Skull morphometry of Pygoscelis (Sphenisciformes): inter and intraspecific variations

ACOSTA HOSPITALECHE, C & C. TAMBUSSI

POLAR BIOLOGY

SPRINGER

Año: 2006 vol. 29 p. 728 - 734

0722-4060

Morphological diversity of 47 pygoscelid skulls was tested empirically through geometric morphometrics approach. Using 14 landmarks, shape is analyzed independently of other aspects of the body form. The shape disparity within and between the three living species of Pygoscelis is explored as well as how the structure of the skull is related to food references. Comparison of the three mean configurations of the species suggests that differences mong groups are small relative to the variability within each group. However, some differences at the posterior portion of the braincase are indicated. Sexual dimorphism within each species is not noticeable. Comparison with a piscivorous species (Spheniscus humboldti) shows two cranial patterns: pygoscelid type with wide nasal gland depression limited by well-marked edges, shallow temporal fossae, and a poorly developed temporal nuchal crest; the second type represented by Spheniscus humboldti with laterally open nasal gland depression, deep temporal fossae, and a well-developed temporal nuchal crest.