Primitive air-breathing fish, whose direct ancestors first appeared around 400 million years ago, show mechanisms controlling the heart which were previously considered to be found only in mammals -- according to a new study.

This is a South American lungfish, Lepidosiren paradoxa [Credit: Gustavo M. Oda]

Mammals show an increase in heart rate when breathing in and a decrease during expiration -- a cardiorespiratory process known as respiratory sinus arrhythmia (RSA). This process and its underlying control mechanisms have been considered by many scientists to be solely mammalian but the present study questions this assumption.

Scientists in Britain and Brazil studied the South American lungfish, Lepidosiren paradoxa, and discovered that systems enabling this primitive vertebrate to control blood flow during bouts of air-breathing have close similarities to those identified in mammals.

Lungfish are members of an ancient group of lobe-finned fishes (Class Dipnoi), having a continuous fossil record originating in the Devonian period around 400 million years ago. This was a time when the first vertebrates crawled on to land to give rise to amphibians and over succeeding millennia reptiles, birds and mammals.

With their proto-lungs and proto-limbs, lungfish represent the earliest stage in the evolution of air-breathing vertebrates. They inhabit tropical, freshwater pools and slow-flowing rivers, which often contain very low levels of dissolved oxygen and can disappear during the dry season.

The lungfish shares a periodic breathing pattern with the terrestrial vertebrates, rising to the water's surface at regular intervals to ventilate its lung-like air-breathing organ and depending exclusively on these lungs for oxygen uptake during drought.

Led by experts at the University of Birmingham and the Federal University of São Carlos (UFSCar), in São Paulo, the international team published its findings in Science Advances.

Professor Ted Taylor, from the University of Birmingham, said: "When lungfish gulp air at the water's surface, their heart rate instantly increases -- signalling a diversion of blood to the creature's lungs.

"This is possible because the animal has an undivided heart, enabling the proportion of blood diverted to the lungs to be varied; unlike mammals, as we have a completely divided heart with equal volumes of blood pumped separately to lungs and body with each heartbeat.

"Our study established a clear function in lungfish for these increases in heart rate in maximising oxygen uptake during each air breath that has not been definitively demonstrated for RSA in mammals. This suggests that it may be a relic of their link to ancient amphibious ancestors."

Professor Taylor added that "The lungfish has a relatively complex control system which generates these respiration-related changes in heart rate, with properties that anticipate those described for mammals.

"We found that these include multiple locations for nerve cells in the brainstem that innervate the heart with insulated fibres that conduct rapid impulses, causing an instantaneous cardiac response to each air-breath."

This illustration in a fish with a proven ancient lineage of a highly evolved system controlling variations in heart rate suggests that its evolution was necessarily linked to the advent of air breathing over primitive vertebrate lungs rather than the much later appearance of mammals.

This understanding questions assumptions over the primacy of mammals made by some biomedical physiologists and many psychobiologists, demonstrating that "primitive" mechanisms though early are not necessarily simple.

Source: University of Birmingham [March 05, 2018]

An international team of researchers has produced one of the most comprehensive evolutionary pictures to date by looking at one of the world's most iconic animal families - namely elephants, and their relatives mammoths and mastodons-spanning millions of years.

Crushed dentine from a Woolly Mammoth for DNA extraction [Credit: JD Howell, McMaster University]

The team of scientists-which included researchers from McMaster, the Broad Institute of MIT and Harvard, Harvard Medical School, Uppsala University, and the University of Potsdam-meticulously sequenced 14 genomes from several species: both living and extinct species from Asia and Africa, two American mastodons, a 120,000-year-old straight-tusked elephant, and a Columbian mammoth.

The study, published in the Proceedings of the National Academy of Science, sheds light on what scientists call a very complicated history, characterized by widespread interbreeding. They caution, however, the behaviour has virtually stopped among living elephants, adding to growing fears about the future of the few species that remain on earth.

"Interbreeding may help explain why mammoths were so successful over such diverse environments and for such a long time, importantly this genomic data also tells us that biology is messy and that evolution doesn't happen in an organized, linear fashion," says evolutionary geneticist Hendrik Poinar, one of the senior authors on the paper and Director of the McMaster Ancient DNA Centre and principal investigator at the Michael G. DeGroote Institute for Infectious Research.

"The combined analysis of genome-wide data from all these ancient elephants and mastodons has raised the curtain on elephant population history, revealing complexity that we were simply not aware of before," he says.

Graduate student Emil Karpinski holds a tibial cross section from a Siberian Woolly Mammoth. This permafrost preserved sample still contains fat entombed marrow [Credit: JD Howell, McMaster University]

A detailed DNA analysis of the ancient straight-tusked elephant, for example, showed that it was a hybrid with portions of its genetic makeup stemming from an ancient African elephant, the woolly mammoth and present-day forest elephants.

"This is one of the oldest high-quality genomes that currently exists for any species," said Michael Hofreiter at the University of Potsdam in Germany, a co-senior author who led the work on the straight-tusked elephant.

Researchers also found further evidence of interbreeding among the Columbian and woolly mammoths, which was first reported by Poinar and his team in 2011. Despite their vastly different habitats and sizes, researchers believe the woolly mammoths, encountered Columbians mammoths at the boundary of glacial and in the more temperate ecotones of North America.

Strikingly, scientists found no genetic evidence of interbreeding among two of the world's three remaining species, the forest and savanna elephants, suggesting they have lived in near-complete isolation for the past 500,000 years, despite living in neighbouring habitats.

These are African savanna elephants in the San Diego Zoo. In the middle is Swazi, the female elephant from which the reference genome was sequenced [Credit: San Diego Zoo Global]

"There's been a simmering debate in the conservation communities about whether African savannah and forest elephants are two different species," said David Reich, another co-senior author at the Broad Institute who is also a professor at the Department of Genetics at Harvard Medical School (HMS) and a Howard Hughes Medical Institute Investigator. "Our data show that these two species have been isolated for long periods of time - making each worthy of independent conservation status."

Interbreeding among closely related mammals is fairly common, say researchers, who point to examples of brown and polar bears, Sumatran and Bornean orangutans, and the Eurasian gold jackal and grey wolves. A species can be defined as a group of similar animals that can successfully breed and produce fertile offspring.

"This paper, the product of a grand initiative we started more than a decade ago, is far more than just the formal report of the elephant genome. It will be a reference point for understanding how diverse elephants are related to each other and it will be a model for how similar studies can be done in other species groups," said co-senior author Kerstin Lindblad-Toh, a senior associate member of the Broad Institute and Director of the Science for Life Laboratory at Uppsala University in Sweden.

"The findings were extremely surprising to us," says Eleftheria Palkopoulou, a post-doctoral scientist in at HMS. "The elephant population relationships could not be explained by simple splits, providing clues for understanding the evolution of these iconic species."

Researchers suggest that future work should explore whether the introduction of new genetic lineages into elephant populations-both living and ancient-played an important role in their evolution, allowing them to adapt to new habitats and fluctuating climates.

Source: McMaster University [February 26, 2018]

Experts have pieced together the fossil remains of a 20 million-year-old giant rhino at a museum in Chengdu, capital city of southwest China’s Sichuan province.

Judging from its skeleton, which is 8.8 meters in length, 4.2 meters in height, and 2 meters in width, it is estimated that it weighed more than 20 tons when it was alive.

The large rhino got stuck in mud before it died, palaeontological experts inferred. In March, the rhino skeleton will be shipped to a museum in Wuhan, central China.

The restoration project took three years and 1.5 million yuan to complete.

Source: People's Daily Online [February 13, 2018]

A fossilized trackway on public lands in Lake County, Oregon, may reveal clues about the ancient family dynamics of Columbian mammoths.

Footprints of mammoths, dated to 43,000 years ago, are seen in a portion of a trackway that was uncovered by researchers  in 2017 in an ancient dry lake bed in Lake County, Oregon [Credit: Greg Shine, Bureau of Land Management]

Recently excavated by a team from the University of Oregon Museum of Natural and Cultural History, the Bureau of Land Management and the University of Louisiana, the trackway includes 117 footprints thought to represent a number of adults as well as juvenile and infant mammoths.

Discovered by Museum of Natural and Cultural History paleontologist Greg Retallack during a 2014 class field trip on fossils at the UO, the Ice Age trackway is the focus of a new study appearing online ahead of print in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Retallack returned to the site with the study's coauthors, including UO science librarian Dean Walton, in 2017. The team zeroed in on a 20-footprint track, dating to roughly 43,000 years ago, that exhibited some intriguing features.

"These prints were especially close together, and those on the right were more deeply impressed than those on the left-as if an adult mammoth had been limping," said Retallack, also a professor in the UO Department of Earth Sciences and the study's lead author.

Mammoth trackway at Fossil Lake [Credit: Greg Shine, Bureau of Land Management]

But, as the study reveals, the limping animal wasn't alone: Two sets of smaller footprints appeared to be approaching and retreating from the limper's trackway.

"These juveniles may have been interacting with an injured adult female, returning to her repeatedly throughout the journey, possibly out of concern for her slow progress," Retallack said. "Such behavior has been observed with wounded adults in modern, matriarchal herds of African elephants."

The tracks were made in a layer of volcanic soil at Fossil Lake, a site first excavated by UO science professor Thomas Condon in 1876 and today administered by the Bureau of Land Management.

"America's public lands are some of the world's greatest outdoor laboratories. Localities such as this mammoth tracksite are unique parts of America's heritage and indicate that there are many special sites still to be discovered," said study co-author Brent Breithaupt, a paleontologist in the Wyoming State Office of the Bureau of Land Management.

Panoramic view with mammoth trackway in foreground [Credit: Greg Shine, Bureau of Land Management]

Specimens from the 1876 Fossil Lake excavation-along with the rest of Condon's extensive assemblage of fossils and geologic specimens-were donated to UO in the early 1900s and form the core of the museum's Condon Fossil Collection, now under Retallack's direction and boasting upwards of 50,000 fossil specimens.

Last month a new state law went into effect, making the UO museum Oregon's default repository for fossils found on state lands. The museum is also a designated repository for artifacts and paleontological specimens collected from BLM-administered lands in Oregon, ensuring they are available to future generations for education and research.

As part of the 2017 study, Neffra Matthews of the BLM's National Operations Center in Denver, helped survey, map and document the trackway using photogrammetry, which helps scientists perform accurate measurements based on land-based or aerial photographs.

"There is a vast storehouse of natural history found on BLM-managed land, and it's exciting to work with researchers like Professor Retallack in capturing 3D data on fragile paleontological resources," she said.


Retallack said that trace fossils such as trackways can provide unique insights into natural history.

"Tracks sometimes tell more about ancient creatures than their bones, particularly when it comes to their behavior," he said. "It's amazing to see this kind of interaction preserved in the fossil record."

Elephants once roamed across much of North America. Woolly mammoths (Mammuthus primigenius) were common in Canada and Alaska. Columbian mammoths (Mammuthus columbi) occupied the region that became Washington state to South Dakota and south into Mexico. Most mammoths went extinct about 11,500 years ago, but some isolated Arctic island populations of woolly mammoth persisted until 4,000 years ago.

Source: University of Oregon [February 12, 2018]

A slab of sandstone discovered at NASA's Goddard Space Flight Center contains at least 70 mammal and dinosaur tracks from more than 100 million years ago, according to a new paper published in the journal Scientific Reports. The find provides a rare glimpse of mammals and dinosaurs interacting.

Detail view of a cast from the sandstone slab imprinted with more than 70 dinosaur and mammal tracks discovered at NASA's Goddard Space Flight Center in Greenbelt, Maryland [Credit: NASA's Goddard Space Flight Center/Rebecca Roth]

The tracks were discovered by Ray Stanford -- a local dinosaur track expert whose wife, Sheila, works at Goddard. After dropping off Sheila at work one day in 2012, Stanford spotted an intriguing rock outcropping behind Shelia's building on a hillside. Stanford parked his car, investigated, and found a 12-inch-wide dinosaur track on the exposed rock. Excavation revealed that the slab was the size of a dining room table and examination in the ensuing years found that it was covered in preserved tracks.

The remarkable Goddard specimen, about 8 feet by 3 feet in size, is imprinted with nearly 70 tracks from eight species, including squirrel-sized mammals and tank-sized dinosaurs. Analysis suggests that all of the tracks were likely made within a few days of each other at a location that might have been the edge of a wetland, and could even capture the footprints of predator and prey.

"The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world," said Martin Lockley, paleontologist with the University of Colorado, Denver, a co-author on the new paper. Lockley began studying footprints in the 1980s, and was one of the first to do so. "I don't think I've ever seen a slab this size, which is a couple of square meters, where you have over 70 footprints of so many different types. This is the mother lode of Cretaceous mammal tracks."

After Stanford's initial find, Stephen J. Godfrey, curator of paleontology at the Calvert Marine Museum, coordinated the excavation of the slab and produced the mold and cast that formed the basis of the scientific work.

Detail view of a cast from the sandstone slab imprinted with more than 70 dinosaur and mammal tracks discovered at NASA's Goddard Space Flight Center in Greenbelt, Maryland [Credit: NASA's Goddard Space Flight Center/Rebecca Roth]

The first track Stanford found was of a nodosaur -- "think of them as a four-footed tank," Stanford said. Subsequent examination revealed a baby nodosaur print beside and within the adult print, likely indicating that they were traveling together. The other dinosaur tracks include: a sauropod, or long-necked plant-eater; small theropods, crow-sized carnivorous dinosaurs closely related to the Velociraptor and Tyrannosaurus rex; and pterosaurs, a group of flying reptiles that included pterodactyls.

"It's a time machine," Stanford said. "We can look across a few days of activity of these animals and we can picture it. We see the interaction of how they pass in relation to each other. This enables us to look deeply into ancient times on Earth. It's just tremendously exciting."

The dinosaur tracks are impressive, but it is the collection of mammal tracks that make the slab significant. At least 26 mammal tracks have been identified on the slab since the 2012 discovery -- making it one of two known sites in the world with such a concentration of prints. Furthermore, the slab also contains the largest mammal track ever discovered from the Cretaceous. It is about four inches square, or the size of a raccoon's prints.

Lockley and Stanford said most of these ancient footprints belong to what we would consider small mammals -- animals the size of squirrels or prairie dogs. Most Cretaceous mammals discovered to date have been the size of rodents, their size usually determined only from their teeth. "When you have only teeth, you have no idea what the animals looked like or how they behaved," Lockley said.


Lockley and Stanford believe the wide diversity and number of tracks show many of the animals were in the area actively feeding at the same time. Perhaps the mammals were feeding on worms and grubs, the small carnivorous dinosaurs were after the mammals, and the pterosaurs could have been hunting both the mammals and the small dinosaurs.

The parallel trackway patterns made by four crow-sized carnivorous dinosaurs suggests they were hunting or foraging as a group. "It looks as if they were making a sweep across the area," Lockley said.

Several of the mammal tracks occur in pairs, representing hind feet. "It looks as if these squirrel-sized animals paused to sit on their haunches," Lockley said. The team gave the new formal scientific name of Sederipes goddardensis, meaning sitting traces from Goddard Space Flight Center, to this unusual configuration of tracks.

"We do not see overlapping tracks -- overlapping tracks would occur if multiple tracks were made over a longer period while the sand was wet," said Compton Tucker, a Goddard Earth scientist who helped with the excavation, coordinated bringing in multiple scientists to study the tracks, and has worked to create a display of the cast in Goddard's Earth science building. "People ask me, 'Why were all these tracks in Maryland?' I reply that Maryland has always been a desirable place to live."

What is now Maryland would have been a much hotter, swampier place in the Cretaceous, when sea levels would have been hundreds of feet higher than today. As scientists continue to study the slab and compare the tracks to others found in the area and around the world, they will continue to discover more about prehistoric life that existed here.

"This could be the key to understanding some of the smaller finds from the area, so it brings everything together," Lockley said. "This is the Cretaceous equivalent of the Rosetta stone."

Author: Ashley Hume and Patrick Lynch | Source: NASA/Goddard Space Flight Center [January 31, 2018]

Senckenberg scientist Hervé Bocherens has studied the extinction of mega-herbivores – plant-eating animals that weighed more than one ton – that occurred approx. 12,000 years ago. The scientist from Tübingen reached the conclusion that, on the one hand, modern man was the cause of these giant terrestrial animals' extinction, and on the other hand, humans took over part of the animals' ecosystem functions. In his study, recently published in the scientific journal Frontiers in Ecology and Evolution, he concludes that the reintroduction of large animals in certain parts of the world could have a positive effect in regard to species diversity.

Extinct mega-herbivore: the American Mammoth [Credit: Senckenberg]

Today, there are only few animals that weigh in at a ton or more. Elephants, hippopotamuses and rhinoceroses are among these "mega-herbivores," and despite their large size, their populations are endangered. "Under geological aspects, the small number of so few large animal species presents an anomaly," explains Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen, and he continues, "The most prominent example of prehistoric giants is, of course, the dinosaurs."

But the more recent geological history also included colossal animals such as the giant sloths, woolly rhinoceroses, and mammoths. The biogeologist from Tübingen now examined the reasons for these animals' extinction around 12,000 years ago and its consequences for the environment.

"Like modern-day elephants, these mega-herbivores acted as 'ecosystem engineers.' They reduced the tree cover and kept open the landscape and the watering holes that are of vital importance for many animals. Plant seeds were transported over many kilometers in the animals' digestive tract, thus aiding in their distribution," explains Bocherens.

In his recent study, he shows that these tasks were taken over in part by modern humans in the period between 45,000 and 12,000 years ago. "During this epoch, modern man spread across northern Eurasia, North and South America and Australia, and the giant herbivores gradually became extinct," adds Bocherens.

With the "Neolithic revolution," the rise of agriculture and animal husbandry, the keeping of stores and a sessile lifestyle, the functions of the extinct "ecosystem engineers" were partially replaced. But in certain areas, such as the agriculturally ill-suited Subarctic – once home to the mammoth steppe – there remained a gap in this respect that continues until today. The lifestyle of these giant animals impacted the entire vegetation – trees were kept small and other plants had sufficient room and nutrients for their growth. The diversity of the flora, in turn, had a positive effect on the faunal diversity.

Following the extinction of the giant herbivores, the steppes turned into boreal coniferous forests. This led to a reduction of the so-called "albedo effect": Instead of a white layer of snow in the winter or a yellow landscape with dry grasses in the summer, the forests' dark green color reflects less solar radiation, leading to a warming of the climate. Moreover, the soils of the mammoth steppe were drier and emitted less of the greenhouse gas methane. Bocherens comments, "The presence of giant herbivores thus not only contributed to a higher species diversity, it also had an effect on the global climate."

According to the study, a better understanding of the differences as well as the similarities between the effects of the extinct mega-herbivores and the human landscape on the ecosystems may aid in better predicting the future of terrestrial ecosystems. "In some areas of the world, it may even make sense to reintroduce such mega-herbivores in order to increase biodiversity, thereby avoiding global warming," adds Bocherens in summary.

Source: Senckenberg Research Institute and Natural History Museum [January 30, 2018]

Scientists have long wondered how the horse evolved from an ancestor with five toes to the animal we know today. While it is largely believed that horses simply evolved with fewer digits, researchers at New York Institute of Technology College of Osteopathic Medicine (NYITCOM) pose a new theory that suggests remnants of all five toes are still present within the hooves of the horse.

Silhouettes show Mesohippus primigenium, an early ancestor of the modern horse that lived 40 million years ago and was previously believed to have three toes, and the modern horse. Photographs of both animals' hand bones  appear alongside renderings of the researchers' proposed digit identities. The researchers argue that missing digits one and five are partially expressed on the surfaces of the side toes (shown in red/blue). While the horse  is described as being monodactyl, with only one complete digit, the researchers demonstrate that digits two  and four are expressed as the splint bones and frog (padding of the foot), as shown in yellow/green. Missing digits one and five are expressed as ridges on the splint bones and as the hoof cartilages, as shown in the lower red/blue areas [Credit: NYITCOM]

Humans and horses are descendants of a common ancestor with five digits. As horses evolved to live on open grassland their anatomy required a more compact design to enable movement across the hard plains. Until now, scientists believed horses adapted to these conditions by gradually evolving with fewer digits than its five-toed ancestor, with the first horse retaining only four digits, its later descendant reduced to three, and today's horse retaining just the central digit known as the metacarpal, the long bone above the hoof.

For the first time, as published in Royal Society Open Science, NYITCOM researcher, Nikos Solounias, Ph.D., paleontologist and anatomy professor, and a team of researchers propose that the reduction in the number of digits is not a matter of simple attrition; instead, they believe that all five digits have merged to form the compacted forelimbs with hooves that we know today.

Currently, scientists accept that splints, small bones found along the outer sides of the metacarpal in modern horses, are partially formed remnants of second and fourth digits. Tapering mid-way down the metacarpal, these fragments were inherited from an earlier ancestor, but ceased to develop into fully formed digits in modern horses. While the NYITCOM researchers note that this explanation of the second and fourth digits is viable, they argue that it is incomplete and fails to account for the animal's first and fifth digits. Arguing that the horse is not truly monodactyl, that is, one-toed, these researchers contend that fragments of the "missing" digits can be found in the form of ridges on the backside of the splints. According to the researchers, this demonstrates that the first and fifth digits were not simply lost to evolution, but attached to their neighboring second and fourth digits.

Back view of 40 million-year-old Mesohippus' metacarpal. While three fully formed toes are visible, the researchers contend that ridges on the side of the toes represent the two missing digits,  and that therefore, all 5 digits are expressed [Credit: NYITCOM]

"With a distinct surface from the metacarpal, we know the splints on today's horses to be the remnants of the second and fourth digits," said Solounias. "However, these partially formed digits also appear to contain their own elevated surfaces which hold additional evolutionary clues. We find these ridges, located on the posterior of each splint, to be the partially formed remains of the first and fifth digits, which were once connected to the cartilages of the hoof."

Solounias first considered this theory in 1999 while studying fossil evidence from an eight-million-year-old horse known as Hipparion primigenium. The famous Laetoli footprints in Tanzania demonstrate Hipparion walked alongside early humans, and was believed to have had three digits. However, Solounias noticed that the bottom surface of Hipparion's fossilized forelimb appeared to be divided in five sections, as though small toes had bonded together. After further studying images of the Laetoli footprints, he confirmed his finding in several of the impressions, and considered that Hipparion not only had five compacted toes, but likely passed this trait on to its descendants.

"Interestingly, we not only find hints of the missing digits on the modern horse, but also its ancestors, such as Hipparion and Mesohippus, two species believed to have three toes," said Solounias.

Bottom of fossilized forelimb with five surfaces of differing texture, which suggests  five digits are still present on today's horse [Credit: NYITCOM]

Melinda Danowitz, D.O., a recent NYITCOM graduate and Solounias' co-investigator in the study added, "While the horse's lineage is classically described as having evolved from four to three toes, and eventually one single toe, we show that its extinct ancestors exhibit the reduced toes both at the wrist and at the hoof. These findings show that today's horse is not truly monodactyl, and earlier ancestors were not in fact tridactyl or tetradactyl, that is, three-toed or four-toed."

The researchers have also discovered neurovascular evidence in support of the five-digit theory, with dissections of modern equine fetus forelimbs revealing a greater number of arteries and nerves than would be expected in a single digit.

"If today's horse does indeed have one digit per forelimb, we would expect each forelimb to have a total of two veins, two arteries, and two nerve bundles," said Danowitz. "However, our dissections found between five and seven neurovascular bundles per forelimb, suggesting that additional toes begin to develop, but do not become fully differentiated."

Source: New York Institute of Technology [January 25, 2018]

The fossilized remains of a giant burrowing bat that lived in New Zealand millions of years ago have been found by a UNSW Sydney-led international team of scientists.

Artist's impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. The new fossil  find, Vulcanops jennyworthyae, that lived millions of years ago in New Zealand, is an ancient relative  of burrowing or short-tailed bats [Credit: Gavin Mouldey]

Teeth and bones of the extinct bat -- which was about three times the size of an average bat today -- were recovered from 19 to 16-million-year-old sediments near the town of St Bathans in Central Otago on the South Island.

The study, by researchers from Australia, New Zealand, the UK and USA, is published in the journal Scientific Reports.

Burrowing bats are only found now in New Zealand, but they once also lived in Australia. Burrowing bats are peculiar because they not only fly; they also scurry about on all fours, over the forest floor, under leaf litter and along tree branches, while foraging for both animal and plant food.

With an estimated weight of about 40 grams, the newly found fossil bat was the biggest burrowing bat yet known. It also represents the first new bat genus to be added to New Zealand's fauna in more than 150 years

It has been named Vulcanops jennyworthyae, after team member Jenny Worthy who found the bat fossils, and after Vulcan, the mythological Roman god of fire and volcanoes, in reference to New Zealand's tectonic nature, but also to the historic Vulcan Hotel in the mining town St Bathans.

Other research team members include scientists from UNSW Sydney, University of Salford, Flinders University, Queensland University, Canterbury Museum, Museum of New Zealand Te Papa Tongarewa, the American Museum of Natural History, and Duke University.

The fossil dig site at St Bathans in New Zealand where the fossilised remains of an extinct giant burrowing bat,  Vulcanops jennyworthyae, were found [Credit: Trevor Worthy]

"Burrowing bats are more closely related to bats living in South America than to others in the southwest Pacific," says study first author and UNSW Professor Sue Hand.

"They are related to vampire bats, ghost-faced bats, fishing and frog-eating bats, and nectar-feeding bats, and belong to a bat superfamily that once spanned the southern landmasses of Australia, New Zealand, South America and possibly Antarctica."

Around 50 million years ago, these landmasses were connected as the last vestiges of the southern supercontinent Gondwana. Global temperatures were up to 12 degrees Celsius higher than today and Antarctica was forested and frost-free. With subsequent fragmentation of Gondwana, cooling climates and the growth of ice-sheets in Antarctica, Australasia's burrowing bats became isolated from their South American relatives.

"New Zealand's burrowing bats are also renowned for their extremely broad diet. They eat insects and other invertebrates such as weta and spiders, which they catch on the wing or chase by foot. And they also regularly consume fruit, flowers and nectar," says Professor Hand, who is Director of the PANGEA Research Centre at UNSW.

"However, Vulcanops's specialized teeth and large size suggest it had a different diet, capable of eating even more plant food as well as small vertebrates -- a diet more like some of its South American cousins. We don't see this in Australasian bats today," she says.

Study co-author, Associate Professor Trevor Worthy of Flinders University says: "The fossils of this spectacular bat and several others in the St Bathans Fauna show that the prehistoric aviary that was New Zealand also included a surprising diversity of furry critters alongside the birds."

Washing of St Bathans sediments through sieves in Manuherikia River in New Zealand to collect fossil bones  and teeth of an ancient burrowing bat [Credit: Vanesa De Pietri]

Study co-author Professor Paul Scofield of Canterbury Museum says: "These bats, along with land turtles and crocodiles, show that major groups of animals have been lost from New Zealand. They show that the iconic survivors of this lost fauna -- the tuataras, moas, kiwi, acanthisittid wrens, and leiopelmatid frogs -- evolved in a far more complex community that hitherto thought."

This diverse fauna lived in or around a 5600-square-km prehistoric Lake Manuherikia that once covered much of the Maniototo region of the South Island. When they lived, in the early Miocene, temperatures in New Zealand were warmer than today and semitropical to warm temperate forests and ferns edged the vast palaeolake.

Vulcanops provides new insight into the original diversity of bats in Australasia. Its lineage became extinct sometime after the early Miocene, as did a number of other lineages present in the St Bathans assemblage. These include crocodiles, terrestrial turtles, flamingo-like palaelodids, swiftlets, several pigeon, parrot and shorebird lineages and non-flying mammals. Most of these were probably warm-adapted species. After the middle Miocene, global climate change brought colder and drier conditions to New Zealand, with significant changes to vegetation and environments.

It is likely that this general cooling and drying trend drove overall loss in bat diversity in New Zealand, where just two bat species today comprise the entire native land mammal fauna. All other modern land mammals in New Zealand have been introduced by people within the last 800 years.

Source: University of New South Wales [January 10, 2018]