Image right: Gymnosperm pollen attached to the abdomen and wing of a thysanopteran from the Alava amber (Credit: Enrique Peñalver, IGME).

The international team of scientists comprises: Enrique Peñalver and Eduardo Barrón from the Instituto Geológico y Minero de España in Madrid; Xavier Delclòs from the University of Barcelona; Andre and Patricia Nel from the Muséum national d’histoire naturelle in Paris; Conrad Labandeira from the Smithsonian’s National Museum of Natural History in Washington D.C.; and Carmen Soriano and Paul Tafforeau from the European Synchrotron Radiation Facility in Grenoble, France. The amber samples were from the collection of the Museo de Ciencias Naturales de Álava in Spain.

Today, more than 80 percent of plant species rely on insects to transport pollen from male to female flower parts. Pollination is best known in flowering plants but also exists in so-called gymnosperms, seed-producing plants like conifers. Although the most popular group of pollinator insects are bees and butterflies, a myriad of lesser-known species of flies, beetles or thrips have co-evolved with plants, transporting pollen and in return for this effort being rewarded with food.

Image left: An artist’s conception of of Gymnospollisthrips with pollen attached to the body over an ovulate organ of a gingko (Credit: Enrique Peñalver, IGME).

During the last 20 years, amber from the Lower Cretaceous found in the Basque country in Northern Spain has revealed many new plant and animal species, mainly insects. Here, the amber featured inclusions of thysanopterans, so-called thrips, a group of minute insects of less than 2 millimeters long that feed on pollen and other plant tissues. They are efficient pollinators for several species of flowering plants.

Two amber pieces revealed six fossilized specimens of female thrips with hundreds of pollen grains attached to their bodies. These insects exhibit highly specialized hairs with a ringed structure to increase their ability to collect pollen grains, very similar to the ones of well known pollinators like domestic bees. The scientists describe these six specimens in a new genus (Gymnopollisthrips) comprising two new species, G. minor and G. major.

The most representative specimen was also studied with synchrotron X-ray tomography at the European Synchrotron Radiation Facility to reveal the pollen grain distribution over the insect’s body in 3D and at very high resolution. The pollen grains are very small and exhibit the adherent features needed so that insects can transport them. The scientists conclude that this pollen is from a kind of cycad or ginkgo tree, a kind of living fossil of which only a few species are known to science. Ginkgos are either male or female, and male trees produce small pollen cones whereas female trees bear ovules at the end of stalks which develop into seeds after pollination.

Image right: Synchrotron tomography image of Gymnospollisthrips minor showing pollen. (Credit: ESRF).

Why did these tiny insects collect and transport gingko pollen 100 million years ago? Their ringed hairs cannot have grown due to an evolutionary selection benefiting the trees. The benefit for the thrips can only be explained by the possibility their larvae ate pollen. This suggests that this species formed colonies with larvae living in the ovules of some kind of gingko for shelter and protection, and female insects transporting pollen from the male gingko cones to the female ovules to feed the larvae and at the same time pollinate the trees.

More than one hundred million years ago, flowering plants started to diversify enormously, eventually replacing conifers as the dominant species. “This is the oldest direct evidence for pollination, and the only one from the age of the dinosaurs,” says Carmen Soriano, who led the investigation of the amber pieces with X-ray tomography at the ESRF. “The co-evolution of flowering plants and insects, thanks to pollination, is a great evolutionary success story. It began about 100 million years ago, when this piece of amber fossil was produced by resin dropping from a tree, which today is the oldest fossil record of pollinating insects. Thrips might indeed turn out to be one of the first pollinator groups in geological history, long before evolution turned some of them into flower pollinators.” –Source: European Synchrotron Radiation Facility

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“We were shocked. Basically what we are looking at is a technology that was learned from one person to another, from father to son or from uncle to nephew,” explains Stanford, co-author of a recent paper on the discovery in the Journal of Archaeological Science.

Image right: Clovis stone points from the Drake Cache of Colorado. Click to enlarge. (Photo by Chip Clark, Smithsonian)

The researchers believe encounters between Clovis knappers, or stone point makers, from different groups at stone quarry sites or in settlements certainly “facilitated the sharing of technological information by allowing knappers to observe tools and techniques used by other artisans,” explains co-author Sabrina Sholts of the Human Evolution Research Center at the University of California in Berkeley. “The tools selected by the knappers, as well as how they were handled and applied, certainly were part of the Clovis technology,” that was shared between families and tribes.

This video was created by Sabrina Sholts of the Human Evolution Research Center at the University of California in Berkeley using 3D digital scans of a Clovis stone projectile point from the collections of the Department of Anthropology, National Museum of Natural History, Smithsonian Institution.

In fact, the researchers say, through a strong communication network  Clovis spear point technology spread across North America in as little as 200 years. Radiocarbon dating of the stone points backs this theory. Many Clovis points “have been recovered from kill sites, in association with the remains of animals such as mammoths and bison,” Sholts says. This “suggests that they were effective for hunting large prey.”

The scientists used high-tech 3D scanning to create detailed images of the Clovis points from the collection of the Smithsonian’s National Museum of Natural History. The researchers focused particularly on the contours of the scars on the front and back of each bi-face spear point where individual stone flakes were carefully and systematically removed centuries ago by striking with an implement made of antler, bone, ivory or even perhaps hardwood. Each 3D scan records millions of minute measurements, revealing “subtle differences in the various steps of reduction [flaking off tiny pieces of stone] and nuances that you can’t see with your eyes,” Stanford explains.

Right: Images of 3D models and overlaid front and back flake scar contours from projectile points from the Colby Cache, Wyoming (left), Drake Cache, Colorado (center left), and two modern replicas (center right and right). The Colby and Drake points have markedly different bases, but this difference is much less prominent in the flake scar contours. For the two modern replicas, their flake scar contours are generally more uneven, and also display larger differences between the overlaid contours.

“One nice thing about the study is its relative objectivity,” Sholts points out. With the 3D imaging, “it is really very automated. What we are doing is essentially data analysis, capturing the contours and curvature of the surface of each biface in a standard way. The results were surprising to me.”

This 3D study has laid to rest the theory that Clovis technology spread region by region from knappers who copied lost or discarded stone points they had found, Stanford says. In fact, the paper reveals, part of the research included projectile points made by an expert modern-day knapper who closely studied and copied Clovis points in the Smithsonian collection. Computer analysis revealed these modern creations do not share the same symmetry as do the authentic Clovis points—further proof that the real Clovis points were a learned technology.

“We are now working on a new study with Clovis points from California that we are putting into that same computer matrix,” Stanford says.–John Barrat

Article link:  “Flake scar patterns of Clovis points analyzed with a new digital morphometrics approach: evidence for direct transmission of technological knowledge across early North America,” authored by Sabrina Sholts, Dennis Stanford, Louise Flores and Sebastian Wärmländer, will appear in a forthcoming issue of the Journal of Archaeological Science.

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The researchers discovered periodic increases in the amount of the isotope strontium-87 found in marine fossils. The timing of these increases corresponds to previously discovered low points in marine biodiversity that occur in the fossil record roughly every 60 million years. Authors of the study are Adrian Melott, professor of physics and astronomy at the University of Kansas, paleobiologist Richard Bambach of the Smithsonian’s National Museum of Natural History, Kenni Petersen of Aarhus University, Denmark, and John McArthur of University College London.

Image right: Yosemite Valley and Half Dome from Glacier Point. (Photo by Jon Sullivan)

Melott, lead author, thinks the periodic extinctions and the increased amounts Sr-87 are linked. “Strontium-87 is produced by radioactive decay of another element, rubidium, which is common in igneous rocks in continental crust,” Melott says. “So, when a lot of this type of rock erodes, a lot more Sr-87 is dumped into the ocean, and its fraction rises compared with another strontium isotope, Sr-86.”

An uplifting of the continents, Melott explains, is the most likely explanation for this type of massive erosion event.

“Continental uplift increases erosion in several ways,” he said. “First, it pushes the continental basement rocks containing rubidium up to where they are exposed to erosive forces. Uplift also creates highlands and mountains where glaciers and freeze-thaw cycles erode rock. The steep slopes cause faster water flow in streams and sheet-wash from rains, which strips off the soil and exposes bedrock. Uplift also elevates the deeper-seated igneous rocks where the Sr-87 is sequestered, permitting it to be exposed, eroded, and put into the ocean.”

The massive continental uplift suggested by the strontium data would also reduce sea depth along the continental shelf where most sea animals live. That loss of habitat due to shallow water, Melott and collaborators say, could be the reason for the periodic mass extinctions and periodic decline in diversity found in the marine fossil record.–Source: University of Chicago Press Journals

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Image right: The hand print of a baby dinosaur from the nesting site in South Africa. (Images courtesy University of the Witwatersrand)

A new study, entitled Oldest known dinosaur nesting site and reproductive biology of the Early Jurassic sauropodomorph Massospondylus and published in the international journal Proceedings of the National Academy of Sciences, was led by Canadian palaeontologist Robert Reisz, a professor of biology at the University of Toronto at Mississauga, and co-authored by Hans-Dieter Sues of the Smithsonian’s National Museum of Natural History; Eric Roberts of James Cook University, Australia; and Adam Yates of the Bernard Price Institute for Paleontological Research.

The study reveals clutches of eggs, many with embryos, as well as tiny dinosaur footprints, providing the oldest known evidence that the hatchlings remained at the nesting site long enough to at least double in size.

The authors say the newly unearthed dinosaur nesting ground is more than 100 million years older than previously known nesting sites.

Image left: A fossil from the nesting site showing seven eggs, some with the embryos exposed.

At least 10 nests have been discovered at several levels at this site, each with up to 34 round eggs in tightly clustered clutches. The distribution of the nests in the sediments indicate that these early dinosaurs returned repeatedly (nesting site fidelity) to this site, and likely assembled in groups (colonial nesting) to lay their eggs, the oldest known evidence of such behavior in the fossil record.

The large size of the mother, at six meters in length, the small size of the eggs, about six to seven centimetrs in diameter, and the highly organized nature of the nest, suggest that the mother may have arranged them carefully after she laid them.

“The eggs, embryos, and nests come from the rocks of a nearly vertical road cut only 25 meters long,” Reisz says. “Even so, we found ten nests, suggesting that there are a lot more nests in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time, as natural weathering processes continue.”

Image right: A nest of dinosaur eggs from the South African nesting site.

The fossils were found in sedimentary rocks from the Early Jurassic Period in the Golden Gate Highlands National Park in South Africa. This site has previously yielded the oldest known embryos belonging to Massospondylus, a relative of the giant, long-necked sauropods of the Jurassic and Cretaceous periods.

“This amazing series of 190 million year old nests gives us the first detailed look at dinosaur reproduction early in their evolutionary history, and documents the antiquity of nesting strategies that are only known much later in the dinosaur record,” says Evans.

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In a new study  in the journal Palaeontology, University of Florida and Smithsonian Tropical Research Institute scientists describe a new 20-foot extinct species discovered in the same Colombian coal mine with Titanoboa, the world’s largest snake. The findings help scientists better understand the diversity of animals that occupied the oldest known rainforest ecosystem, which had higher temperatures than today, and could be useful for understanding the impacts of a warmer climate in the future.

Image right: This illustration shows how Acherontisuchus guajiraensis, a 60-million-year-old ancestor of crocodiles, would have looked in its natural setting. Titanoboa, the world’s largest snake, is pictured in the background. (Illustration by Danielle Byerley/click to enlarge)

The 60-million-year-old freshwater relative to modern crocodiles is the first known land animal from the Paleocene New World tropics specialized for eating fish, meaning it competed with Titanoboa for food. But the giant snake could have consumed its competition, too, researchers say.

“The younger individuals were definitely not safe from Titanoboa, but the biggest of these species would have been a bit much for the 42-foot snake to handle,” said lead author Alex Hastings, a graduate student at the Florida Museum of Natural History and UF’s department of geological sciences.

Image left: University of Florida researchers unearth fossils from the 60-million-year-old Cerrejon formation in northeastern Colombia, one of the world’s largest open-pit coal mines. (Photo by Edwin Cadena)

The new species is a dyrosaurid, commonly believed to be primarily ocean-dwelling, coastal reptiles. The new adult specimens challenge previous theories the animals only would have entered freshwater environments as babies before returning to sea.

Fossils of a partial skeleton of the species, Acherontisuchus guajiraensis, show dyrosaurids were key players in northeastern Colombia and that diversity within the family evolved with environmental changes, such as an asteroid impact or the appearance of competitors from other groups, said Christopher Brochu, an associate professor of vertebrate paleontology in the department of geoscience at the University of Iowa, who was not involved in the study.

“We’re facing some serious ecological changes now,” Brochu said. “A lot of them have to do with climate and if we want to understand how living things are going to respond to changes in climate, we need to understand how they responded in the past. This really is a wonderful group for that because they managed to survive some catastrophes, but they seemed not to survive others and their diversity does seem to change along with these ecological signals.”

Image left: This photograph shows the size difference in the jawbones of two 60-million-year-old crocodile ancestors found in northeastern Colombia by University of Florida researchers.The newly described Acherontisuchus guajiraensis, top, and Cerrejonisuchus improcerus, bottom. C. improcerus was the first ancient crocodyliform found in the Cerrejon open-pit coal mine. The new species is the first known land animal from the Paleocene New World tropics specialized for eating fish. (Photo by Kristen Grace)

The species is the second ancient crocodyliform found in the Cerrejon mine of northern Colombia, one of the world’s largest open-pit coal mines. The excavations were led by study co-authors Jonathan Bloch, Florida Museum associate curator of vertebrate paleontology, and paleobotanist Carlos Jaramillo of the Smithsonian Tropical Research Institute.

“This one is related to a group that typically had these long snouts” Hastings said. “It would have had a relatively similar diet to the other (coastal) species, but surprisingly it lived in a more freshwater environment.”

The genus is named for the river Acheron from Greek mythology, “the river of woe,” since the animal lived in a wide river that emptied into the Caribbean. Unlike the first crocodile relative found in the area, which had a more generalized diet, the snout of the new species was long, narrow and full of pointed teeth, showing a specialization for hunting the lungfish and relatives of bonefish that inhabited the water.

“The general common wisdom was that ancestrally all crocodyliforms looked like a modern alligator, that all of these strange forms descended from a more generalized ancestor, but these guys are showing that sometimes one kind of specialized animal evolved from a very different specialized animal, not a generalized one,” Brochu said. “It’s really showing us a level of complexity to the history that 10 years ago was not anticipated.”

During the Paleocene in South America, the environment was dominated by reptiles, including giant snakes, turtles and crocodiles. The dyrosaurid family originated in Africa about 75 million years ago, toward the end of the age of dinosaurs, and arrived in South America by swimming across the Atlantic Ocean.

“The same thing that snuffed out the dinosaurs killed off most of the crocodiles alive at the time,” Hastings said. “The dyrosaurids are one of the few groups to survive the extinction and later become more successful.”

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Image right: Unlike other baleen whales, gray whales feed on bottom-dwelling organisms by suctioning sediments and filtering out worms and crustaceans. (Courtesy of Flip Nicklin)

The researchers, who analyzed California gray whale (Eschrichtius robustus) responses to climate change over the past 120,000 years, also found evidence to support the idea that the population of gray whales along the Pacific Coast before the arrival of humans was two to four times today’s population, which stands at about 22,000. The whale is considered a conservation success story because protections instituted as early as the 1930s have allowed populations to rebound from fewer than 1,000 individuals in the early 20th century, after less than 75 years of systematic whaling.

Image left: An 1872 illustration of a gray whale by Charles Melville Scammon.

“There almost certainly were higher gray whale populations in the past,” said evolutionary biologist David Lindberg, a UC Berkeley professor of integrative biology who coauthored the paper with his former student, Nicholas D. Pyenson, now curator of fossil marine mammals at the Smithsonian’s National Museum of Natural History in Washington, D.C. The paper appeared in the online, open-access journal PLoS ONE.

Lindberg and Pyenson suggest that higher populations in the past were possible because gray whales utilized a greater variety of food resources – resources that today’s whales are only now beginning to exploit. According to Lindberg, gray whales were once thought to feed only by suctioning seafloor sediment and filtering out worms and amphipods – so-called benthic organisms. But some whales are now eating herring and krill as well, just like their baleen whale relatives, which include the humpback and the blue.

Image right: This 19th century drawing depicts gray whales cavorting among ice floes in the norhtern Pacific Ocean. This observation suggests that gray whales can tolerate pack ice, a trait that helped it survive ice ages. (From Scammon, 1874)

Some whales are even dropping out of the migratory rat race. One group hangs out year-round off Vancouver Island in Canada, where they chase herring and krill.

“We propose that gray whales survived the disappearance of their primary feeding ground by employing generalist filter-feeding modes, similar to the resident gray whales found between northern Washington State and Vancouver Island,” the scientists write in their paper.

“A combination of low population numbers and a species migrating between places where humans didn’t bother them gave us the impression that gray whales have a stereotypical migratory and feeding behavior that may not be historically correct,” Lindberg said.

Image left: A gray whale pushing its mouth and head above the water.

The new population numbers accord with a 2007 estimate that the California gray whale population was likely 76,000 to 120,000 before humans began hunting them. That estimate, by Stephen Palumbi of Stanford University and his collaborators, was based on an analysis of gray whale genetic diversity.

The numbers clash, however, with claims by some ecologists that populations of between 15,000 and 20,000 are likely the most that the Pacific Coast – specifically along the whales’ 11,000 kilometer (6,900 mile) migratory route from Baja California to the Bering Sea – could support, today or in the past.

“Our data say that, if the higher estimates are right, gray whales would have made it through the Ice Ages in numbers sufficiently large to avoid bottlenecking,” Pyenson said. “If gray whale populations were at the lower levels, they would only have squeaked through the ice ages with populations of hundreds or a few thousand. That would have left bottlenecking evidence in their DNA.”

Bottlenecking is when populations drop so low that inbreeding becomes common, decreasing the genetic diversity in the species and making them less able to adapt to environmental change.

Gray whales are survivors

The new assessment is good news for gray whales, which appear to have “a lot more evolutionary plasticity than anyone imagined,” Lindberg said. This could help them survive the climate change predicted within the next few centuries that is characterized by an expected sea level rise of several meters.

Image right: A gray whale calf. (Photo by Patty Geary)

“I suspect the gray whales will be among the winners in the great climate change experiment,” Pyenson said.

Lindberg and Pyenson initiated the study several years ago in the face of conflicting and contentious estimates for past gray whale populations. They thought that an understanding of how gray whales adapted to climate change over the past 3 million years, the period called the Pleistocene, might provide insight into how they will adapt to climate change today.

Since gray whales arose – the oldest fossils date from 2.5 million years ago – Earth has gone through more than 40 major cycles of warming and cooling, each of which significantly affected the world’s flora and fauna. During the last glacial cold spell, between 50,000 and 10,000 years ago, most of the large terrestrial mammals disappeared through a combination of climate change and human depredation, Lindberg noted. The marine realm, however, experienced almost no extinctions and very few new originations during that same period.

--Source: Robert Sanders, University of California, Berkeley

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Image right: Dog remains from a burial on Santa Rosa Island. (Photos courtesy Torben Rick)

In recent research on Santa Rosa Island off the coast of Southern California, isotope readings of carbon and nitrogen found in the bones of Chumash Indians and domestic dogs excavated from archaeological sites (dating from the Late Holocene–130AD-1830) show that both humans and dogs have nearly identical signatures of stable isotopes. The discovery illustrates that the Chumash and their dogs shared virtually the same diet of food from the sea—finfish, shellfish, marine mammals and sea birds. By contrast, isotope analysis of fox remains from the same period, also from Santa Rosa Island, shows the foxes ate a diet of terrestrial foods, such as insects and mice. The study was conducted by a scientific team led by Torben Rick of the Department of Anthropology at the Smithsonian’s National Museum of Natural History.

Image left: An island fox (Photo by Rene Vellanoweth, Cal State University Los Angeles)

The data show that domestic dogs and humans were living in close proximity and the dogs were either fed scraps and leftovers from human meals, or they were scavenging in kitchen middens and refuse heaps and consuming human feces. The Santa Rosa Island findings confirm what archaeologists have discovered elsewhere in North America–that the isotopic signatures of the bones of humans and their dogs are extremely similar.

Image right: Torben Rick excavating an archaeological site on Santa Rosa Island.

In some situations where the destruction of human remains for isotope analysis is objectionable or banned, the researchers say, dog remains might easily be substituted for human remains to help reveal the diets of the humans. A paper on this research “Stable isotope analysis of dog, fox and human diets at a Late Holocene Chumash village on Santa Rosa Island, California,” was recently published in the Journal of Archaeological Science.–John Barrat

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