16-million-year-old fossil shows springtails hitchhiking on winged termite

By: Thomas Schmitt Attorney on November 25, 2019 / comment : 0 Dominican Republic, Fossils, Palaeontology

When trying to better the odds for survival, a major dilemma that many animals face is dispersal -- being able to pick up and leave to occupy new lands, find fresh resources and mates, and avoid intraspecies competition in times of overpopulation.

Distribution of springtails on termite and ant hosts within ~ 16 Ma old Dominican amber [Credit: N. Robin, C. D'Haese and P. Barden]

For birds, butterflies and other winged creatures, covering long distances may be as easy as the breeze they travel on. But for soil-dwellers of the crawling variety, the hurdle remains: How do they reach new, far-off habitats?

For one group of tiny arthropods called springtails (Collembola), a recent fossil discovery now suggests their answer to this question has been to piggyback on the dispersal abilities of others, literally.

In findings published in BMC Evolutionary Biology, researchers at the New Jersey Institute of Technology (NJIT) and Museum national d'Histoire naturelle have detailed the discovery of an ancient interaction preserved in 16-million-year-old amber from the Dominican Republic: 25 springtails attached to, and nearby, a large winged termite and ant from the days of the early Miocene.

The fossil exhibits a number of springtails still attached to the wings and legs of their hosts, while others are preserved as if gradually floating away from their hosts within the amber. Researchers say the discovery highlights the existence of a new type of hitchhiking behavior among wingless soil-dwelling arthropods, and could be key to explaining how symphypleonan springtails successfully achieved dispersal worldwide.

Distribution of springtails on termite and ant hosts within ~ 16 Ma old Dominican amber, and illustration of location of springtails on social insects [Credit: N. Robin, C. D’Haese and P. Barden]

"The existence of this hitchhiking behavior is especially exciting given the fact that modern springtails are rarely described as having any interspecfic association with surrounding animals," said Ninon Robin, the paper's first author whose postdoctoral research at NJIT's Department of Biological Sciences was funded by the Fulbright Program of the French-American Commission. "This finding underscores how important fossils are for telling us about unsuspected ancient ecologies as well as still ongoing behaviors that were so far simply overlooked."

Today, springtails are among the most common arthropods found in moist habitats around the world. Most springtails possess a specialized appendage under their abdomen they use to "spring" away in flee-like fashion to avoid predation. However this organ is not sufficient for traversing long distances, especially since most springtails are unable to survive long in dry areas.

The hitchhikers the researchers identified belong to a lineage of springtails found today on every continent, known as Symphypleona,which they say may have been "pre-adapted" to grasping on to other arthropods through prehensile antennae.

Because springtails would have encountered such winged termites and ants frequently due to their high abundance during the time of the preservation, these social insects may have been their preferred hosts for transportation.

Allacma fusca is a species belonging to one of the three main groups of springtails today known as Symphypleona [Credit: Urmas Tartes/Wikipedia]

"Symphypleonan springtails are unusual compared to other Collembola in that they have specialized antennae that are used in mating courtship," said Phillip Barden, assistant professor of biology at NJIT and the study's principal investigator. "This antennal anatomy may have provided an evolutionary pathway for grasping onto other arthropods. In this particular fossil, we see these specialized antennae wrapping around the wings and legs of both an ant and termite. Some winged ants and termites are known to travel significant distances, which would greatly aid in dispersal."

Barden says that the discovery joins other reports from the Caribbean and Europe of fossil springtails attached to a beetle, a mayfly and a harvestman in amber, which together suggest that this behavior may still exist today.

Barden notes that evidence of springtail hitchhiking may not have been captured in such high numbers until now due to the rarity of such a fossilized interaction, as well as the nature of modern sampling methods for insects, which typically involves submersion in ethanol for preservation.

"Because it appears that springtails reflexively detach from their hosts when in danger, evidenced by the detached individuals in the amber, ethanol would effectively erase the link between hitchhiker and host," said Barden. "Amber derives from fossilized sticky tree resin and is viscous enough that it would retain the interaction. ... Meaning, sometimes you have to turn to 16-million-year-old amber fossils to find out what might be happening in your backyard."

Author: Jesse Jenkins | Source: New Jersey Institute of Technology [November 25, 2019]

Skull dimensions of Dominicans and Haitians differ despite close physical proximity

By: Thomas Schmitt Attorney on October 31, 2019 / comment : 0 Anthropology, Caribbean islands, Dominican Republic, Forensics, Haiti

Forensic anthropologists analyze skeletal remains to establish the biological profile (sex, age, ancestry and stature). While ancestry is an important component, most research has focused on identifying individuals of African-American and European-American descent.

Linear Measurements used according to craniometric points [Credit: Cordeiro et al. 2015]

Now for the first time, researchers from Boston University School of Medicine (BUSM) have conducted a craniometric study (measuring the main part of the skull) on understudied and marginalized groups and found that skull dimensions of Dominicans and Haitians, who occupy a relatively small island of Hispaniola, are different from each other.

According to the researchers, while skeletal and genetic studies show that Caribbean groups are incredibly diverse, they are often lumped together under the broad ancestral category of "Hispanic," along with many other Latin American groups.

Using standard anthropometric craniometric measurements (28 measurements) of both Dominicans and Haitians from computerized tomography (CT) scans from a major hospital in Santo Domingo, the researchers analyzed the measurements to determine similarities and differences.

"Our study demonstrates that, despite sharing a small island, Dominican and Haitian individuals can be differentiated with a fair amount of statistical certainty, which is possible due to complex population histories that have kept them separate despite their geographically close proximity," explained corresponding author Michelle Herrera, a graduate student in the MS Program in Forensic Anthropology at BUSM.

The authors believe it is important to conduct research on groups that are not represented in the typically researched skeletal collections. "Ultimately, this research can aid forensic specialists in identifying missing persons on the island of Hispaniola," added Herrera.

The findings are published in Forensic Science International.

Source: Boston University School of Medicine [October 31, 2019]

Meet the 'mold pigs,' a new group of invertebrates from 30 million years ago

By: Thomas Schmitt Attorney on October 08, 2019 / comment : 0 Dominican Republic, Fossils, Palaeontology

Fossils preserved in Dominican amber reveal a new family, genus and species of microinvertebrate from the mid-Tertiary period, a discovery that shows unique lineages of the tiny creatures were living 30 million years ago.

Fossils preserved in Dominican amber reveal a new family, genus and species of microinvertebrate from the mid-Tertiary period, a discovery that shows unique lineages of the tiny creatures were living 30 million years ago [Credit: Provided by George Poinar Jr.]

The findings by George Poinar Jr. of the Oregon State University College of Science give a rare look at a heretofore unknown clade of invertebrates, along with their fungal food source and other animals that lived in their habitat.

Poinar, an international expert in using plant and animal life forms preserved in amber to learn more about the biology and ecology of the distant past, informally calls the new animals "mold pigs" for their resemblance to swine, and their diet. Scientifically, they are Sialomorpha dominicana, from the Greek words for fat hog (sialos) and shape (morphe).

Invertebrate means not having a backbone, and invertebrates account for roughly 95 percent of animal species.

"Every now and then we'll find small, fragile, previously unknown fossil invertebrates in specialized habitats," Poinar said. "And occasionally, as in the present case, a fragment of the original habitat from millions of years ago is preserved too. The mold pigs can't be placed in any group of currently existing invertebrates - they share characteristics with both tardigrades, sometimes referred to as water bears or moss pigs, and mites but clearly belong to neither group."

The several hundred individual fossils preserved in the amber shared warm, moist surroundings with pseudoscorpions, nematodes, fungi and protozoa, Poinar said.

"The large number of fossils provided additional evidence of their biology, including reproductive behavior, developmental stages and food," he said. "There is no extant group that these fossils fit into, and we have no knowledge of any of their descendants living today. This discovery shows that unique lineages were surviving in the mid-Tertiary."

The Tertiary period began 65 million years ago and lasted for more than 63 million years.

About 100 micrometers long, the mold pigs had flexible heads and four pairs of legs. They grew by molting their exoskeleton and fed mainly on fungi, supplementing that food source with small invertebrates.

"No claws are present at the end of their legs as they are with tardigrades and mites," Poinar said. "Based on what we know about extant and extinct microinvertebrates, S. dominicana appears to represent a new phylum. The structure and developmental patterns of these fossils illustrate a time period when certain traits appeared among these types of animals. But we don't know when the Sialomorpha lineage originated, how long it lasted, or whether there are descendants living today."

The findings were published in Invertebrate Biology.

Author: Steve Lundeberg | Source: Oregon State University [October 08, 2019]

Daily grind: The biography of a stone axe

By: Thomas Schmitt Attorney on April 18, 2019 / comment : 0 Archaeology, Caribbean islands, Dominican Republic

Tom Breukel analysed some 250 stone axes from the Caribbean and reconstructed their biographies, thus increasing our knowledge of production and trade in the period around the arrival of Columbus. His Ph.D. defence is on 18 April.

Credit: Tom Breukel

Breukel researched how the stone axes – a collective term in archaeology that also includes adzes and chisels – were produced, traded, and used in the Dominican Republic and the Windward Islands between 1200 and 1600. Previous research had already shown that there was intensive barter between the islands in that region: some axes 'travelled' as far as 1000 km to their final destination.

Breukel studied the axes and discovered that many were only partly finished before they were transported. He found unusual semi-finished products among the traded goods. "The buyers probably wanted to finish the stone axes themselves," he says. "This may have helped them develop a close relationship with the object. Even today, the users in some indigenous communities in the Amazon have a personal relationship with an object, and that's not as easy if you order a ready-made axe."

Credit: Tom Breukel

In addition, Breukel concluded that the majority of the axes were actually used for the purpose for which they were made. He only found one that had never been used and thus may have primarily served ceremonial purposes. "Sometimes you find beautiful jade stones that have been polished until you can see your reflection in them. Then it's tempting to think that the stone was only used as a talisman or pendant, but if you look closely, you nearly always find traces of wear."

Breukel made his discoveries under a microscope. He studied the 250 stone axes by looking, one millimetre at a time, for wear traces and information about the type of stone and production method. This resulted in a biography for each individual object. "Each time the object is usedm traces are left behind that archaeologists can find later, even on a cup as you stir your tea," he says as he holds a greenish axe. "You can read from the grooves in the stone or the residue left behind whether the tool has been used to grind, polish or hack."

Credit: Tom Breukel

Another aspect of Breukel's research was an experiment that involved reproducing how axes were used. He worked with fellow archaeologists and the local community to build a stone age house on Saint Vincent, using only stone tools. This allowed him to compare the traces on the experimental axe with traces on real stone age axes. "I spent two whole weeks hacking at posts with my stone axe – in the sun at least."

Author: Merijn Van Nuland | Source: Leiden University [April 18, 2019]

Elevation matters when it comes to climate change, deforestation and species survival

By: Thomas Schmitt Attorney on February 25, 2019 / comment : 0 Climate Change, Dominican Republic, Ecosystems, Natural Heritage, Wildlife

University of Toronto student George Sandler was shocked to see the rainforest floor suddenly come to life around him, as if in a scene from an Indiana Jones movie.

This is an Anolis olssoni lizard [Credit: Luke Mahler]

"The forest floor started rustling around me," says Sandler, "as dozens of crabs emerged from holes and crevices. Some were huge, the size of dinner plates. I even spotted a hermit crab climbing up a tree, lugging its heavy shell along with it."

But Sandler wasn't in the field to study crabs. He was in the Dominican Republic to take a census of the region's Anolis lizard species for a study on the effects of deforestation being conducted by researchers Luke Mahler, Luke Frishkoff and collaborators. In the Caribbean nation, deforestation is the main form of natural habitat loss as residents cut down rainforest in order to produce charcoal, as well as create pastures for livestock and farmland for crops.

It is no surprise that deforestation has a profound effect on biodiversity; scientists have been studying this problem around the globe for decades. What is surprising is the difficulty they still face in making detailed predictions about which species survive, especially in relation to other factors such as climate change and natural local conditions.

Now, using the data collected in the census, the research team has discovered details about how Anolis lizards are being affected by the loss of their habitat.

"When it comes to predicting the effects of deforestation," says Mahler, "elevation matters."

Mahler is an assistant professor in the Department of Ecology & Evolutionary Biology (EEB) in the Faculty of Arts & Science at the University of Toronto. Frishkoff led the research while he was a postdoctoral fellow in Mahler's lab at U of T and is lead author of the paper describing their findings, published in Nature Ecology & Evolution; he is currently an assistant professor at the University of Texas at Arlington. Sandler and researchers from the National Museum of Natural History in Santo Domingo were also co-authors.

Mahler and Frishkoff analyzed populations of lizards in both lowland and highland regions affected by deforestation. Generally, the lowlands are warmer than the highlands due to altitude; also, forest canopy blocks direct sunlight, making forests at any altitude cooler than their immediate surroundings.

"It turns out that deforestation changes lizard communities in fundamentally different ways in the lowlands as compared to the highlands," says Mahler. "In the lowlands, deforestation reduces the number of individuals, but not which species occur in an area. In the highlands, it's the opposite."

"When the forest is cut down at higher elevations," says Frishkoff, "the newly created high elevation pastures become filled with species we saw down in the warmer lowlands. But, the locally adapted mountain lizards cannot survive."

The invasion into the highlands by lowland-dwelling lizards was made possible by a combination of human activity and natural factors; i.e. deforestation and elevation respectively. Thanks to the altitude, the temperature of deforested fields in the highlands was comparable to the temperature of forested lowlands.

As it is in many regions around the world, the problem of deforestation in the Dominican Republic is dire. In 2016, Mahler announced the discovery of a previously unknown chameleon-like Anolis lizard on the island of Hispaniola. In the paper describing the discovery, Mahler and his co-authors recommended that the new species, dubbed Anolis landestoyi, be immediately classified as critically endangered because the lizard was threatened by illegal clear-cutting in the region.

Unlike the crabs that crowded around Sandler in the rainforest, the lizards were more elusive and difficult to survey. In order to obtain accurate counts, the students employed a technique known as mark-resight.

"We hiked out to our designated plots," says Sandler, who was an undergraduate student while conducting the field work and is currently an EEB graduate student at U of T. "Then we walked around looking for lizards. We carried a paint spray gun filled with a non-toxic, water soluble paint--a different colour for each of the six observation periods. If we saw a lizard we would note the species, if it had any paint on it already, and the colour of the paint. Then we would spray the lizard with the paint gun we were carrying, a task that was a little tricky with some of the more skittish species!"

Paint on a lizard indicated that it had already been counted; and the number of unpainted lizards that were observed during each period allowed the researchers to calculate how many lizards were going uncounted.

"It's not your typical summer job," says Mahler. "Each survey is essentially a game in which you try to find all the lizards in an area and zap them with paint. It's a messy affair, but we get great data from it."

"Our results help us better understand the likely consequences of climate change and how it will interact with human land-use," says Frishkoff.

For lowland forest Anolis lizards, deforestation just means a decline in abundance or relocating to the highlands. But for highland species, the situation is more critical. Unlike their lowland cousins, they have reached high ground already and in the face of deforestation have nowhere to go--a situation facing more and more species around the world.

"Our data suggest that while many lowland Anolis species might not be seriously affected by deforestation and the gradual warming brought about by climate change," says Frishkoff, "the opposite is true for the unique mountain lizard species which do not tolerate land-use change well, and which are already on the top of the island.

"Land-use and climate change are a double whammy for these species. If we cut down the mountain forests these lizards have nowhere left to go. Gradual warming might push species up slope, but when you're already at the top of the mountain, you can't move any higher."

Source: University of Toronto [February 25, 2019]

Mosquitoes, other blood-sucking flies have been spreading malaria for up to 100 million years

By: Thomas Schmitt Attorney on November 27, 2018 / comment : 0 Burma, Canada, Dominican Republic, Fossils, Mexico, Palaeontology

The microorganisms that cause malaria, leishmaniasis and a variety of other illnesses today can be traced back at least to the time of dinosaurs, a study of amber-preserved blood-sucking insects and ticks show.

Fossilised black fly [Credit: Oregon State University]

In addition to demonstrating the antiquity of vectors and their long-term association with parasitic microorganisms, the findings are remarkable for several reasons.

First, bloodsuckers like mosquitoes, fleas, sand flies, ticks and biting midges aren't frequently found in amber, and rarer yet is evidence of any microorganisms they might have been carrying.

But a review by entomologist George Poinar of Oregon State University showed that amber from five regions around the world contained hematophagous arthropods carrying preserved, identifiable pathogens and parasites.

"Feeding on vertebrate blood evolved as an efficient way for certain insects and acarines to get protein for growth and reproduction," said Poinar, professor emeritus in the College of Science and an international expert on plant and animal life forms found preserved in amber. "It's likely that primitive mosquitoes and other arthropod vectors were present back in the Jurassic and were even transmitting pathogens at that period. This would have resulted in widely dispersed diseases, many of which were probably fatal to vertebrates when they first appeared."

Poinar looked at bloodsucking insects and ticks encased in Dominican, Mexican, Baltic, Canadian and Burmese amber dating back from 15 million to 100 million years.

Among the vectors were mosquitoes, sand flies, biting midges, bat flies, black flies, fleas, kissing bugs and ticks. They carry a cornucopia of microorganisms that today cause diseases such as filariasis, sleeping sickness, river blindness, typhus, Lyme disease and, perhaps most significantly, malaria.

Fossilised flea [Credit: Oregon State University]

Malaria remains a relentless public health concern, with multiple nations reporting increases in infections for 2018. In Venezuela alone, Poinar notes, more than 650,000 new cases of malaria have been reported this year.

"Numerous malaria species parasitize vertebrates today, and we now know that over the past 100 million years, malaria was being vectored by mosquitoes, biting midges, bat flies and ticks," Poinar said. "Obtaining fossil records of pathogens carried by biting arthropods establishes a timeline when and where various diseases appeared and how they could have affected the survival, extinction and distribution of vertebrates over time."

Poinar stresses, however, that while his research shows what parasites and pathogens specific bloodsuckers were transmitting at particular periods and locations in the past, "these fossils are not old enough to tell us when and how associations between vectors, pathogens and vertebrates originated."

Poinar believes that the microorganisms first infected blood-sucking arthropods and only after equilibria had been reached between them were the microorganisms then vectored to vertebrates.

"That topic has been and will continue to be under discussion for years to come," he said.

The findings are published in Historical Biology.

Author: Steve Lundeberg | Source: Oregon State University [November 27, 2018]

Set in amber, fossil ants help reconstruct evolution of fungus farming

By: Thomas Schmitt Attorney on October 01, 2018 / comment : 0 Dominican Republic, Fossils, Palaeontology

Some 50 million years before humans figured it out, agriculture arrived in the world in a seemingly unlikely place: an ant hill.

A fungus-farming ant is covered in white symbiotic bacteria, which the ant relies on to produce  antibiotics to protect its garden from a parasitic fungus [Credit: Alex Wild]

Eschewing wheat or rice for feathery white fungus, the ants cultivated their fungal crop, providing it with care in exchange for nourishment. But like their human counterparts who would come after them, the ants faced the perennial problem of crop disease, in this case a parasitic fungus, which threatened to wipe out their harvests.

So the ant farmers evolved another partnership. They offered safe harbor and nutrition to a certain group of bacteria -- the Actinobacteria -- that in turn produced antibiotics capable of keeping the parasite at bay. To help the bacteria stick around, the ants' exoskeletons evolved specialized pockets that protected and fed their partners.

These structures seemed so intricate that scientists believed they only had the chance to evolve once as the original fungal farmers eventually diverged into the 250-some ant farming species we find today. But writing in the Proceedings of the National Academy of Sciences, University of Wisconsin-Madison researchers reveal that these bacteria-harboring structures evolved independently three times.

The results make it clear that the constant threat of crop parasites repeatedly pushed evolution in strikingly similar directions, creating structures that helped the ants reinforce their partnership with bacteria. And their successful use of protective antibiotics for eons suggests the ants may have lessons for human medicine, which has quickly come up against resistance by pathogens to our most important antibiotics.

The work was led by UW-Madison Professor of Bacteriology Cameron Currie and Hongjie Li, a postdoctoral researcher in the Currie lab. They partnered with colleagues at Arizona State University, the University of Sao Paulo, Harvard Medical School and the Smithsonian.

"This work provides fascinating insights into an animal using bacteria to provide antibiotics over a long period of time," says Currie, who has researched the dynamics of farming ants for 20 years.

The researchers performed an exhaustive survey of 69 ant species, sourcing diverse ant samples from the collections at Arizona State University and the Smithsonian. The research team reconstructed the ants' evolutionary tree using pieces of their genomic sequences. The resulting tree suggested that the partnership between ants and bacteria evolved soon after the ants began farming.

Further evidence for the ancient origin of the ant-bacteria relationship came from a handful of fungus-farming ants fortuitously frozen in amber from what is now the Dominican Republic. Through the hardened tree sap, the researchers could spot the telltale signs of bacteria clinging to the ants' bodies. With the amber dated to between 15 and 20 million years old, Currie's team could validate their genomic data and show that the ant-bacteria symbiosis was at least as old as the amber samples.

Earlier work had hinted at the early evolution of the ant-bacteria partnership, says Li, but "this paper provides much more evidence that this is an ancient system."

Using ultra-high-magnification electron microscopy, the researchers examined the ants for the specialized structures housing bacteria, known as crypts. The microscopic images showed that most living species of farming ants had crypts and related structures that could support Actinobacteria. But a number of ant species were missing these structures.

When they mapped the crypt data over the reconstructed evolutionary tree, Currie's team saw that crypts had evolved not once, but three separate times during the evolution of farming ants.

But the crypts were not ubiquitous. Some species have lost any obvious structures for supporting bacteria. The researchers showed that ants that have done away with crypts have also lost any trace of symbiotic Actinobacteria.

Currie and Li venture that ants that now farm in more arid areas no longer contend with the constant threat of the parasitic fungal disease. Since harboring and feeding the bacteria can use up to a quarter of an ant's energy, it became more advantageous for the ants to part ways with their erstwhile partners.

Apparently not content to mimic the ant's farming lifestyle, humans would later turn to the same group of bacteria, the Actinobacteria, for most of our clinical antibiotics. That the ants have, for millions of years, used similar antibiotics to protect their fungal gardens from pests suggests that we might learn from their success.

"I strongly believe there are mechanisms here that reduce the emergence of antibiotic resistance," says Currie.

Discovering what those mechanisms are might just help us extend the useful life of our own antibiotics.

Author: Eric Hamilton | Source: University of Wisconsin-Madison [October 01, 2018]