Welcome to Altmetric’s “High Five” for July, a discussion of the top five scientific papers with the highest Altmetric scores this month. On a monthly basis, my High Five posts examine a selection of the most popular research outputs Altmetric has seen attention for that month.
The theme this month is shocking (and not-so-shocking) discoveries.
Tetrapodophis specimen. Credit: Dave Martill.
Paper #1. Four-legged fossil snake is a world first
Our top paper this month is “A four-legged snake from the Early Cretaceous of Gondwana,” published in Science on July 24, 2015. The study, authored by researchers based in the US, the UK and Germany, details the discovery of a fossil snake… with four legs.
The discovery of snakes with two legs has shed light on the transition from lizards to snakes, but no snake has been described with four limbs, and the ecology of early snakes is poorly known. We describe a four-limbed snake from the Early Cretaceous (Aptian) Crato Formation of Brazil. The snake has a serpentiform body plan with an elongate trunk, short tail, and large ventral scales suggesting characteristic serpentine locomotion, yet retains small prehensile limbs. – Martill, Tischlinger, Longrich, 2015
According to the Science editor’s summary of the study, this ancestor of today’s snakes, named Tetrapodophis amplectus, “appears to have been a burrower and shows clearly the early transitional stages from a lizardlike body plan to the smooth legless snakes we know today.”
The paper, shared by members of the public and scientists alike, received coverage from major news sources including CBS News, “Fossil shows prehistoric snake had four feet,” the Telegraph, “Four-legged snake discovered,” Wired, “Four-legged ‘hugging snake’ could be a missing link,” and the Washington Post, “Four-limbed, long-fingered snake hints at a creepy crawly evolutionary journey.” The discovered fossil of Tetrapodophis amplectus is about 110 million years old.
I thought, ‘Bloody hell, it’s got back legs!’ It had front legs. Nobody had ever seen a snake before with four legs, and yet evolutionary theory predicts that there should be an animal that is transitional between four-legged lizards and snakes, and here it was. – David Martill, study co-author, as quoted by Laura Geggel, LiveScience
The crazy part is that David Martill had this “Bloody hell” moment not in the field, but when he was looking closely at the unidentified fossil as he led a student group through the collections at the Bürgermeister Müller Museum in Solnhofen, Germany.
I looked closer and the little label said: Unknown fossil. Understatement! I looked even closer—and my jaw was already on the floor by now—and I saw that it had tiny little front legs! […] But no snake has ever been found with four legs. This is a once-in-a-lifetime discovery. – Paleobiologist David Martill, as quoted by Ed Yong, Not Exactly Rocket Science
Ed Yong did a fantastic job describing the implications of this fossil find in his blog post on the subject at National Geographic:
There are two competing and fiercely contested ideas about this transition. The first says that snakes evolved in the ocean, and only later recolonised the land. This hypothesis hinges on the close relationship between snakes and extinct marine reptiles called mosasaurs (yes, the big swimming one from Jurassic World). The second hypothesis says that snakes evolved from burrowing lizards, which stretched their bodies and lost their limbs to better wheedle their way through the ground. In this version, snakes and mosasaurs both independently evolved from a land-lubbing ancestor—probably something like a monitor lizard. Tetrapodophis supports the latter idea. It has no adaptations for swimming, like a flattened tail, and plenty of adaptations for burrowing, like a short snout. It swam through earth, not water.
The discovery of this four-legged snake is not without controversy, however. There is some debate over how the fossil came to reside in a private collection when it was identified as originating in Brazil, where the export of such fossils is generally illegal. Shaena Montanari, a writer who covers paleontology, dinosaurs and comparative biology, wrote in a July 24th Forbes article: “I am slightly surprised that Science allowed this to be published despite the fact the legality and provenance of this specimen can in no way be proven beyond a guess, albeit a very educated one.”
It appears that the technicalities surrounding the collection and discovery of this fossil are as intriguing as is the fossil’s implications for the history of snakes.
I think this creature is far more exciting for what it might be than for what [the team] says it is. – Michael Caldwell, vertebrate paleontologist, University of Alberta, as quoted by Sid Perkins for ScienceNOW
Credit: Brandon Motz, Flickr.com
Paper #2. Insights into Sexism… via Video Games
Our next High Five paper was published in PLOS ONE this month, titled “Insights into Sexism: Male Status and Performance Moderates Female-Directed Hostile and Amicable Behaviour.” The researchers, Michael Kasumovic and Jeffrey Kuznekoff, used online video games to study gender-directed behavior. Gender-directed behavior of online gamers was prompted by the sound of another player’s voice (e.g. male or female voice).
We used an online first-person shooter video game that removes signals of dominance but provides information on gender, individual performance, and skill. We show that lower-skilled players were more hostile towards a female-voiced teammate, especially when performing poorly. In contrast, lower-skilled players behaved submissively towards a male-voiced player in the identical scenario. This difference in gender-directed behaviour became more extreme with poorer focal-player performance. We suggest that low-status males increase female-directed hostility to minimize the loss of status as a consequence of hierarchical reconfiguration resulting from the entrance of a woman into the competitive arena. Higher-skilled players, in contrast, were more positive towards a female relative to a male teammate. – PLOS ONE study
The study sparked headlines in several online news outlets, such as “Study: Online gaming ‘losers’ are more likely to harass women” in Ars Technica. Most outlets ran with the analogy that males who exhibit the most sexist behavior in online gaming environments are the “losers.”
Talk to women who play games online, especially first-person shooters, and you’ll quickly hear tales of them being bombarded with gender-focused harassment if and when they decide to speak up on a groupchat channel. Now, a new study suggests that the players most likely to engage in this kind of harassment are the ones who are actually worst at the game itself. – Kyle Orland, Ars Technica
However, a few of those writing about the study pointed out that Kasumovic and Kuznekoff have relatively little evidence to back up their claims that the sexist behavior seen from low-performing males is at its core an evolutionary response to threat. But the results themselves resonated with many of those writing about the study.
I prefer my gameplay without sexual harassment, but on any given evening that may not be in the cards when I hop online to play Call of Duty. I’ve learned to take these rare vocal assaults with a heavy sigh and the understanding that trolls are much like bullies: They harass others as a way to cope with their own insecurities. But I’ve always wondered why women always seemed to be singled out. Were their sexist remarks really of the same mentality as a bully; researchers say, in a way, yes. – Natalie Shoemaker, Big Think
Possible layout of the quarks in a pentaquark particle. Image: Daniel Dominguez. Source: CERN press release.
Paper #3. Pentaquarks
Our next High Five paper, a report from the European Organization for Nuclear Research or CERN published in Physical Review Letters, is difficult for the non-specialist to read. It details the sighting of an elusive subatomic particle called the pentaquark. Nature News reports, “an exotic particle made up of five quarks has been discovered a decade after experiments seemed to rule out its existence.”
The pentaquark is not just any new particle — it represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted. – Large Hadron Collider spokesperson Guy Wilkinson, via Nature News
The report got the attention of several online news and specialty outlets, including Smithsonian magazine, “What Is a Pentaquark and Why Are Physicists so Excited About It?” Quartz, “Scientists at the Large Hadron Collider have discovered an exotic new state of matter,” and Ars Technica, “CERN experiment spots two different five-quark particles.”
Pentaquarks are an exotic form of matter first predicted back in 1979. Everything around us is made of atoms, which are mode of a cloud of electrons orbiting a heavy nucleus made of protons and neutrons. But since the 1960s, we’ve also known that protons and neutrons are made up of even smaller particles named “quarks”, held together by something called the “strong force”, the strongest known force in nature in fact. – Gavin Hesketh, The Conversation
The discovery of a five-quark particle opens up many new questions, as detailed in many of the news reports of this particle sighting. What holds these quarks together, and how are the five quarks oriented and put together to form the pentaquark?
Scientists had a devilishly hard time finding these particles, even though they likely exist in high-energy settings, like dying stars collapsing to form black holes – or the moments just after the Big Bang. In 2013, tetraquarks were convincingly unmasked by two research teams. The pentaquark, however, has been a brutal tease. [Until now.] – Physics Buzz
Normal (left) versus cancerous (right) mammography image. Wiki.
Paper #4. Breast Cancer Screening: “The more we look, the more you find.”
Our next High Five paper sparked some debate online about the limited effectiveness and risks of breast cancer screening. The study, published in JAMA, examined 6 million women in 547 counties self-reporting to the Surveillance, Epidemiology and End Results cancer registries during the year 2000. The study authors, including researchers from Seattle, Harvard University in Cambridge, and The Dartmouth Institute for Health Policy and Clinical Practice in Hanover, conclude:
Across US counties, there was a positive correlation between the extent of screening and breast cancer incidence (weighted r = 0.54; P < .001) but not with breast cancer mortality (weighted r = 0.00; P = .98). […] The clearest result of mammography screening is the diagnosis of additional small cancers. Furthermore, there is no concomitant decline in the detection of larger cancers, which might explain the absence of any significant difference in the overall rate of death from the disease. Together, these findings suggest widespread overdiagnosis. – JAMA study
The findings were picked up by several major news outlets and discussed in a variety of science and medicine blogs. Nancy Shute wrote for NPR’s shots: “Here’s more evidence that mammograms don’t always deliver the results that women want. They find more small cancers, but don’t lower a woman’s risk of dying of breast cancer, a study finds.”
This study shows that the more we look, the more you find. – Joann Elmore, M.D., as quoted by Nancy Shute, NPR
The trouble with overdiagnosis is that while the cancers doctors find wouldn’t have harmed their patients, the treatment and stress that result from the diagnosis probably will. – Julia Belluz, Vox
But some writers and cancer screening advocates took issue with the JAMA paper’s conclusions.
What’s clear from other published data (curiously omitted in this paper), is that rates of death from breast cancer in women fell during this same decade, 2000 to 2010, across the United States. I find it hard to reconcile the authors’ findings of a lack of change in incidence-based breast cancer mortality, whether or not women were screened in the two years before 2000, with the clear pattern of reduced mortality from the disease. – Elaine Schattner, Forbes, Why Women Shouldn’t Cower To Concerns About Overdiagnosis Of Breast Cancer
David Gorski at Science-Based Medicine provides an in-depth breakdown of the JAMA study and previous research on the effectiveness of breast cancer screening.
A native bumblebee, Bombus auricomus. Photo: S. Droege. USGS Native Bee Inventory and Monitoring Lab.
Paper #5. A world of change for bumblebees
Our last but not least top paper this month is a Science report titled “Climate change impacts on bumblebees converge across continents.” The internationally authored study tested for climate change-related shifts in bumblebee ranges. The authors found bumblebee losses at the southern range limits of these species, as southern species have shifted to higher elevations but failed to shift to more northern regions.
Responses to climate change have been observed across many species. There is a general trend for species to shift their ranges poleward or up in elevation. Not all species, however, can make such shifts, and these species might experience more rapid declines. Kerr et al. looked at data on bumblebees across North America and Europe over the past 110 years. Bumblebees have not shifted northward and are experiencing shrinking distributions in the southern ends of their range. Such failures to shift may be because of their origins in a cooler climate, and suggest an elevated susceptibility to rapid climate change. – Editor’s Summary
In other words, “It’s too hot for bumblebees in the south—and they’re not moving north,” according to a headline in Quartz. Numerous news outlets, science magazines and science blogs picked up the study to report on the narrowing range of bumblebees, with headlines such as “A Century of Data Reveal that Climate Change is Shrinking Bumblebee Ranges,” (IFLscience) and “A Smaller World for Bumblebees,” (The Scientist). Most media coverage of the study was straightforward in highlighting the findings as significant and robust.
Kerr compared the situation of bumblebees to a vice. He explained that as temperatures have warmed since 1975, many species of bumblebees are being forced into smaller and smaller habitats. On the southern ends of their habitat in Europe and North America, bumblebees are losing about 9 km per year (5.6 miles), and have already lost 300 km (about 186 miles). – Katherine Ellen Foley, qz.com