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modern downstroke where the arm moves outward <strong>and</strong> forward (protraction),<br />
making the flight stroke overall less powerful in terms of generating<br />
thrust (Close & Ray<strong>field</strong> 2012). As discussed above, enantiornitheans had<br />
shortened their tails but consequently lost most of their tail feathers. This<br />
severely restricted their ability <strong>to</strong> control their flight speed <strong>and</strong> would have<br />
made precise l<strong>and</strong>ings nearly impossible. The retention of wing claws in<br />
these species indicates that they may still have relied on climbing <strong>to</strong> a large<br />
degree when moving around trees, taking off, <strong>and</strong> l<strong>and</strong>ing.<br />
The evolution of the fan tail <strong>and</strong> rectrical bulb in euornitheans allowed<br />
higher maneuverability <strong>and</strong> speed control, though in many primitive<br />
species the fan-tail was long <strong>and</strong> extravagant, suggesting it may have<br />
evolved initially for display, possibly an elaboration of the ribbon-tails of<br />
more primitive <strong>birds</strong>. Euornitheans soon reduced their wing claws, however,<br />
suggesting that the need <strong>to</strong> climb was becoming lessened. This is probably<br />
due in large part <strong>to</strong> the combination of the fan-tail <strong>and</strong> a more aquatic,<br />
shorebird-like lifestyle, as well as improvements in the wing ana<strong>to</strong>my that<br />
led <strong>to</strong> an increased ability <strong>to</strong> launch from flat ground or water.<br />
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