the pectoral girdle to the region of the inner ear, or boneconduction. “Whether body tissue will transport sound ornot depends on its biomechanical properties. With X-rayimaging techniques here at the ESRF, we could establishthat neither the pulmonary system nor the muscles ofthese frogs contribute significantly to the transmission ofsound to the inner ears,” says Peter Cloetens, a scientistat the ESRF who took part in the study. “As these animalsare tiny, just one centimetre long, we needed X-ray imagesof the soft tissue and the bony parts with micrometricresolution to determine which body parts contribute tosound propagation.”eye movement response to nerve stimulation; anatomically,examining how muscles were attached to the eyes andhead; and behaviorally, examining eye positions.Numerical simulations helped to investigate the thirdhypothesis, that the sound was received through the frog’sheads. These simulations confirmed that the mouth actsas a resonator, or amplifier, for the frequencies emittedby this species. Synchrotron X-ray imaging on differentspecies showed that the transmission of the sound fromthe oral cavity to the inner ear has been optimized by twoevolutionary adaptations: a reduced thickness of the tissuebetween the mouth and the inner ear and a smaller numberof tissue layers between the mouth and the inner ear. “Thecombination of a mouth cavity and bone conduction allowsGardiner’s frogs to perceive sound effectively without useof a tympanic middle ear,” concludes Renaud Boistel.Science DailySeptember 2013Turtle Eye Muscle Adapts To Deal WithObstructed VisionIn a recent study published in The Journal ofComparative Neurology, Saint Louis Universityprofessor of pharmacological and physiologicalscience Michael Ariel, Ph.D., reported surprisingfindings about the eye movements of pond turtleswho can retract their head deep into their shell. Whileresearchers expected that the pond turtle’s eyeswould operate like other animals with eyes on the sideof their heads, this particular species of turtle appearsto have characteristics of both front and side-eyedanimals, affecting a specific eye muscle’s direction ofpull and the turtle’s eye position when its peripheralvision is blocked by its shell.Humans, and many mammals like cats and monkeys,have their eyes viewing forward. In contrast, most lowervertebrates, including turtles, have eyes that are lateral -- on the side of their heads. Of the six muscles that moveeach eye, the muscles that move lateral eyes differ fromthe muscles of animals that move eyes viewing forward.In an earlier study, Ariel and his research team made anunexpected observation that a nerve that moves one ofthe pond turtle’s eye muscles, the superior oblique muscle,was active when that turtle moved its head from side toside, much like that of animals whose eyes view forward.In the current study, Ariel and the research team tested histheory that the pond turtle had characteristics of a fronteyedanimal in three ways: physiologically, looking at the42A turtle pulls its eyes in different directions when its head is outof its shell compared to when its head is retracted deep within itsshell.And, indeed, the researchers found that a turtle pulls itseyes in different directions when its head is out of its shellcompared to when its head is retracted deep within its shell.Because the pond turtle can pull its head entirely into itsshell, resulting in an obstructed field of vision, it appearsthat this turtle has developed a way to compensate anddirect its eyes forward to best examine its environment.Moreover, the superior oblique muscle may play a role inthis behavior as its direction of pull is more like that of afront-eyed animal than that of animals with eyes on theside of their heads.Eye movements are related to the vestibulo-ocular reflex(VOR), a reflex whose brain pathways are also studied byAriel. The VOR allows your eyes to adjust their positionwhen you move your head. For example, when you turnyour head to the right, your eyes move to the left to keepthe image you’re looking at within your field of view. TheVOR also is a clinical test used to check eye reflexes inpeople. When this process is not working, people canexperience vertigo, for example.Ariel, who has studied pond turtles for 25 years, says theyare unique among all animals because they block theirperipheral vision by pulling their heads into their shell. “Notall turtles can do this. A sea turtle, for example, cannotpull its head into its shell. We expected that pond turtleswould be like other turtles and other lateral eye animals”said Ariel. “That wasn’t the case. Surprising, their eyemovements can also be like that of humans.”Science DailySeptember 2013Welsh Woman On Night Out GetsSnakebiteA woman had to be taken to a British hospital afterapparently being bitten by a three-metre python as shetook a short-cut home from a night out at the pub.
Sue Cull, 47, felt her legs sting as she cut across grassnear her home, in Swansea, south Wales, and thought shehad wandered into nettles in the dark.But within minutes of getting home, her panicked partnerwas calling for the paramedics after failing to stem theblood streaming from both legs.Unlike today’s crocodiles that mostly live in freshwaterhabitats and feed on mammals and fish, their ancientrelatives were extremely diverse.Some behaved like dogs and others adapted to life in theopen ocean, imitating the feeding behaviour of today’skiller whales.The research uncovers the hidden past of crocodiles -showing for the first time how the jaws of the fierce reptilesevolved, enabling them to survive in vastly differentenvironments in a dinosaur-dominated world 235 to 65million years ago.The study was conducted by Tom Stubbs and Dr EmilyRayfield from the University of Bristol, together with DrStephanie Pierce from The Royal Veterinary Collegeand Dr Phil Anderson from Duke University in the UnitedStates.A Welsh woman thought she had been stung by stinging nettles butwas surprised to find out a python on the loose had bitten herA stunned Cull was informed by paramedics she hadprobably been bitten by a snake as she was being whiskedto hospital in an ambulance.They were then informed en route that police had a reportof a python on the loose around that time, Cull claimed.Despite being forced to spend a night in hospital on anantibiotic drip, Cull shrugged off her ordeal.“I was on my way from the pub to get a take-away when ithappened. I cut across the grass and felt my legs sting,”she said.“It bit me on the right side first and the puncture woundsthere are more prominent. When I got to hospital I had tohave an x-ray to ensure no fangs were left inside.”Mr Stubbs says the ancestors of today’s crocodiles have afascinating history that is relatively unknown compared totheir dinosaur counterparts.“They were very different creatures to the ones we arefamiliar with today, much more diverse and, as this researchshows, their ability to adapt was quite remarkable,” hesaid.“Their evolution and anatomical variation during theMesozoic Era was exceptional.“They evolved lifestyles and feeding ecologies unlikeanything seen today.”The research team examined variation in the morphology(shape) and biomechanics (function) of the lower jaws inover 100 ancient crocodiles, using a unique combinationof numerical methods.Released from hospital the following day she said she felt“cold and shaken” but has since made a full recovery.“If I had seen it or realised what had happened I wouldhave run for my life back to the pub,” she said.A police spokesman confirmed that officers received areport of a lost python at Swansea on Thursday night.The reptile was recovered in a pipe at the owner’s propertyand was safely back in its box within 33 minutes.ANTHONY STONEAAP NewsSeptember 2013Prehistoric Crocs ‘Ran Like Dogs’Prehistoric crocodiles survived a dinosaur-dominated worldby running around like dogs, new research has found.Prehistoric crocodiles survived a dinosaur-dominated world bybehaving like dogs, research found.Dr Pierce said they were curious how extinction events andadaptations to extreme environments during the Mesozoic- a period covering over 170 million years - impacted thefeeding systems of ancient crocodiles.43
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