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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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.

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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.

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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.

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This illustration by Carl Buell depicts Ocucajea picklingi (center) and Supayacetus muizoni (bottom), two ancient whales that lived off the Peruvian coast during the Eocene, between 56-34 million years ago.  At top is an unnamed whale and the fossil penguin Perudyptes devriesi. Nicholas Pyenson, paleobiologist at the Smithsonian’s National Museum of Natural History, helped discover fossils of these whales in Peru’s Pisco Basin. Read his account of the discovery on this Ocean Portal blog post.

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The dodo’s large size and inability to fly were adaptations that allowed this bird to survive some of the most hostile conditions and climactic events imaginable. Only in the 1600s did a force more deadly than extreme drought and volcanic eruptions lead to its extinction: humans.

Image right: Painting of a dodo head by Cornelis Saftleven. Done in 1638,  this painting may be one of the last illustrations made of a live dodo. (Image from Boijmans Museum, Rotterdam)

In a recent paper in the journal “The Holocene” a team of scientists detail the extreme conditions that caused the death of some 500,000 animals on Mauritius during the mid-Holocene at around 4000 years ago. The evidence is a thick bed of fossil bones on Mauritius that spans an area of about 5 acres—the site of a former freshwater lake bed. The fossil layer is dominated by the remains of thousands of dodos and giant tortoises, as well as many small reptiles and flying birds.

Image left: Dodo bone in a matrix of mud, seed and other fossils excavated in a dry lake bed on the Island of Mauritius. (Image copyright Kenneth Rijsdijk/Dodo Research Programme)

Using radiocarbon dating of the bones, oxygen isotope analysis of geologic features on Mauritius and nearby islands, and the study of the island’s water table, the scientists determined the animals died during an extreme drought that lasted several decades. “Dodos, tortoises, lizards and other animals gathered here because the lake was one of the few sites on the island with fresh water,” says Hanneke Meijer, an ornithologist at the Smithsonian’s National Museum of Natural History and one of the paper’s co-authors.

“It is evident that a lot of animals suffered and died during this period, and their populations were greatly reduced,” Meijer continues, “but no species, including the dodo, went extinct during this extreme drought.” Fossil evidence reveals that “all animals were still living and the island’s ecosystem was intact at the time humans arrived in the 1600s.”

Image right: The excavation site on the island of Mauritius where the remains of some 500,000 animals were found, victims of an extreme drought some 4,000 years ago. (Image copyright Mikel Rijsdijk/Dodo Research Programme)

The dodo was resilient, and perfectly adapted to the island’s habitat, Meijer explains. “The island had no predators or carnivores and the dodo had no need to flee, so it lost its ability to fly. It received a reputation as stupid because it did not flee from humans” and human-introduced predators after they arrived at the dodo’s home in the 1600s.

Today, Meijer says, the forest cover on Mauritius has been reduced by 98 percent with only a few patches of original forest remaining. Considerable resources have been directed to preserving the island’s few remaining endemic species, such as the Mauritian kestrel. (The island’s giant tortoises went extinct in the 1800s when Dutch trade ships filled their holds with these long-lived animals to use as fresh meat on long voyages to and from Indonesia. “Mauritius was a popular stop because it provided fresh water and lots of food,” Meijer says)

Image left: Researchers at the Mauritius Island excavation site sieving excavated mud for small bones, teeth and plant remains. (Image copyright Mikel Rijsdijk/Dodo Research Programme)

Should another extended drought occur similar to the mid-Holocene event, it is very likely the remaining endemic species on Mauritius would not survive as the environment is so degraded. “Even many of the native plant species in the few remaining forest patches would probably perish,” Meijer says.

“With modern climate change scientists are very interested in how island animals adapt, as their ability to move to less disturbed areas is limited,” Meijer explains. “It has always been thought that animals on islands are particularly sensitive to climate change.” In the case of the dodo and other species on Mauritias, this new study reveals an island population highly resilient to climate change.

The article “Mid-Holocene (4200 kyr BP) mass mortalities in Mauritius (Mascarenes): Insular vertebrates resilient to climatic extremes but vulnerable to human impact,” appeared recently in the scientific journal “The Holocene.” (Rijsdijk, K.F., Zinke, J., de Louw, P.G.B., Hume,J.P., van der Plicht, J., Hooghiemstra, H., Meijer, H.J.M., Vonhof, H.B., Porch, N., Florens, F.B.V., Baider, C., van Geel, B., Brinkkemper, J., Vernimmen, T. & Janoo, A., 2011. Mid-Holocene (4200 kyr BP) mass mortalities in Mauritius (Mascarenes): Insular vertebrates resilient to climatic extremes but vulnerable to human impact. The Holocene, doi:10.1177/0959683611405236)

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The hatchling nodosaur fossil was donated to the Smithsonian’s National Museum of Natural History by Stanford, where it is on display to the public and also available for research.

After finding the fossil Stanford identified it as a nodosaur and called David Weishampel, a professor of anatomy at Johns Hopkins and a paleontologist and expert in dinosaur systematics. Weishampel and his colleagues established the fossil’s identity as a nodosaur by identifying a distinctive pattern of bumps and grooves on the skull. The body in the tiny fossil was only 13 cm long, just shorter than the length of a dollar bill. Adult nodosaurs are estimated to have been 20 to 30 feet long.

They then did a computer analysis of the skull shape, comparing its proportions to those of ten skulls from different species of ankylosaurs, the group that contains nodosaurs. They found that this dinosaur was closely related to some of the nodosaur species, although it had a shorter snout overall than the others. Comparative measurements enabled them to designate a new species, Propanoplosaurus marylandicus. In addition to being the youngest nodosaur ever found, it is the first hatchling of any dinosaur species ever recovered in the eastern United States.  Source: Johns Hopkins Medicine

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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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The series of four broadcasts will take place in the museum’s fourth-level classroom Friday, July 15; Sunday, July 17; Tuesday, July 19; and Wednesday, July 20, from 12:30 to 2:30 p.m. The final two broadcasts will be webcast at www.AmericanIndian.si.edu/webcasts. Audience members across the world are invited to submit questions for the research team via the museum’s Facebook page and Twitter feed.

Images of the Inka Road, right and below, by Lucia Abranovich Cusco

One of civilization’s most impressive engineering achievements, the Inka Road (or Qhapaq ñan, “The Royal Road”) was built without the use of iron, the wheel or stock animals. While much has been written about the Inka Empire as a whole, little has been published on how the Inka planned and built the road, which united the four regions of the ancient empire that encompassed large territories of present-day Peru, Bolivia, Ecuador, Colombia, Argentina and Chile. At its height, the Inka Road and its attendant “chaski” (runner) system was the fastest communication network in the New World, and the system of roads remains an integral part of infrastructure for present-day indigenous communities.

These broadcasts will explore new theories and discoveries about the construction of the Inka Road and how these ancient techniques can be applied by modern engineers and city planners. The research will also be highlighted in a subsequent exhibition at the museum in Washington, D.C.

The research team in Peru is led by the museum’s Latin America scholars Ramiro Matos and Jose Barreiro, and joined by Cliff Schexnayder, Eminent Scholar Emeritus at Arizona State University; Ed Jaselskis, the inaugural Jimmy D. Clark Distinguished Professor in Construction Engineering and Management at North Carolina State University; Wu Chueh Hung, professor of civil engineering at National Taiwan University; Manop Kaewmoracharoen, professor of engineering at Chiang Mai University in Thailand; and students from the Universidad de Piura in Peru, the Universidad Nacional de Cordoba in Argentina, the Universidad Catolica de Chile, the Universidad Tecnica Particular de Loja in Ecuado and the University of Colorado at Boulder.

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