South American bush dogs discovery in Costa Rica


This 2013 video is called bush dog, Speothos venaticus.

From the University of Massachusetts at Amherst in the USA:

Ecologists find bush dog, native of South America, in remote central Costa Rica

Trail cam documents unexpected, most northerly sighting of pack-hunting canids

May 23, 2019

Wildlife ecologists at the University of Massachusetts Amherst who are studying different conservation practices in the forests of Costa Rica recently made a startling discovery on a wildlife camera trap — wild bush dogs documented farther north than ever before and at the highest elevation.

Doctoral student Carolina Saenz-Bolaños is in Costa Rica comparing land use, management techniques, their effects on species presence and abundance, and human attitudes in four different areas in the rugged Talamanca Mountains: a national park, an adjacent forest reserve, an indigenous territory and nearby unprotected areas.

She and her advisor, professor of environmental conservation Todd Fuller at UMass Amherst, with others, report in an article today in Tropical Conservation Science the new, repeated sightings of bush dogs (Speothos venaticus) on trailcams well outside the limit of their previously known range on the Costa Rica-Panama border. The dogs are native to South America but are considered rare and are very seldom seen even there, the two ecologists point out.

Fuller says, “They aren’t supposed to be there, but Carolina’s work shows they really are, and they seem to be doing well. Not only is this wild dog rare wherever it is found, but this mountain range is very remote, with very little access. They could have been there before and we wouldn’t know it. So we’re documenting them with this report.”

Saenz-Bolaños says that because the roadless area is so huge, she and colleagues are not sure if the dogs are expanding their range, returning to a former range, or if they’ve been there all along but eluded detection. She works with Victor Montalvo, a fellow UMass Amherst doctoral student, and Eduardo Carrillo of the Universidad Nacional de Costa Rica and UMass Amherst adjunct professor of environmental conservation.

Once the dogs were spotted on camera, the researchers contacted Michael Mooring of San Diego’s Point Loma Nazarene University who, with Junior Porras of Costa Rica’s National System of Conservation Areas (SINAC), also had obtained new bush dog photos from southern Costa Rica.

Saenz-Bolaños, who has been operating trap cameras in the area since 2012, says, “I know most of the things that live here, so when I saw them on the camera I said ‘Wow, what is that — bush dogs here?’ I was very excited and thrilled to see them.” She adds, “The native people have a name for these dogs and their oral tradition says the dogs have been there in the past, but people living there now have never seen one.”

Bush dogs have been spotted north of the Panama Canal near the Costa Rica border in the past 10 years, she adds, but they are completely unexpected in the northern parts of the Talamanca Mountains.

Fuller says that bush dogs have lived in South America for thousands of years, and no one knows why they have not moved farther north into Central America, where the habitat is similar, but they are so rare that studying them is quite difficult. “There are still definitely interesting things to find out about them, especially if they’re expanding their range,” he says.

Curious about what it would take to collect more sightings of bush dogs in Costa Rica, he and Saenz-Bolaños worked with Paul Sievert of the U.S. Geological Survey and UMass Amherst to calculate how many camera-trap hours it might take to have even a 50-50 chance of seeing the animals again in an area of roughly 2,000 square miles (5,000 sq. km). Fuller says they estimate that it would require at least 25 camera traps set out for 100 nights, a difficult task in such remote, mountainous and tropical terrain.

The ecologists hope that their report will spark the imaginations of other wildlife ecologists, park managers and rangers in the region, who might set up their own camera traps in promising areas. Saenz-Bolaños plans to continue monitoring her study area and plans to try to talk to more local people about the dogs. Fuller adds, “At this point the mountain range looks like good bush dog habitat, but we just don’t know if they are getting started there or are already at home.”

The Stone Zoo in Stoneham, Mass., part of Zoo New England, has a family of bush dogs on exhibit where visitors can see these small wild dogs. The zoo participates in species survival planning for the bush dog to manage and conserve threatened or endangered animals.

Advertisements

Sea turtles in Costa Rica, video


This 23 May 2019 video says about itself:

Sea Turtles Nesting in Costa Rica – 360 | National Geographic

Several times a year, thousands of sea turtles make their way to this beach in Ostional Wildlife Refuge to lay their eggs.

Costa Rican frogs, new species discovery


A male Warszewitsch's frog in its natural habitat (El Valle de Antón, Panama). Credit: Dr Robert Puschendorf

From ScienceDaily:

The truth about a true frog: Unknown Costa Rican frog hidden amongst a widespread species

The discovery highlights the urgent need of modern DNA tools when studying rapidly declining animal groups like amphibians

April 11, 2019

Known to science since 1857, a common species of true frog (a “true frog” is one assigned to the family Ranidae), found from north-eastern Honduras, through Nicaragua and Costa Rica to central Panama, turns out to have been keeping its “multiple identities” a secret all along.

According to British and Costa Rican herpetologists, who recently used DNA barcoding to study the species in question, what we currently call Warszewitsch’s frog is in fact a group of “cryptic” species. The study, conducted in the Área de Conservación Guanacaste (ACG), Costa Rica, by James Cryer, Dr Robert Puschendorf, Dr Felicity Wynne from the University of Plymouth, and Dr Stephen Price, UCL, is published in the open-access journal ZooKeys.

In their paper, the authors suggest that the well-known Central American frog species, commonly known as the Warszewitsch’s frog, may in fact consist of multiple different “cryptic” species. This phenomenon is well documented among tropical amphibian fauna, where high levels of genetic variation within populations of a single species surpass levels found between different, classified species.

By utilizing a technique known as DNA barcoding, which compares short snippets of DNA sequences between individuals sampled, the scientists analysed specimens from three different geographic areas within Costa Rica and Panama. In this case, the researchers used sequences derived from mitochondria, the energy-producing “power houses” found in animal cells. Their results indicated there was enough genetic variation to suggest cryptic species are indeed present.

The team chose this particular species because cryptic species were previously identified at two Panamanian sites. Now, the samples from Costa Rica broaden the study area, suggesting that there could be multiple species going by the name Warszewitsch’s frog all across its known distribution.

Conservation biologist and lead author James Cryer says:

“The next step will be to gather more samples throughout the full range of the species. Additionally, if we are to fully discern one species variant from another, further studies that compare the physical, behavioural and ecological characteristics of the frogs, alongside more genetic testing is needed.”

Overall, findings like these are important to help improve our understanding of amphibian biodiversity and, thus, work towards its conservation.

“If indeed there are multiple species, it may be that they have different ecological requirements, and therefore different approaches to their conservation are needed.” Cryer says. “This study further reinforces the power of DNA barcoding for rapid, preliminary species identification. Especially in the tropics, where habitat loss, climate change and infectious disease continually threaten many undescribed amphibian species.”

Japanese scientists have identified the molecular mechanism that gives the skin secretions of a species of frog effective antimicrobial properties. Unraveling the molecular mechanism that facilitates antimicrobial activity of these peptides can help us better understand how the defense system of the frog has evolved, and how this can be used to fight microbial infections of medical importance: here.

Splendid leaf frog in Costa Rica, video


This 31 March 2019 video says about itself:

On this episode of Breaking Trail, the Brave Crew is in location in Costa Rica, and they FINALLY find a very special frog… the Splendid Leaf Frog! This is one RARE frog!

Get ready, you’re about to meet a rare frog that leaps back!

Breaking Trail leaves the map behind and follows adventurer and animal expert Coyote Peterson and his crew as they encounter a variety of wildlife in the most amazing environments on the planet!

Costa Rican singing mice, new study


This 2013 video says about itself:

Singing Mouse Serenades The Sky. Really.

Move over Celine Dion. Alston’s singing mouse (Scotinomys teguina) emits sopranino trills to mark its boundaries deep in mountain cloud forests. [The little vocalist even takes a bow.]

From the NYU Langone Health / NYU School of Medicine in the USA:

Study of singing mice suggests how mammalian brain achieves conversation

Research may lead to future solutions to speech problems

February 28, 2019

By studying the songs of mice from the cloud forests of Costa Rica, researchers have discovered a brain circuit that may enable the high-speed back and forth of conversation.

Males of the study species, Alston’s singing mouse (Scotinomys teguina), produce songs with nearly a hundred audible notes. They challenge competitors by singing in turns, alternating like talking humans, say the study authors. In contrast, standard laboratory mice produce ultrasonic sounds without evident exchanges.

Thus, the new study, led by researchers at NYU School of Medicine, launches a new field by employing a novel mammalian model to examine brain mechanisms behind the sub-second precision of vocal turn-taking.

“Our work directly demonstrates that a brain region called the motor cortex is needed for both these mice and for humans to vocally interact,” says senior study author Michael Long, PhD, an associate professor of neuroscience at NYU School of Medicine.

“We need to understand how our brains generate verbal replies instantly using nearly a hundred muscles if we are to design new treatments for the many Americans for whom this process has failed, often because of diseases such as autism or traumatic events, like stroke,” says Long.

Published online as the cover story of Science on March 1, the study found that, along with brain areas that tell muscles to create notes, separate circuits in the motor cortex enable the fast starts and stops that form a conversation between vocal partners.

“By segregating sound production and control circuits, evolution has equipped the brains of singing mice with the tight vocal control also seen in cricket exchanges, bird duets, and possibly, human discussion,” adds study co-first author Arkarup Banerjee, PhD, a post-doctoral scholar in Long’s lab.

Despite the ubiquity of vocal exchanges in the natural world, he says, there are no suitable mammalian models in neuroscience for their study. Before the new report, the leading model for studying this back-and-forth was the marmoset, a primate whose conversational turns are considerably slower than human speech, and unlikely to result from the fast muscle response to sensory cues (e.g. motor cortical circuitry).

Social Songs Different

The research team found that S. teguina songs — series of notes that evolve predictably as the song goes on — changed in social situations as the mice had to “bend and break the songs” to converse. The tight connection between song patterns and readings taken by electromyography, which captures electrical signals as the brain generates muscle contractions, enabled the team to determine the relationships between brain centers and song musculature while two mice coordinated their responses.

In contrast to the findings of past studies, the researchers found that a functional “hotspot” located at the front of the motor cortex to one side — the orofacial motor cortex or OMC — regulated song timing.

To study the contributions of these specialized brain circuits to social singing, the team interfered with cortical regions in the mice using a number of techniques, including devices that cooled the OMC during songs. Long has helped to pioneer the cooling technique in the study of human brain circuits related to speech.

Called focal cooling, it is a safe way to slow the pace of vocalizations without changing the pitch, tone, or duration of individual notes, say the study authors. They argue that the observed, functional separation in the brain between sound generation and timing functions, this hierarchy, is what makes socially relevant exchanges possible.

Moving forward, the researchers are already using their mouse model to guide related exploration of speech circuits in human brains. By understanding the activity that helps to engage two brains in conversation, they can look for the processes that go awry when disease interferes with communication, potentially spurring the development of new treatments for many disorders.

Along with Long, study authors from the NYU Neuroscience Institute and Department of Otolaryngology at NYU School of Medicine were co-first authors Arkarup Banerjee and Daniel Okobi Jr, as well as Andrew Matheson. The work was done in collaboration with Steven Phelps, PhD, director of the Center for Brain, Behavior and Evolution at the University of Texas at Austin, whose lab pioneered the study of the singing mouse in the lab and field. Some of the authors are also members of the Center for Neural Science at New York University.

This research was supported by the New York Stem Cell Foundation, the Simons Foundation Society of Fellows, and the Simons Collaboration on the Global Brain.

How hermit crabs get new shells


This 25 February 2019 video says about itself:

Hermit crabs are drawn to smell of flesh torn from their kin | Science News

Within three minutes on a beach at Osa Peninsula, Costa Rica, land hermit crabs (Coenobita compressus) crowd a tube containing flesh bits of their own kind. Researchers say the smell signals that an empty shell may be available for the taking.

By Yao-Hua Law, 8:00am, February 25, 2019:

Hermit crabs are drawn to the smell of their own dead

Competition for abandoned shells turns into a lively gathering

The death of a millionaire with no heir draws an opportunistic crowd. So, too, does the demise of a land-dwelling hermit crab. Researchers working in Costa Rica found that the curious crabs are drawn to the smell of flesh torn from one of their own.

Dartmouth College biologist Mark Laidre, along with undergraduate student Leah Valdes, set out 20 plastic tubes on a beach, each holding bits of hermit crab flesh. Within five minutes, almost 50 hermit crabs (Coenobita compressus) swarmed around each sample, the pair reports online February 10 in Ecology and Evolution. “It’s almost like they were celebrating a funeral,” Laidre says.

The reality, however, is more macabre. That scent of flesh is a signal that a fellow land hermit crab has been eaten, and that its empty shell is available for the taking, Laidre says. The crabs “are all in an incredible frenzy to try to move into that leftover shell.”

None of the roughly 850 known hermit crab species, most of which live in the sea and some on land, can grow their own shells. Instead, the crabs occupy shells originally left behind by dead snails. A hermit crab grows to the size of its shell, but to grow further, the creature must find and occupy a larger shell.

For the roughly 20 or so species of land hermit crabs, finding a suitable shell can be especially challenging. Big shells with lots of extra room to grow may be too heavy in the short term for a hermit crab to tote around on land without the buoyancy of water to help lighten the load, and lighter shells may be too small.

Land hermit crabs can remodel their shells, making them bigger, Laidre reported in 2012. The animals use corrosive secretions and scraping to widen a shell’s opening, remove the internal spiral and reduce wall thickness. Remodeling can double the available space while trimming one-third the weight. But remodeling is taxing and slow. It’s much faster to take over an already remodeled shell of another land hermit crab, alive or dead. Hence the strong attraction of land hermit crabs toward smells that suggest another is dead, Laidre says.

The researchers also found that land hermit crabs approached bits of snail flesh, though the scent appears to be far less alluring than that of their own species. Sea hermit crabs, however, didn’t find the smell of another hermit crab’s corpse more attractive than those of snails.

That makes sense to Laidre. For sea hermit crabs, upsizing to bigger and heavier shells is relatively easy, thanks to water’s buoyancy that helps the crabs support a shell that’s a little too big at first. That, combined with the fact that there are also many more empty shells in the sea than on land, means that sea hermit crabs face less competition when looking for a home, he says.

By highlighting that shell availability is limited for land hermit crabs, the study makes an important point for conservation, says ecologist Chia-Hsuan Hsu, who studies hermit crabs at National Taiwan University in Taipei and wasn’t involved in the research. “We can tell the public: ‘Don’t take shells from the beach’, ” he says.