Analysis of skull morphometric characters in Owls (Strigiformes)

Abstract

Owls (Strigiformes) are small to large birds, mostly solitary and nocturnal predators. They can be found all around the Earth except Antarctica and some remote islands. The species differ in size, diet and habitat, which led to different morphological adaptations of the skull. The main differences are in the orbital and the otical region, which are connected to the visual and hearing capabilities. The aim of the recent study is to increase our knowledge of the relationship between skull shape and foraging habits and tried to find those characters that are related to diet. A geometric morphometric approach was used to analyse two-dimensional cranial landmarks. We used principal component (PC) analyses on measurements that may be related to visual and hearing abilities. The PCs are resulted in the robusticity of the skull and the asymmetry of the otical region. There are differences in position and shape of postorbital processes (POP) and tympanic wings (TW). Species with symmetrical skull shape are basically crepuscular or diurnal predators and species with more asymmetrical skulls are mostly nocturnal hunters and have better hearing capabilities.

Cranial evolution in the extinct Rodrigues Island owl Otus murivorus (Strigidae), associated with unexpected ecological adaptations

“…The landmarks/semi-landmarks analyses show that the main deformation across the species is correlated with body size, concurring with Pecsics et al 27 . In this context, the deformation observed between O. sunia and O. murivorus consists of the following morphological modifications.…”

“…In dorsal view, 100 semi-landmarks, and in lateral view 4 landmarks and 65 semi-landmarks in two dimensions (Supplementary Fig. 17 , Supplementary Table 5 ; and see Supplementary Text, for justification) were digitised using Tps Dig 2 41 ; semi-landmarks were allowed to slide 27 . After Procrustes superimposition using TPS Relw 32 41 , consensus configurations and relative warps were processed and visualised as a Principal Component Analysis (PCA) with PAST 3 42 .…”

Skull morphometric characters in parrots (Psittaciformes)

“…In our former study, we used conventional morphometric variables, which were selected a priori (Pecsics et al 2017). In this case, the meaningful variables are discovered by the analysis that was performed in previous studies (Pecsics et al 2018(Pecsics et al , 2019.…”

Analysis of skull morphometric characters in diurnal raptors (Accipitriformes and Falconiformes)

“…The variation of cranial morphology is analysed using landmark-based geometric morphometry. In our former study, we used conventional morphometric variables which were selected a priori (Pecsics et al 2017), however in this case the meaningful variables are discovered by the analysis presented in a more recent study (Pecsics et al 2018). We should not choose them before the analysis.…”