New whip scorpion species discovered in Amazon


Mating march in Surazomus whip scorpion. Male dragging locked female by the flagellum (note female chelicerae in vertical position). Credit: Ruiz et al, 2019  Read more at: https://phys.org/news/2019-03-short-tailed-scorpion-species-amazon.html#jCp

From PLOS:

New short-tailed whip scorpion species discovered in Amazon

Mating habits provide new insight into the ‘mating march’

March 20, 2019

A new species of Surazomus, which belongs to the class Arachnida and the order Schizomida, has been discovered in the eastern Amazon, according to a study published March 20 in the open-access journal PLOS ONE by Gustavo Ruiz and Roberta Valente of the Universidade Federal do Pará in Brazil.

Schizomids are rare, small arachnids that are found in humid tropical and subtropical forests, mainly in leaf litter, caves, tree bark or under stones. They are all known as short-tailed whip scorpions due to the presence of a short flagellum — a lash-like appendage — in males and females. The flagellum of the male is held by the female’s chelicerae — appendages in front of the mouth — during copulation in what is known as the mating march. But relatively little is known about the different shapes of male flagellum within Surazomus in terms of evolution, or the mechanism by which the female chelicerae anchor onto the male flagellum.

The authors named this new species, collected in the eastern Amazon, Surazomus saturninoae after arachnologist Dr Regiane Saturnino, who collected the specimen on which the species description is based. S. saturninoae is less than 5mm long and the male of the species has a distinctive pentagonal flagellum, similar to those of three other species in the genus. The existence and placement of two coupling pockets on the male flagellum offers insight into the position of a couple in the mating march, in particular, how the female chelicerae anchor onto the male flagellum. According to the authors, the findings shed new light on the poorly understood mating march and evolutionary changes that may have occurred in the male flagellum within the Surazomus genus.

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American blackpoll warblers, their long migration


This April 2015 video from the USA says about itself:

Amazing Migration: Blackpoll Warbler

New technology is allowing researchers to track the incredible 1,700-mile non-stop migration of Blackpoll Warblers over the Atlantic Ocean from their home in the Adirondacks and Eastern Canada to South America.

From the University of Guelph in Canada:

Tiny song bird makes record migration

March 19, 2019

Summary: The bird’s trek between its breeding grounds in the central and western boreal forest of North America and its winter home in the Amazon Basin is one of the longest songbird migrations recorded. Describing a route arcing across North America and including a transoceanic flight to South America, the study confirms an epic migration journey that scientists had long suspected but not yet proved. Tracking their route is key to solving the birds’ decline.

It’s an epic journey for a tiny bird.

For the first time, University of Guelph biologists have tracked an annual migration of up to 20,000 kilometres made by the 12-gram blackpoll warbler, one of the fastest declining songbirds in North America.

The bird’s trek between its breeding grounds in the central and western boreal forest of North America and its winter home in the Amazon Basin — one of the longest songbird migrations recorded — is the topic of a new paper by a research team headed by U of G biologist Ryan Norris.

The paper was published today in the journal Ecology.

Describing a “great circle route” arcing across North America and including a transoceanic flight to South America, the study confirms an epic migration journey that scientists had long suspected but not yet proved.

In 2015, Norris and other biologists were the first to show that blackpolls breeding in the Maritimes and New England complete a non-stop transoceanic flight of up to three days and about 2,700 km along the eastern coast of the United States.

For this new study, they looked at the full migration of birds from central and western breeding populations.

“It’s amazing,” said Norris, who worked on the study with Hilary Cooke, associate conservation scientist with Wildlife Conservation Society Canada. “A bird weighing a couple of loonies travels from the western edge of North America all the way to the Amazon basin — and, in between, traverses the Atlantic Ocean.”

Other co-authors were integrative biology professor Amy Newman and U of G grad students Bradley Woodworth, Nikole Freeman and Alex Sutton, as well as researchers from other universities, conservation groups and national parks in Canada, the U.S. and Australia.

For the study, researchers tracked birds outfitted with tiny geolocators from four boreal forest sites across northern Canada and Alaska.

Total southward migration took about 60 days on average over distances ranging from 6,900 km for birds breeding in Churchill, Manitoba, to 10,700 km for populations on the western edge of the continent in Nome, Alaska.

Blackpolls from Nome took 18 days to fly across North America to the Atlantic coast of the Carolinas. There, the birds spent almost a month fattening up to double their body weight before a non-stop, 2 ½-day flight across open water to overwintering grounds in northern Colombia, Venezuela and Brazil.

They covered between 2,250 and 3,400 km for that transoceanic hop.

Norris said scientists had long believed that blackpolls followed the great circle route. Few of the birds have ever been found in the central or western States during fall migration.

He said population numbers have fallen in recent years, perhaps caused by habitat loss and declines in insect prey related to climate change.

“To understand what’s causing the decline, we need to know their full annual cycle,” he said.

In their paper, the researchers say climate change may make extreme coastal weather events more frequent and more extreme, with unknown impacts on long-distance migratory birds.

“As a conservation scientist, what strikes me most is that in a single year a blackpoll warbler has to navigate 20,000 kilometres across land and ocean, facing risks of cat predation, storms and collisions with buildings and vehicles, all while trying to find islands of habitat to rest and refuel in our human-dominated landscapes,”said Cooke. “In comparison, the boreal region of northern Canada provides safe and high-quality breeding habitat for this declining species. Protecting Canada’s boreal forest is critical to saving this amazing songbird.”

Norris is now working with biologists in Colombia looking at the overwintering portion of the warblers’ life cycle. He said learning whether populations from across the boreal forest overwinter separately or together in South American rainforests may help improve habitat management along the migration route.

Extinct Miocene giant animals of the Amazon


This 2017 video is called National Geographic Documentary – Secrets in the Amazon Rainforest – Wild Amazon.

From the Fundação de Amparo à Pesquisa do Estado de São Paulo in Brazil:

Giant animals lived in Amazonian mega-wetland

Lake systems existing in regions over 10 million years ago survived the Amazon River reversal due to Andean uplift

February 25, 2019

A land of giants. This is the best definition for Lake Pebas, a mega-wetland that existed in western Amazonia during the Miocene Epoch, which lasted from 23 million to 5.3 million years ago.

The Pebas Formation was the home of the largest caiman and gavialoid crocodilian ever identified, both of which were over ten meters in length, the largest turtle, whose carapace had a diameter of 3.5 meters, and rodents that were as large as present-day buffaloes.

Remains of the ancient biome are scattered over an area of more than 1 million square meters in what is now Bolivia, Acre State and western Amazonas State in Brazil, Peru, Colombia and Venezuela. The oldest datings in this biome are for fossils found in Venezuela and show that Lake Pebas existed 18 million years ago.

Until recently, scientists believed that the mega-swamp dried up more than 10 million years ago, before the Amazon River reversed course. During most of the Miocene, this river flowed from east to west, opposite to its present direction. The giant animals disappeared when the waters of Pebas receded.

While investigating sediments associated with vertebrate fossils from two paleontological sites on the Acre and Purus Rivers, Marcos César Bissaro Júnior, a biologist affiliated with the University of São Paulo’s Ribeirão Preto School of Philosophy, Science and Letters (FFCLRP-USP) in Brazil, obtained datings of 8.5 million years with a margin of error of plus or minus 500,000 million years.

There is evidence that the Amazon was already running in its present direction 8.5 million years ago, draining from the Peruvian Andes into the Atlantic Ocean. By then, the Pebas system must have no longer resembled the magnificent wetlands of old. Rather, the system resembled a floodplain similar to the present-day Brazilian Pantanal. This is the view of Annie Schmaltz Hsiou, a professor in the Biology Department at FFCLRP-USP and supervisor of Bissaro Júnior’s research, which is described in a recently published article in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

The study was supported by São Paulo Research Foundation -FAPESP and Brazil’s National Council for Scientific and Technological Development (CNPq). The participants also included researchers from the Federal University of Santa Maria (UFSM), the Zoobotanic Foundation’s Natural Science Museum in Rio Grande do Sul, São Paulo State University (UNESP), the Federal University of Acre, and Boise State University in Idaho (USA).

The Pebas system encompasses several geological formations in western Amazonia: the Pebas and Fitzcarrald Formations in Peru and Brazil, the Solimões Formation in Brazil, the Urumaco and Socorro Formations in Venezuela, the La Venta Formation in Colombia, and the Quebrada Honda Formation in Bolivia.

“While the Solimões Formation is one of the best-sampled Neogene fossil-bearing stratigraphic units of northern South America, assumptions regarding deposition age in Brazil have been based largely on indirect methods,” Bissaro Júnior said.

“The absence of absolute ages hampers more refined interpretations on the paleoenvironments and paleoecology of the faunistic associations found there and does not allow us to answer some key questions, such as whether these beds were deposited after, during or before the formation of the proto-Amazon River.”

To answer these and other questions, Bissaro Júnior’s study presents the first geochronology of the Solimões Formation, based on mineral zircon specimens collected at two of the region’s best-sampled paleontological sites: Niterói on the Acre River in the municipality of Senador Guiomar and Talismã on the Purus River in the municipality of Manuel Urbano.

Since the 1980s, many Miocene fossils have been found at the Niterói site, including crocodilians, fishes, rodents, turtles, birds, and xenarthran mammals (extinct terrestrial sloths). Miocene fossils of crocodilians, snakes, rodents, primates, sloths, and extinct South American ungulates (litopterns) have been found in the same period at the Talismã site.

As a result of the datings, Bissaro Júnior discovered that the rocks at the Niterói and Talismã sites are approximately 8.5 million and 10.9 million years old (maximum depositional age), respectively.

“Based on both faunal dissimilarities and maximum depositional age differences between the two localities, we suggest that Talismã is older than Niterói. However, we stress the need for further zircon dating to test this hypothesis, as well as datings for other localities in the Solimões Formation,” he said.

Drying up of Pebas

Lake Pebas was formed when the land rose in the proto-Amazon basin as a result of the Andean uplift, which began accelerating 20 million years ago. At that time, western Amazonia was bathed by the Amazon (which then flowed toward the Caribbean) and the Magdalena in Colombia. The Andes uplift that occurred in what is now Peru and Colombia eventually interrupted the flow of water toward the Pacific, causing water to pool in western Amazonia and giving rise to the mega-wetland.

However, the Andes continued to rise. The continuous uplifting of land in Amazonia had two effects. The proto-Amazon, previously pent up in Lake Pebas, reversed course and became the majestic river we now know. During this process, water gradually drained out of the Pebas mega-swamp.

The swamp became a floodplain full of huge animals, which still existed 8.5 million years ago, according to new datings by Bissaro Júnior. Unstoppable geological forces eventually drained the remains of the temporary lagoons and lakes in western Amazonia. This was the end of Pebas and its fauna.

“The problem with dating Pebas has always been associating datings directly with the vertebrate fauna. There are countless datings of rocks in which invertebrate fossils have been found, but dating rocks with vertebrates in Brazil was one of our goals,” Schmaltz Hsiou said.

The new datings, she added, suggest that the Pebas system — i.e., the vast wetland — existed between 23 million and 10 million years ago. The Pebas system gave way to the Acre system, an immense floodplain that existed between 10 million and 7 million years ago, where reptiles such as Purussaurus and Mourasuchus still lived.

“The Acre system must have been a similar biome to what was then Venezuela, consisting of lagoons surrounding the delta of a great river, the proto-Orinoco,” she said.

Giant rodents

Rodents are a highly diversified group of mammals that inhabit all continents except for Antarctica. Amazonia is home to a large number of rodent species.

“In particular, a rodent group known scientifically as Caviomorpha came to our continent about 41 million years ago from Africa,” said Leonardo Kerber, a researcher at UFSM’s Quarta Colônia Paleontological Research Support Center (CAPPA) and a coauthor of the article published in Palaeogeography, Palaeoclimatology, Palaeoecology.

“In this period, known as the Eocene Epoch, Africa and South America were already totally separated, with at least 1,000 kilometers between the closest points of the two continents, so there couldn’t have been any biogeographical connections enabling terrestrial vertebrates to migrate between the two land masses,” Kerber said. “However, the ocean currents drove dispersal by means of natural rafts of tree trunks and branches blown into rivers by storms and swept out to sea. Some of these rafts would have borne away small vertebrates. An event of this kind may have enabled small mammals such as Platyrrhini monkeys, as well as small rodents, to cross the ocean, giving rise to one of the most emblematic groups of South American mammals, the caviomorph rodents.”

According to Kerber, the continent’s caviomorph rodents have undergone a long period of evolution since their arrival, becoming highly diversified as a result. In Brazil, the group is currently represented by the paca, agouti, guinea pig, porcupine and bristly mouse, as well as by the capybara, the world’s largest rodent.

“In Amazonia, above all, we now find a great diversity of bristly mice, porcupines, agoutis and pacas. In the Miocene, however, the Amazonian fauna was very different from what we can observe now,” Kerber said.

“In recent years, in addition to reporting the presence of many fossils of species already known to science, some of which had previously been recorded in the Solimões Formation and others that were known from other parts of South America but recorded in Solimões for the first time, we’ve described three new medium-sized rodent species (Potamarchus adamiae, Pseudopotamarchus villanuevai and Ferigolomys pacarana — Dinomyidae) that are related to the pacarana (Dinomys branickii).”

Kerber said an article to be published shortly in the Journal of Vertebrate Paleontology will recognize Neoepiblema acreensis, an endemic Brazilian Miocene neoepiblemid rodent that weighed some 120 kg as a valid species.

“The species was described in 1990 but was considered invalid at the end of the decade. These fossil records of both known and new species help us understand how life evolved in the region and how its biodiversity developed and experienced extinctions over millions of years in the past,” Kerber said.