Smithsonian Science » paleontology

First ever record of insect pollination captured in 100 million-year-old amber

John Barrat — Tue, 15 May 2012 13:24:47 +0000

Amber from Cretaceous deposits (110-105 million years ago) in Northern Spain has revealed the first-ever record of insect pollination. Scientists have discovered several specimens of tiny insects covered with pollen grains in two pieces of amber, revealing the first record of pollen transport and social behavior in this group of animals. The results are published in the Proceedings of the National Academy of the Science (PNAS) dated 14-18 May 2012.

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

3D imaging adds remarkable new understanding of North America’s mysterious Clovis people

John Barrat — Thu, 10 May 2012 13:53:57 +0000

New high-tech 3D computer analysis of 50 spear points made more than 10,000 years ago by North America’s mysterious Clovis people has revealed the stone points display an astounding symmetry despite having been found in caches as far apart as Maryland, Arizona and Colorado. The only explanation for such symmetry across these vast distances, explains Smithsonian anthropologist Dennis Stanford, is that the method of creating the points was handed down from person to person.

“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.

Killer carnivores: Titanoboa vs. T-Rex — Premieres April 1 on Smithsonian Channel

John Barrat — Thu, 22 Mar 2012 13:52:33 +0000

Meet the 125-million-year-old pollinator “Jeholopsyche liaoningensis”

John Barrat — Mon, 19 Mar 2012 18:45:23 +0000

What: Jeholopsyche liaoningensis is a new genus and species of flying insect from northeastern China, recently revealed in two new fossil specimens. Moderate in size, adults have a remarkably long, straw-like, ridged proboscis (or “tongue”) covered with well-developed, dense hairs that ended in a fleshy tip. Other characteristics included large separated eyes, long antennae and long wings.

When: J. liaoningensis lived some 125 million years ago alongside the dinosaurs just as flowering plants (angiosperms) were beginning to appear. This species has long been extinct. It is the first member of the Aneuretopsychidae, a prehistoric family of insects, to be discovered so exquisitely preserved that scientists can see and study the anatomical detail of its body parts, including the abdomen, antennae, thorax, forewings, legs and the head and mouthparts, especially the proboscis. This new specimen also reveals previously unknown ancient relationships between plants and these spectacular insects.

Image above: J. liaoningensis gen. et sp. n. Holotype, specimen CNU-M-LB-2005-002-2, counterpart. Image below: Close-up of the proboscis of J. liaoningensis accompanied by a scientific illustration of the proboscis as well. (Click photos to enlarge)

How: This insect lived by sucking nectar-like fluid from deep funnels or similar tubular structures that were part of the reproductive features of seed-producing plants such as certain conifer, cycad and ginkgo-like hosts, collectively known as gymnosperms. J. liaoningensis was one of a diverse guild of long-proboscis insects that fed upon these plants, including flies, lacewings and possibly moths. Scientists know that it “nectared” gymnosperms and not angiosperms because at that time the most primitive angiosperms did not have deep-throated, tubular flowers whereas some gymnosperm hosts did have reproductive structures that would accommodate the proboscis of J. liaoningensis.

Where: Discovered recently in China’s Yixian Formation, near Beipiao City of Liaoning Province, China. The Yixian Formation is a geological formation holding deposits that span several millions of years during the Early Cretaceous Period. It is well known for the abundant fossils of plants, animals, such as feathered dinosaurs, and insects that have been discovered there, broadly known as the Jehol Biota.

Image left: J. liaoningensis gen. et sp. n. Holotype, specimen CNU-M-LB-2005-002-1, part.

Who: These specimens were described and named in the journal Zookeys recently by Dong Ren and ChungKun Shih of the Capital Normal University, Beijing, and Conrad Labandeira of the Smithsonian’s National Museum of Natural History. Article link: “A well-preserved aneuretopsychid from the Jehol Biota of China (Insecta, Mecoptera, Aneuretopsychidae)”

Natural History Museum curator Nick Pyenson explains how scientists know what dinosaurs and other extinct animals ate

John Barrat — Mon, 12 Mar 2012 16:28:28 +0000

Wayne Clough & Carlos Jaramillo, at a research site near the Panama Canal.

John Barrat — Thu, 16 Feb 2012 18:31:09 +0000

Smithsonian Secretary Wayne Clough, left, talks with Carlos Jaramillo, scientist at the Smithsonian Tropical Research Institute in Panama, at a research site near the Panama Canal. Jaramillo and his team are collecting and examining prehistoric fossils exposed during the recent widening of the Canal. To date, they have discovered the fossils of a 12-inch-tall horse, a tiny camel, huge rhinos, turtles and trees 17- to 23-million-years-old. They have also uncovered evidence indicating the Isthmus of Panama did not emerge three million years ago, but as early as 22 million years ago. (Photo by Johnny Gibbons)

190-million-year-old dinosaur nesting site discovered in South Africa

John Barrat — Fri, 27 Jan 2012 14:39:08 +0000

An excavation at a site in South Africa has unearthed the 190-million-year-old dinosaur nesting site of the prosauropod dinosaur Massospondylus–revealing significant clues about the evolution of complex reproductive behavior in early dinosaurs.

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.

Ancient popcorn discovered in Peru

John Barrat — Wed, 18 Jan 2012 13:06:35 +0000

People living along the coast of Peru were eating popcorn 2,000 years earlier than previously reported and before ceramic pottery was used there, according to a new paper in the Proceedings of the National Academy of Sciences co-authored by Dolores Piperno, curator of New World archaeology at the Smithsonian’s National Museum of Natural History and emeritus staff scientist at the Smithsonian Tropical Research Institute.

Image right: These ancient corn cobs date roughly from 6,500-4,000 years ago. A is Proto-Confite Morocho race; B, Confite Chavinense maize race; and C is Proto-Alazan maize race.. (Photo by Tom Dillehay)

Some of the oldest known corncobs, husks, stalks and tassels, dating from 6,700 to 3,000 years ago were found at Paredones and Huaca Prieta, two mound sites on Peru’s arid northern coast. The research group, led by Tom Dillehay from Vanderbilt University and Duccio Bonavia from Peru’s Academia Nacional de la Historia, also found corn microfossils: starch grains and phytoliths. Characteristics of the cobs—the earliest ever discovered in South America—indicate that the sites’ ancient inhabitants ate corn several ways, including popcorn and flour corn. However, corn was still not an important part of their diet.

Image left: Wild forms of Zea mays are called ‘teosinte’. Over time, selective breeding modifies teosinte’s few fruitcases (left) into modern corn’s rows of exposed kernels (right). (Photo courtesy John Doebley.).

“Corn was first domesticated in Mexico nearly 9,000 years ago from a wild grass called teosinte,” Piperno says. “Our results show that only a few thousand years later corn arrived in South America where its evolution into different varieties that are now common in the Andean region began. This evidence further indicates that in many areas corn arrived before pots did and that early experimentation with corn as a food was not dependent on the presence of pottery.”

Understanding the subtle transformations in the characteristics of cobs and kernels that led to the hundreds of maize races known today, as well as where and when each of them developed, is a challenge. Corncobs and kernels were not well preserved in the humid tropical forests between Central and South America, including Panama—the primary dispersal routes for the crop after it first left Mexico about 8,000 years ago.

“These new and unique races of corn may have developed quickly in South America, where there was no chance that they would continue to be pollinated by wild teosinte,” Piperno says. “Because there is so little data available from other places for this time period, the wealth of morphological information about the cobs and other corn remains at this early date is very important for understanding how corn became the crop we know today.”

“Preceramic corn from Pardones and Huaca Prieta, Peru,” Grobman, A., Bonavia, D., Dillehay, T.D., Piperno, D.R., Iriarte, J., Holst, I. 2012. . PNAS early online edition, week of Jan. 16, 2012.

Fossil feathers from a Hawaiian cave help reveal lineage of extinct, flightless ibis

John Barrat — Mon, 21 Nov 2011 14:44:02 +0000

A remarkable first occurred recently at the Smithsonian’s National Museum of Natural History when ornithologists Carla Dove and Storrs Olson used 700- to 1,100-year-old feathers from a long extinct species of Hawaiian ibis to help determine the bird’s place in the ibis family tree. So fragile that some parts disintegrated as they were being mounted on microscope slides, the feathers are the only known plumage of any of the prehistorically extinct birds that once inhabited the Hawaiian Islands.

Discovered with a nearly complete skeleton, the feathers retained enough microscopic structure to allow the scientists to confirm the classification of the bird, known by its scientific name Apteribis sp, as a close relative of the American white ibis and scarlet ibis. DNA analysis confirmed this classification.

Image left: Skull (top) and (below) detail of feathers adhering to the cranium of Apteribis sp. from Lanai, Hawaii Islands (Photo courtesy Carla Dove)

Remarkably, the feathers also retained enough pigmentation to allow Dove and Olson to determine the bird had been brown-black to ivory-beige/light brown in color. Before now, any reconstruction of the appearance of a prehistorically extinct Hawaiian bird had been only speculation.

Image right: This scanning electron photomicrograph shows the prongs on the downy barbules of an Apteribis sp. feather. (Photo courtesy Carla Dove)

Apteribis sp. is one of only two species of ibises, both now extinct, known to be flightless. Its skeleton differs so much from its mainland ancestors that the bird’s relationship to other ibises could only be determined through the study of its feathers and DNA analysis, Olson says.

The find is highly unusual because “feathers do not preserve well and often decay before a bird is fossilized,” Dove says. “These weren’t fossil imprints in a rock, but feathers and bones we could actually pick up.”

Exceptional geologic circumstances led to the preservation of the feathers inside a lava cave on the Hawaiian Island of Lanai. The floor of the cave was partially covered in a deep layer of flaky gypsum crystals, which, for hundreds of years absorbed humidity in the cave and created an arid environment ideal for preservation of the feathers. The crystals were shaken off of the walls and ceiling of the lava tube by seismic tremors.

Image right: American white ibis (Photo by Terry Foote at en.wikipedia); below, scarlet ibis (Photo by Hans Hillewaert). Both of these birds are closely related to the extinct Apteribis sp., which did not fly.

From a taxonomic standpoint feathers are significant because the shape of microscopic barbs on specific areas of a feather have distinct features that taxonomists can use to determine what bird group it belongs to, Dove says.

“The barbs are unique only on the downy, fluffy part at the base of the feather, not at the tip,” Dove says. “These microstructures are similar among orders of birds—pigeons, ducks, songbirds, for example.

Using the extensive collections in the Division of Birds at the National Museum of Natural History, Dove compared the microscopic structures of the ancient feathers (which she describes as “short barbules with these long prongs,”) to those of modern day birds.

Her analysis confirmed that Apteribis sp. is most closely related the New World ibises of the genus Eudocimus, the American white ibis (Eudocimus albus) and scarlet ibis (Eudocimus buber). Apteribis sp. was first described from fossils found on the Hawaiian Islands of Molokai and Maui. It is one of dozens of bird species known to have gone extinct following the arrival of humans on the Hawaiian Islands.

“Fossil Feathers from the Hawaiian Flightless Ibis (Apteribis SP.): Plumage Coloration and Systematics of a Prehistorically Extinct Bird,” by Carla Dove and Storrs Olson appeared in the September 2011 issue of the Journal of Paleontology.

Details of ancient shark attack preserved in fossil whale bone

John Barrat — Wed, 09 Nov 2011 16:52:52 +0000

A fragment of whale rib found in a North Carolina strip mine is offering scientists a rare glimpse at the interactions between prehistoric sharks and whales some 3- to 4-million years ago during the Pliocene.

Image right: Whale bone fossil showing the three tooth marks from a shark. Click photos to enlarge. (Photo by Stephen Godfrey)

Three tooth marks on the rib indicate the whale was once severely bitten by a strong-jawed animal. Judging by the 6 centimeter (2.4 inch) spacing between tooth marks, scientists believe the attacker was a mega toothed shark Carcharocles megalodon, or perhaps another species of large shark which was alive at that time. The whale appears to have been an ancestor of a great blue or humpback.

“One certainly doesn’t expect to find evidence of animal behavior preserved in the fossil record, but this fossil shows just that, a failed predation,” explains Stephen Godfrey, paleontologist at the Calvert Marine Museum in Solomons, Md. and a Smithsonian research collaborator, who discovered the fossil. “The shark may have gone away with a mouthful, but it didn’t kill the whale”

Image left: This illustration shows one plausible way, and the most likely, in which the three calluses preserved on the whale rib came about: a bite from one of the large Pliocene sharks with which these huge baleen whales had to contend. (Illustration by Timothy Scheirer © CMM; used with permission)

Scientists know the whale survived because “most of the fossil fragment is covered with a type of bone known as woven bone, which forms rapidly in response to localized infection,” explains Don Ortner, an anthropologist at the Smithsonian’s National Museum of Natural History and authority on the effect of disorders on skeletal tissue. “Biomechanically woven bone is not very strong. The body eventually remodels it into compact bone, but it takes time.” CT scans reveal evidence of inflammation in the bone marrow consistent with infection.

The presence of the woven bone indicates the healing was incomplete and the whale died, the scientists estimate, between two and 6 weeks after the attack. The whale’s death may have been unrelated to its infection and injury, Ortner says. “We don’t know why it died.”

Based on the curvature of the shark’s jaw, as indicated by the arc of the impressions of its teeth, the scientists believe the shark was relatively small, between 4- and 8-meters (13-20 feet) long.

In the realm of paleontology, “only a handful of fossils show these kinds of interactions,” Godfrey explains. “There are lots of bite marks on fossils showing where the animal died and its carcass was scavenged. This fossil is one of a very few examples that shows a trauma clearly attributed to another animal, yet also shows the victim survived the event.”

“Bone Reactions on a Pliocene Cetacean Rib Indicate Short-Term Survival of Predation Event” was published in the International Journal of Osteoarchaeology and is co-authored by Robert Kallal and Stephen Godfrey of the Calvert Marine Museum in Solomons, Md., and Donald Ortner of the Smithsonian’s National Museum of Natural History.