鹦形目鸟类胸骨的形态结构特征及其相关功能分析

鸟类胸骨的形态结构不仅是区分鸟类类型的主要特征，也是判断鸟类飞行等功能的重要依据。鹦形目鸟类作为攀禽中的一部分，其胸骨在形态上表现出明显的特性，如胸骨较宽，喙突相对发育，龙骨突较高，其背棘呈似刀状，龙骨突的前端尚未与锁骨发生愈合，最为显著的相似特征是胸骨后侧缘的凹口均存在不同程度的简化，后缘凹口对称位于后缘外侧，并愈合为2个封闭的不规则圆孔。此外，文中还对11科35件鸟类胸骨的变量指标进行了统计学分析，认为根据胸骨的长度（L）、宽度（W）分别与龙骨突高度（H）的比值（L／H、W／H）可以有效判断不同鸟类的生态习性。综合上述对鸟类胸骨形态学和统计分析的结果得出：鹦形目鸟类特有的胸骨后侧缘凹口的愈合简化以及胸骨变量比值的大小表明了它们不是善飞的鸟类，而是以攀缘为主生活的鸟类。

Morphological Characteristics of Bird Sternum of Psitteciformes and Its related Function Analysis

Morphological characteristics of bird sternum is not only the main character for bird classification, but also the major criterion to infer its flight ability and other important functions. The sternum of Pshtaciformes, a kind of climbers, was characterized by following structures ： wide with well developed sterno - coracoidal process, high sternal crest and blade - like dorsal spina, no fusion of cranial process with clavicle, simplification of lateral caudal notch located symmetrically at lateral sides of caudal sternum and fused into two apertures. The statistic analysis of variable indexes of 35 individual specimen from 11 families showed that the ratio （ L/H and W/H ） of sternal length （L） and width （ W ） to the height （ H ） of sternal crest were able to judge the habit of the bird. Conclusion from the morphological study and statistic analysis was that the fusion and simplification of the lateral caudal notch and the ratio of sternal variables determined their lack of the strong flight ability and adaptation to climbing habit.