Dancing red squirrel, video


This 20 February 2019 video shows a dancing red squirrel in the Netherlands.

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Dugong ancestor discovery in Panama


About 19-21 million years old, this dugong is the oldest marine mammal found in Central America and the first from the Pacific side of the Panama Canal. Here, the skull is seen from the side with the snout pointing to the right. Credit: Jeff Gage, Florida Museum

From the Florida Museum of Natural History in the USA:

20-million-year-old tusked sea cow is Central America’s oldest marine mammal

February 19, 2019

Summary: A researcher searching the shoreline of the Panama Canal for fossil plants instead found an ancient sea cow. An ’emergency fossil excavation’ due to rising water levels yielded a remarkably complete skeleton of a new genus and species of dugong, estimated to be about 20 million years old, the first evidence of a marine mammal from the Pacific side of the canal.

Steven Manchester didn’t set out to discover Central America’s oldest known marine mammal. He was hoping to find fossil plants.

Manchester, curator of paleobotany at the Florida Museum of Natural History, had left a group of vertebrate paleontologists uphill of the Panama Canal to do his own prospecting, clambering down onto the narrow, exposed shoreline to look for fossil leaves, petrified wood and mineralized fruits and nuts.

It was a dangerous place to be: The rolling wake from passing ships could sweep a person off shore and into the canal. Manchester noticed that people were occasionally shouting at him through megaphones as they cruised past, but not understanding Spanish, he continued to comb the shore when he spotted bone.

“He quickly walked us over to where he’d found a skeleton sticking out of the rock exposure,” said Aaron Wood, then a museum postdoctoral researcher leading fieldwork in Panama. “There were two or three vertebrae, orange-ish in color, dipping into the black rock on the side of the canal and a couple of ribs around them. We guessed that there would be more under the rock.”

What Wood described as an “emergency fossil excavation” due to rising water levels yielded a remarkably complete skeleton of an ancient sea cow, estimated to be about 20 million years old, the first evidence of a marine mammal from the Pacific side of the canal.

The fossil skull, vertebrae, ribs and other bones belong to a new genus and species, Culebratherium alemani, a tusked seagrass-grazing relative of modern dugongs, which live in the warm coastal waters of the Indo-Pacific.

Wood and lead author Jorge Velez-Juarbe, also a former museum postdoctoral researcher, published their findings in the Journal of Vertebrate Paleontology.

About 15 feet long, this C. alemani was not done growing, Velez-Juarbe said. Its tusks had only begun to protrude and its newest molars showed little wear, indicating it was not yet an adult.

But it was a powerful eater. The researchers propose that its thick neck muscles, tusks and downward-pointing snout were adaptations for digging pits in the ocean floor to get to the underground stems of seagrass, the plants’ most nutritional parts.

“Finding C. alemani is pretty good evidence that there was seagrass in this region 20 million years ago,” said Velez-Juarbe, now assistant curator of marine mammals at the Natural History Museum of Los Angeles County. “This particular group of sirenians” — the order that includes dugongs and manatees — “are seagrass specialists.”

While only one species of dugong is alive today — a second, Steller’s sea cow, was hunted to extinction within 27 years of its discovery — about 30 species have been recovered in the fossil record, Velez-Juarbe said. The group originated in the West Atlantic and Caribbean and dispersed westward through Panama, whose seaway did not close until a few million years ago, and south to Brazil.

“Today, Panama is the juncture between two continents, and that’s where we have a mixture of mammals between North and South America,” said Wood, now director of Iowa State University’s Carl F. Vondra Geology Field Station and a lecturer in the department of geological and atmospheric sciences. “In the early Miocene, when this dugong lived, it wasn’t a land connection but a sea connection between the Atlantic and Pacific. We would expect to see communities of sea cows there, too.”

Previous research shows that multiple species of dugongs commonly lived together, each with slightly differently shaped tusks, snouts and body sizes that would have enabled them to divide up food resources, Velez-Juarbe said.

“Some would eat larger species of seagrass buried deeply in the sand while others would feed on smaller grasses closer to the surface,” he said. “Evidence from many other places in the world shows that multispecies communities were the norm. To only have one species of dugong now is freaky.”

These communities also made for healthier seagrass beds, he said. Whereas a single seagrass species, Thalassia testudinum, dominates the Caribbean and West Atlantic, grass beds in Australia have a better balance of species because modern dugongs feed on the larger grass species, keeping them in check and giving smaller grasses a shot at flourishing.

The researchers named C. alemani after the Culebra Formation where it was found and Alberto Aleman Zubieta, the former chief executive officer of the Panama Canal, whose support they described as essential to the fieldwork’s success.

C. alemani was excavated as part of a large-scale, years-long project to salvage fossils during the expansion of the Panama Canal, which temporarily exposed fresh outcrops. Wood said that while he and the rest of the field crew understood the significance of their work, the discovery of the dugong “really brought that home”.

“We found the fossil dugong when water levels were at their lowest,” he said. “After the first day, they steadily rose. We put sandbags on the edge of the site just to keep water out long enough for us to collect it. Within a week, the site was flooded. We couldn’t go back. The idea that this was a once-in-a-century opportunity was wrapped up in this one specimen.”

The researchers began the work as postdoctoral fellows under the advisership of Jonathan Bloch and Bruce MacFadden, Florida Museum curators of vertebrate paleontology.

Marsupial lived among Alaskan dinosaurs


This 15 February 2019 video says about itself:

An animation of a fossilized jaw belonging to Unnuakomys hutchisoni, an ancient marsupial that lived in what is now the North Slope of Alaska.

From the University of Alaska Fairbanks:

Marsupial lived among Arctic dinosaurs

February 19, 2019

A research team has discovered a previously unknown species of marsupial that lived in Alaska’s Arctic during the era of dinosaurs, adding a vivid new detail to a complex ancient landscape.

The thumb-sized animal, named Unnuakomys hutchisoni, lived in the Arctic about 69 million years ago during the late Cretaceous Period. Its discovery, led by scientists from the University of Colorado and University of Alaska Fairbanks, is outlined in an article published in the Journal of Systematic Palaeontology.

The discovery adds to the picture of an environment that scientists say was surprisingly diverse. The tiny animal, which is the northernmost marsupial ever discovered, lived among a unique variety of dinosaurs, plants and other animals.

Alaska’s North Slope, which was at about 80 degrees north latitude when U. hutchisoni lived there, was once thought to be a barren environment during the late Cretaceous. That perception has gradually changed since dinosaurs were discovered along the Colville River in the 1980s, with new evidence showing the region was home to a diverse collection of unique species that didn’t exist anywhere else.

Finding a new marsupial species in the far north adds a new layer to that evolving view, said Patrick Druckenmiller, the director of the University of Alaska Museum of the North.

“Northern Alaska was not only inhabited by a wide variety of dinosaurs, but in fact we’re finding there were also new species of mammals that helped to fill out the ecology,” said Druckenmiller, who has studied dinosaurs in the region for more than a decade. “With every new species, we paint a new picture of this ancient polar landscape.”

Marsupials are a type of mammal that carries underdeveloped offspring in a pouch. Kangaroos and koalas are the best-known modern marsupials. Ancient relatives were much smaller during the late Cretaceous, Druckenmiller said. Unnuakomys hutchisoni was probably more like a tiny opossum, feeding on insects and plants while surviving in darkness for as many as four months each winter.

The research team, whose project was funded with a National Science Foundation grant, identified the new marsupial using a painstaking process. With the help of numerous graduate and undergraduate students, they collected, washed and screened ancient river sediment collected on the North Slope and then carefully inspected it under a microscope. Over many years, they were able to locate numerous fossilized teeth roughly the size of a grain of sand.

“I liken it to searching for proverbial needles in haystacks — more rocks than fossils,” said Florida State University paleobiologist Gregory Erickson, who contributed to the paper.

Jaelyn Eberle, curator of fossil vertebrates at the University of Colorado Museum of Natural History, led the effort to examine those teeth and a few tiny jawbones. Their analysis revealed a new species and genus of marsupial.

Mammal teeth have unique cusps that differ from species to species, making them a bit like fingerprints for long-dead organisms, said Eberle, the lead author of the study.

“If I were to go down to the Denver Zoo and crank open the mouth of a lion and look in — which I don’t recommend — I could tell you its genus and probably its species based only on its cheek teeth,” Eberle said.

The name Unnuakomys hutchisoni combines the Iñupiaq word for “night” and the Greek word “mys” for mouse, a reference to the dark winters the animal endured, and a tribute to J. Howard Hutchison, a paleontologist who discovered the fossil-rich site where its teeth were eventually found.

Other co-authors of the Journal of Systematic Palaeontology paper include William Clemens, of the University of California, Berkeley; Paul McCarthy, of UAF; and Anthony Fiorillo, of the Perot Museum of Nature and Science.

Red fox in Quebec, Canada winter


This December 2018 video says about itself:

Red fox showing snow-dive hunting technique in the wild

The footage shows a red fox hunting in the snow in the most southern part of the province of Quebec in Canada. … In a ”spur of the moment” display of opportunistic hunting, the fox catches a prey at mark 2:53.