Some cases of morphofunctional adaptations of the limb skeleton in birds
Journal Title: Бранта: Сборник научных трудов Азово-Черноморской орнитологической станции - Year 2016, Vol 19, Issue
Abstract
Bipedalism in birds has significant effect on their limb morphology that is very conservative. Overspecialization of limbs leads to more significant adaptations of the skeleton. In this work, the limb bones of seven bird species were investigated. They are humerus, ulna, radius, femur, tibiotarsus and tarsometatarsus (Table 1). The following parameters were evaluated: bone mass (m, g), total bone length (l, mm), frontal (df, mm) and sagittal (ds, mm) diameters of the mid-shaft; parameters of cross-sectional geometry of the mid-shaft: cortical area (А, mm2), second moments of area (Imax, Imin, mm4), polar moment of area (J, mm4) (Table 2). The following indices were also calculated: ratio of mid-shaft diameters (df/ds), cross-sectional index (ik), and ratio of second moments of area (Imax/Imin) (Table 3). Cortical area, second moments of area and polar moment of intertia represent the bone resistance to the various mechanical loads: compression, bending and torsion, respectively. The cross-section shape of the mid-shaft is directly associated with these parameters. Interspecific allometry of bone characteristics was investigated as well (Table 4 and 5). It was established that wing bones are mainly characterized by elliptical cross-section shape (Fig. 1). However, in representatives of the genus Anas this shape is circular. It is explained by significant torsional loads caused by the intensity of flight. The most typical cross-section shape of hindlimb bones (especially femur) is circular (Fig. 2). This indicates the predominance of torsional loads in hindlimbs, caused by the most types of terrestrial locomotion. Swimming is accompanied by a significant increase of bending loads in the sagittal plane thereby resulting in an elliptical cross-section shape of the Anas femur. However, the latter characteristic is not the single adaptation to swimming. Mechanical characteristics increase more intensively to adapt bird limb bones to the growth of relative mechanical loads induced by increasing of their body mass. It is demonstrated by positive allometry of these characteristics (b > 0.67 – for cortical area, b > 1.33 – for second moments of area). Linear dimensions of bones are mainly isometric to the body mass. Thus, in bipedalism, limb bone properties undergo qualitative changes (increase in strength and resistance to loads) rather than quantitative ones (relative enlargement).
Authors and Affiliations
Ye. O. Broshko
Keywords
Related Articles
- EP ID EP198180
- DOI -
- Views 152
- Downloads 0
Spatial distribution of the Yellow-legged Gull (Larus cachinnans) based on ringing results in the north-western part of the Azov Sea region
Based on long-term ringing results (1988-2012) the territorial links of the Yellow-legged Gull from breeding colonies of the north-western part of the Azov Sea region (Pryazovia) were considered. Spatial distribution of...
On the stay of the Kittiwake in the Azov-Black Sea basin
The article discusses the data collected by M. A. Dinkevich (2010) during sea expeditions in the Black Sea and the Sea of Azov. Records of Kittiwakes in this region, where up to 100–900 individuals can concentrate in win...
Some cases of morphofunctional adaptations of the limb skeleton in birds
Bipedalism in birds has significant effect on their limb morphology that is very conservative. Overspecialization of limbs leads to more significant adaptations of the skeleton. In this work, the limb bones of seven bird...
The birds of Yagorlyk reserve’s wetlands
The article deals with the information about wetland birds of Yagorlyk Nature Reserve, their nature stay, number, protection status, the dates of registration of rare species and other information on the ecology and dis...
On the Common Crane duets during the breeding period
Basing on the long-term observations carried out over the period 1989-2015 during excursions, from hide and by the method of direction finding (Markin, 1978) in three study areas of the Left-bank Ukraine it was analyzed...