Unique sled dogs helped the inuit thrive in the North American Arctic

By: Thomas Schmitt Attorney on November 27, 2019 / comment : 0 Archaeology, Arctic, Genetics, Indigenous Cultures, North America, Ticker

A unique group of dogs helped the Inuit conquer the tough terrain of the North American Arctic, major new analysis of the remains of hundreds of animals shows.

A team of Greenland sled dogs working in Greenland’s Disko Bay  [Credit: Tatiana Feuerborn]

The study shows that the Inuit brought specialised dogs with them when they migrated from Alaska and Siberia instead of adopting local dogs they would have come across during their migration. They instead maintained their own dogs, suggesting they were keen to enhance or keep the special features they had. By analysing the shape of elements from 391 dogs, the study shows that the Inuit had larger dogs with a proportionally narrower cranium to these earlier dogs. The Inuit dogs are the direct ancestors of modern Arctic sledge dogs, although their appearance has continued to change over time.

Experts had thought the Inuit used dogs to pull sledges, and this is the first study which shows they introduced a new dog population to the region to do this. These dogs then spread across the North American Arctic alongside Inuit migrants.

Dr Carly Ameen, an archaeologist from the University of Exeter who led the study, said: "Dogs have lived in North America for as long as humans, but we show here that the Inuit brought new dogs to the region which were genetically distinct and physically different from earlier dogs.

"Thousands of years ago there was not the huge number of dog breeds as we know them today. Through analysing the DNA and morphology of the remains of hundreds of dogs we've found that the dogs used by the Inuit had distinctive skull and teeth shapes, and would have likely looked different in life to dogs already in the Arctic."

The ancestors of these dogs arrived with the Inuit to the North American Arctic [Credit: Tatiana Feuerborn]

Experts also examined the DNA from 921 dogs and wolves who lived during the last 4,500 years. This analysis of the DNA, and the locations and time periods in which they were found, shows dogs from Inuit sites occupied from around 2,000 years ago were genetically different from the dogs already in the region.

Study co-lead author Tatiana Feuerborn, from the Globe Institute in Denmark and the Centre for Palaeogenetics in Sweden, said: "Archaeological evidence has shown us that before the Inuit arrived in North America dog sledging was a rarity. Our analysis of the DNA suggests dogs brought by the Inuit were distinct from the earlier dogs of the North American Arctic to fill specialist role in helping communities thrive in this hostile environment by aiding with transportation and hunting. The genetic legacy of these Inuit dogs can still be seen today in Arctic sledge dogs."

The Inuit were specialised sea mammal hunters, and were more mobile than other groups living in the Arctic, migrating huge distances across the region over 1,000 years ago, with the help of dog sledges and water craft. Today, sledge dogs whose origins can be traced back to the Inuit period continue to be an important part of Arctic communities.

The article is published in the journal Proceedings of the Royal Society B.

Source: University of Exeter [November 27, 2019]

Did human hunting activities alone drive great auks' extinction?

By: Thomas Schmitt Attorney on November 26, 2019 / comment : 0 Early Birds, Fossils, Genetics, Iceland, North America, Palaeontology, Scotland

New insight on the extinction history of a flightless seabird that vanished from the shores of the North Atlantic during the 19th century has been published in eLife.

A mounted great auk skin, The Brussels Auk (RBINS 5355), from the collections at the Royal Belgian Institute of Natural Sciences (RBINS) [Credit: Thierry Hubin, RBINS]

The findings suggest that intense hunting by humans could have caused the rapid extinction of the great auk, showing how even species that exist in large and widespread populations can be vulnerable to exploitation.

Great auks were large, flightless diving birds thought to have existed in the millions. They were distributed around the North Atlantic, with breeding colonies along the east coast of North America and especially on the islands off Newfoundland. They could also be found on islands off the coasts of Iceland and Scotland, as well as throughout Scandinavia.

But these birds had a long history of being hunted by humans. They were poached for their meat and eggs during prehistoric times, and this activity was further intensified in 1500 AD by European seamen visiting the fishing grounds of Newfoundland. Their feathers later became highly sought after in the 1700s, contributing further to their demise.

"Despite the well-documented history of exploitation since the 16th century, it is unclear whether hunting alone could have been responsible for the species' extinction, or whether the birds were already in decline due to natural environmental changes," says lead author Jessica Thomas, who completed the work as part of her PhD studies at Bangor University, UK, and the University of Copenhagen, Denmark, and is now a postdoctoral researcher at Swansea University, Wales, UK.

Great auk humeri from Funk Island. These samples are part of the great auk collection at the American Museum of Natural History [Credit: J. Thomas]

To investigate this further, Thomas and her collaborators carried out combined analyses of ancient genetic data, GPS-based ocean current data, and population viability - a process that looks at the probability of a population going extinct within a given number of years. They sequenced complete mitochondrial genomes of 41 individuals from across the species' geographic range and used their analyses to reconstruct the birds' population structure and dynamics throughout the Holocene period, the last 11,700 years of Earth's history.

"Taken together, our data don't suggest that great auks were at risk of extinction prior to intensive human hunting behaviour in the early 16th century," explains co-senior author Thomas Gilbert, Professor of Evolutionary Genomics at the University of Copenhagen. "But critically, this doesn't mean that we've provided solid evidence that humans alone were the cause of great auk extinction. What we have demonstrated is that human hunting pressure was likely to have caused extinction even if the birds weren't already under threat from environmental changes."

Gilbert adds that their conclusions are limited by a couple of factors. The mitochondrial genome represents only a single genetic marker and, due to limited sample preservation and availability, the study sample size of 41 is relatively small for population genetic analyses.

"Despite these limitations, the findings help reveal how industrial-scale commercial exploitation of natural resources have the potential to drive an abundant, wide-ranging and genetically diverse species to extinction within a short period of time," says collaborator Gary Carvalho, Professor in Zoology (Molecular Ecology) at Bangor University. This echoes the conclusions of a previous study* on the passenger pigeon, a bird that existed in significant numbers before going extinct in the early 20th century.

"Our work also emphasises the need to thoroughly monitor commercially harvested species, particularly in poorly researched environments such as our oceans," concludes co-senior author Michael Knapp, Senior Lecturer in Biological Anthropology and Rutherford Discovery Fellow at the University of Otago, New Zealand. "This will help lay the platform for sustainable ecosystems and ensure more effective conservation efforts."

Source: eLife [November 26, 2019]

Dinosaur skull turns paleontology assumptions on their head

By: Thomas Schmitt Attorney on November 25, 2019 / comment : 0 Dinosaurs, Fossils, North America, Palaeontology

A team of researchers at the University of Alberta has unearthed a well-preserved Styracosaurus skull--and its facial imperfections have implications for how paleontologists identify new species of dinosaurs.

Styracosaurus skull [Credit: Pixabay]

The skull was discovered by Scott Persons in 2015, then a graduate student in the Department of Biological Sciences, during an expedition in the badlands northwest of Dinosaur Provincial Park.

Nicknamed Hannah, the dinosaur was a Styracosaurus - a horned dinosaur over five metres in length with a fan of long horns. UAlberta paleontologists led by Robert Holmes, professor in the Department of Biological Sciences, have learned much from those horns--because they aren't symmetrical.

"When parts of one side of the skull were missing, paleontologists have assumed that the missing side was symmetrical to the one that was preserved," explained Persons. "Turns out, it isn't necessarily. Today, deer often have left and right antlers that are different in terms of their branching patterns. Hannah shows dramatically that dinosaurs could be the same way."

Hannah's skull, seen from all sides. The jacket used to recover Hannah’s skull weighed 2500 kilograms—requiring a helicopter to retrieve from the field! [Credit: Scott Persons]

The differences in the skull's left and right halves are so extreme that had the paleontologists found only isolated halves, they might have concluded that they belong to two different species

"The skull shows how much morphological variability there was in the genus," said Holmes. Like the antlers of modern deer and moose, Hannah shows that the pattern of dinosaur horns could vary significantly--meaning some fossils that were once assumed to be unique species will have to be reevaluated.

Tradition dictates that the person who finds an important dinosaur specimen gets to give it a nickname. "Hannah the dinosaur is named after my dog," explained Persons, now a professor and museum curator at the College of Charleston. "She's a good dog, and I knew she was home missing me while I was away on the expedition."

Paleontologist Scott Persons, pictured alongside the partially-uncovered skull. The Styracosaurus skull has implications for how horned dinosaurs are identified [Credit: Scott Persons]

Despite the nickname, paleontologists have no way of knowing if the dinosaur was female. But they have learned other details from the skull--from a partnership with researchers in the Faculty of Engineering.

"Ahmed Qureshi and graduate student Baltej Rupal in the Faculty of Engineering assisted us in performing a 3D laser scan of the skull," said Persons. "That let our publication to include a digital reconstruction, allowing scientists all over the world to download the 3D model and inspect it in detail."

"This is the future of paleontological collections: digital dinosaurs."

The paper was published in Cretaceous Research.

Author: Andrew Lyle | Source: University of Alberta [November 25, 2019]

Scientists use modern technology to understand how ochre paint was created in rock art

By: Thomas Schmitt Attorney on November 19, 2019 / comment : 0 Americas, Archaeology, Canada, North America

Ochre, one of Earth's oldest naturally occurring materials, was often used as a vivid red paint in ancient rock art known as pictographs across the world. Despite its broad use throughout human history and a modern focus on how the artistic symbolism is interpreted, little research exists on the paint itself and how it was produced.

One of the pieces of rock art found at Babine Lake. It is representative of the rock art that was analyzed in the study [Credit: University of Missouri]

Now, scientists led by Brandi MacDonald at the University of Missouri are using archaeological science to understand how ochre paint was created by hunter-gatherers in North America to produce rock art located at Babine Lake in British Columbia.

"Ochre is one of the only types of material that people have continually used for over 200,000 years, if not longer," said MacDonald, who specializes in ancient pigments. "Therefore, we have a deep history in the archeological record of humans selecting and engaging with this material, but few people study how it's actually made."

This is the first study of the rock art at Babine Lake. It shows that individuals who prepared the ochre paints harvested an aquatic, iron-rich bacteria out of the lake -- in the form of an orange-brown sediment.

In the study, the scientists heated a single grain of ochre and watched the effects of temperature change under an electron microscope at MU's Electron Microscopy Core facility [Credit: University of Missouri]

In the study, the scientists used modern technology, including the ability to heat a single grain of ochre and watch the effects of temperature change under an electron microscope at MU's Electron Microscopy Core facility. They determined that individuals at Babine Lake deliberately heated this bacteria to a temperature range of approximately 750°C to 850°C to initiate the color transformation.

"It's common to think about the production of red paint as people collecting red rocks and crushing them up," MacDonald said. "Here, with the help of multiple scientific methods, we were able to reconstruct the approximate temperature at which the people at Babine Lake were deliberately heating this biogenic paint over open-hearth fires. So, this wasn't a transformation done by chance with nature. Today, engineers are spending a lot of money trying to determine how to produce highly thermo-stable paints for ceramic manufacturing or aerospace engineering without much known success, yet we've found that hunter-gatherers had already discovered a successful way to do this long ago."

The study was published in Scientific Reports.

Author: Eric Stann | Source: University of Missouri-Columbia [November 19, 2019]

Fossil dig leads to unexpected discovery of 91-million-year-old shark new to science

By: Thomas Schmitt Attorney on November 18, 2019 / comment : 0 Fossils, North America, Palaeontology

A 91-million-year-old fossil shark newly named Cretodus houghtonorum discovered in Kansas joins a list of large dinosaur-era animals. Preserved in sediments deposited in an ancient ocean called the Western Interior Seaway that covered the middle of North America during the Late Cretaceous period (144 million to 66 million years ago), Cretodus houghtonorum was an impressive shark estimated to be nearly 17 feet or slightly more than 5 meters long based on a new study appearing in the Journal of Vertebrate Paleontology.

Credit: Taylor & Francis

The fossil shark was discovered and excavated in 2010 at a ranch near Tipton, Kansas, in Mitchell County by researchers Kenshu Shimada and Michael Everhart and two central Kansas residents, Fred Smith and Gail Pearson. Shimada is a professor of paleobiology at DePaul University in Chicago. He and Everhart are both adjunct research associates at the Sternberg Museum of Natural History, Fort Hays State University in Hays, Kansas. The species name houghtonorum is in honor of Keith and Deborah Houghton, the landowners who donated the specimen to the museum for science.

Although a largely disarticulated and incomplete skeleton, it represents the best Cretodus specimen discovered in North America, according to Shimada. The discovery consists of 134 teeth, 61 vertebrae, 23 placoid scales and fragments of calcified cartilage, which when analyzed by scientists provided a vast amount of biological information about the extinct shark. Besides its estimated large body size, anatomical data suggested that it was a rather sluggish shark, belonged to a shark group called Lamniformes that includes modern-day great white and sand tiger sharks as distant cousins, and had a rather distinct tooth pattern for a lamniform shark.

"Much of what we know about extinct sharks is based on isolated teeth, but an associated specimen representing a single shark individual like the one we describe provides a wealth of anatomical information that in turn offers better insights into its ecology," said Shimada, the lead author on the study.

"As important ecological components in marine ecosystems, understanding about sharks in the past and present is critical to evaluate the roles they have played in their environments and biodiversity through time, and more importantly how they may affect the future marine ecosystem if they become extinct," he said.

During the excavation, Shimada and Everhart believed they had a specimen of Cretodus crassidens, a species originally described from England and subsequently reported commonly from North America. However, not even a single tooth matched the tooth shape of the original Cretodus crassidens specimen or any other known species of Cretodus, Shimada said.

"That's when we realized that almost all the teeth from North America previously reported as Cretodus crassidens belong to a different species new to science," he noted.

The growth model of the shark calibrated from observed vertebral growth rings indicates that the shark could have theoretically reached up to about 22 feet (about 6.8 meters).

"What is more exciting is its inferred large size at birth, almost 4 feet or 1.2 meters in length, suggesting that the cannibalistic behavior for nurturing embryos commonly observed within the uteri of modern female lamniforms must have already evolved by the late Cretaceous period," Shimada added.

Furthermore, the Cretodus houghtonorum fossil intriguingly co-occurred with isolated teeth of another shark, Squalicorax, as well as with fragments of two fin spines of a yet another shark, a hybodont shark.

"Circumstantially, we think the shark possibly fed on the much smaller hybodont and was in turn scavenged by Squalicorax after its death," said Everhart.

Discoveries like this would not be possible without the cooperation and generosity of local landowners, and the local knowledge and enthusiasm of amateur fossil collectors, according to the authors.

"We believe that continued cooperation between paleontologists and those who are most familiar with the land is essential to improving our understanding of the geologic history of Kansas and Earth as a whole," said Everhart.

Source: Taylor & Francis [November 18, 2019]

Ancient rain gauge: New evidence links groundwater, climate changes in deep time

By: Thomas Schmitt Attorney on November 12, 2019 / comment : 0 Climate Change, Earth Science, Geology, North America, Palaeoclimate, Palaeontology

Changes in groundwater millions of years ago created alternating layers of vivid yellow and brown in the mineral sphalerite, and those variations align with movements in Earth's orbit that impacted climate in the deep past, Penn State scientists found.

Yellow and brown banding in the mineral sphalerite are caused by changes in rainfall and groundwater. Penn State scientists found patterns in the banding match movement in Earth's orbit that impacted climate in the deep past [Credit: Mingsong Li]

The findings provide new evidence for how changes in climate influenced the planet's rainfall and groundwater, a process that scientists have not well documented, the researchers said.

"This study shows sphalerite banding can be used as a fingerprint of groundwater in the geological past," said Mingsong Li, assistant research professor of geosciences at Penn State. "Groundwater is crucial for understanding global sea level change, chemical weathering and landscape evolution, and this study presents a new idea to help discern the role of groundwater in the Earth system."

Increased precipitation influenced the colored banding in sphalerite samples from the Upper Mississippi Valley Ore Mineral District in the U.S. Midwest, the scientists said. More rainfall lead to oxygen-rich groundwater flowing to depths where the mineral formed, and the increased oxidation resulted in lighter yellow bands. Drier times yielded darker brown colors.

Using new dating technology, the scientists found these deposition patterns corresponded with changes in Earth's orbit over tens of thousands to hundreds of thousands of years, known as Milankovitch astronomical cycles.

These cycles refer to changes in the shape of Earth's orbit and variations in the tilt of its rotation that may have led to warmer, wetter conditions for periods from 299 million to 252 million years ago, when the sphalerite formed, the scientists said.

"What we are doing is marrying geochemical research on ores with what we know about astronomical cycles from very different research," said Hubert Barnes, distinguished professor emeritus at Penn State. "No one has ever made an attempt at this before."

The research builds on previous work that shows hydrothermal fluids that created ore deposits in modern day Iowa, Illinois and Wisconsin started as groundwater in the Appalachian Mountains. The water was heated by geothermal processes and picked up metals and solutes along it journey.

But during times of high precipitation, new sources of groundwater flowed to roughly 3,000 feet below the surface carrying higher oxygen levels and mixing with the hydrothermal fluids to create different colored bands in the sphalerite.

The researchers digitized a grayscale profile of the sphalerite from Wisconsin and analyzed the bands using new computer software that can detect periodic signals in the samples. They found distinct frequency peaks in the banding that correlate with the Milankovitch cycles.

The results - published in the journal Geochemical Perspective Letters - could help explain changes in sea level during times in Earth's history when the planet was too warm for ice, the scientists said.

Changes in groundwater can have real impacts on sea level. If all groundwater drained into oceans today, sea level would rise more than 180 feet, according to the scientists.

Yet projections of long-term global mean sea level on times scales of hundreds to thousands of years often do not include the contributions of land water storage, the scientists said. The Intergovernmental Panel on Climate Change, for instance, considers water storage on land contribution to sea level rise to be small.

"This research opens a new way to evaluate climate control on groundwater activities linked to global water cycles," Li said. "This is the first direct evidence to show groundwater activities in the deep past."

Author: Matthew Carroll | Source: Pennsylvania State University [November 12, 2019]

'Ghost' footprints from Pleistocene era revealed by radar tech

By: Thomas Schmitt Attorney on November 11, 2019 / comment : 0 Archaeology, Early Humans, Early Mammals, Fossils, North America

Invisible footprints hiding since the end of the last ice age - and what lies beneath them - have been discovered by Cornell University researchers using a special type of radar in a novel way.

The researchers collecting GPR data at White Sands National Monument in New Mexico  [Credit: Cornell University]

The fossilized footprints reveal a wealth of information about how humans and animals moved and interacted with each other 12,000 years ago.

"We never thought to look under footprints," said Thomas Urban, research scientist at Cornell and lead author on the study. "But it turns out that the sediment itself has a memory that records the effects of the animal's weight and momentum in a beautiful way. It gives us a way to understand the biomechanics of extinct fauna that we never had before."

The researchers examined the footprints of humans, mammoths and giant sloths in the White Sands National Monument in New Mexico. Using ground-penetrating radar (GPR), they were able to resolve 96% of the human tracks in the area under investigation, as well as all of the larger vertebrate tracks.

Human footprints from the last Ice Age at White Sands National Monument in New Mexico [Credit: Matthew Robert Bennett]

"But there are bigger implications than just this case study," Urban said. "The technique could possibly be applied to many other fossilized footprint sites around the world, potentially including those of dinosaurs. We have already successfully tested the method more broadly at multiple locations within White Sands."

While these "ghost" footprints can become invisible for a short time after rain and when conditions are just right, "now, using geophysics methods, they can be recorded, traced and investigated in 3D to reveal Pleistocene animal and human interactions, history and mechanics in genuinely exciting new ways," said co-author Sturt Manning, archaeology professor.

GPR is a nondestructive method that allows researchers to access hidden information without the need for excavation. The sensor - a kind of antenna - is dragged over the surface, sending a radio wave into the ground. The signal that bounces back gives a picture of what's under the surface.

The pressure data from the mammoth footprints closely resembled those of modern elephants [Credit: Matthew Robert Bennett]

In addition to this biomechanical treasure trove of data, the GPR technique gives researchers a way to learn about what early humans did when they were not at a campsite or kill site, the two types of archaeological sites best known for this time period.

The study is published in Scientific Reports.

Author: Linda B. Glaser | Source: Cornell University [November 11, 2019]

Researchers use drones reveal secrets of ancient Florida village

By: Thomas Schmitt Attorney on November 06, 2019 / comment : 0 Archaeology, North America, USA

Using drone technology, a team of UF researchers has uncovered how an ancient Florida village played a pivotal role in pre-Columbian geopolitics.

A drone equipped with Light Detection and Ranging quickly collected architectural details and topographic data about he Raleigh Island settlement with unprecedented resolution. The images revealed rings made of oyster shells surrounding 37 residences [Credit: University of Florida]

In research led by anthropology Ph.D. student Terry Barbour, the team discovered that the settlement on Raleigh Island, located on the northern Gulf coast of Florida around 900–1200 AD, operated as a major producer of beads made from seashells. The beads, used in rituals at the time, were highly prized in communities as far from the coast as the lower Midwest.

"In form, scale and purpose, the Raleigh Island settlement has no parallel in the archaeological record of the American Southeast," said Ken Sassaman, Barbour's advisor and the co-creator of the study. Sassaman is the Hyatt and Cici Brown Professor of Florida Archaeology in the Department of Anthropology.

The researchers used drones to survey the ancient settlement in a fraction of the time traditional methods would have taken. Working with UF partners at the GatorEye Unmanned Flying Laboratory, the team equipped the drone with Light Detection and Ranging (LiDAR) scanners that quickly collected architectural details and topographic data with unprecedented resolution.

The LiDAR shed light on how the settlement—a complex of at least 37 residential spaces surrounded by 4-meter-tall ridges of oyster shells—was organized to make beads in the very place where shells were found. In several of the living spaces, the researchers' excavations uncovered ample evidence of large-scale bead production.

The Raleigh Island settlement is one of the few coastal communities where such extensive craft production has been found.

"What we have here is a settlement at the source of this raw material at the time when marine shell was starting to become a heavily demanded social item," Barbour said. "The fact we have strong evidence of bead manufacture at a site with equally impressive architecture to guide us in understanding how production was organized socially makes this place really special, and as of now the only place like it we are aware of."

The findings have been published in Proceedings of the National Academy of Sciences.

Source: University of Florida [November 06, 2019]