Mid-Pliocene bald ibis ( Geronticus cf. calvus ; Aves: Threskiornithidae) from the Cradle of Humankind, Gauteng, South Africa and its environmental and evolutionary implications

摘要: We document the presence of bald ibis genus Geronticus Wagler, 1832 (Aves: Threskiornithidae) from mid-Pliocene (ca. 3–3.5 Ma) South Africa based on an incomplete skull Bolt’s Farm Cave System (Cradle Humankind, Gauteng, Africa). The fossil cranium is distinct morphometric and structural grounds apelex, only other Pliocene described Southern Africa, but very close in dimensions general morphology to extant G. calvus therefore attributed G. cf. calvus. Modern ibises are localised temperate, open grasslands semi-arid steppe, nest exclusively cliffs similar rocky eminences. Given its attribution as calvus, was likely ecology G. calvus, suggesting that habitat surrounding site during featured grassland cliffs. This record constrains divergence between putative ancestor G. apelex implies has possibly been subject “evolutionary/morphological stasis” for more than 3 million years. postulated stasis would be consistent with notion genera few species (i.e. high genus-to-species ratios) show low rates phenotypic diversification change through Neogene.