Ohio University, Department of Biological Sciences, 107 Irvine Hall, Athens, OH 45701, USA.
Zoology (Jena). 2010 Jan;113(1):39-46. doi: 10.1016/j.zool.2009.05.002. Epub 2010 Jan 13.
The total length and mid-shaft diameters of wing elements of 50 species of pelecaniform birds were examined to investigate how forelimb skeletal morphology varies with body size and flight mode within this group. Pelecaniforms were assigned to flight mode categories based on primary habitual behaviors (soar, flap-glide, continuous flap). Allometric and discriminant function analyses were conducted on wing element variables in both historical (using independent contrasts) and ahistorical contexts. Results of this study indicate that when phylogenetic relationships are taken into account, only the length of the ulna scales with positive allometry, whereas all other variables exhibit isometry. These results differ from the ahistorical allometric analysis. Discriminant function analysis (DFA) significantly separated the flight mode groups (Wilk's lambda=0.002, p<0.00001), with only six individuals from two species (out of n=284) misclassified. Results of historical canonical variates analysis supported the ahistorical DFA and identified two carpometacarpal (CMC) variables as important for separating the flight mode groups: dorsoventral CMC diameter and total CMC length. The carpometacarpus is that portion of the forelimb skeleton that serves as the attachment point for the primary flight feathers, and thus, that portion of the airfoil surface that mediates detailed flight control. Its morphology, more than any other element, reflects differences in flight mode in pelecaniforms. Results of this study indicate that, in pelecaniforms, wing bones generally exhibit isometry (with the exception of the ulna) and do possess specific morphologies reflective of the demands associated with different types of aerial locomotor specialization.
研究了 50 种鹈形目鸟类的翼部元素的总长度和中轴直径，以调查前肢骨骼形态如何随该类群内的体型和飞行模式而变化。根据主要的习惯性行为（翱翔、扑翼滑翔、连续扑翼），将鹈形目鸟类分配到飞行模式类别。在历史背景（使用独立对比）和非历史背景下，对翼部元素变量进行了异速生长和判别函数分析。本研究的结果表明，当考虑到系统发育关系时，只有尺骨的长度与正异速生长相关，而其他所有变量都呈现等速生长。这些结果与非历史异速生长分析不同。判别函数分析（DFA）显著分离了飞行模式组（Wilk's lambda=0.002，p<0.00001），只有来自两个物种的六个个体（n=284）被错误分类。历史典范变量分析的结果支持了非历史 DFA，并确定了两个腕掌骨（CMC）变量对于分离飞行模式组很重要：背侧 CMC 直径和总 CMC 长度。腕掌骨是前肢骨骼作为主要飞行羽毛附着点的部分，因此，是调节详细飞行控制的翼型表面的那部分。它的形态，比任何其他元素，都反映了鹈形目鸟类在飞行模式上的差异。本研究的结果表明，在鹈形目鸟类中，翼骨通常表现出等速生长（尺骨除外），并且确实具有反映与不同类型的空中运动特化相关的需求的特定形态。
