A fossil from a new species of dinosaur is helping to bridge a crucial 20-million-year gap in tyrannosaur evolution.

The key fossil is a 90-million-year-old, grapefruit-sized partial skull from Uzbekistan’s Bissekty Formation. This tyrannosaur braincase, the first well-preserved one found from the mid-Cretaceous period, shows that, although still small, tyrannosaurs of the time already had brain and ear features of later tyrannosaurs. Researchers have dubbed the in-betweener Timurlengia euotica, meaning “well-eared.” They describe the new species in a paper to appear in the Proceedings of the National Academy of Sciences.
The braincase sheds light on a long-standing mystery: how tyrannosaurs evolved in the gap from 100 million to 80 million years ago from an “average Joe” horse-sized predator in the Early Cretaceous to the huge apex predators they became in the Late Cretaceous. “Our study is the first to show that the sophisticated brain and hearing of big tyrannosaurs evolved in smaller-bodied species, long before tyrannosaurs got giant,” says study coauthor Stephen Brusatte, a paleontologist at the University of Edinburgh. These advantages, he adds, may have helped tyrannosaurs become such successful — and eventually enormous — predators.
Analyzed against a database of other tyrannosaur skulls, the braincase shows that Timurlengia’s brain and ear “are almost identical to T. rex, just smaller,” Brusatte says. In particular, the dinosaur’s long cochlea, a part of the inner ear, is a signature of bigger, badder Late Cretaceous tyrannosaurs. “The long cochlea would have meant better sensitivity to low-frequency sound,” Brusatte explains. That sensitivity would have enabled Timurlengia to detect very subtle or distant sounds, giving the dinosaur clear advantages over other predators.

“Timurlengia fills an important gap in both time and evolution,” says Lawrence Witmer, a paleontologist at Ohio University in Athens who was not involved in the study. “Charles Darwin couldn’t have scripted it any better.”

The next step is to determine if the braincase is typical of a mid-Cretaceous tyrannosaur, or just one oddball data point. “We’ve analyzed the heck out of each scrap of Bissekty tyrannosaur bone,” Brusatte says, “so the thing that could move us forward is the discovery of new specimens in other middle Cretaceous rock units in other parts of the world.”

There’s no need to trek to the wilds of Borneo or the deepest Amazon if you want to discover a new species. There is at least one — and perhaps more — hiding among Ceuthophilus cave crickets in Texas, a new study finds.

Jason Weckstein of Drexel University in Philadelphia and colleagues weren’t looking for new species, and they haven’t definitively found any. But they have found some curious characteristics among the Texan crickets, as well as genetic evidence that there may be more species than science officially recognizes.

Ceuthophilus cave crickets have split into two groups. One subgenus — also named Ceuthophilus — is full of species that are trogloxenes, meaning they live in caves and venture out at night to find food. (If they get caught outdoors during the day, they hide under rocks.) The other subgenus, Geotettix, are troglobites that can only survive if they never venture out into the light.

Because crickets in the Ceuthophilus subgenus get out of the caves and perhaps even move between them, those crickets should be able to interbreed more, the researchers figured. Geotettix crickets would be stuck closer to home, and their populations would be more distinct from each other, the team predicted. And those differences should be detectable in the crickets’ DNA.

So the team collected 179 Ceuthophilus and 122 Geotettix crickets from 43 caves in 20 Texas counties, as well as a few caves in Mexico and New Mexico. The researchers then obtained the sequences of two genes found on the crickets’ mitochondria. Mitochondrial DNA evolves rapidly and can be useful for studying populations of organisms.

Crickets in the Ceuthophilus subgenus, the DNA analysis revealed, were not moving about nearly as much as the researchers had expected, they report March 3 in the Journal of Biogeography. The crickets might be limited by streams or other features of the landscape. Those in the Geotettix subgenus, meanwhile, are more homogeneous than expected. The genes from one population to the next are more similar than they should be if they were totally isolated from each other and couldn’t interbreed. Members of those populations may be able to travel underground between caves, the scientists suggest.

The DNA also showed that there might be multiple species lurking in the caves that have not yet been officially recognized and named. At least one, nicknamed “species B,” has been known to cave researchers in central Texas for years, but no one has yet formally described it in a scientific article. Nearly all the currently known species in the Ceuthophilus genus, the researchers note, were described more than 75 years ago, and no one has added any new species to the genus in more than 50 years.

So it looks like there is a good opportunity here for someone who loves caves and insects to make some discoveries — and perhaps name a cricket or two after themselves or someone they love. But more importantly, this shows how little we know about some of the species around us.

The mysteries of the Zika virus are slowly but surely succumbing to the scientific method. Last week, scientists revealed the virus’ structure, gleaned further insight into its ties to the birth defect microcephaly and found out just how little some people seem to know about Zika. Public health researchers at Harvard University released the results of a poll related to Zika awareness on March 29, and lots of respondents flunked. In a survey of 1,275 adults, 23 percent were unaware of Zika’s association with microcephaly and 42 percent did not know the virus could be transmitted sexually.

The survey highlights some general confusion about the facts of Zika, and the latest new tidbits show how quickly researchers are learning new things about this virus. So, let’s take a look at what people are saying about Zika and set the record straight .

Yes, in the case of microcephaly, Zika looks very, very guilty. No, pesticides and vaccines do not cause microcephaly.
A few different things, including viruses, can cause microcephaly, a birth defect in which babies have abnormally small heads and brain damage, as Meghan Rosen notes in the April 2 Science News. At the moment, there’s no smoking gun to convict Zika as the perpetrator behind Brazil’s uptick in microcephaly, but it’s not looking good for the virus. In Brazil, more microcephaly cases have appeared in places with more Zika cases. Zika has also been detected in the amniotic fluid, placenta and brain tissue of fetuses with microcephaly. It attacks specific cells related to fetal development. Zika infection during pregnancy has been linked to miscarriages and placental problems, plus other neurological conditions, including the rare autoimmune disease Guillain-Barré syndrome.

WHO officials noted in their March 31 situation report: “Based on observational, cohort and case-control studies there is strong scientific consensus that Zika virus is a cause of [Guillain-Barré syndrome], microcephaly and other neurological disorders.”

The evidence against other suspects is much less compelling. Still, a report by a group in Argentina calling themselves “Physicians Against Fumigated Towns” sent the Internet into a tizzy in February with the claim that the larvicide pyriproxyfen, not Zika, was to blame for microcephaly cases. The WHO has since reviewed toxicology studies and widespread use of the pesticide and found no evidence that the chemical interfered with human pregnancy or development. Similar rumors that vaccines or genetically modified mosquitoes caused Brazil’s microcephaly uptick simply lack any evidence, the WHO says.
Yes, you can get Zika by having sex with an infected person.
Though Aedes mosquitoes serve as the primary vector for Zika, researchers have had suspicions for a while that Zika could be sexually transmitted. In 2008, a U.S. researcher developed Zika infection symptoms after returning home from studying mosquitoes in Senegal and transmitted the virus to his wife through sex. This was the first documented sexually transmitted case of Zika.

Since then, more sexually transmitted cases have emerged in the U.S., as well as in Italy, France, Argentina, Chile and New Zealand. Thus far, only men have transmitted the virus, and whether women can also transmit the virus to their sexual partners is unknown. Researchers suspect that the virus may linger longer in semen than in blood — another potential source of transmission currently being investigated. (On March 30, the U.S. Food and Drug Administration approved a screening test for Zika in blood donatons.) To prevent the spread of Zika between sexual partners, the CDC recommends the usual precautions.

No, there’s no vaccine for Zika, but people are working on it.
There is currently no vaccine against Zika, and vaccines against other viruses from the same family, like yellow fever, do not offer protection against Zika. That said, concern over Zika’s link to neurological disorders and growing case counts in the Americas has jump-started efforts to develop a vaccine. The idea of a chimeric vaccine that could combat Zika and other related viruses like dengue is an attractive research prospect. On March 31, a team reported the virus’ structure in Science, providing potential clues for vaccine development.

Sometimes Zika symptoms are obvious. Sometimes they’re not.
Only 20 percent of the people who get Zika actually notice symptoms. When they do, those symptoms include fever, rash, sore joints, pink eye and muscle pain. Sometimes Zika cases look a lot like dengue and chikungunya — meaning there’s potential for misdiagnosis.

No, sterilized mosquitoes do not increase the spread of Zika. In fact, they could help fight it.
There’s no evidence that sterilized mosquitoes aid and abet the spread of the virus. Some researchers would actually argue that they are our best chance of stopping it, Susan Milius notes in the April 2 Science News. Sterilization, by zapping males with radiation or genetically tweaking them, could reduce and theoretically wipe out a mosquito population. Meanwhile, gene drives likes CRISPR/Cas9 seem poised to make genetic sterilization methods a lot easier, too. Infecting mosquitoes with Wolbachia bacteria also cuts bloodsucker populations. If all else fails, El Salvador is using the tried and true method of deploying fish to eat all the larvae in mosquito breeding ponds. It goes without saying, but none of these control methods actually aid the spread of Zika.

A team of scientists has built a heat engine out of a single atom.

Heat engines, like steam engines or internal combustion engines, convert heat into motion. To create the minuscule engine, physicist Johannes Roßnagel of University of Mainz and colleagues heated and cooled a calcium ion with an electric field and a laser, causing it to move and do a tiny amount of work. They report their results in the April 15 Science.

Read more about this and other scaled-down engines in “Ultrasmall engines bend second law of thermodynamics.”

Time to add another gorgeous space photo to the Hubble Space Telescope’s list of greatest hits. For the orbiting observatory’s 26th anniversary in space, astronomers snapped a picture of the Bubble Nebula, a seven-light-year-wide pocket of gas being blown away by a blazing massive star about 7,100 light-years away in the constellation Cassiopeia.

The star responsible for the bubble is young, just 4 million years old, and about 45 times as massive as our sun. It is so hot and bright that it launches its own gas into space at more than 6 million kilometers per hour. The vibrant colors in the nebula represent the elements oxygen, hydrogen and nitrogen.

Hubble launched April 24, 1990, aboard the space shuttle Discovery. A series of visits by astronauts have kept the aging telescope’s suite of cameras, spectrometers and ancillary equipment up-to-date and operating well into its third decade.

Danger in ‘swimming hole’  — As warm weather approaches, the old swimming hole will again beckon boys and girls in farm areas. But disease germs lurk in waters exposed to cattle and other animals…. One “swimming hole disease” called leptospirosis is caused by water-borne Leptospira pomona…. Warm summer temperatures are ideal for maintaining leptospiral organisms in water, and heavy rains may transport the organisms downstream.  — Science News, May 14, 1966

UPDATE
An estimated 100 to 200 people get leptospirosis annually in the United States. The disease, which can cause fever, headache and vomiting, is most common in tropical and rural regions worldwide. Summertime swimming is also haunted by another single-celled terror that thrives in warm freshwater: the so-called “brain-eating” amoeba, Naegleria fowleri. The amoeba caused 35 reported infections in the United States from 2005 to 2014. If N. fowleri enters a person’s nose, it can travel to the brain, where swelling triggered by the immune system kills most victims (SN: 8/22/15, p. 14).

In many realms of science today, “statistical wisdom” seems to be in short supply. Misuse of statistics in scientific research has contributed substantially to the widespread “reproducibility crisis” afflicting many fields (SN: 4/2/16, p. 8; SN: 1/24/15, p. 20). Recently the American Statistical Association produced a list of principles warning against multiple misbeliefs about drawing conclusions from statistical tests. Statistician Stephen Stigler has now issued a reminder that there is some wisdom in the science of statistics. He identifes seven “pillars” that collectively provide a foundation for understanding the scope and depth of statistical reasoning.
Stigler’s pillars include methods for measuring or representing aggregation (measures, such as averages, that represent a collection of data); information (quantifying it and assessing how it changes); likelihood (coping with probabilities); intercomparison (involving measures of variation within datasets); regression (analyzing data to draw inferences); design (of experiments, emphasizing randomization); and residual (identifying the unexplained “leftovers” and comparing scientific models).

His approach is to identify the historical origins of these seven key pillars, providing some idea of what they are and how they can assist in making sense of numerical data. His explanations are engaging but not thorough (it’s not a textbook), and while mostly accessible, his writing often assumes a nontrivial level of mathematical knowledge. You’ll have to cope with expressions such as L(Θ)=L(Θ)|Χ and Cov(L,W)=E{Cov(L,W|S)}+Cov(E{L|S}, E{W|S}) every now and then.

While Stigler defends statistics from some of the criticisms against it — noting, for instance, that specific misuses should not be grounds for condemning the generic enterprise — he acknowledges that some issues are still a source of concern, especially in the new era of “big data” (SN: 2/7/15, p. 22). Using common statistical tests when many comparisons are made at once, or applying tests at multiple stages of an experimental process, introduces problems that the seven pillars do not accommodate. Stigler notes that there is room, therefore, for an eighth pillar. “The pillar may well exist,” he writes, “but no overall structure has yet attracted the general assent needed for recognition.”

Overuse of antibiotics in livestock can spread drug-resistant microbes — via farm workers or even breezy weather. But there’s more than one reason stay upwind of drugged cattle.

Dung beetles (Aphodius fossor) make their living on cattle dung pats, which are rich in nutritious microbes. To investigate the effects of cattle antibiotics on this smaller scale, Tobin Hammer of the University of Colorado at Boulder and his colleagues studied the tiny communities around tetracycline-dosed and undosed cows. Compared with untreated cows’ dung, microbes in dung produced by treated cows were less diverse and dominated by a genus with documented resistance, the researchers report May 25 in the Proceedings of the Royal Society B.

Beetles typically reduce methane gas wafting off dung, but pats from treated cows showed a 1.8-fold increase in methane output. How this might figure into greater cattle methane production remains to be studied, but Hammer and company speculate that the antibiotics may wipe out the bacterial competition for microbial methane factories.

Editor’s note: On May 3, 2017, Science retracted the study described in this article. Based on findings from a review board at Uppsala University, Science cites three reasons for pulling the study: The experiments lacked ethical approval, the original data do not appear in the paper and questions emerged about experimental methods.

Microscopic pieces of plastic rule Earth’s oceans, with numbers in the billions — possibly trillions. These tiny plastic rafts provide homes to microbes (SN: 2/20/16, p. 20), but their ecological effects remain murky.
In a lab at Uppsala University in Sweden, researchers exposed European perch (Perca fluviatilis) larvae to a microplastic called polystyrene to see how they might react. The exposure triggered a slew of potentially negative effects: Fewer eggs hatched, growth rates dropped and feeding habits changed, with some larvae preferring polystyrene to more nutritious food options. Exposed larvae were also sluggish in responding to scents that signal approaching predators in the wild, the team reports in the June 3 Science.

European perch, a keystone species in the Baltic Sea, have recently experienced a population dive. Because the drop has been linked to juvenile feeding issues, the researchers argue that microplastics could be to blame.

SAN DIEGO — A remote planet — the first with hints of a limestone shell — has been shredded by its dead sun, a new study suggests.

A generous heaping of carbon is raining down on a white dwarf, the exposed core of a dead star, astrophysicist Carl Melis of the University of California, San Diego said June 13 at a meeting of the American Astronomical Society. The carbon — along with a dash of other elements such as calcium, silicon and iron — is probably all that remains of a rocky planet, torn apart by its dying sun’s gravity. Many other white dwarfs show similar signs of planetary cannibalism (SN Online: 10/21/15), but none are as flooded with carbon atoms as this one.

A planet slathered in calcium carbonate, a mineral found in limestone, could explain the shower of carbon as well as the relative amounts of other elements, said Melis. He and Patrick Dufour, an astrophysicist at the University of Montreal, estimate that calcium carbonate could have made up to 9 percent of the doomed world’s mass.

While a limestone-encrusted world is a first, it’s not shocking, says Melis. The recipe for calcium carbonate is just carbon and calcium in the presence of water. “If you have those conditions, it’s going to form,” he says.

“The real interesting thing is the carbon,” Melis adds. Carbon needs to be frozen — most likely as carbon dioxide — to be incorporated into a forming planet. But CO2 freezes far from a star, beyond where researchers suspect rocky planets are assembled. A limestone planet could have formed in an unexpected place and later wandered in while somehow retaining its carbon stores in the warm environs closer to its sun. Or the carbon might have been delivered to the world after it formed. But, Melis says, it’s not clear how either would happen.