a similar overall appearance to many later dinosaurs indicates that it set this body plan. “We are seeing what it had in common with everything after it,” he says. “It was a forerunner.”

The skeleton is about 40 per cent complete. Vidovic says it actually represents about 80 per cent of the animal because dinosaurs are symmetrical.Its remarkable condition should allow for a more detailed analysis in the future.

Amgueddfa Cymru/National Museum of Wales

Amgueddfa Cymru/National Museum of Wales

Dino tales

Dracoraptor is one of the best preserved meat-eating dinosaurs from the early part of the Jurassic Period – not only in Europe, but globally,” says Paul Barrett, of the Natural History Museum in London, UK. “Its discovery will probably have much to tell us about dinosaur distributions in the wake of the major extinctions.”

He adds that our knowledge of early dinosaurs is based mainly on sites in South America, Africa and Asia, so the discovery of this species in Wales is exciting. “Especially as Wales has not previously been fertile ground for dinosaur hunters.”

Amgueddfa Cymru/National Museum of Wales

Amgueddfa Cymru/National Museum of Wales

There is still some debate about whether Dracoraptor dates from the late Triassic or early Jurassic. This is because there weren’t enough fossils of known species found above and below it that could help to narrow down the chronology.

“There is reasonable argument that it is definitely post-extinction, and probably earliest Jurassic,” says Michael Benton, a palaeontologist at the University of Bristol, UK. “Dinosaurs from this time are pretty rare worldwide.”

Journal reference: PLoS ONE, DOI: 10.1371/journal.pone.0145713

Ref: Article By Sandrine Ceurstemont in New Scientist journal.

Key: WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil Society

 

 

 

How to Read a Prehistoric Temperature

Here’s a recipe for a mass extinction: Introduce a sudden ice age that piles the land with ice, and then, a few hundred thousand years later, rapidly warm the world. This one-two punch killed off about 50% of Earth’s genera 445 million years ago, ranking it as the third largest mass extinction, right below the one that wiped out the dinosaurs. Now, scientists are firmly linking the extinction to climate change, thanks to a new technique that’s allowing them to read a 445-million-year-old Prehistoric Temperature.

The technique, reported online today in Science, relies on a new way of using stable, nonradioactive isotopes—variations in the inner makeup of atoms—to gauge both ancient ocean temperatures and the amount of glacial ice in the distant past. Paleoclimatologists have long used isotopes to estimate both temperatures and ice volumes across recent ice ages. The traditional technique involves measuring two isotopes of oxygen—one heavier than the other—preserved in marine microfossils. But the method requires an independent measure of seawater composition, which isn’t available for the very early geologic record.

Rocky thermometer. A new sort of isotope analysis has extracted a temperature record from fossils (inset) in these 455-year-old rocks in Quebec, Canada. Seth Finnegan/Caltech

Rocky thermometer. A new sort of isotope analysis has extracted a temperature record from fossils (inset) in these 455-year-old rocks in Quebec, Canada.   Seth Finnegan/Caltech

The new technique, called “clumped” isotope paleothermometry, requires nothing but information found in stable isotopes themselves. In the clumped approach, paleoclimatologist Seth Finnegan of the California Institute of Technology in Pasadena and his colleagues measured the conventional isotope ratio in sediments from approximately 445 million years ago. But they also measured how often the heavy isotope of oxygen was bonded to the heavy isotope of carbon in the carbonate skeletons of the microfossils. The frequency of this bonding or clumping does not vary with seawater composition, so the measurement allows scientists to calculate both ocean temperature and glacial ice volume.

Using the clumped isotope technique, Finnegan nailed down the timing and magnitude of ancient climate change. Around 445 million years ago—near the end of the Ordovician Period—he found that temperatures fell quickly by 5°C and glacial ice built up fast until the ice sheets were more massive than during recent ice ages. That was also the geologic moment when a whole raft of brachiopods and bryozoans—stalked seafloor dwellers and mossy-looking colonial organisms—disappeared. Presumably, with so much seawater going into glacial ice on land, falling sea level drained away the shallow inland seas where the victims had lived. Then, at end of the ice age perhaps a million years later, the sudden warming seems to have made it too hot for a drove of cold-loving brachiopods and trilobites, those scimitar-headed crawling creatures familiar from the Cambrian Period. They too went extinct.

“It’s a great technique,” says paleontologist Peter Sheehan of the Milwaukee Public Museum in Wisconsin. “It shows the extent of the glaciation, which has been very controversial.” And the links between climate change and extinction seem plausible to him.

Researchers are flocking to the new technique, says paleoclimatologist Ethan Grossman of Texas A&M University in College Station. “I’m impressed by these results,” he says. “There are a lot of applications” throughout the geologic record that will be keeping geologists busy.

Courtesy: Article by Richard A. Kerr,sciencemag.org,

Key: WFS,Riffin T Sajeev,Russel T sajeev,World Fossil Society

Spinosaurus Devoured Meals Like a Giant Pelican

Spinosaurus gained a notorious reputation in Jurassic Park 3 (spoiler alert), stomping on to the screen to take down the mighty T. rex in a rather memorable duel. Since gaining global fame on the silver screen, researchers now believe Spinosaurus was an adept swimmer, terrorizing local inhabitants of ancient river systems in North Africa some 100 million years ago.

Spinosaurus may have eaten its prey much like a giant pelican or modern day snakes. (Credit: Sergey Krasovskiy)

Spinosaurus may have eaten its prey much like a giant pelican or modern day snakes. (Credit: Sergey Krasovskiy)

A new study of the jaws of Spinosaurus indicates that it may have devoured its prey much like a giant pelican or modern snakes, opening its jaws wide to swallow unlucky critters whole. New fossils from rocks dating to the Cretaceous period from southeastern Morocco, known as the Kem-Kem beds, show that spinosaurs were able to widen their jaws and greatly open the pharynx to swallow over-sized chunks of food.

Part Crocodile, Part Pelican

“Spinosaurs were very strange animals with a crocodile-like skull showing a long and narrow snout and conical teeth,” says Octávio Mateus from Universidade Nova de Lisboa, Portugal. This has usually led to interpretations of spinosaurs as skilled fish hunters that may have even used their long claws as fish hooks.

The new study, published recently in the open-access journal PLOS One, is the first time a pelican-like feeding style has been discovered in dinosaurs. Christophe Hendrickx, lead author of the study and also at the Universidade Nova de Lisboa, noted that an unusual aspect of spinosaur jaws led to this conclusion.

An illustration of Spinosaurus swallowing a snack. (Credit: Jason Poole)

                                                           An illustration of Spinosaurus swallowing a snack. (Credit: Jason Poole)

“The mandibular symphysis [where the jaw bones meet at the front] of spinosaurids shows prominent parallel ridges where connective tissues got attached,” Henrickx says. This was combined with spinosaurs’ highly unusual anatomy where the lower jawbones articulated with the skull, which were much more free and mobile than other theropod dinosaurs.

The design of the spinosaur jaw enabled the left and right jaws to be more movable and widen much more than if they were fused together like other bones in the skull. Similar feeding mechanics have also been suggested in pterosaurs, the cousins of dinosaurs, which are thought to also have preyed largely on fish.

Why spinosaurs adapted to dine like this is still up for debate. Hendrickx suggests that being able to eat large prey rapidly was necessary to sustain an animal of such a massive size. Spinosaurus grew up to 50 feet in length – longer than a T. rex. Gulping down food in a single bite might have also given them a competitive edge in a time when herbivorous dinosaurs, usually the prey of choice for theropod predators, in North Africa were relatively rare.Although often imagined as an adept fisher, Spinosaurus and its large relatives might also have preyed on other animals careless enough to get too close.

Christophe Hendrickx stands before a Spinosaurus skull.

Christophe Hendrickx stands before a Spinosaurus skull.

“It is very possible that the two spinosaurs from Morocco were also eating other type of preys such as herbivorous dinosaurs, pterosaurs, crocodiles, and turtles, and probably swallowed them as a whole if these preys were not too large,” Hendrickx says.

The newly discovered remains also help confirm a previous suspicion that the fossilized remains used to reconstruct Spinosaurus probably came from at least two different closely related species. Serjoscha Evers, a researcher at the University of Oxford who works on North African spinosaurs but was not involved in the present study, thinks the “environment of a near-coast river system would have supported their high diversity,” and that predators like spinosaurs were extreme specialists, “with niche partitioning playing a major role.”

Either way, the vision of a 15-meter-long crocodile-like dinosaur gulping its prey down is pretty terrifying.

Courtesy:Article By  Jon Tennant,Discover Magazine.

Key: WFS,Riffin T Sajeev,Russel T Sajeev,World Fossil Society