Ancient child’s tooth reveals picture of Alaska’s early inhabitants

Research on a newly rediscovered 9,000-year-old child’s tooth has reshaped our understanding of Alaska’s ancient people, their genetic background and their diets.

Ancient child's tooth reveals picture of Alaska's early inhabitants
These artefacts from Helge Larsen’s 1949-1950 excavations at the Trail Creek Caves Site are housed
at the Danish National Museum in Copenhagen, Denmark [Credit: NPS photo by Jeff Rasic]

The tooth is only the third known remnant of a population of early migrants known as Ancient Beringians. Combined with previous University of Alaska Fairbanks research, the find indicates that Ancient Beringians remained in Alaska for thousands of years after first migrating across the Bering Land Bridge that connected eastern Asia and Alaska.

Investigation of the tooth, conducted by researchers at UAF and the National Park Service in Alaska, was part of a larger paper published in the journal Science. That research included genetic analysis of 15 diverse bone samples from sites across North and South America, revealing a broad picture of how the Americas were populated by its earliest peoples.

The Alaska tooth had been largely forgotten since it was excavated in 1949 by Danish archaeologists from the Trail Creek Caves site on Alaska’s Seward Peninsula. For almost 70 years it remained in storage in Copenhagen, Denmark, until it was found in 2016 by Jeff Rasic, a Fairbanks-based NPS archaeologist who was conducting new analyses of this old collection.

Radiocarbon dating determined the tooth, which belonged to a 1½-year-old child, is by far the oldest human specimen in the North American Arctic — more than twice as old as the next oldest remains. Genomic testing connected the tooth to the Ancient Beringian lineage. The first traces of that population were discovered in 2013 by a team led by UAF professor Ben Potter at a site in Alaska’s Interior.

“This one small tooth is a treasure trove of information about Alaska’s early populations, not only their genetic affinities but also their movements, interactions with other people and diet,” said Rasic.

Ancient child's tooth reveals picture of Alaska's early inhabitants
This aerial view includes the Trail Creek Caves Site on Alaska’s Seward Peninsula. Analysis of a 9,000-year-old tooth
from the site has broadened understanding of Alaska’s early people [Credit: NPS photo by Jeff Rasic]

When looked at together, those two sites — separated by about 400 miles and 2,500 years — show that Ancient Beringians were present across the vast expanse of Alaska for millennia.

“This new find confirms our predictions that Ancient Beringians are directly linked with the cultural group known as the Denali Complex, which was widespread in Alaska and the Yukon Territory from 12,500 to about 6000 years ago,” said Potter, who wasn’t involved in the Science paper.

Researchers worked with tribal officials from the Seward Peninsula village of Deering to coordinate efforts to study the tooth.

Analysis at UAF’s Alaska Stable Isotope Facility also revealed surprising details about the lives of the child and, by proxy, the mother who fed the child. By studying chemical signatures preserved in the tooth, ASIF Director Matthew Wooller was able to analyze their diet.

“The child’s food sources were entirely terrestrial, a sharp contrast with other sites that indicate inclusion of anadromous fish and marine resources.” said Wooller, who also works at UAF’s College of Fisheries and Ocean Science, and Water and Environmental Research Center.

That land-based diet is a surprise — during the time the child lived on the Seward Peninsula, sea levels had risen to nearly modern levels. Those rising waters had cut off the Bering Land Bridge and surrounded most of the peninsula, making marine resources accessible.

Further isotope results and modeling, which were conducted by Rasic, Wooller and Clement Bataille from the University of Ottawa, also determined the family resided in the region surrounding the caves, and were not migrants from elsewhere in Alaska or Siberia.

“The combination of isotope signatures found in the tooth is pretty specific to the interior Seward Peninsula, making a local origin for the family very probable,” Bataille said.

Author: Jeff Richardson | Source: University of Alaska Fairbanks [November 08, 2018]



Most complete study on Europe’s greatest Hadrosaur site published

The Basturs Poble site is what is known in English as a bone bed, a geological stratum containing a great amount of fossils. The stratum dates back some 70 million years. It is the only one to have been found in Europe exclusively containing hadrosaur remains. The excavations conducted during the past ten years have yielded approximately one thousand fossils. The remains are disjointed and possibly belong to only one species: the Pararhabdodon isonensis.

Most complete study on Europe's greatest Hadrosaur site published
The journal PLOS ONE recently published the most complete study of fossils recovered from the site of Basturs
Poble and reveals the presence of many young individuals. Palaeontologists from the ICP, the UAB and
the Museum of Conca Dellà participated in the study [Credit: UAB]

“We think the individuals died due to unfavourable environmental conditions, perhaps an extreme dry spell. After their death, the remains got washed away by water and then began to fossilise, but we know that the place where they died was not far away from the site”, explains Víctor Fondevilla, researcher at the Institut Català de Paleontologia Miquel Crusafont (ICP) and the Universitat Autònoma de Barcelona (UAB) and first author of the paper.
The research recently published in PLOS ONE analysed the 270 fossil remains at the site which were prepared to be studied, including skulls, jaws, teeth, vertebrae and limb bones. Researchers however did not have enough with describing and measuring each specimen, they also analysed the interior of the fossils to extract information on the age of each individual. “We can cut open the fossils and analyse their inner structure. It gives us a lot of information on the vital cycle of each of the animals”, says ICREA research lecturer at ICP Meike Köhler. Similar to the rings of trees, in sections of elongated bones we find lines of arrested growth (LAGs) which are indicators corresponding to the alternation between favourable and unfavourable periods. In this way we can calculate at what age they died.

Using this system, palaeontologists detected that at the site were a large number of young individuals and, to a lesser extent, sub-adults and adults. But no recently hatched dinosaur fossils were found. “We estimated that the youngest individuals died at two years of age and that the adults were 14 to 15”, Fondevilla explains. The fact that researchers found so many young samples makes them think that the accumulation of bones at Basturs Poble represents a natural population of herbivores, where young individuals are more abundant. “It may also be that the abundance of young remains is due to these individuals being more vulnerable to crises and therefore dying in larger quantities than adults would”, the main researcher of the study comments.

Also participating in the study were researchers from the Museum of Conca Dellà and the Friulian Museum of Natural History in Udine, Italy.

Hadrosaurs, A Well-Known Group in Catalonia

Hadrosaurs, also known as “duck-billed” dinosaurs, are a group of ornithischian herbivorous dinosaurs which lived in the Late Cretaceous period. This is probably the most well-known group of dinosaurs. Among the subfamilies there are the lambeosaurines, which can be found in Catalonia’s sites. They characteristically had a robust medium to large-sized body (weighing one kilogramme when hatching and reaching up to 3000 kilogrammes as adults), with smaller front limbs and larger hind limbs. This last trait made it possible for them to walk on two or four feet indifferently.

Most complete study on Europe's greatest Hadrosaur site published
Pararhabdodon isonensis [Credit: Oscar Sanisidro/ICP]

The skull is long and duck-billed shaped, and the jaw holds rows of stacked teeth. Their most distinctive characteristic was their cranial crest, formed by several more or less developed cranial bones. What the crest was used for remains unclear, but scientists believe it could have acted as a resonating chamber with which to amplify sounds and facilitate recognising members of the same species. Other hypotheses point to the possibility of only males having crests which aimed to attract the females.
The Pararhabdodon isonensis species is only known to have existed in the Pallars Jussà region. The species was described in 1985 after the discovery of remains found at Sant Romà d’Abella and its specific name – isonensis – refers to the town of Isona located near the site. These dinosaurs measured from 6 to 7 metres in length and it is estimated that the adults weighed some three tonnes.

The Pyrenees, Home to the Last Dinosaurs in Europe

Catalonia is very rich in fossiliferous sediment. Of the most relevant are the pre-Pyrennean basins, which conserve remains of different life forms from the Late Cretaceous Period (between 70 and 66 million years ago). In geological terms, that is very shortly before the great extinction which marked the end of many life forms, including non-avian dinosaurs. Located at the Pyrennean sites, therefore, are the last dinosaurs to have lived in Europe, a few hundreds of years before they disappeared from the world entirely.

The Basturs Poble site was located by scientific communicator Marc Boada in August 2001. Upon discovering fossils on the surface, he contacted palaeontologists from the Museum of Conca Dellà. Few months later a palaeontology dig was conducted which confirmed the exceptional nature of this site. After a first research dig, twelve more campaigns have been conducted as part of research projects led by Àngel Galobart, Head of the Mesozoic Fauna Research Group at ICP, and Rodrigo Gaete from the Museum of Conca Dellà.

The fossils found at Basturs Poble are conserved at the Museum of Conca Dellà. The museum’s dinosaur exhibition hall contains a sample of the most outstanding bones found at the site and a life-size recreation of a Pararhabdodon isonensis dinosaur.

Source: Autonomous University of Barcelona [November 08, 2018]



Tiny footprints, big discovery: Reptile tracks oldest ever found in Grand Canyon

A geology professor at the University of Nevada, Las Vegas, has discovered that a set of 28 footprints left behind by a reptile-like creature 310 million years ago, are the oldest ever to be found in Grand Canyon National Park.

Tiny footprints, big discovery: Reptile tracks oldest ever found in Grand Canyon
UNLV geologist Stephen Rowland discovered that a set of 28 footprints left behind by a reptile-like creature 310 million
years ago are the oldest ever to be found in Grand Canyon National Park [Credit: Stephen Rowland]

The fossil trackway covers a fallen boulder that now rests along the Bright Angel Trail in the national park. Rowland presented his findings at the recent annual meeting of the Society of Vertebrate Paleontology.

“It’s the oldest trackway ever discovered in the Grand Canyon in an interval of rocks that nobody thought would have trackways in it, and they’re among the earliest reptile tracks on earth,” said Rowland.

Rowland said he’s not prepared to say that they’re the oldest tracks of their kind ever discovered, but it’s a possibility, as he’s still researching the discovery.

“In terms of reptile tracks, this is really old,” he said, adding that the tracks were created as the supercontinent Pangaea was beginning to form.

Rowland was first alerted to the tracks in spring 2016 by a colleague who was hiking the trail with a group of students. The boulder ended up along the trail after the collapse of a cliff.

Tiny footprints, big discovery: Reptile tracks oldest ever found in Grand Canyon
An illustration by Stephen Rowland shows how the reptile-like creature might have made
the sideways tracks in the ancient sand dune [Credit: Stephen Rowland]

A year later, Rowland studied the footprints up close.

“My first impression was that it looked very bizarre because of the sideways motion,” Rowland said. “It appeared that two animals were walking side-by-side. But you wouldn’t expect two lizard-like animals to be walking side-by-side. It didn’t make any sense.”

When he arrived home, he made detailed drawings, and began hypothesizing about the “peculiar, line-dancing gait” left behind by the creature.

“One reason I’ve proposed is that the animal was walking in a very strong wind, and the wind was blowing it sideways,” he said.

Another possibility is that the slope was too steep, and the animal sidestepped as it climbed the sand dune. Or, Rowland said, the animal was fighting with another creature, or engaged in a mating ritual.

“I don’t know if we’ll be able to rigorously choose between those possibilities,” he said.

He plans to publish his findings along with geologist Mario Caputo of San Diego State University in January. Rowland also hopes that the boulder is soon placed in the geology museum at the Grand Canyon National Park for both scientific and interpretive purposes.

Meanwhile, Rowland said that the footprints could belong to a reptile species that has never yet been discovered.

“It absolutely could be that whoever was the trackmaker, his or her bones have never been recorded,” Rowland said.

Author: Natalie Bruzda | Source: University of Nevada, Las Vegas [November 08, 2018]