COULD Brazil really miss out on the knockout stages in Russia? Well, it’s possible, if a little unlikely, but as Argentina showed on Wednesday morning (EST) anything can happen when under enormous pressure. Brazil’s situation isn’t as desperate as Argentina’s - a draw against Serbia will be enough to see them through - but any slip up against a team featuring the likes of Nemanja Matic, Aleksandar Kolorov and Sergej Milinkovic-Savic could prove fatal. Group E is certainly delicately poised. Brazil lead on goal difference from Switzerland on four points. Serbia are one point back. Costa Rica are last, without both a point and a goal. If Serbia beat Brazil and Switzerland beat Costa Rica then Brazil are out. A Serbia win and a Switzerland draw - depending on the amount of goals scored - would leave Brazil in serious trouble as well. A draw would secure Brazil at least second place - and a probable clash with Mexico in the round of 16. A win would guarantee first - but that would mean playing either Sweden, Germany or even South Korea if results get turned on their head.

The Pakistan Cricket Board (PCB) will seek an explanation from wicketkeeper Umar Akmal after he said in a television interview that he had been approached to fix matches. The PCB's anti-corruption unit has scheduled a hearing for Wednesday after Akmal, who has made 116 ODI appearances, told a local channel that he had been offered $200,000 to "leave two balls alone" in a World Cup match against India in Adelaide in 2015. India won that match by 76 runs and Akmal was out for a duck off only four balls. The 28-year-old also said he regularly received offers to fix other games against India and that he had always rejected them. But he could be in hot water with both the PCB and International Cricket Council if he failed to report such approaches. Match-fixing has become a major concern for the sport in recent years, and a high-profile incident involving Pakistan on tour to England in 2010 saw Salman Butt, Mohammad Asif and Mohammad Amir found guilty of being part of a plot to bowl no-balls at pre-arranged times during a Test.

AUSTRALIA will face Pakistan, India and arch-rivals New Zealand in the group stages of the Women’s World T20 in November. The International Cricket Council has released the schedule for the event, to be hosted by the West Indies, later this year with 10 teams to compete. Australia, beaten finalists in 2016, will kick off its campaign in Group B against Pakistan on November 9 at Guyana National Stadium before clashes with a qualifier, New Zealand and India. Reigning champions West Indies, England, South Africa, Sri Lanka and a qualifier are in Group A. Eight nations - Bangladesh, Ireland, the Netherlands, Papua New Guinea, Scotland, Thailand, Uganda and the UAE - are fighting for the two qualification places. Captain Meg Lanning said Australia was looking to avenge its loss in 2016 and make up for a disappointing World Cup in 2017. “It’s the next big tournament on the horizon and we have a good chance to nail down our T20 gameplan and focus,” she said. “The group is always looking forward to World Cups and this time around is no different. The World Cup last year did not go as well as we would have liked to, so we are very hungry to become world champions again. “We know it is a very open competition and you need to be consistent and be brave with how you play but we are in a very good space to go down that path and see that when the time comes we are playing really good cricket.”

NSW captain Peter Nevill wants his young squad to pick the brains of Steve Smith and David Warner this season, adding he'd love to see the banned duo return in the Sheffield Shield final. Former Test keeper Nevill was appointed Blues skipper on Tuesday, filling one of many voids left by Smith. Smith and Warner are serving 12-month bans that preclude them from playing international cricket, but also representing NSW or taking part in the Big Bash League. Those suspensions, resulting from the Cape Town cheating scandal, expire on March 28. That is the same date the Shield final starts, giving Smith and Warner hope of an unexpected hit with the Blues. "I certainly would not be against them playing any games for us. I'd love to have them around, any time," Nevill told reporters on Tuesday. "Hopefully we can see them, at some point this season, playing for us. If that's the Shield final, we'll have to make sure we make that." Many members of the NSW squad were understood to be incredulous when Cricket Australia (CA) slapped long suspensions on Smith and Warner, unhappy because they felt the punishment was too harsh and did not match their crimes. The players' union and past players, including Shane Warne, voiced their concern publicly. The latter accused CA of bowing to public "hysteria". There is no prospect of the governing body softening those sanctions, but Smith and Warner will be playing grade cricket later this year after returning via Canada's new Twenty20 league. Two of the world's best batsmen, who have a combined 138 Tests of experience, are also likely to train alongside NSW teammates this season. "It doesn't have to be on a formal basis," Nevill said. "Some of the best learning experiences for people are quite informal things. "Having that kind of knowledge around the place is only going to help upskill some of these young guys, but also our more experienced guys." Smith spent recent weeks visiting schools as part of his charity work with the Gotcha 4 Life Foundation, opening up about his personal lows during discussions about mental health. News Corp Australia has published a story based on Smith's recent movements around New York, having shadowed the gifted batsman while he was en route to Toronto for the T20 competition that starts later this week. "I didn't see that. That's obviously disappointing," Nevill said. "You don't want to see that happen to anybody really. "Steve is a lovely human being. He's a friend of mine and I care about him a lot."

AUSTRALIA T20 captain Aaron Finch says his players have no fears about travelling to Zimbabwe later this week despite increased political tensions in the troubled African nation and a bomb blast last weekend. The Aussie team will travel to Zimbabwe for a T20 tri-series in the middle of an election campaign that is becoming increasingly violent after a deadly bomb blast at a rally in Bulawayo last week, which was an assassination attempt on President Emmerson Mnangagwa. Cricket Australia has been monitoring the situation closely all week and has had discussions with government officials both at home and in Zimbabwe. The Department of Foreign Affairs and Trade (DFAT) is warning Australians that “instances of conflict cannot be ruled out in the lead up to, during and soon after the election” on July 30, and that the security situation could “deteriorate quickly”. Australian visitors are currently advised to “exercise a high degree of caution in Zimbabwe”. Team security staff briefed the 14-members of the Aussie T20 squad, in Birmingham for Thursday morning’s (EST) one-off clash with England, and Finch said none had expressed any concerns about travelling. “We were briefed on it last night by Frank (Dimasi) our security guy and all systems are go,” Finch said. “With DFAT, the Australian Government and Cricket Australia, they’ll make sure that all the due diligence is done to make sure it is safe. But at this stage I haven’t heard any unease from the player in regards to going.” In 2004 former Test leg-spinner Stuart MacGill boycotted a tour of Zimbabwe on conscientious objection grounds, during the regime of long-time president Robert Mugabe, which was ended last year in a military coup. Australia will play four games, five if it makes the final, against Zimbabwe and Pakistan at the Harare Sports ground, over the course of seven days. Australia T20 squad: Aaron Finch (c), Alex Carey (vc), Ashton Agar, Travis Head, Nic Maddinson, Glenn Maxwell, Jhye Richardson, Kane Richardson, D’Arcy Short, Billy Stanlake, Marcus Stoinis, Mitchell Swepson, Andrew Tye, Jack Wildermuth. T20I tri-series Tour of Zimbabwe July 1: Zimbabwe vs Pakistan July 2: Pakistan vs Australia July 3: Australia vs Zimbabwe July 4: Zimbabwe vs Pakistan July 5: Pakistan vs Australia

WEST COAST might’ve been “as flat as a whoopee cushion at a clown convention” last Thursday, but things aren’t as bad as they seem, according to the West Australian chief football writer Mark Duffield and The Sunday Times sports editor Glen Quartermain. After dismissing the pre-season doomsayers with 10 wins from their first 11 games, the Eagles have plateaued in recent weeks with consecutive losses to Sydney and Essendon. Adam Simpson’s chargers handed an eight-goal head-start to the Bombers in round 14 and were unable to match their opponents’ intensity in the midfield. West Coast plays the Crows at Adelaide Oval on Saturday and could slip to fourth spot on the ladder with defeat, given Collingwood’s match-up against the lowly Suns. But Quartermain is optimistic the Eagles’ dip form is nothing more than a blip on the radar. “I’m not as concerned as some,” he said. “I actually think Adelaide will win this week and I’m not panicking about West Coast. “OK, it might cost them top two, but let’s just divorce ourselves from that at the moment. “Everyone has one of these shockers and they’ve had theirs. Great sides can overcome that. “I still think it’s pretty positive for West Coast and that one shocker – they can put that in a box (and) put it aside. “They’ve got enough credit in the bank now to still finish top for, certainly, and this with a loss this week against Adelaide.” Injured pillars Jack Darling and Josh Kennedy were sorely missed after quarter time, as West Coast struggled to capitalise on the lopsided 59-45 inside 50 count. The pair will spend at least another fortnight on the sidelines, placing great responsibility on the shoulders of 20-year-old tall target Jake Waterman. West Coast resorted to sending Jeremy McGovern forward in the final quarter last weekend, a tactic Quartermaine believes the Eagles should only use in a crisis. “One thing I don’t want to see is McGovern go permanent forward straight away,” he said. “OK, your forward line is being smashed because of those two absences, but you don’t want to do the same thing to your defence, particularly with Barrass missing. “McGovern stays (back) for mine, unless you get to a situation as you did late in the game against Essendon where all hope is lost, let’s just try something out of the box.” Duffield reserved his concerns for the Eagles’ midfield stocks, which were dealt a hiding by Bombers onballers Zach Merrett, Dyson Heppell, Brendon Goddard and Devon Smith. Elliot Yeo (22 possessions, 12 tackles), Andrew Gaff (32 possessions, four marks) and Jack redden (26 possessions, six marks) tried hard but lacked support from dynamic on-baller Luke Shuey (18 possessions, seven clearances). It is the second match in a row Shuey has tallied less than 20 touches after injuring his hamstring against Port Adelaide in round seven. “I haven’t seen explosiveness from Luke Shuey since he came back off the hamstring so obviously he’s still getting comfortable playing again after that injury,” Duffield said. Duffield was also quick to point out the importance of Mark LeCras, who hurt his wrist against the Bombers but trained strongly at Monday’s session. “If they were to go to Adelaide to play Adelaide without Mark Lecras and without Kennedy and without Darling, I’d be tipping Adelaide,” he said. “LeCras has a good record at Adelaide Oval.” “LeCras would be a massive in for West Coast (but) he would also be a massive out in the context of them not having Darling or Kennedy.” Bounce down for the Eagles clash with the Crows is at 2:35, AWST.

MEGAN Gale has taken to Instagram to pen a heartfelt tribute to her fiance Shaun Hampson after he announced his retirement from the AFL. The supermodel told of the Tigers star’s battle with a chronic back condition, a medical issue that caused him to play “on & on... in agony”. “He’ll probably be quite embarrassed that I’ve posted this,” Gale wrote. “When he wasn’t injured, he was one of the best tap ruckmen in the AFL. “Unfortunately, injuries for him were common, often debilitating & most of the time, pushed to one side while he played on & on & often in agony unbeknownst to a lot of people.” Hampson, 30, joined the Tigers at the end of 2013, and in her emotional caption, Gale said her partner had a stellar season in 2016. She said it was devastating to see Hampson miss out on a spot in last year’s AFL Grand Final. “2016 was his best season to date & he dominated in the ruck for @richmond_fc & 2017 was looking bright...until his back gave out on him,” she wrote. “After enduring countless procedures to get his back right again so he could reclaim his position in the squad (I’ve lost count how many needles he’s had into his spine & his L5 disc) he fought back bloody hard & he almost got there at the end of the season, listed as an emergency for the Tigers for the 2017 AFL Grand Final. “But it wasn’t to be.” Gale explained she couldn’t imagine the feeling of trying to overcome the plethora of physical, emotional and mental obstacles, but despite it all, she said the strong-willed Hampson never complained. “I’ve never seen someone persevere, persist & be so professional while battling & dealing with some serious levels of pain,” she wrote in her caption. “And all the while managing to laugh, joke, keep his spirits up, support his teammates to the enth degree & do everything in his power to still give 100% to his club. “And then at the end of those long, hard days, still manage to come home & give 100% to his kids & not let the strain of the day impact on his ability to be an amazing Dad & partner.” Prior to his career with the Tigers, the Richmond ruckman played 63 matches with Carlton after he was selected in the 2006 national draft. “Shaun worked bravely and tirelessly to give himself the best chance to overcome this painful injury,” Tigers footy boss Neil Balme said. “We wish Shaun, Megan and their children River and Rosie all the best for the future.” Gale revealed she and Hampson were set to tie the knot in an Instagram post last year, after she’d found a special “rock” at the beach. “I know you’re not supposed to remove shells and rocks from the beach and take them home with you,” she wrote at the time. “But I did find one rock that was pretty special and I just had to keep it.” The couple have been together since 2011.

AFTER debating a possible twilight Grand Final the AFL has locked in the start time for this year’s decider. The Grand Final will remain in its traditional 2.30pm (EST) timeslot, at least for this year. The decider will be played on Saturday, September 29 at the MCG. A possible twilight Grand Final was debated before the AFL Commission settled on the start time in April. “Heritage and tradition prevails,” AFL chief executive Gillon McLachlan said. “Someone will change it one day, whether it’s next year (or) in 10 years I’m sure at some point there’ll be a change.” The day before the Grand Final — Friday, September 28 — is a public holiday in Victoria. The Grand Final parade is held through the streets of Melbourne on that day, ending at the MCG where both participating teams are presented on a stage outside the ground. AFL GRAND FINAL 2018 When: Saturday, September 29, 2.30pm (EST) Where: MCG TV: Live broadcast on Channel 7

JACOB Dawson doesn’t have to try too hard to imagine his first game at Metricon Stadium — he’s probably watched the Suns play there as much as anyone at the club. Dawson became the sixth Palm Beach-Currumbin High School graduate to make his AFL debut for the Suns when he ran out against Hawthorn in Launceston last week. After a solid first-up effort, he should hold his spot this week against Collingwood in what has traditionally been the club’s biggest game of the year. The crowd record of 24,032, the stadium’s only ever sellout for an AFL match, was against the Pies in 2014 — a game made famous by the shoulder injury that cost Gary Ablett close to two years of footy and potentially a third Brownlow Medal. Dawson’s wish was to get any game in his first season but admits a close second was to play against the Magpies. “I was always looking ahead and wanting to play in that game,’’ he said. “The last few weeks I was getting closer and I was lucky enough to get picked last week. “I can’t wait. “It has always been the biggest game of the year at Metricon and hopefully a few of my friends and family and people I’ve played footy with along the Gold Coast can get along.’' The midfielder was a huge Gary Ablett fan as a kid. He has been in Gold Coast’s academy since he was 13 years old and, along with Brayden Crossley, is the first Suns player to spend most of their childhood dreaming of playing for the club. While the Hawks robbed him of a win on debut with their 53-point victory, he says the day will always be a memory he cherishes. “It was a dream come true, growing up on the Coast as soon as the club came in it was where I wanted to end up,’’ he said. “It was disappointing we didn’t get the result, but on a selfish personal level it was a dream come true and a day I will never forget.’’ Dawson, who was selected as an academy selection in last year’s rookie draft, had to wait while school mates Crossley and Jacob Heron and fellow draftee Charlie Ballard got their first opportunities at senior level before him. He said it was tough to wait for his chance but is happy he forced his way in with strong NEAFL form. “Having to earn your chance and your opportunity by playing good footy at NEAFL made the debut even more special instead of just rolling in,’’ he said. “In hindsight it’s unreal having to really earn your spot and I wouldn’t have wanted it any other way looking back.”

GWS spearhead Jeremy Cameron will spend the next five games on the sidelines as punishment for the sickening hit on Harris Andrews last Saturday that left the Lions defender in hospital with bleeding on the brain. Cameron launched late at the ball with Andrews running in his direction, turned his body, raised his left forearm and hit the 21-year-old flush in the jaw. Andrews crashed to the ground and laid motionless while medical staff tended to him, before placing his head in a neck brace and taking him from the ground on a stretcher. He appeared responsive and in good spirits immediately post-match before his condition significantly worsened. The Brisbane vice-captain was later admitted to hospital for testing, while the club consulted a neurosurgeon. Cameron was sent directly to the tribunal by Match Review Officer Michael Christian with the incident graded as intentional, severe impact and high conduct. The 25-year-old argued his actions were careless rather than intentional and appealed for a downgraded sanction of four weeks. He said his intention was initially to spoil the ball before bracing for contact, claiming he didn’t have time to lower his elbow when Andrews reached him. But the tribunal rejected this claim, and suggestions from AFL representative Nick Payne QC that the incident warranted a six-week ban. After a marathon hearing and 33 minutes of deliberations, it was determined Cameron would miss five matches - against Hawthorn, West Coast, Richmond, Port Adelaide and St Kilda. The result is a body-blow for the underperforming Giants, who were already without a raft of players from their best starting side including Rory Lobb (back), Toby Greene (foot), Daniel Lloyd (knee), Brett Deledio (calf), Tom Scully (ankle), Zac Williams (Achilles) and highly touted youngsters Will Setterfield (knee) and Lachie Tiziani (knee). Cameron’s output in attack (35 goals) is almost three times that of the club’s next highest contributors (Zac Langdon and Ryan Griffin with 12 goals apiece). GWS’ other tall targets, Jon Patton (nine goals from 11 games) and Harrison Himmelberg (nine from 13), have struggled this season and, on current form, look unequipped to lead the Giants’ forward line. Leon Cameron’s team is two points and four percent shy of eighth-placed North Melbourne and faces an uphill battle to qualify for finals. Andrews has been ruled out of Brisbane’s clash with Fremantle at Optus Stadium on Sunday will be monitored closely in the following weeks.

RICHMOND premiership forward Jack Riewoldt says the Tigers’ clash with Sydney on Thursday night is “mouth-watering.” The top of the table clash sees both Richmond and Sydney battle it out for top spot, with both teams sitting with a 10-3 win-loss record. Thursday night’s spectacle will be a finals like preview with Riewoldt saying the big match will suit the Tigers’ big game players. “This is what you play footy for,” Riewoldt said on AFL 360. “The only game on a Thursday night to lead off a pretty good round of footy, and we’re playing against a side that is probably the in-form side of the competition at the moment. “I think we play a brand of footy that is suited to finals, which is that contested tackle pressure, get it forward, win the crucial one-on-ones. “It’s certainly a mouth-watering battle for us and for our contested players they really thrive on that.” The Tigers will play their only home game at Etihad Stadium for the season with the forward joking they “would’ve got 90,000 if it was at the ‘G.” It will be the Tigers’ second top of the table clash for the season, having been involved in a clash with West Coast back in Round 9 — which they lost by 47 points. Riewoldt says that being out of Melbourne means the Swans have flown under the radar, despite winning their last six matches. “They go under the radar and they started really poorly last year and they might’ve lost their first six games last year, and then they were right there at the end of the year in the hunt of it,” Riewoldt said. “They do go under the radar and they stay out of sight, out of mind. But they are certainly the yardstick in terms of you know what they are going to bring.” Riewoldt believes the return of small forward Daniel Rioli has improved the team dramatically. “We’ll probably get a couple of players back over the next fortnight which will help out,” Riewoldt said. “Getting Rioli back a few weeks ago was a really big plus for us, sometimes people sort of see Rioli and if you look at the total output he might have, maybe 10-12 touches, “Our small forwards — generally one misses out every week and to get him back and he comes in and has nine tackles, and some really big bits of play that you look back and go ‘oh we missed that’.” Riewoldt also suggested the battle between Richmond defender Alex Rance and Swans forward Lance Franklin isn’t a battle to miss. “Arguably the greatest forward to have played the game in the last 20 years to play arguably the greatest back to have played the game in the last 20 years, it’s going to be one hell of a battle.”

JEREMY Cameron has been rubbed out for five weeks for the errant elbow that knocked out Lion Harris Andrews. After deliberating for over 30 minutes the AFL tribunal rejected the GWS spearhead’s argument that the contact was reckless but not intentional. Cameron’s counsel presented video clips of similar incidents that were deemed reckless and argued he had initially been attempting to spoil the ball and only had six/50ths of a second to change position. They also produced a text message exchange between the two players to highlight Cameron’s remorse. The AFL wanted a six-week penalty and a contrite Cameron afterwards said he accepted the five-week ban. “I didn’t mean to hurt Harris, unfortunately I did and I’m very sorry for that and I hope he gets back to playing football very soon,’’ he said. “I think it was a fair hearing, my main concern at the moment is around Harris and his family, I’m sure it caused him a lot of stress over the past few days and I’m looking forward to seeing him back on the field where he belongs.’’ It is the second major suspension involving a Lions player after Sun Steven May was also rubbed out for five weeks for a hit on Lions ruckman Stefan Martin in 2016. Cameron has also served a previous four week ban for breaking Rhys Mathieson’s jaw. According to Martin, the Lions accepted incidents happened in footy and held no grudges. “I think most blokes in the AFL are genuinely good blokes,” he said. “There’s that fine line you tread. It’s going to happen. “I could do it next week, who knows. “As long as they show some sort of remorse, everyone’s going to accept that.” Andrews suffered a severe concussion and a small bleed on the brain and will not be considered until after an assessment from a neurosurgeon in two weeks’ time. Brisbane said the advice from specialist was that Andrews will make a full recovery. However, with an alarming history of players’ careers being ended by head knocks the Lions will take an ultra-cautious approach to Andrews’ return to football. Chairman Andrew Wellington said there was no way to predict how a player would respond when they returned to training and vowed Andrews’ wellbeing would be the number one priority. Veteran Jonathan Brown and Matt Maguire both finished before they were ready because of concussion while Justin Clarke had to give away footy at just 22-years-of-age when repeated attempts to return to training brought back the symptoms of the concussion. Martin admitted he feared for Andrews’ future when he saw the incident take place. “It obviously looked really graphic,” Martin said. “It was pretty hard to see Harris on the ground making noises and right out of it. “We’ve seen enough times that it can end careers, it would have to go through your mind.’’

A new paper appearing in Proceedings of the Royal Society B shows a varied collection of lizards throughout Asia to be unexpectedly close cousins of beach-dwelling mourning geckos, all descended from a common ancestor species that thrived along an ancient archipelago in the West Pacific that served as a "superhighway" of biodiversity. The dispersal of these lizards, of the genus Lepidodactylus, touches upon a major theory of island biogeography developed by celebrated biologist E.O. Wilson, dubbed the "taxon cycle" model. The new paper also sheds light on lineage diversity and habitat use in the world's most geologically complex insular region -- Pacific island arcs spanning from the Philippines to Fiji. "One of the things that I find exciting about this work is how our phylogeny, estimated from DNA sequence data, provides evidence for a giant, widespread radiation of variably sized mourning geckos, scaly-toed geckos and their relatives," said co-author Rafe Brown, professor of ecology & evolutionary biology and senior curator at the KU Biodiversity Institute. "It was a big surprise to find groups of large-bodied, morphologically diverse, deep forest specialists, nested within a widespread clade of small-bodied coastal generalists -- we didn't think they were related at all." Brown said some of the mourning geckos' closest relatives are physically very different, but all "conspicuously" live along island arcs or lost island arcs that have merged into continents, including the modern-day Philippines, northern and eastern New Guinea, eastern Melanesia, Vanuatu, Fiji, Christmas Island and Borneo. Of 12 major Lepidodactylus lineages, interesting groups include a genus of obligate forest "slender gecko" species and two groups of mysterious "flap-legged" geckos endemic to the Philippines. "The slender, long-bodied geckos of the genus Pseudogekko live deep in forests, and we didn't think they were related to the small, primarily coastal scaly-toed geckos," Brown said. "Another is Luperosaurus, the flap-legged geckos. They're big and robust and have thorns and flaps all over their bodies, and some are orders of magnitude larger than mourning geckos. It's astounding that these lizards that are so physically different have turned out to be close relatives." Brown's collaborators included lead author Paul Oliver of Australian National University as well as Fred Kraus of the University of Michigan, Eric Rittmeyer of Rutgers University, Scott Travers of KU and Cameron Siler of the University of Oklahoma. "To me, this work underscores how much we have yet to understand about the complexity of species diversification on our planet, particularly in island systems," said Siler. "It is amazing to think about the role these ancient island systems played in the evolution of endemic communities in Wallacea, the West Pacific and Australasia." According to Brown, the findings were the result of extensive fieldwork among researchers as well as genetic analysis and data gleaned from biodiversity collections. "No one research group could ever have put this together alone," he said. "Firstly, we never knew these groups were closest relatives, and with separate research groups focusing on different regions with what we thought were unrelated lizard faunas, we might not have even put their DNA sequences into analyses together. The sheer magnitude of the sampling around New Guinea, Australasia, Borneo, Melanesia, Christmas Island, the Philippines and across the Pacific made this study possible. The key was putting together the efforts of many friends and colleagues who provided access to their samples and allowed us to paint the whole picture. Some of these lizards are super rare -- there's no way, in a single person's career, could an individual go to all these places and collect all the necessary samples." Brown said the evolution of Lepidodactylus may be tied to the Vitiaz Arc, a near continuous chain of island arcs that stretched across the West Pacific some 30-40 million years ago during the Oligocene, which today is incorporated into present-day landforms ranging from the Philippines to Fiji. "We used DNA sequencing data and sophisticated statistical analysis to estimate divergence of major groups in the phylogeny," he said. "Those initial divergences probably date back to between 30 and 40 million years. When you scroll back into Earth's history, the landmasses looked very different. One thing that jumps out is the inferred existence of a long chain of islands that stretched out across the Pacific called the Vitiaz Arc. This configuration of fragments of modern-day landmasses and islands that have since shifted but once lined up like a kind of superhighway for biodiversity across the Pacific. Given the timing, it seems like that big long chain of islands may have played a role in the evolution of this group." Brown said as the Vitiaz Arc fragmented and parts turned into the Philippines, Solomons, Fiji, Vanuatu and other islands that today are all very far apart, they may have facilitated the broad distribution of Lepidodactylus. "If ancient lineages evolved and gained widespread distribution across this ancient arc, some really may have persisted for the past 30 to 40 million years," he said. The dispersal of the Lepidodactylus touches upon the model of the "taxon cycle" proposed by E.O. Wilson in his study of ants in Fiji and New Guinea. Wilson's idea was that colonizer species are specialized to survive harsh island coastal terrains but eventually evolve traits to adapt to habitats away from island margins -- more inland and upland -- where some successor species thrive and others go extinct. In the meantime, the original costal colonizers often are replaced by successive waves of new invaders. "It's a very famous, influential idea about how species may colonize new islands and habitats and possibly evolve through predictable ecological transitions," Brown said. "The idea is very provocative because we commonly think about evolution as determined in part by chance, but what some components of species geographical range evolution were almost deterministic? The brilliance of E.O. Wilson was his ability to conceive of a cyclic process based solely on patterns he saw in ant species' distributions. He didn't have the phylogenies we have today, but he inferred relations and put this together as a very clear model, with predictions that we can test today with DNA, sophisticated statistics and knowledge of species' distributions." According to Brown, findings in the new paper include support for the taxon cycle model in Lepidodactylus but also some evidence that runs counter to it. "In some cases, lizard lineages limited to continental fragments have persisted," he said. "And in some cases, we did not find the most ancient lizards to be specialists from interior habitats on the oldest land masses. Some ancient lineages are found today on the margins of arc islands or just on the edges of larger landmasses. There are exceptions to any rule, of course. For instance, Lepidodactylus ranauensisis -- a species that looks like the kind of common lizard that you might expect to find on a coconut tree on a beach in the Philippines -- is actually endemic to Mount Kinabalu on Borneo, maybe 32 million years old, and has no close relatives. Perhaps it is the only surviving member of a once more diverse group of lineages that have gone extinct. We just don't know. But to find these single evolutionary relics is sort of exciting for a phylogeneticist."

New research has revealed how the history of life can be distorted by the ways animals decompose and lose body parts as they decay -- and the ways in which decayed bodies ultimately become fossilised. In a new study published in the journal Palaeontology, a group of palaeontologists from the UK and Ireland, led by the University of Leicester, has followed a macabre, and nasally-challenging road to knowledge -- watching carefully as animal carcasses decompose in order to better understand the process. Like on-screen zombies in popular TV programmes such as The Walking Dead that gradually deteriorate through time, fossils preserve only incomplete remains of the living body. A key part of palaeontological research involves reconstructing long-extinct creatures to understand what they were like when they were alive. This knowledge allows us to answer fundamental questions -- how did they move and interact with their environment? How did they feed and reproduce? Which of today's organisms are they most like and most closely related to? Understanding how much of a fossil is missing, and what has been changed by decay and fossilisation, helps to create a more accurate picture of ancient animals and ecosystems. This is particularly important for things lacking hard skeletons and shells -- including crucial fossil evidence of early animal life on Earth. "As soon as an organism dies, it starts to decay, and this process of decomposition inevitably involves changes in how features or body parts look: they may collapse, alter their shape or position; all too soon they liquefy and are eaten by bacteria until nothing remains," says Professor Sarah Gabbott from the University of Leicester's School of Geography, Geology and the Environment. Professor Mark Purnell, lead author of the study adds: "The more a body deteriorates over time, the more body-parts are missing -- rather like modern representations of zombies in Game of Thrones and The Walking Dead. "One consequence of this decay is that palaeontologists have to work with incomplete fossils. Some of the features that are present don't look anything like they did when the animal was alive, and many features are missing completely. The trick is to be able to recognise partially-decomposed features, and where body parts have rotted away completely." The approach used in the UK-Irish collaboration involves 'laboratory decay experiments': keeping careful records of every body part as it decays away. The results of rotting a whole range of dead animals, from hagfish and lampreys (primitive eel-like creatures) to insects and various worms, show that carefully designed experiments provide unique insights into the processes of decomposition and fossilisation. In the new paper they highlight the importance of understanding how a fossil is formed before trying to reconstruct it -- how the processes of decay that lead to loss of body parts interact with the processes that cause them to become preserved and fossilised. Dr Maria McNamara, collaborator in the study, adds: "If we understand this we are better able to avoid producing incomplete restorations of animals with crucial parts missing or decayed, and to recognize and be aware of the gaps in our knowledge,." The research is supported by the Natural Environment Research Council.

A University of Cincinnati geology student is helping NASA determine whether life existed on other planets. Doctoral candidate Andrew Gangidine is working with UC geology professor Andrew Czaja to develop a marker for ancient bacterial life on Mars. The research could help scientists put to rest one of our most fundamental mysteries. "We're trying to answer the question: How rare is life in the universe?" Gangidine said. Czaja, an assistant professor in UC's McMicken College of Arts and Sciences, serves on a NASA advisory committee that will decide where on Mars to send the next remote-controlled rover. Among other objectives, the rover will look for evidence that life once existed on the red planet. The advisory committee has narrowed the list of landing-site candidates to three and will recommend a finalist later this year. Meanwhile, Gangidine is studying microbial life in silica hot springs to come up with a useful indicator of life on Mars. For the past two years, he has conducted fieldwork in the geyser basins of Wyoming's Yellowstone National Park to examine what elements are associated with bacteria that live in these geothermal pools. "We want to remain objective. Some people think there has to be life on Mars," Gangidine said. "Others think there certainly isn't life on Mars. And either side has a good chance of being correct. Both have valid arguments. Which is why if we go there and don't see anything, it won't be 'mission fail.'" Gangidine presented his research April 25 at the Second International Mars Sample Return conference in Berlin, Germany. Today, we know that life cannot exist on Mars, at least not on its dry surface. Solar radiation split most of its surface water into its elemental parts nearly 3 billion years ago when the red planet lost its protective magnetic field. But scientists are debating whether life might exist somewhere deep underground, among pockets of water trapped around geothermal areas similar to Yellowstone's geysers. Finding evidence of life on Mars is surprisingly complicated. If Mars ever sustained life, it's possible that it was wiped out when most of its atmosphere vanished in the solar wind, Czaja said. So NASA scientists must be prepared to look for fossil evidence of bacterial life dating back that far. Gangidine said the good news is that similar fossils of early bacterial life more than 3.5 billion years ago have been found on Earth. This makes him optimistic that if similar life ever existed on Mars, NASA has a chance of finding a fossil record of it. "We can look at life being preserved in these silica deposits today. We have evidence of this happening throughout geologic time," Gangidine said. "What we're trying to do is catch fossilization as it happens. What happens to the microbes themselves? And what happens to the trace elements we think are associated with them while they're alive?" To unearth clues about ancient life on Mars, geologists look to hot springs such as those found in America's first national park. Gangidine and his colleagues need permits to collect samples in the park's backcountry. But exploring the geyser basins can be tricky and dangerous. A tourist died in 2017 after falling into one of the basin's boiling pools while hiking off-trail. "These things really can strip the flesh off your bones," Gangidine said. "At the bottom of hot springs we study you see skulls of bison and other animals that were unfortunate enough to wander too close." Gangidine's team includes an experienced backcountry field researcher, UC postdoctoral fellow Jeff Havig who is now with the University of Minnesota. They pick their way carefully across the caldera. Sometimes, they can see where a bison's hoof has broken through the thin crust to reveal steaming mud. The geology work takes them across "quaking bogs," a thin layer of peat and grass covering deep shifting mud. Gangidine was walking alongside a colleague on one such hike when he sank above his knees in the treacherous mire. "Luckily, that place wasn't super hot. But I was walking just a foot away from someone else. The ground can really change quickly," he said. "When we go into these settings, we have to be very careful." Boiling acid and lava-like mud aren't the only hazards for researchers in the geyser basins. They also have to be careful not to spend too long around the steam vents, which contain a mix of gases such as carbon dioxide, hydrogen sulfide and methane that can asphyxiate a person under the right conditions. The U.S. Geological Survey documented this phenomenon in 1888 in part of the park nicknamed "Death Gulch," a natural depression between two steep hills where toxic gases bubble up from Cache Creek. Harvard University geologist T.A. Jaggar Jr. returned to the area in 1899 and found six bears, an elk and various small animals that died apparently after succumbing to the toxic fumes. But even in the fresh air, the gas rising from the ground can have a cumulative effect, Gangidine said. "These hot springs emit a lot of gases you don't want to breathe in. They bind to the hemoglobin that carries oxygen through your body. Breathing that in, you get very fatigued," Gangidine said. "That's why we try to schedule a day out of the field for every three days we work in the field. If you're there for four days, you can really feel like a zombie. It's really hard to think, hard to move." As a biology undergraduate at UC, Gangidine worked with UC biology professor Dennis Grogan to examine microbial life called extremophiles that live in hostile places such as Yellowstone's acidic or alkaline hot springs. Now as a geologist, Gangidine is studying the fossils these hardy single-celled creatures leave behind. "Hot springs make silica deposits that preserve life really well," Gangidine said. "When left exposed on a planet's surface, it doesn't crystallize and doesn't metamorphose. So these samples should be relatively well preserved if we find them." In UC professor Czaja's geology lab, Gangidine peers through a microscope at slides he prepared from chunks of Yellowstone silica he took from a mountainous steam cone geyser. The bacterial filaments from samples taken at the top of the geyser are full of color. But the older samples, some perhaps thousands of years old, are colorless, even if they hold their shape. So for more clues about this basic form of life, Gangidine subjects the bacterial samples to elemental analysis using a secondary ion mass spectrometer. The analysis renders the elements in vivid color: deep yellows, reds and greens representing chromium or gallium perhaps associated with the bacterial life. If Gangidine finds a correlation between the concentrations and spatial distributions of particular elements and the bacteria, it might serve as a biosignature that scientists can use to identify past life on Mars. "The reason we chose gallium is it's not known to be associated with life. But when we look at the fossilized bacterial samples, we find it, so there must be something going on," Gangidine said. "Do the bacteria store certain elements preferentially as opposed to what you would find elsewhere in these rocks?" Gangidine is working with researchers in Australia, home to some of the world's oldest fossils, some dating back 3.5 billion years. "If I want to create a biosignature, I have to prove that it persists throughout time," Gangidine said. "It exists in these relatively younger samples. But does it exist in these ancient samples, too? That will be crucial to figure out." Gangidine also plans to build an artificial hot spring in a lab aquarium using similar elements found in geysers. By introducing a super-saturation to the water, the excess silica will precipitate much the same way it does in nature. Then he can add trace chemicals associated with life and study what happens in a miniature world absent of life. "To prove we found a biosignature, we have to prove the signature doesn't occur without life," he said. "Gallium is the one we were surprised by," Czaja said. "It is associated with silica near the bacteria but isn't in the bacteria." Like Gangidine, Czaja got his start in the sciences by studying biology before pursuing a career in paleontology. Czaja's NASA advisory committee will meet in October to decide where on Mars they would like to send the rover among the three preferred destinations. The rover is tentatively slated for launch in July or August of 2020, arriving on Mars about seven months later. "NASA tends to like to go new places to push the frontier. Geologists like to go back to the same places over and over to ask new questions," Czaja said. The rover will collect samples in sealed containers for shipping back to Earth in a later mission. So it could be many years before geologists such as Czaja and Gangidine know whether their hunches about where best to look for life on Mars were correct. Helping to frame a question that you may never live to see answered is one of science's most selfless pursuits, Czaja said. "One thing I like about these NASA missions is the long-term thinking and planning," he said. "People working on these projects now may never see the results. But they're still willing to put in the work because it's such a fascinating question." The Mars 2020 mission will not be a failure if scientists find no evidence of life. Quite the contrary, Gangidine said. "If we find it, we can say maybe life is not that rare among planets," Gangidine said. "But if we don't find life in places that would be the most ideal and best preserved candidates, then maybe life is pretty rare." But if NASA does find evidence of life on Mars, that might suggest that sparking life from a primordial soup isn't so extraordinary after all. And the first question will be how life on Mars compares to life on Earth, Czaja said. Was there a common ancestor? "Maybe we're all Martians," Czaja said. Any claim about the existence or absence of life on Mars will be subjected to worldwide scrutiny and skepticism. Czaja said researchers must be prepared to provide a wealth of evidence to fortify their findings. "It's not nearly enough to find something that looks like a bacterial cell," Czaja said. "There are nonbiological things that could look like that. But if you have a cascade of traits -- this and this and this added together -- it's hard to explain it any other way except for life."

A new article in the journal Science provides guidance for those intending to study ancient human remains in the Americas. The paper, written by Indigenous scholars and scientists and those who collaborate with Indigenous communities on studies of ancient DNA, offers a clear directive to others contemplating such research: First, do no harm. Scientists studying ancestral remains have similar obligations to those that bind researchers working with living human subjects, the authors wrote. The descendants or people affiliated with those who lived hundreds or thousands of years ago deserve to be consulted before their ancestors are disturbed. Even in cases where the remains were collected long ago and moved far from their original burial place, and even when the surviving lineages are in doubt, scientists ought to consult Indigenous groups living on the land or claiming ancestral ties to the region where the ancestors were found, the authors said. "Right now, there are inconsistent or no regulations for working with ancient ancestors," said University of Illinois anthropology professor Ripan Malhi, a co-author of the report. "And there are no requirements for working with descendant or affiliated communities, even though new scientific findings relating to their ancestors can have serious implications for them." Malhi partners with Indigenous communities to study ancient DNA from individuals found on lands their descendants still live on. Malhi, along with Indigenous scientists, scholars and other scientists who work with Native American and First Nations communities, worked to create the Summer internship for INdigenous Peoples in Genomics, which trains Indigenous scientists in genomics techniques and explores ethical concerns. Not consulting Indigenous communities before analyzing ancient DNA potentially harms those groups, said Alyssa Bader, a co-author and graduate student at the University of Illinois. "Genetic analyses can reveal information not just about the ancestors, but also their descendants. If genetic variants associated with specific diseases are identified in ancestors, for example, this can influence how we think about disease susceptibility in the descendant community -- and that community could be stigmatized," she said. New findings also may interfere with ongoing treaty negotiations, she said. "For Indigenous communities involved in negotiating land claims or repatriation, new genetic findings could either bolster or complicate those claims," she said. Studying ancient DNA without consulting descendant communities is also a missed opportunity, said Concordia University professor Jessica Bardill, the lead author of the article. "The engagements we highlight show that collaboration with communities not only strengthens the analysis but also can allow for better questions to be asked in the research, informed by community narratives about the ancestors, their lands and their relationships," she said. For these and other ethical and practical reasons, Malhi said, it's in a scientist's interest to identify and locate potentially affected groups, consult with them about the research and invite them to join the effort, thereby improving the scientist's understanding of the context in which the ancient peoples lived. It also allows Indigenous communities to guide the science and ask research questions that are of interest to them. "Engaging communities at the outset is critical for understanding their concerns or questions about research involving ancient relatives. Without feedback from the community, scientific interpretations remain one-sided and inherently biased," said Nanibaa' Garrison, a bioethics professor at Seattle Children's Research Institute and the University of Washington School of Medicine, and a co-author of the article.

If you want to know about your ancestors today, you can send a little saliva to a company where -- for a fee -- they will analyze your DNA and tell you where you come from. For scientists trying to find out about ancient peoples, however, the challenge is more complex. Research published in the journal PLOS ONE by a team of archaeologists and microbiologists from Nevada's Desert Research Institute (DRI) and Southern Illinois University Carbondale (SIU) showcases the use of modern research methods to uncover clues about the genetic ancestry of Native Americans who inhabited the Desert Southwest during the last thousand years. "We were surprised by the consistency with which we were able to recover intact human DNA from a common type of plant-based artifact," explained co-principal investigator Duane Moser, Ph.D., an associate research professor of microbiology at DRI and director of DRI's Environmental Microbiology Laboratory. During the Late Holocene Epoch, which began 12,000 to 11,500 years ago and continues through the present, occupants of the Mule Spring Rockshelter in the foothills of the Spring Mountains of southern Nevada commonly gathered agave and yucca plants for food. The artichoke-like hearts and inner leaves of the plants were roasted then chewed to consume the sweet fleshy pulp. This left wads of stringy fibers called 'quids,' which spat out and left behind. In the late 1960s, researchers from DRI and the University of Nevada, Las Vegas (UNLV) led by Richard Brooks, recovered thousands of quids at the rockshelter. Put into storage for half a century without any consideration for DNA preservation, a DRI-led research team decided to re-examine the quid specimens as possible repositories for ancient DNA. "The quid's coarse texture is excellent for capturing skin cells from the mouth, making them the equivalent of the modern-day cheek swab," explained Susan Edwards, an associate research archaeologist at DRI and co-principal investigator who first thought of applying DNA extraction techniques to the quid samples. The research team used laboratory and computational resources at DRI's Southern Nevada Science Center in Las Vegas, and later at SIU, to identify changes in the mitochondrial DNA sequences that are maintained in ancestrally related populations called haplogroups. These haplogroups can then be compared to Native American tribes and other ancient DNA lineages. The study showed that the Mule Spring Rockshelter quid specimens ranged in age from about 350 to 980 years old. Because Mule Spring Rockshelter sits at a crossroads between the southern Great Basin, the Mojave Desert, and the Southwest Puebloan cultures, these results may provide a better timeline for an important but contentiously debated event in human history known as the Numic Spread. Today's Numic people contend they have always been here, a position some scientists readily support. However, some evidence suggests that Numic-speaking ancestors of contemporary native peoples spread from southern California throughout the Great Basin about 500 to 700 years ago; a date range which overlaps with the current study. Other studies suggest a much earlier arrival. This research marks only the second time that scientists have been able to sequence human DNA from plant-based artifacts, expanding upon an approach utilized by Steven LeBlanc of Harvard University. "Since these materials were also radiocarbon dated, in essence, they provide a time-resolved hotel registry for this unique site over a period of hundreds of years," added Moser. As an added benefit of utilizing DNA from quid samples (rather than from more traditional sources such as bones or teeth), the research team found that they were able to obtain the information they needed while being respectful of cultural sensitivities. "The distinct advantage of this genetic technique, is that it does not require the sampling of human remains," said Scott Hamilton-Brehm, lead author on the study and assistant professor of microbiology at SIU who completed his postdoctoral research at DRI. In the future, the team hopes to continue this work by targeting additional quids from the Mule Spring Rockshelter collection, with the possibility of corroborating evidence of older dates for habitation of the site suggested by prior studies of more traditional cultural artifacts. Plans are in the works to perform similar studies on quids from other Great Basin sites to glean additional information about the movements of ancient peoples and utilize more powerful analytical approaches to obtain greater DNA sequence coverage than was obtained by this pilot study. "We look forward to learning more about Native American presence in the Great Basin and Southwest area, and how the data compares over time," added Lidia Hristova, a graduate of the UNLV Anthropology Program who conducted much of the hands-on DNA extraction from the samples while working as an undergraduate research assistant at DRI and studying at UNLV.

The ancient genomes of the Tsimshian indigenous people left tell-tale markers on the trail of their past, revealing that at least 6,000 years ago their population size was on a slow but steady decline. The American Journal of Human Genetics published the findings, which draw from the first population-level nuclear DNA analysis of a Native American group from ancient to modern times. "The finding contradicts a popular notion," says John Lindo, a geneticist in Emory University's Department of Anthropology and first author on the paper. "There is this idea that after Native Americans came in through the Bering Strait that they were all expanding in population size until Europeans showed up. At least for this one population, we've shown that was not the case." A boon in next-generation DNA sequencing technology has opened the possibility to explore the evolutionary history of different populations. "Ancient nuclear DNA analysis is a relatively new field," Lindo says. "Not until recently have we had methods to sequence an entire genome quickly and inexpensively." Nuclear DNA provides information on an individual's lineages going back hundreds of thousands of years. Lindo is one of the few geneticists looking at ancient whole genomes of Native Americans. He is especially interested in understanding how the genomes of their different populations evolved over time. "Their evolutionary histories are radically different," Lindo says. "Over thousands of years, various Native American populations have adapted to living in every ecology throughout North and South America, from the Arctic to the Amazon. That's about as an extreme as you can get for differences in environments." The Tsimshian people historically lived in longhouses in coastal British Columbia and southern Alaska where they harvested the abundant sea life. Lindo and his colleagues sequenced the genomes of 25 living Tsimshian people and 25 ancient individuals who lived in the same region between 6,000 and 500 years ago, and confirmed that they were a continuous population through time. In a previous paper, drawing from the same data set, they found a dramatic shift between the two time periods in a class of genes associated with the immune system, suggesting a strong evolutionary pressure on the population to adapt to pathogens. A demographic model indicated a crash in the Tsimshian population size of about 57 percent during the early-to-mid 19th century. That finding fitted with historical accounts for how smallpox, introduced by European colonization, devastated the Tsimshian population during two epidemics within that timeframe. The current paper looked at broader genetic variations between the ancient and modern DNA. An analysis showed both how the variation declined slowly in the ancient population before the collapse, but has since recovered. "After a population collapse, only a subset of the genetic diversity remains," Lindo says. "We find a more nuanced story, that despite the population collapse, the genetic diversity of modern Tsimshian people varies significantly." Intermarriage with other Native American groups and non-native populations increased the genetic diversity of some of the modern-day Tsimshian people so that it is near the levels prior to their population collapse, the analysis showed. "A population with relatively high genetic diversity has a greater potential to fight off pathogens and avoid recessive traits," Lindo says. "It exemplifies the benefits of gene flow between populations, especially following catastrophic events such as the small pox epidemics that the Tsimshian endured." Senior authors on the paper are Michael DeGiorgio from Pennsylvania State University and Ripan Malhi from the University of Illinois. The paper's coauthors include Tsimshian representatives Joycelynn Mitchell and Barbara Petzelt from the Metlakatla Treaty Office in Prince Rupert, Canada. Malhi, a leader in forging trusting relationships between genetic researchers and indigenous people, was a mentor to Lindo, who earned his PhD at the University of Illinois at Champaign-Urbana. Lindo is continuing that tradition of building trust and working closely with indigenous populations. His ancient DNA research at Emory integrates the approaches of ancient whole genomes, statistical modeling and functional methods. One of his projects is focused on genetic fluctuations to help understand ancient adaptions in various Native American populations. He is currently working with 10 different tribes from throughout North America. "Community engagement is essential when working with indigenous communities," says Lindo, explaining that he first meets personally with a tribal community to talk about how a genetic study might add to their knowledge of their own history. "I listen to their stories and how they are working to keep their cultures alive," he says. "One elder from a southwestern tribe told me that his grandfather was taken away in the early 1900s because he was a shaman and Christianity was swelling through the area. Each tribe's stories are different but they are all powerful, and sometimes difficult, stories to hear." Most ancient DNA analyses have come out of Europe, where more ancient DNA labs are based and cold temperatures have helped preserve specimens. Lindo wants to bring some of the same insights that those of European ancestry are gaining about their past to Native Americans. "I'd like to disentangle this idea that Native Americans are part of a singular race," he says. "I want to help Native American tribes to reclaim knowledge of their very ancient evolutionary histories -- histories that have been largely wiped away because of colonialism."

Some of the earliest animals on Earth were soft-bodied ocean-dwellers that ranged from a few inches to several feet and were shaped like circular discs, tubes, or cushion-like bags. While fossil impressions from the Ediacaran Era -- 635 to 541 million years ago -- reveal their existence, little is known about this fascinating group of animal-like creatures, which preceded more complex animals with skeletons. In a paper published Friday, May 4, in Nature Communications, researchers at the University of California, Riverside, used biomarkers in ancient rocks to learn more about the environmental conditions and food sources that sustained this group of animals, called the Ediacara Biota. Led by Gordon Love, a professor of biogeochemistry at UCR, the team studied molecular fossils, known as lipid biomarkers, made by the ancient biological communities and preserved within sedimentary rocks that contain early animal fossils. The communities they studied lived off the coast of the ancient continent Baltica -- encompassing modern day Russia, Ukraine and the Baltic States -- between 560 to 540 million years ago. Love said the Ediacara Biota lived in nutrient-poor regions of the sea on the continental shelf, an extension of land under the ocean that results in relatively shallow water. Despite this oligotrophic environment, the researchers found there were sufficient nutrients and organic debris for feeding sustained by bacterial primary production and dissolved organic matter. The team also observed a dearth of sponge biomarkers, suggesting possible niche competition between the Ediacara Biota and sponges in different marine settings. "Different environmental conditions and nutritional resources could have selected for very different community structures in different regions of the Ediacaran oceans," Love said.

An international collaboration of scientists, led by the University of Leicester, has investigated Earth's climate over half a billion years ago by combining climate models and chemical analyses of fossil shells about 1mm long. The research, published in Science Advances, suggests that early animals diversified within a climate similar to that in which the dinosaurs lived. This interval in time is known for the 'Cambrian explosion', the time during which representatives of most of the major animal groups first appear in the fossil record. These include the first animals to produce shells, and it is these shelly fossils that the scientists used. Scientists have long thought that the early Cambrian Period was probably a greenhouse interval in Earth's climate history, a time when there were no permanent polar ice sheets. Until now, however, scientists have only had a sense of what the Cambrian climate was like because of the types of rock that were deposited at this time -- while it has long been believed that the climate was warm, specific details have largely remained a mystery. Data from the tiny fossil shells, and data from new climate model runs, show that high latitude (~65 °S) sea temperatures were in excess of 20 °C. This seems very hot, but it is similar to more recent, better understood, greenhouse climates like that of the Late Cretaceous Period. Thomas Hearing, a PhD student from the University of Leicester's School of Geography, Geology and the Environment, explained: "Because scientists cannot directly measure sea temperatures from half a billion years ago, they have to use proxy data -- these are measurable quantities that respond in a predictable way to changing climate variables like temperature. In this study, we used oxygen isotope ratios, which is a commonly used palaeothermometer. "We then used acid to extract fossils about 1mm long from blocks of limestone from Shropshire, UK, dated to between 515 -- 510 million years old. Careful examination of these tiny fossils revealed that some of them have exceptionally well-preserved shell chemistry which has not changed since they grew on the Cambrian sea floor." Dr Tom Harvey, from the School of Geography, Geology and the Environment, added: "Many marine animals incorporate chemical traces of seawater into their shells as they grow. That chemical signature is often lost over geological time, so it's remarkable that we can identify it in such ancient fossils." Analyses of the oxygen isotopes of these fossils suggested very warm temperatures for high latitude seas (~65 °S), probably between 20 °C to 25 °C. To see if these were feasible sea temperatures, the scientists then ran climate model simulations for the early Cambrian. The climate model simulations also suggest that Earth's climate was in a 'typical' greenhouse state, with temperatures similar to more recent, and better understood, greenhouse intervals in Earth's climate history, like the late Mesozoic and early Cenozoic eras. Ultimately, these findings help to expand our knowledge of the early animals of the period and the environment in which they lived. Thomas Hearing said: "We hope that this approach can be used by other researchers to build up a clearer picture of ancient climates where conventional climate proxy data are not available." The research was carried out as an international collaboration involving scientists from the University of Leicester (UK), British Geological Survey (BGS; UK), and CEREGE (France). This collaboration brought together expertise in geochemistry, palaeontology and climate modelling to tackle this longstanding problem. The scientists have co-authored an open access (publicly available) paper in the journal Science Advances.

New research by an international team including scientists from the Max Planck Institute for the Science of Human History, the University of Tübingen, EPFL Lausanne and the University of Zurich has revealed that there was much more diversity in the leprosy strains circulating in Medieval Europe than previously thought. This finding, based on the sequencing of 10 new ancient genomes from the leprosy-causing bacterium Mycobacterium leprae, complicates prior assumptions about the origin and spread of the disease, and also includes the oldest M. lepraegenome sequenced to date, from about 400 AD in the United Kingdom. Leprosy is one of the oldest recorded and most stigmatized diseases in human history. The disease was prevalent in Europe until the 16th century and is still endemic in many countries, with over 200,000 new cases reported annually. The bacterium Mycobacterium leprae is the main cause of leprosy. Previous research on the bacterium suggested that it clusters into several strains, only two of which were present in Medieval Europe. The present study, published in the journal PLOS Pathogens, aimed to further investigate the history and origin of M. leprae by looking for genetic evidence from a large number of ancient samples from throughout Europe. 10 new ancient genomes of M. leprae dating from approximately 400-1400 AD The current study examined approximately 90 individuals with skeletal deformations that were characteristic of leprosy, from across Europe and from time periods ranging from approximately 400 AD to 1400 AD. From these samples, 10 new medieval M. leprae genomes were fully reconstructed. These genomes represent all known strains, including strains that are today associated with different locations around the globe, including Asia, Africa and the Americas. Additionally, in this study multiple strains were often found in the same cemetery, illustrating the diversity of the leprosy strains circulating throughout the continent at the time. "We found much more genetic diversity in ancient Europe than expected," explains Johannes Krause, senior author of the study and a director at the Max Planck Institute for the Science of Human History. "Additionally, we found that all known strains of leprosy are present in Medieval Europe, suggesting that leprosy may already have been widespread throughout Asia and Europe in antiquity or that it might have originated western Eurasia." Oldest leprosy genome to date One M. leprae genome reconstructed by the team was from Great Chesterford, England, and dates to between 415-545 AD. This is the oldest M. leprae genome sequenced to date and comes from one of the oldest known cases of leprosy in the United Kingdom. Interestingly, this strain is the same found in modern-day red squirrels and supports the hypothesis that squirrels and the squirrel fur trade were a factor in the spread of leprosy among humans in Europe during the medieval period. "The dynamics of M. leprae transmission throughout human history are not fully resolved. Characterization and geographic association of the most ancestral strains are crucial for deciphering leprosy's exact origin" states lead author Verena Schuenemann of the University of Zurich. "While we have some written records of leprosy cases that predate the Common Era, none of these have yet been confirmed on a molecular level." The abundance of ancient genomes in the current study has resulted in a new and older estimate for the age of M. leprae than previous studies, placing its age at least a few thousand years old. "Having more ancient genomes in a dating analysis will result in more accurate estimates," explains Krause. "The next step is to search for even older osteological cases of leprosy than currently available, using well-established methods for identification of potential cases."

A 180-million-year-old fossil has shed light on how some ancient crocodiles evolved into dolphin-like animals. The specimen -- featuring a large portion of backbone -- represents a missing link in the family tree of crocodiles, and was one of the largest coastal predators of the Jurassic Period, researchers say. The newly discovered species was nearly five metres long and had large, pointed teeth for grasping prey. It also shared key body features seen in two distinct families of prehistoric crocodiles, the team says. Some Jurassic-era crocodiles had bony armour on their backs and bellies, and limbs adapted for walking on land. Another group had tail fins and flippers but did not have armour. The new species was heavily armoured but also had a tail fin, suggesting it is a missing link between the two groups, researchers say. It has been named Magyarosuchus fitosi in honour of the amateur collector who discovered it, Attila Fitos. The fossil -- unearthed on a mountain range in north-west Hungary in 1996 and stored in a museum in Budapest -- was examined by a team of palaeontologists, including a researcher from the University of Edinburgh. It was identified as a new species based on the discovery of an odd-looking vertebra that formed part of its tail fin. The study, published in the journal PeerJ, also involved researchers in Hungary and Germany. It was supported by the Leverhulme Trust and the SYNTHESYS project, part of the European Commission's Seventh Framework Programme. Dr Mark Young, of the University of Edinburgh's School of GeoSciences, who was involved in the study, said: "This fossil provides a unique insight into how crocodiles began evolving into dolphin and killer whale-like forms more than 180 million years ago. The presence of both bony armour and a tail fin highlights the remarkable diversity of Jurassic-era crocodiles."

A new study is suggesting many of the plants and animals that call Latin America home may actually have their roots in the Amazon. The study, co-authored by Harvard Visiting Scholar Alexandre Antonelli and an international team of researchers, found that a dynamic process of colonization and speciation led to the formation of the American tropics, which is today the most species-rich region on the planet. The study is described in a May 14 paper published in the Proceedings of the National Academy of Sciences. "We were astonished to detect so much movement across such different environments and over such large distances," said Antonelli, the study's lead author. "Up until now, these natural dispersal events were assumed to be quite rare. Our results show how crucial these events have been in the formation of tropical America's unique and outstandingly rich biodiversity." Over tens of millions of years, thousands of species have naturally made their way to new regions, where some of them survived and adapted to new conditions. These adaptations added up, and when the offspring were sufficiently different from earlier generations, new species were formed. Over time, this dynamic process occurred so many times in the American tropics that the area became the exceptionally diverse region we see today. To understand that process, Antonelli and colleagues used information on the evolutionary relationships, distribution, and timing of the origin of thousands of tropical species to calculate how often species dispersed into new regions or new environments. Much of this information comes from natural history collections, including specimens at Harvard University Herbaria and the Museum of Comparative Zoology, where Antonelli is currently working. What they found, he said, is that while all regions in the American tropics have exchanged species with one another, Amazonia stood out as the main source. "Two main factors seem to explain the key role of Amazonia in exporting so much diversity: its huge area, and the large amount of time that species have existed there. Together, these have increased the chances of species dispersing into new habitats and regions," says Antonelli. For all the groups researchers examined -- from plants to birds to frogs to mammals, and even frogs, snakes and lizards -- Antonelli said that pattern remained essentially the same, suggesting that biotic movements are important for generating diversity among all life forms. "Most evolutionary research focuses on how new species form. But we want to understand how whole ecosystems evolve, and what makes some regions much more species-rich than others. This is important because it shows us how plants and animals deal with new environments and what factors determine biodiversity," Antonelli concludes. This study highlights the far-reaching importance of tropical regions -- comprising rainforests, savannas and mountain ecosystems, among others -- in sustaining the world's biodiversity. Most tropical ecosystems are now threatened due to human activities, and many species are on the edge of extinction, further highlighting the need for immediate and widespread protection. "This study brings together a truly massive amount of data and distills it down in a way that gives crucial insights into the history of biodiversity in the tropics," said Kyle Dexter, Senior Lecturer in the School of GeoSciences at the University of Edinburgh and Research Associate at Royal Botanic Garden Edinburgh." The previous paradigm in the tropics focused on local evolution when explaining high tropical diversity, but clearly there is a shift happening to acknowledge the importance of dispersal, and this study contributes decisively to this shift." Going forward, Antonelli hopes to continue to examine the dynamic processes that drive the distribution and evolution of species, especially in tropical regions. To this end, his group is combining data and techniques from several disciplines, from fossils to genomes and from fieldwork to software development. "Biodiversity is the dark matter of our planet: we know there must be millions of species that we haven't found yet. Finding, understanding, and protecting this diversity is probably humanity's toughest but most important challenge."

Australia has a bunch of kangaroo species, Madagascar has multiple species of lemurs, the Galapagos Islands have boulder-sized tortoises -- islands get lots of cool animals. That's because when animals are isolated on islands, they can evolve into strange new species found nowhere else on Earth. But what's the cut-off -- how small can an island be and still support the evolution of multiple new species from a single common ancestor? A team of mammalogists just discovered that four species of mice evolved from one common ancestor on Connecticut-sized Mindoro Island in the Philippines, making it the smallest known island where one kind of mammal has branched out into many more. "The single most remarkable thing about planet Earth is there are so many species here, so much biodiversity. We take it for granted, but holy cow, there's a whole lot of stuff out there -- how did it get here?" says Lawrence Heaney, Negaunee Curator of Mammals at Chicago's Field Museum and co-lead author of a recent paper in the Journal of Biogeography. "This is one of the few papers ever written to look at whether there's a limit to how small an island can be for species diversification to occur, and it's the only one looking at it in mammals. Mindoro is by far the smallest island on which we've seen this happen." According to Heaney, this quest to find the smallest island that can support new mammals started with a thought experiment posed in 1980. Michael Soulé, a conservation biologist, wondered if new animal species could diversify in an area the size of the largest of existing national parks. Diversification means that multiple species arise from one parent species. "There are many islands that have species that arrived from somewhere else and that subsequently changed into something distinctive. Many of these islands are much smaller than Mindoro," explains Heaney. "Rather, the key to this study is whether a single species that arrived from somewhere else has produced multiple species that all evolved within the given island from the single ancestral species. It is the issue of an increase in the number of species within the island, by evolution within the island." Previously, the smallest island where scientists knew mammal species had diversified was Luzon, the largest island in the Philippines. But Luzon is one of the biggest islands in the world, about the size of Virginia. Heaney and his team wanted to see if they could do one better -- "We looked at a map and said, okay, where's there a smaller island where diversification may have occurred?" The scientists didn't have to look far -- they turned to Mindoro, a small island just across a channel from Luzon. Mindoro is a tenth the size of Luzon -- it's about two-thirds the size of Connecticut. Heaney's colleague Danny Balete, now deceased, led the fieldwork missions on Mindoro for four field seasons, searching for the island's mammals. This is where the worm-eating mice come in. "The mice we looked at in this study are all members of the "earthworm mouse" group Apomys -- they love earthworms, but they also eat seeds and fruits. They've got big dark eyes, great big ears, long soft fur, white feet, dark tails -- they're very pretty little mice," says Heaney. When the team analyzed the DNA of Mindoro's earthworm mice, they found that the mice belonged to four separate species, three of which were new to science. And all four of the species, Heaney says, evolved on Mindoro from a common ancestor. "The results are unambiguous -- we've got four species of forest mice on Mindoro from one colonization event from Luzon about 2.8 million years ago," says Heaney. "And three of those four mouse species are found on their own separate mountains." Chris Kyriazis, Heaney's former undergraduate student and co-first author on the paper, led the DNA analysis from the Field Museum's Pritzker DNA Lab. "By examining genetic variation across these populations, we were able to confirm not only that these mice originated from a single colonist on Mindoro, but also that they are distinctive enough to be considered different species. The fact that variation in external measurements show the same pattern only strengthens the case," says Kyriazis, who is now pursuing his PhD in biology at UCLA. The fact that the four mouse species evolved on this little island means that there's a new answer to the question posed by Soulé in 1980: mammals can diversify in an area as small as Mindoro. And since Mindoro is the same size as Yellowstone National Park, that means that new mammal species can evolve from one ancestor in areas as small as at least some large wildlife preserves. The implications of Heaney and Kyriazis's discovery goes far beyond a thought experiment, though: it gives scientists a valuable tool for planning conservation spaces. "This study changes how I think about conservation," says Heaney. "When we think about how to design protected areas, we need to think about the topography of the Earth, not just a flat map. The fact that these mice evolved on their own separate mountains within a limited geographic area tells us that mountains are important." And figuring out how to plan protected wildlife spaces is crucial for preserving biodiversity. "As human population continues to expand, what's going to happen to everything else? How will new species be able to evolve?" asks Heaney. "This project is a step forward in being able to answer that." This project was supported by a grant from the National Geographic Society. It was contributed to by scientists from the Field Museum, Florida State University, and the Natural History Museum of Utah.

A new study, led by scientists at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing, China, including University of Bristol PhD student Zhang Hanwen, examined the feeding habits of ancient elephant relatives that inhabited Central Asia some 17 million years ago. Professor Wang Shiqi from IVPP, the study's senior author, said: "We found ancient elephant teeth in the Junggar Basin, in China's far North West and they belong to two species, Gomphotherium connexum, and the larger G. steinheimense." Zhang Hanwen, from Bristol's School of Earth Sciences, added: "Gomphotherium was most obvi-ously different from modern elephants by its very long lower jaw that still had lower tusks. "It also had a shorter, more elongate, barrel-like body shape compared to modern elephants. In essence, a small elephant with short legs." Professor Wang explained: "Our study of their evolution shows that Gomphotherium connexum became extinct, but G. steinheimense was part of the line that eventually gave rise to the modern elephants." To understand if feeding preference was playing a role in survival and extinction of these ele-phants, Dr Wu Yan of IVPP, the study's lead author, analysed tiny remnants of plant matter found stuck to the fossil teeth, called phytoliths. About 30 percent of the phytoliths extracted from the teeth of G. connexum are from soft foliage, whereas another 50 percent or so comes from grasses. Dr Wu said: "Given that foliage naturally produces far less phytoliths than grasses, this indicates that G. connexum was mainly feeding on foliage, maybe a generalist feeder of all kinds of plant matter. "When I examined the phytoliths extracted from the cheek teeth of G. steinheimense, I saw a very different pattern -- grass phytoliths comprise roughly 85 percent of the total, suggesting this spe-cies was perhaps primarily a grazer 17 million years ago." To confirm these results, the team also examined tiny wear patterns on the fossil tooth surfaces called microwear. Zhang Hanwen added: "Now things start to get interesting. When our team analysed fossil pollen samples associated with the sediments where the Gomphotherium teeth were found, we realised that woodlands were rapidly transforming into semi-arid savannahs when the two species lived together. "By adopting a much more grass-based diet, G. steinheimensewas apparently responding better to this habitat change than G. connexum. "Gomphotherium had primitive dentition consisting of low molar crowns, and numerous conical cusps arranged in few transverse enamel ridges on the chewing surface of the teeth. "This was adapted for feeding on leaves, the primitive diet. But later on, the lineage leading to modern elephants and the extinct mammoths evolved an increased number of enamel ridges, and these eventually became densely packed tooth plates for shearing tough vegetation. "Our new evidence shows that the diet switch from leaves to grass happened long before the anatomical switch in tooth shape."