How sticky toepads evolved in geckos


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The rapid rise of biomimetics over the last decade is a sign that people are tired of useless just-so stories.  Real cutting-edge science for the 21st century, on the rise in both medical genetics and biomimetics, is based on the implicit assumption that natural structures are intelligently designed and full of potential for enlightenment, wonder, invention, benefit, application, and progress.



Another “feathered dinosaur” story has caused a flap and flurry of news reports.  But are they really feathers, and do they help evolutionary theory?

  • Another “feathered dinosaur” story has caused a flap and flurry of news reports.  But are they really feathers, and do they help evolutionary theory?

  • An exceptionally preserved juvenile in typical “dinosaur death pose” was unearthed in German limestone and given the name Sciurumimus (“squirrel-mimic”).  Labelled Jurassic by the researchers who announced the discovery in PNAS,1 this is the first non-coelurosaur species described with integumentary structures.  It is leading some to postulate that all the branches of dinosaurs had “feathers,” as stated in National Geographic’s article: “‘Probably all dinosaurs were feathered,’ scientist concludes.



One will look in vain, though, for veined feathers with barbs and barbules as found in birds.  The authors label the structures “type 1 feathers,” meaning single filaments protruding from the skin (see 9/15/2011 entry).  They are actually little more than fuzz, barely noticeable in the photos.  Co-author Helmut Tischlinger said, “Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton.”

  • One will look in vain, though, for veined feathers with barbs and barbules as found in birds.  The authors label the structures “type 1 feathers,” meaning single filaments protruding from the skin (see 9/15/2011 entry).  They are actually little more than fuzz, barely noticeable in the photos.  Co-author Helmut Tischlinger said, “Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton.”



Some, like Brian Switek at Nature News, dub them “protofeathers.”  He wrote,

  • Some, like Brian Switek at Nature News, dub them “protofeathers.”  He wrote,

  • Palaeontologist Paul Barrett of London’s Natural History Museum agrees that the structures on Sciurumimus are probably protofeathers. Although additional geochemical work is needed to study the features’ details, Barrett says, the fossilized wisps are very similar to the fuzz seen on other dinosaurs. But he notes that the presence of these filaments among all dinosaurs is “speculation”. Feathery structures might be a common feature of dinosaurs, but it’s also possible that they evolved multiple times. “We need more examples in both non-coelurosaurian theropods, and particularly in the other big dinosaur groups, before we can really speculate that these features are a character of dinosaurs as a whole,” Barrett says.



Reporters seem unsure what to make of the news.  Co-author Mark Norell said, according to Science Daily, “This is a surprising find,” noting that it appeared in the same limestone in northern Bavaria as Archaeopteryx (discovered 150 years ago), that was fully fledged with flight feathers: meaning, at the very least, that this creature and birds with powered flight were contemporaries.  Clearly whatever the fuzz was on this creature, it had nothing to do with flight.  Though the juvenile in the fossil was only 28″ long, “Adult megalosaurs reached about 20 feet in length and often weighed more than a ton,” Science Daily reported.  “They were active predators, which probably also hunted other large dinosaurs.”  Not even believers in dinosaur-to-bird evolution think this creature was closely related to birds.

  • Reporters seem unsure what to make of the news.  Co-author Mark Norell said, according to Science Daily, “This is a surprising find,” noting that it appeared in the same limestone in northern Bavaria as Archaeopteryx (discovered 150 years ago), that was fully fledged with flight feathers: meaning, at the very least, that this creature and birds with powered flight were contemporaries.  Clearly whatever the fuzz was on this creature, it had nothing to do with flight.  Though the juvenile in the fossil was only 28″ long, “Adult megalosaurs reached about 20 feet in length and often weighed more than a ton,” Science Daily reported.  “They were active predators, which probably also hunted other large dinosaurs.”  Not even believers in dinosaur-to-bird evolution think this creature was closely related to birds.



Of note is that this fossil came from a private collector and looks, at first glance, almost too good to be true.  Assuming it is authentic and trustworthy, though, paleontologists have their work cut out for them.  “Although the feathers look similar among different dinosaur groupsit’s still possible the trait evolved independently, without a common ancestor,” National Geographic suggested (look for phrase “repeated evolution” in the 7/01/2012 entry).  Everyone seems to agree there’s not enough information to make sweeping conclusions.  NG reporter Christine Dell’Amore quoted Corwin Sullivan saying, “We paleontologists are going to need to find more fossils—of things even less closely related to birds than Sciurumimus—to be sure.

  • Of note is that this fossil came from a private collector and looks, at first glance, almost too good to be true.  Assuming it is authentic and trustworthy, though, paleontologists have their work cut out for them.  “Although the feathers look similar among different dinosaur groups, it’s still possible the trait evolved independently, without a common ancestor,” National Geographic suggested (look for phrase “repeated evolution” in the 7/01/2012 entry).  Everyone seems to agree there’s not enough information to make sweeping conclusions.  NG reporter Christine Dell’Amore quoted Corwin Sullivan saying, “We paleontologists are going to need to find more fossils—of things even less closely related to birds than Sciurumimus—to be sure.





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