SEPARATING BLACK-BROWED ALBATROSS THALASSARCHE MELANOPHRIS AND ATLANTIC YELLOW-NOSED ALBATROSS T. CHLORORHYNCHOS BY OSTEOLOGICAL MORPHOMETRY ANALYSIS

摘要

Identifying albatross species in the wild involves recognizing plumage pattern and bill coloration. However, skeletal specimens in museums or deteriorated beached carcasses may lack the external characters needed for identification. Although it is possible to distinguish Black-browed Albatross Thalassarche melanophris from Atlantic Yellow-nosed Albatross T. chlororhynchos based on skull morphology, the specimen remains unidentified if the skull is not available. We measured 96 specimens of Black-browed and 55 Atlantic Yellow-nosed albatross, performing 64 measurements for the entire skeleton. Fifty-nine measurements were based on the literature and five new measurements were established specifically for this work. To search for morphometric differences, we first carried out f-tests and principal component analysis (PCA). Then, we performed discriminant function analysis on PCA results and on six selected postcranial measurements to generate a discriminant function. Sixty-one means (93.85 %) of Black-browed Albatross measurements were significantly larger than those of Atlantic Yellow-nosed Albatross. The discriminant function containing the six selected postcranial measurements correctly identified 97.35 % of the specimens through reclassification. This is the first work on osteological morphometric analysis of the entire skeleton for Black-browed and Atlantic Yellow-nosed albatross that is based on a large sample of specimens.