Salt Water Fish Have Fresh Water Roots.
A study by scientists at the State University of New York at Stony Brook suggests a somewhat surprising origin for most of today’s ocean fish. While studying ray-finned fish, a broad group that comprises almost all of today’s ocean and fresh water species, they realized that the ancestors of ocean fish were fresh water fish that lived some 300 million years ago. Their study further suggests that almost all of today’s ocean fish did not find their way from fresh water locations into the world’s oceans until about 170 million years ago. Interestingly, scientists already knew that whales and dolphins originally came from rivers. In trying to answer the more difficult question why this pattern evolved, scientists speculate that ocean environments might have been more prone to extinction events, while more isolated land-based fresh water habitats offered protection and those fish went on to repopulate the oceans.
Read more at New Scientist.
Beware the Lady in Red.
Ladybugs’ pigmentation is a signal to predators that they are toxic. A new experiment shows that the redder the ladybug’s color, the more potent its toxic punch. To prove the point, an experiment was conducted in which two groups of ladybugs were separated and fed meals of lesser and greater nutritional value. The more nutritionally enriched ladybugs had higher levels of the chemical precoccinelline, which is toxic to insect predators. In another part of the experiment, the researchers ascertained that the better fed insects also had a richer, redder coloration, which while not visible to humans, is a warning that could be more readily detected by the color-sensitive birds that eat ladybugs.
Read more at Science Daily.
Books for Chimps.
Global Animal reports on an effort by the Washington Post’s Kids Post to have kids mail board books to the chimps at Chimp Haven, a sanctuary for chimpanzees. Apparently the effort was a success. Chimps clearly enjoy looking at picture books and even show them off to friends. The kids received thank-you letters, but they were written by humans.
Bat Parasite Fossil Preserved in Amber.
An insect known as a bat fly is a parasite that specifically feeds on bats. Here, the almost perfectly preserved specimen is encapsulated in amber and scientists think it dates back 20-30 million years. Apparently, bat flies and bats are a good example of co-evolution, since the insect’s body is perfectly adapted for crawling through bat fur in a parasite-host relationship that still exists today. Even today, these bat flies are carriers of malaria, which infects bats.
Read more at Discovery.
Record Dolphin Strandings Puzzle Scientists.
A record number of dolphins have stranded themselves in the Cape Cod area in January. Strandings are often puzzling, but the number in this case — 129 individuals — is of special concern. As many as 92 of the dolphins have died so far, but no common disease has been identified. Other alternative explanations include a misguided herd instinct in which healthy individuals follow a lost or confused leader, or a common disease that has not yet been identified. Volunteers are doing their best to protect the animals from seagulls and sun exposure.
Read more at Red Orbit.
Reconstructing a 165 Million Year Old Seranade.
A 165 million-year-old cricket or katydid specimen that is extremely well preserved is allowing scientists to attempt a reconstruction of its song. Katydid males court females with their music, and this ancient specimen was no exception. Appropriately named A. musicus, the insect used structures in its wings to create a music-like tone, just as the modern version does. But what did it sound like? There may be an answer in the analysis of existing Katydids, because they use the same wing structures and methods to create modern cricket serenades. Estimating the likely tone that would have been generated by A. Musicus may be simply a matter of comparing its particular structure to modern crickets, whose melodies are already known. The article in Nature News includes a videotape of that reconstruction.
Read more at nature.com
The Big Drill in the Big Chill.
Over two miles below the surface of Antarctica lies Lake Vostok, one of the largest lakes in the world. It is also unexplored … until now. After years of drilling, scientists from Russia, joined by American and British colleagues, appear to have reached the lake water itself. Estimates are that the lake has not been exposed to surface air for some 20 million years. To what extent the lake has shared flow with other subterranean lakes in Antarctica is yet unknown. However, the conditions in Lake Vostok might be comparable to those on Mars or the ice moons of Jupiter, such as Europa. Great precautions are being taken to insure that no contamination is introduced into the lake during the drilling process. Results of testing are not expected until sometime later this year.
Read more at Red Orbit.
Neanderthals Still Among Us?
Until recently, conventional thinking has been that the Neanderthals were replaced by modern humans who either killed them off or out-competed them for resources. However, more recent developments have shown a 1-4% Neanderthal contribution in the DNA of modern humans, especially those of European descent. This has led to a hypothesis that rather than having been killed off, the Neanderthal population was absorbed by modern humans through interbreeding. As one researcher put it: “While they disappeared as a distinctive form of humanity, they live on in our genes. What we do in this study is propose one model of how this could have happened and show that behavioral decisions were probably instrumental in this process.”
Read more at Arizona State University.
Tarsiers Turn Up the Frequency.
Of all primates, the Philippine Tarsier vocalizes at the highest frequency. In fact, its pitch is so high that it is beyond the hearing register of humans. While humans can hear at frequencies up to 20 kHz, tarsiers can crank it up to an ultrasonic 91 kHz. When a tarsier opens its mouth to vocalize, it appears to us that no sound is coming out. There may be an advantage to such high-pitch sounds. Tarsiers are small nocturnal animals and they are less likely to be spotted by predators if they communicate on their own special wave length.
Read more at Discovery.
Sponges May Have Been the First Animal Kingdom Members.
Scientists working at Namibia’s Etosha National Park in South Africa may have pushed back the starting date for animal life on earth by more than 100 million years. The sponge fossils they detected using electron microscopy may date back as far as 750 million years. Under the microscope, pores necessary for feeding on algae and bacteria can be seen in the fossils.
Read more at The Register.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.