Eurybelodon shoshanii: a new Unusual Shovel-tusked Gomphothere From Miocene Neogene Oregon

Eurybelodon shoshanii, an unusual new shovel-tusked gomphothere (Mammalia, Proboscidea) from the late Miocene of Oregon

Author:

Lambert

Abstract:

Unusual shovel-tusked gomphothere material from the late Clarendonian Black Butte Local Fauna (Juntura Formation, Oregon), including a lower tusk, partial upper tusk, and two mandibles including a second and a third molar, has been described and referred to Platybelodon. Platybelodon has the following diagnostic characteristics: molars strongly double-trefoiled; third molar with five lophs; lower tusks short with broad and very flat profiles lacking significant dorsoventral curvature; and lower tusks lacking obvious lamination but instead filled with small, short dentinal rods. However, the Black Butte shovel-tusked gomphothere was referred to Platybelodon despite having the following conflicting features: molars with weakly developed single trefoiling; third molar with only four lophids (the fourth little more than a talonid); broad, moderately flattened, relatively elongated lower tusk with strong dorsal curvature; and lower tusk internal structure showing lamination rather than dentinal rods. In addition, both the upper and lower tusks of the Black Butte shovel-tusker have prominently corrugated enamel cortices, a feature unknown in any other gomphothere. Thus, given the lack of a single clear-cut shared diagnostic feature and the large number of differences between these taxa, the identification of the Black Butte shovel-tusker as Platybelodon must be refuted. Refutation of the Platybelodon identification requires an alternate identification to be made for the Black Butte shovel-tusker. No other known shovel-tusker genus, including the genera Amebelodon, Serbelodon, and Torynobelodon, possesses the unusual combination of tusk and cheek tooth features observed in this animal. Accordingly, it is here referred to a new genus and species, Eurybelodon shoshanii.

Oregon Coast Range was 11 C Colder Than During Last Glacial Maximum

Lush greenery rich in Douglas fir and hemlock trees covers the Triangle Lake valley of the Oregon Coast Range. Today, however, geologists across the country are more focused on sediment samples dating back 50,000 years that were dug up by University of Oregon scientists.

The sediment indicates that the mountainous region, which was not covered in glaciers during the last ice age, was a frost-covered grassy landscape that endured erosion rates at least 2.5 higher than today's, an eight-member team reports in a paper in the journal Science Advances.

The research raises the possibility that non-glaciated terrain across North America was similar to that found 40 miles northwest of Eugene. The findings also suggest that mean annual temperatures were about 11 degrees Celsius cooler than modern temperatures, and that frost cracking -- not rainfall -- drove erosion as the region began emerging out of the Last Glacial Maximum.

Core samples containing telling signatures of frost were drilled up from 200 feet below today's surface near Little Lake. The valley, also home to the much larger Triangle Lake, is the result of a massive landslide 50,000 years ago. Eroding sediment then continued to fill a large lake and transform the valley floor.

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Redwoods Will be Forced to Migrate North due to Global Warming

In a study published in the research journal Global Change Biology, climate scientists from the University of California, NatureServe and the German Centre for Integrative Biodiversity Research (iDiv) conclude that a warmer future with normal rainfall on California's coast will leave coast redwoods south of San Francisco Bay with significantly different climate than they have experienced for decades.

Fourteen redwood parks are located in this area, including Big Basin Redwoods in the Santa Cruz Mountains, Julia Pfeiffer Burns State Park south of Carmel, and Garrapata State Park between Carmel and Big Sur on the Monterey coast.

Scientists also predict that redwood forest bioclimate, marked by fog, ample winter rain and moderate year-round temperatures, will expand by 34 percent northward from the coast of California into southern Oregon.

"With warmer climate forecast for more than half the coast redwood range in the next 10-15 years, we are eager for research that helps identify those areas that are most sensitive to climate change," says Paul Ringgold, Chief Program Officer for San Francisco-based Save the Redwoods League, the land trust which catalyzed the study under its Redwoods and Climate Change Initiative (RCCI). "These key findings help us better understand the future impacts of climate change and how to manage for these impacts on our redwood forests."

"Redwoods will still exist in the most vulnerable areas, while continued research on changing redwood bioclimate will help us identify and address redwood forest regeneration challenges. Moreover, locally unique weather patterns such as fog may influence projected climate trends in the future," he says.

"Coast redwoods have endured climatic changes over thousands of years. We are encouraged by our RCCI research, which shows that redwood trees continue to grow, even under warmer conditions, and will thrive further north into Oregon."

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More Than one Species of Chalicothere Present in Miocene Neogene Oregon

New material of Moropus (Perissodactyla, Chalicotheriidae, Schizotheriinae) from the early Hemingfordian Rose Creek Member of the John Day Formation, Oregon, U.S.A.

Authors:

Coombs et al

Abstract:

A juvenile maxilla of Moropus with DP3–M1, collected from the early Hemingfordian (He1) Picture Gorge 36 local fauna of the Rose Creek Member of the John Day Formation of Oregon, U.S.A., is the best-preserved chalicothere specimen yet collected from the John Day Basin. It also provides additional understanding of early Miocene Schizotheriinae (Perissodactyla, Chalicotheriidae) in western North America. Although Coombs et al. attributed all of the John Day chalicotheres to Moropus oregonensis, the new specimen resembles in size and morphology some of its early Hemingfordian contemporaries from the Runningwater Formation of the Great Plains and is referred to Moropus sp. Moropus sp. can thus be added to the oreodont Merycochoerus magnus, the amphicyonid Daphoenodon (Borocyon) robustum, the dromomerycid Barbouromeryx, the moschid Parablastomeryx schultzi, and the equid Parahippus pawniensis as John Day taxa with close relatives in the early Hemingfordian of the Great Plains. Further, the identification of the fragmentary chalicothere fossils from the John Day Formation is made more complex by the likely presence of more than one species there during the early Miocene.

Oregon State University Emu Bot (ATRIAS) Able to Handle 6 Inch Obstacles Without Vision Systems

The Equid Diets From Miocene Climatic Optimum Oregon

Dietary niche stability of equids across the mid-Miocene Climatic Optimum in Oregon, USA

Author:

Maguire

Abstract:

During the middle Miocene in North America, hypsodont equids became more diverse and more abundant than brachydont equids. This pattern is evident in middle Miocene deposits of Oregon in which the brachydont taxa became extinct while the hypsodont equids flourished. This turnover, associated with morphological tooth differences, is hypothesized to be a result of dietary differences between taxa, with hypsodont species exploiting the increasing grassland landscape and demise of the brachydont species a result of less vegetation suitable for browsers. Here this hypothesis is tested and the dietary niches of four equid genera are examined using stable carbon and oxygen isotopes. Dietary niche partitioning is evident based on δ13C and δ18O values and tooth morphology: Archaeohippus, a small brachydont equid, had a narrow dietary niche most likely consuming crown leaf vegetation in the clearings of a woodland habitat; Parahipppus and Desmatippus, medium sized brachydont to incipiently hypsodont equids, ate C3 vegetation in a relatively open environment; and aff. Acritohippus, a larger hypsodont equid, had a broad dietary niche eating C3 grasses in a relatively open environment. The dietary niches of these four genera did not change through time or across the mid-Miocene Climatic Optimum. Local extinction of the browsing genera, especially Archaeohippus with its narrow niche breadth, was most likely due to the opening of habitats as C3 grasses spread after the mid-Miocene Climatic Optimum. There is no evidence of C4 vegetation in the diet of aff. Acritohippus consistent with the idea that C4 grasses did not invade the Pacific Northwest during the middle Miocene, in contrast to other regions of North America during that time.

PaleoClimate Change Evidence From Early Eocene Paleogene to Miocene Neogene

Petrified wood of southwestern Oregon: Implications for Cenozoic climate change

Authors:

Ellis et al

Abstract:

Over 1,900 petrified wood specimens were collected from six localities spanning the Eocene to Miocene along a northeast transect parallel to the dip of the Payne Cliffs Formation and Western Cascades Group in southwestern Oregon. This study also presents new 40Ar/39Ar plateau age data for Cenozoic deposits in southern Oregon. Lower to Middle Eocene deposits yielded 305 specimens of petrified wood from sandstones and conglomerates of the basal part of the Payne Cliffs Formation with only 6% of dicotyledons exhibiting distinct growth rings and none having ring porous or semi-ring porous wood. Middle Eocene exposures just stratigraphically above the first locality produced 278 specimens from the lower to middle part of the Payne Cliffs Formation, with 66% of the dicotyledons exhibiting distinct growth rings. Two specimens of Palmoxylon were also collected from sediments at this locality. An Upper Eocene exposure produced 792 petrified wood specimens from volcaniclastic sediments with 88% of the dicotyledons exhibiting distinct growth rings. Sediments at this locality also produced one specimen of Cibotium oregonensis (Oregon tree fern) and several specimens of Palmoxylon. Middle Oligocene deposits yielded 218 petrified wood specimens from volcaniclastic sediments of the middle part of the Western Cascades Group with 97% of the dicotyledons exhibiting distinct growth rings. An Upper Oligocene exposure yielded 254 specimens from volcaniclastic sediments of the upper part of the Western Cascades Group with all dicotyledons exhibiting distinct growth rings and 59% having ring porous or semi-ring porous wood. Further, this study establishes a 40Ar/39Ar plateau age date of 24.09 ± 0.24 Ma from plagioclase crystals in a tuffaceous sandy to pebbly siltstone at this locality. Finally, Lower Miocene rocks yielded 101 specimens, including 20 dicotyledons, of which 70% were ring porous or semi-ring porous, with most specimens consisting of gymnosperms. The increase over time in the percentages of dicotyledon specimens with distinct growth rings and with ring porous and semi-ring porous wood from this study suggests an overall climatic shift from tropical (Early Eocene) to cool temperate (Early Miocene) in southwestern Oregon. These results are consistent with a similar climatic shift evidenced by paleoecological reconstructions for the Eocene to Miocene of the John Day Fossil Beds in central Oregon.

Paisley Caves Show Prehistoric America Diversity

A new study of Oregon's Paisley Caves confirms that humans used the site as early as 12,450 radiocarbon years ago, and the projectile points they left behind were of the "Western Stemmed" tradition and not Clovis – which suggests parallel technological development of early inhabitants to the Americas.

The study, published this week in the journal Science, could have a major impact on theories of how the Western Hemisphere was populated. The research was funded by multiple organizations, including the National Science Foundation.

Lead author Dennis Jenkins, from the University of Oregon, and second author Loren Davis, from Oregon State University, were part of a large multidisciplinary team that spent much of the past two years combing through deposits and collecting more than 100 high-precision radiocarbon dates from Paisley Caves, located in south-central Oregon's Summer Lake basin.

What cemented the authors' findings was a thorough examination of the stratigraphy in the caves, which confirmed that coprolites containing human DNA were definitely associated with layers of sediment ranging in age from 2,295 to 12,450 years ago – and were not contaminated by humans or animals at later dates. The researchers last year also found additional Western Stemmed projectile points.

"The Western Stemmed and Clovis traditions include different technological strategies," said Davis, an associate professor of anthropology in OSU's School of Language, Culture and Society. "The Western Stemmed artifacts from Paisley Caves are at least as old – and may predate – the oldest confirmed Clovis sites, indicating that the peopling of the Americas was at least technologically divergent, if not genetically divergent."

The projectile points were found in deposits dating back to 11,070 to 11,340 radiocarbon years ago, and thus were not quite as old as the oldest coprolites. But DNA from coprolites of that era was similar to that found in the oldest coprolites, Davis pointed out. "They were from the same genetic group," he said.

The difference in technology between Clovis and Western Stemmed projectile points revolves around how they were attached to spears, which relates to the strategy of finding and shaping pieces of rock in the first place. Clovis artifacts have a distinct notch at the base, where a piece has been removed. The tool builder starts with a large rock and reduces it considerably.

Western Stemmed points and Clovis points primarily differ in the construction of their hafting portions, Davis said. Stemmed points bear constricted bases, while the hafting element of a Clovis point is thinned through the removal of a large flake from the base. Western Stemmed points are also often made by modifying smaller flakes in a different way than Clovis peoples manufactured their spear points.

"These two approaches to making projectile points were really quite different," Davis said, "and the fact that Western Stemmed point-makers fully overlap, or even pre-date Clovis point makers likely means that Clovis peoples were not the sole founding population of the Americas."

Clovis technology has only been found in the New World, while Western Stemmed technology can be related to archaeological patterns seen in northeastern Asia.

"We seem to have two different traditions co-existing in the United States that did not blend for a period of hundreds of years," said the University of Oregon's Jenkins.

Past studies of Paisley Caves also have reported on human coprolites with ancient DNA, but questions arose about whether those samples could have been contaminated, and whether they were found in context with artifacts from the same era. So the researchers did an exhaustive examination of the stratigraphy, which is one of Davis' specialties.

Davis conducted microscopic analysis of the soil structure using a petrographic microscope to eliminate signs of liquid – such as water or urine from humans or animals – moving downward through the soil. The team also carefully analyzed the silt lens where the stem points were found and bracketed above and below those layers to see if radiocarbon dates synchronized.

"The stemmed points were in great context," Davis said. "There is no doubt that they were in primary context, associated with excellent radiocarbon dates."

The earliest models for peopling of the Americas suggest that the first inhabitants arrived from Asia via a land bridge at the end of the last Ice Age and fanned out across the continent. However, those models can't explain the presence of two separate and distinct stone tool technologies at the end of the last glacial period.

"Given these recent results from Paisley Caves, it's clear that we need to come up with some better models," Davis said.

There are several releases about this.  When added to the news about the genetics side, things are...interesting.