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Is it better to repeat old mistakes or profusely invent new ones? In a week when the Feduccian camp returned like a dog to its collagen fibres, Mackovicky et al drew a number of false conclusions from Buitreraptor gonzalezorum (which they take as the first good evidence of the dromaeosaur line in S. Am). Since a Kuhnian model of science as a battle of theories is not to their taste, they don't match the new evidence up against all theories but consider uncritically only their own - for example "the ancestors of dromaeosaurs were flightless" - and celebrate any extent to which their theory is compatible with the newcomer; in other words, if the evidence is not totally incompatible with their theory, and never mind how much more compatible it is with others' theories. Since the S.Am/N.Am split occurred before the latest J, they deduce the first dromaeosaurs had evolved and spread to both hemispheres by soon after the mid J. More interestingly they consider Buitreraptor and Rahonavis reasonably close relatives, and conclude from the relationships the new cladogram produces, that flight evolved separately in both "birds" and "dromaeosaurs" such as Rahonavis. I knew this would happen; it's inevitable with their upsidedown cladograms. But it's worse than just two lines evolving flight: ovis (Omnivopteryx), and troodonts (Mei) also had flying representatives. That much parallelism is unbelievable unless something like internal genetic long-term predestination is at work, as Jeff Hecht, the non-palaeontologist who gave the world mussell-eating pteranodonts, now wonders. Such predestination is not unknown (eg the haploid/diploid hymenoptera caste thing) but it's an unnecessary complication, particularly when the "pretendency" sleeps for millions of years and then suddenly bursts out for no apparent reason. So much simpler for dino-birds to have evolved flight just once, and for dromaeosaurs not to have been so successful as to spread both north and south but stay hidden in the south for tens of millions of years. Years ago I predicted the false claims of multiple flight evolution among dino-birds, and of genetic predestiny, and I pointed out that intercontinental flight made early evolution of some lines unnecessary, but I never expected that some would only now recognise Rahonavis as a dromaeosaur! How many more decades before they realise it's a bird too?! And how many centuries before the likes of Mackovicky et al learn that it's good scholastic practice to refer to points of view other than just your own when publishing research? __________________________________ Start your day with Yahoo! - Make it your home page! http://www.yahoo.com/r/hs
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