Bird fossils from Ankilitelo Cave: Inference about Holocene environmental changes in Southwestern Madagasca

Abstract

The identifications of non-permineralized fossil bird bones recovered from Ankilitelo Cave in southwestern Madagascar are presented. Among the more than 560 elements recovered, 29 different taxa were identified, the vast majority being species that still occur in this region of the island. Eggshell remains from the extinct elephant bird (Family Aepyornithidae) and assigned to Aepyornis sp. were found at the site. Two identified extant taxa, Scopus umbretta and Monias benschi, no longer occur in the area immediately surrounding the cave. The available radiocarbon measurements of collagen from fossil bird bones and avian eggshell carbonate of recovered from the cave range from 13,270 Cal yr BP to modern times. Hence, the presumed ecological shifts that took place resulting in the disappearance or range contractions of these three taxa is within the Holocene and are presumed to be associated with natural climatic change and in more recent centuries associated human pressures. Information is also presented on the origin of guinea fowl (Numida) and inference on the period of colonization of Corvus albus on Madagascar.Key words: Ankilitelo Cave, birds, Aepyornis, Monias benschi, Numida meleagris, fauna, environmental shifts, C14 dates Résumé Les identifications des os d'oiseaux fossiles récupérés dans la Grotte d'Ankilitelo dans le Sud-ouest de Madagascar sont présentées ici. Parmi les 560 éléments et plus récupérés, 29 taxa différentes ont été identifiées dont la majorité sont des espèces qui se trouvent encore dans cette région de l'île. Des restes de coquilles d'oeuf de l'oiseau-éléphant éteint (famille des Aepyornithidae) et affecté à Aepyornis sp. ont été trouvés sur le site. Par ailleurs, deux taxa actuels, Scopus umbretta et Monias benschi, ont été identifiés mais ne se rencontrent plus à proximité de la grotte. Sur la base des mesures disponibles de radiocarbone de fossiles d'oiseaux récupérés dans la grotte, le matériel le plus ancien est daté à 11 310 ± 40 14 C BP et le plus récent à l'époque moderne. Par conséquent, les changements écologiques présumés, ayant entraîné la disparition ou la restriction de la zone de répartition de ces trois taxons, ont eu lieu dans l'histoire récente. Ces changements sont probablement associés à perturbations climatiques naturelles et aux pressions humaines ultérieures. Des informations sont aussi présentées sur l'origine de la pintade (Numida) et l'inférence sur la période de la colonisation de Corvus albus à Madagascar.

Island‐wide aridity did not trigger recent megafaunal extinctions in Madagascar

“…Factors that contributed to megafaunal demise continue to be debated. While some researchers have suggested that direct competition with introduced domesticated species or hypervirulent diseases may have killed the megafauna (Dewar , MacPhee and Marx ), most have focused on climate change (increasing aridity), hunting by humans, or anthropogenic habitat alteration (Battistini , Burney and MacPhee , Burney , , Godfrey and Jungers , Burney et al , Kaufmann , Clarke et al , Godfrey and Irwin , Virah‐Sawmy et al , , Crowley , Crowley et al , Godfrey and Rasoazanabary , Crowley and Samonds , Goodman et al , Goodman and Jungers , Burns et al ). Because aridification and anthropogenic deforestation can have similar effects on vegetation, resolving which of these factors (if either) triggered megafaunal extinctions in Madagascar has remained a challenge.…”

Patterns of Dental Macrowear in Subfossil Lemur catta from Ankilitelo Cave, Madagascar: Indications of Ecology and Habitat Use over Time

“…Most important is the assessment of localities where specimens of extant forms whose fossils are found in sympatry with the recently extinct lemur 'megafauna'. The cave site of Ankilitelo, in southwestern Madagascar, 45 km northeast of the city of Toliara, is one such location [Godfrey et al, 1999;Simons et al, 2004;Muldoon and Simons, 2007;Muldoon et al, 2009;Goodman et al, 2013]. Ankilitelo may be the most recent location preserving extinct forms and sympatric subfossil representatives of extant lemurs, with dates for these primates being as recent as ∼ 500 to ∼ 600 years ago [Simons, 1997;Godfrey et al, 1999;Simons et al, 2004;Muldoon et al, 2009;Goodman et al, 2013].…”

“…The cave site of Ankilitelo, in southwestern Madagascar, 45 km northeast of the city of Toliara, is one such location [Godfrey et al, 1999;Simons et al, 2004;Muldoon and Simons, 2007;Muldoon et al, 2009;Goodman et al, 2013]. Ankilitelo may be the most recent location preserving extinct forms and sympatric subfossil representatives of extant lemurs, with dates for these primates being as recent as ∼ 500 to ∼ 600 years ago [Simons, 1997;Godfrey et al, 1999;Simons et al, 2004;Muldoon et al, 2009;Goodman et al, 2013]. Although dates for Ankilitelo's primates are very recent (see above), new data from avian bones and eggshells at Ankilitelo suggest that portions of the fossil assemblage here date to as far back as ∼ 13,000 BP [Goodman et al, 2013].…”

“…Ankilitelo may be the most recent location preserving extinct forms and sympatric subfossil representatives of extant lemurs, with dates for these primates being as recent as ∼ 500 to ∼ 600 years ago [Simons, 1997;Godfrey et al, 1999;Simons et al, 2004;Muldoon et al, 2009;Goodman et al, 2013]. Although dates for Ankilitelo's primates are very recent (see above), new data from avian bones and eggshells at Ankilitelo suggest that portions of the fossil assemblage here date to as far back as ∼ 13,000 BP [Goodman et al, 2013]. However, from geological, paleontological and evolutionary perspectives, this remains a 'recent' fossil assemblage, herein defining 'recent' as the Holocene ( ≈ post-Pleistocene).…”

“…However, from geological, paleontological and evolutionary perspectives, this remains a 'recent' fossil assemblage, herein defining 'recent' as the Holocene ( ≈ post-Pleistocene). Also, to date, the only known ages for Ankilitelo's primates are within historic times [Goodman et al, 2013], especially in light of the new data on human arrival [Dewar et al, 2013].…”