There aren’t many parts of the world where you can discover a completely new assemblage of living creatures. But after sampling underground water in a remote, arid region of northern Australia, we discovered at least 11, and probably more, new species of stygofauna.
Stygofauna are invertebrates that have evolved exclusively in underground water. A life in complete darkness means these animals are often blind, beautifully translucent and often extremely localised – rarely living anywhere else but the patch they’re found in.
The species we discovered live in a region earmarked for fracking by the Northern Territory and federal government. As with any mining activity, it’s important future gas extraction doesn’t harm groundwater habitats or the water that sustains them.
Our findings, published today, show the importance of conducting comprehensive environmental assessments before extraction projects begin. These assessments are especially critical in Australia’s north, where many plants and animals living in surface and groundwater have not yet been documented.
Stygofauna were first discovered in Western Australia in 1991. Since then, these underground, aquatic organisms have been recorded across the continent. Today, more than 400 Australian species have been formally recognised by scientists.
Stygofauna are the ultimate climate change refugees. They would have inhabited surface water when inland Australia was much wetter. But as the continent started drying around 14 million years ago, they moved underground to the relatively stable environmental conditions of subterranean aquifers.
Today, stygofauna help maintain the integrity of groundwater food webs. They mostly graze on fungal and microbial films created by organic material leaching from the surface.
In 2018, the final report of an independent inquiry called for a critical knowledge gap regarding groundwater to be filled, to ensure fracking could be done safely in the Northern Territory. We wanted to determine where stygofauna and microbial assemblages occurred, and in what numbers.
Our project started in 2019, when we carried out a pilot survey of groundwater wells (bores) in the Beetaloo Sub-basin and Roper River region. The Beetaloo Sub-basin is potentially one of the most important areas for shale gas in Australia.
The stygofauna we found range in size from centimetres to millimetres and include:
two new species of ostracod: small crustaceans enclosed within mussel-like shells
a new species of amphipod: this crustacean acts as a natural vacuum cleaner, feeding on decomposing material
multiple new species of copepods: tiny crustaceans which form a major component of the zooplankton in marine and freshwater systems
a new syncarid: another crustacean entirely restricted to groundwater habitats
a new snail and a new worm.
These species were living in groundwater 400 to 900 kilometres south of Darwin. We found them mostly in limestone karst habitats, which contain many channels and underground caverns.
Perhaps most exciting, we also found a relatively large, colourless, blind shrimp (Parisia unguis) previously known only from the Cutta Cutta caves near Katherine. This shrimp is an “apex” predator, feeding on other stygofauna — a rare find for these kinds of ecosystems.
The Beetaloo Sub-basin in located beneath a major freshwater resource, the Cambrian Limestone Aquifer. It supplies water for domestic use, cattle stations and horticulture.
Surface water in this dry region is scarce, and it’s important natural gas development does not harm groundwater.
The stygofauna we found are not the first to potentially be affected by a resource project. Stygofauna have also been found at the Yeelirrie uranium mine in Western Australia, approved by the federal government in 2019. More research will be required to understand risks to the stygofauna we found at the NT site.
The discovery of these new NT species has implications for all extractive industries affecting groundwater. It shows the importance of thorough assessment and monitoring before work begins, to ensure damage to groundwater and associated ecosystems is detected and mitigated.
Groundwater is vital to inland Australia. Underground ecosystems must be protected – and not considered “out of sight, out of mind”.
Our study provides the direction to reduce risks to stygofauna, ensuring their ecosystems and groundwater quality is maintained.
Comprehensive environmental surveys are needed to properly document the distribution of these underground assemblages. The new stygofauna we found must also be formally recognised as a new species in science, and their DNA sequence established to support monitoring programs.
Many new tools and approaches are available to support environmental assessment, monitoring and management of resource extraction projects. These include remote sensing and molecular analyses.
Deploying the necessary tools and methods will help ensure development in northern Australia is sustainable. It will also inform efforts to protect groundwater habitats and stygofauna across the continent.
Jenny Davis, Professor, Research Institute for Environment & Livelihoods, Charles Darwin University, Charles Darwin University; Daryl Nielsen, Principal Research Scientist, CSIRO; Gavin Rees, Principal Research Scientist, CSIRO, and Stefanie Oberprieler, Research associate, Charles Darwin University
When it comes to new botanical discoveries, one might imagine it’s done by trudging around a remote tropical rainforest. Certainly, that does still happen. But sometimes seemingly familiar plants close to home hold unexpected surprises.
We recently discovered a new genus of Australian daisies, which we’ve named Scapisenecio. And we did so on the computer screen, during what was meant to be a routine analysis to test a biocontrol agent against a noxious weed originally from South Africa.
The term “genus” refers to groups of different, though closely related, species of flora and fauna. For example, there are more than 100 species of roses under the Rosa genus, and brushtail possums are members of the Trichosurus genus.
This accidental discovery shows how much is still to be learned about the natural history of Australia. Scapisenecio is a new genus, but thousands of visitors to the Australian Alps see one of its species flowering each summer. If this species was still misunderstood, surely similar surprises are still out there waiting for us.
It all started with a biocontrol researcher asking a plant systematist, who looks at the evolutionary history of plants, to help figure out the closest Australian native relatives of the weed, Cape ivy (Delairea odorata).
Weeds like Cape ivy cause major damage to agriculture in Australia, displace native vegetation and require extensive management. Biological control (biocontrol) is one way to reduce their impact. This means taking advantage of insects or fungi that attack a weed, generally after introducing them from the weed’s home range.
A well-known Australian example is the introduction of the Cactoblastis moth in 1926 to control prickly pear in Queensland and New South Wales. Even today it continues to keep that weed in check.
To minimise the risk of selecting a biocontrol agent that will damage native flora, ornamental plants or crops, it’s tested carefully against a list of species of varying degrees of relatedness to the target weed.
Authorities will approve the release of a biocontrol agent only if scientists can show it’s highly specific to the weed. Assembling a list of species to test therefore requires us to understand the evolutionary relationships of the target weed to other plant species.
If such relationships are poorly understood, we might fail to test groups of species that are closely related to the target.
Our target weed Cape ivy is a climbing daisy that has become invasive in temperate forests and coastal woodlands throughout south-eastern Australia. One of us, Ben Gooden, is researching the potential use of Digitivalva delaireae — a stem-boring moth — for its biocontrol.
We tried to design a test list, but could not find up-to-date information on Cape ivy’s relatives. We already knew it is related to the large groundsel genus Senecio, but we didn’t know how closely. And no genetic data existed for many Australian native species of Senecio.
So, we set out to solve this problem together.
First, we assembled already-published DNA sequences for as many Senecio species and relatives as we could find, and then generated sequences for an additional 32 native Australian species.
We then united all these genetic data into a comprehensive phylogenetic analysis. “Phylogenetics” infers the evolutionary relatedness of organisms to each other.
The resulting “evolutionary tree” showed many of the native Senecio species where we expected them to be. More importantly, however, it showed us that Cape ivy is actually quite distantly related to Senecio.
To our surprise, the analysis also placed several Australian species traditionally belonging to the Senecio genus far outside of it, indicating they didn’t belong to Senecio at all and needed to be renamed.
The most interesting group of not-actually-Senecio are five species with leaf rosettes and one (or rarely, a few) flowerheads carried on distinctive stalks.
They’re all restricted to alpine or subalpine areas of south-eastern Australia, and all except one are found only in Tasmania. They turned out to be so unrelated, and so distinct from any other named plant genera, that they have to be recognised as a genus in its own right.
We have now named this new genus as Scapisenecio, after the long flower stalks (scapes) characterising the plants.
The most widespread and common species is Scaposenecio pectinatus, commonly known as the alpine groundsel, which is a familiar sight to hikers and bushwalkers in the Australian mainland alps and the central highlands of Tasmania.
Apart from the excitement of finding a previously undescribed, distinctive genus, these results were also directly relevant to the original purpose of our work: informing a plant list to test possible biocontrol agents.
The traditional misclassification of these species would have misled us about their true relationships. Our new genetic data now allow us to test biocontrol agents on an appropriate sample of species, to minimise risks to our native flora.
It is not often we find that a new, unexpected lineage of plants has existed all along, right in front of us.
Significant coral bleaching at one of Western Australia’s healthiest coral reefs was found during a survey carried out in April and May.
The survey took a combined effort of several organisations, together with tour operators more used to taking tourists, but with time spare during the coronavirus lockdown.
WA’s arid and remote setting means many reefs there have escaped some of the pressures affecting parts of the east coast’s Great Barrier Reef), such as degraded water quality and outbreaks of crown of thorns starfish.
The lack of these local pressures reflects, in part, a sound investment by governments and communities into reef management. But climate change is now overwhelming these efforts on even our most remote coral reefs.
As the 2020 mass bleaching unfolded across the Great Barrier Reef, a vast area of the WA coastline was bathed in hot water through summer and autumn. Heat stress at many WA reefs hovered around bleaching thresholds for weeks, but those in the far northwest were worst affected.
The remoteness of the region and shutdowns due to COVID-19 made it difficult to confirm which reefs had bleached, and how badly. But through these extraordinary times, a regional network of collaborators managed to access even our most remote coral reefs to provide some answers.
Australia’s Bureau of Meteorology provided regional estimates of heat stress, from which coral bleaching was predicted and surveys targeted.
At reefs along the Kimberley coastline, bleaching was confirmed by WA’s Department of Biodiversity, Conservation and Attractions (DBCA), Bardi Jawi Indigenous rangers, the Kimberley Marine Research Centre and tourist operators.
At remote oceanic reefs hundreds of kilometres from the coastline, bleaching was confirmed in aerial footage provided by Australian Border Force.
Subsequent surveys were conducted by local tourist operators, with no tourists through COVID-19 shutdown and eager to check the condition of reefs they’ve been visiting for many years.
Within just a few days, a tourist vessel chartered by the North West Shoals to Shore Research Program, with local operators and a DBCA officer, departed from Broome for the Rowley Shoals. These three reef atolls span 100km near the edge of the continental shelf, about 260km west-north-west offshore.
One of only two reef systems in WA with high and stable coral cover in the last decade, the Rowley Shoals is a reminder of beauty and value of healthy, well managed coral reefs.
But the in-water surveys and resulting footage confirmed the Rowley Shoals has experienced its worst bleaching event on record.
All parts of the reef and groups of corals were affected; most sites had between 10% and 30% of their corals bleached. Some sites had more than 60% bleaching and others less than 10%.
The heat stress also caused bleaching at Ashmore Reef, Scott Reef and some parts of the inshore Kimberley and Pilbara regions, all of which were badly affected during the 2016/17 global bleaching event.
This most recent event (2019/20) is significant because of the extent and duration of heat stress. It’s also notable because it occurred outside the extreme El Niño–Southern Oscillation phases – warming or cooling of the ocean’s surface that has damaged the northern and southern reefs in the past.
The impacts from climate change are not restricted to WA or the Great Barrier Reef – a similar scenario is playing out on reefs around the world, including those already degraded by local pressures.
By global standards, WA still has healthy coral reefs. They provide a critical reminder of what reefs offer in terms of natural beauty, jobs and income from fisheries and tourism.
But we’ve spent two decades following the trajectories of some of WA’s most remote coral reefs. We’ve seen how climate change and coral bleaching can devastate entire reef systems, killing most corals and dramatically altering associated communities of plants and animals.
And we’ve seen the same reefs recover over just one or two decades, only to again be devastated by mass bleaching – this time with little chance of a full recovery in the future climate.
Reducing greenhouse gas emissions is the only way to alleviate these pressures. In the meantime, scientists will work to slow the rate of coral reef degradation though new collaborations, and innovative, rigorous approaches to reef management.
You’re probably familiar with earthquakes as relatively short, sharp shocks that can shake the ground, topple buildings and tear rips in the Earth. These earthquakes, and their aftershocks, happen because although tectonic plates move at centimetres per year, this motion is seldom steady. Earthquakes result from a “stick-slip” motion, where rocks “stick” along fault planes while stress accumulates until a “slip” occurs – a bit like pulling on a stuck door until it suddenly opens. This slip also releases energy as the seismic waves that, in large magnitude earthquakes, create substantial damage.
In the last two decades another class of stick-slip motion has been discovered worldwide. These “slow slip events” last for weeks to months, compared to seconds to minutes for earthquakes. Slow slip events occur faster than average plate motion, but too slow to generate measurable seismic waves. This means they need to be studied by GPS networks rather then seismometers.
Although their motion is slow, the amount of movement that occurs in a slow slip event is substantial. Earthquake magnitude depends on the distance that rocks move and the area this movement occurs over. Using the same definition, many slow slip events would have had magnitudes above 7.0 if they slipped at earthquake speeds.
Slow slip events repeat at intervals of a year to a few years. Compared to major earthquakes, which have repeat times of hundreds of years (or more), slow slip events are actually very frequent. Even in the short time of a couple of decades that we’ve observed these types of slip, many cycles have occurred in several places – notably around the Pacific Rim.
Slow slip events generally happen next to areas where faults are locked and expected to rupture in major earthquakes. It’s therefore possible that these slow slip events can trigger earthquakes on neighbouring locked faults. It has, for example, been suggested that slow slip events preceded the 2011 magnitude 9.1 Tohoku earthquake in Japan and the 2014 magnitude 8.1 Iquique earthquake in Chile. That said, numerous slow slip events have also been observed without any immediate, subsequent major earthquakes on neighbouring faults.
Earthquakes may also trigger slow slip. In particular, the magnitude 7.8 Kaikōura earthquake in New Zealand in 2016 triggered slow slip events up to 600km away from its epicentre.
It is not known why some fault segments host slow slip and others host earthquakes. Neither is it known whether the same area can change behaviour and host either slow slip or earthquakes at different times. It’s therefore important to characterise the source of slow slip, and find out what materials help create slow slip and under what conditions.
The Hikurangi subduction zone (where the Pacific ocean floor is pulled underneath the New Zealand continent) offshore New Zealand’s North Island is potentially the country’s largest earthquake fault and is a unique opportunity to investigate slow slip events. This is because slow slip here happens shallower and closer to the shoreline than anywhere else in the world.
The shallow slow slip events in New Zealand have been observed by onshore GPS and ocean bottom pressure sensors. Oceanic scientific drilling expeditions recently sampled sediments and installed observatories along this margin.
These International Ocean Discovery Program expeditions – which drilled to just over 1km deep in water depths of 3.5km in late 2017 and early 2018 – revealed that the seafloor rocks and sediments hosting slow slip in Hikurangi are extremely variable. The range of rocks, described in a recent Science Advances paper led by Philip Barnes of NIWA (New Zealand’s National Institute of Water and Atmospheric Research), include mudstones, sands, carbonates, and sedimentary deposits from oceanic volcanic eruptions. The seafloor samples show that the source of the slow slip is a mixture of very soft sediment and hard, solid rocks.
The diverse seafloor sediments are not the only variability offshore of New Zealand. The seafloor itself is also very rough, including seamounts (submarine mountains rising over a kilometre above the seafloor). This seafloor roughness also makes the fault vary depending on where along it you are.
The observations are consistent with a hypothesis where slow slip events occur in rocks that are transitional between moving steadily and moving in earthquakes. One way to think of this model is as rigid rocks interacting with softer, more ductile surroundings. Researchers using numerical simulations and laboratory experiments have also suggested that variable fault rocks can cause slow slip.
But diverse fault rock isn’t the only model for the mechanics of slow slip. Another possibility is that pressurised fluids decrease frictional resistance and slip speed along faults. It is also possible that some rocks become stronger when they move faster – so that faults start accelerating but slow down before reaching earthquake speeds.
The recent discoveries in New Zealand may be applicable to other depths and locations around the world. However, future studies will undoubtedly lead to further insights and complexities – including in the relationship between slow slip events and earthquakes.
Finding a species that’s entirely new to science is always exciting, and so we were delighted to be a part of the discovery of two new sixgill sawsharks (called Pliotrema kajae and Pliotrema annae) off the coast of East Africa.
We know very little about sawsharks. Until now, only one sixgill species (Pliotrema warreni) was recognised. But we know sawsharks are carnivores, living on a diet of fish, crustaceans and squid. They use their serrated snouts to kill their prey and, with quick side-to-side slashes, break them up into bite-sized chunks.
Sawsharks look similar to sawfish (which are actually rays), but they are much smaller. Sawsharks grow to around 1.5 metres in length, compared to 7 metres for a sawfish and they also have barbels (fish “whiskers”), which sawfish lack. Sawsharks have gills on the side of their heads, whereas sawfish have them on the underside of their bodies.
Together with our colleagues, we discovered these two new sawsharks while researching small-scale fisheries that were operating off the coasts of Madagascar and Zanzibar. While the discovery of these extraordinary and interesting sharks is a wonder in itself, it also highlights how much is still unknown about biodiversity in coastal waters around the world, and how vulnerable it may be to poorly monitored and managed fisheries.
Despite what their name might suggest, small-scale fisheries employ around 95% of the world’s fishers and are an incredibly important source of food and money, particularly in tropical developing countries. These fisheries usually operate close to the coast in some of the world’s most important biodiversity hotspots, such as coral reefs, mangrove forests and seagrass beds.
For most small-scale fisheries, there is very little information available about their fishing effort – that is, how many fishers there are, and where, when and how they fish, as well as exactly what they catch. Without this, it’s very difficult for governments to develop management programmes that can ensure sustainable fishing and protect the ecosystems and livelihoods of the fishers and the communities that depend on them.
While the small-scale fisheries of East Africa and the nearby islands are not well documented, we do know that there are at least half a million small-scale fishers using upwards of 150,000 boats. That’s a lot of fishing. While each fisher and boat may not catch that many fish each day, with so many operating, it really starts to add up. Many use nets – either driftnets floating at the surface or gillnets, which are anchored close to the sea floor. Both are cheap but not very selective with what they catch. Some use longlines, which are effective at catching big fish, including sharks and rays.
In 2019, our team reported that catch records were massively underreporting the number of sharks and rays caught in East Africa and the nearby islands. With the discovery of two new species here – a global hotspot for shark and ray biodiversity – the need to properly assess the impact of small-scale fisheries on marine life is even more urgent.
How many other unidentified sharks and other species are commonly caught in these fisheries? There is a real risk of species going extinct before they’re even discovered.
Efforts to monitor and manage fisheries in this region, and globally, must be expanded to prevent biodiversity loss and to develop sustainable fisheries. There are simple methods available that can work on small boats where monitoring is currently absent, including using cameras to document what’s caught.
The discovery of two new sixgill sawsharks also demonstrates the value of scientists working with local communities. Without the participation of fishers we may never have found these animals. From simple assessments all the way through to developing methods to alter catches and manage fisheries, it’s our goal to make fisheries sustainable and preserve the long-term future of species like these sawsharks, the ecosystems they live in and the communities that rely on them for generations to come.
We have discovered a new species of orangutan – the third known species and the first new great ape to be described since the bonobo almost a century ago.
The new species, called the Tapanuli orangutan (Pongo tapanuliensis), has a smaller skull than the existing Bornean and Sumatran orangutans, but has larger canines.
As we and our colleagues report in the journal Current Biology, the new species is represented by an isolated population of fewer than 800 orangutans living at Batang Toru in northern Sumatra, Indonesia.
The existence of a group of orangutans in this region was first reported back in 1939. But the Batang Toru orangutans were not rediscovered until 1997, and then confirmed in 2003. We set about carrying out further research to see whether this isolated group of orangutans was truly a unique species.
On the basis of genetic evidence, we have concluded that they are indeed distinct from both the other two known species of orangutan: Pongo abelii from further north in Sumatra, and Pongo pygmaeus from Borneo.
The Batang Toru orangutans have a curious mix of features. Mature males have cheek flanges similar to those of Bornean orangutans, but their slender build is more akin to Sumatran orangutans.
The hair colour is more cinnamon than the Bornean species, and the Batang Toru population also makes longer calls than other orangutans.
To make completely sure, we needed more accurate comparisons of their body dimensions, or “morphology”. It was not until 2013 that the skeleton of an adult male became available, but since then one of us (Anton) has amassed some 500 skulls of the other two species, collected from 21 institutions, to allow for accurate comparisons.
Analyses have to be conducted at a similar developmental stage on male orangutan skulls, because they continue growing even when adult. Anton found 33 skulls of wild males that were suitable for comparison. Of 39 different measurement characteristics for the Batang Toru skull, 24 of them fall outside of the typical ranges of northern Sumatran and Bornean orangutans.
Overall the Batang Toru male has a smaller skull, but bigger canines. Combining the genetic, vocal, and morphological sources of evidence, we have confidently concluded that Batang Toru orangutan population is a newly discovered species – and one whose future is already under threat.
Despite the heavy exploitation of the surrounding areas (hunting, habitat
alteration and other illegal activities), the communities surrounding the habitat of the Tapanuli orangutan still give us the opportunity to see and census the surviving population. Unfortunately, we believe that the population is fewer than 800 individuals.
Of the habitat itself, no more than 10 square km remains. Future development has been planned for that area, and about 15% of the orangutans’ habitat has non-protected forest status.
The discovery of the third orangutan in the 21st century gives us an understanding that the great apes have more diversity than we know, making it all the more important to conserve these various groups.
Without the strong support of, and participation from, the communities surrounding its habitat, the future of the Tapanuli orangutan will be uncertain. Government, researchers and conservation institutions must make a strong collaborative effort to make sure that this third orangutan will survive long after its discovery.
The link below is to an article reporting on the discovery of over 50 new species of spider in Queensland, Australia.