RESUMO
By analysing ancient DNA (aDNA) from 74 (14)C-dated individuals of the extinct South Island giant moa (Dinornis robustus) of New Zealand, we identified four dyads of closely related adult females. Although our total sample included bones from four fossil deposits located within a 10 km radius, these eight individuals had all been excavated from the same locality. Indications of kinship were based on high pairwise genetic relatedness (rXY) in six microsatellite markers genotyped from aDNA, coupled with overlapping radiocarbon ages. The observed rXY values in the four dyads exceeded a conservative cutoff value for potential relatives obtained from simulated data. In three of the four dyads, the kinship was further supported by observing shared and rare mitochondrial haplotypes. Simulations demonstrated that the proportion of observed dyads above the cutoff value was at least 20 times higher than expected in a randomly mating population with temporal sampling, also when introducing population structure in the simulations. We conclude that the results must reflect social structure in the moa population and we discuss the implications for future aDNA research.
Assuntos
Extinção Biológica , Fósseis , Repetições de Microssatélites , Paleógnatas/genética , Animais , Osso e Ossos , DNA Mitocondrial/genética , Feminino , Genética Populacional , Haplótipos , Funções Verossimilhança , Nova Zelândia , Análise de Sequência de DNARESUMO
The ratite moa (Aves: Dinornithiformes) were a speciose group of massive graviportal avian herbivores that dominated the New Zealand (NZ) ecosystem until their extinction approximately 600 years ago. The phylogeny and evolutionary history of this morphologically diverse order has remained controversial since their initial description in 1839. We synthesize mitochondrial phylogenetic information from 263 subfossil moa specimens from across NZ with morphological, ecological, and new geological data to create the first comprehensive phylogeny, taxonomy, and evolutionary timeframe for all of the species of an extinct order. We also present an important new geological/paleogeographical model of late Cenozoic NZ, which suggests that terrestrial biota on the North and South Island landmasses were isolated for most of the past 20-30 Ma. The data reveal that the patterns of genetic diversity within and between different moa clades reflect a complex history following a major marine transgression in the Oligocene, affected by marine barriers, tectonic activity, and glacial cycles. Surprisingly, the remarkable morphological radiation of moa appears to have occurred much more recently than previous early Miocene (ca. 15 Ma) estimates, and was coincident with the accelerated uplift of the Southern Alps just ca. 5-8.5 Ma. Together with recent fossil evidence, these data suggest that the recent evolutionary history of nearly all of the iconic NZ terrestrial biota occurred principally on just the South Island.
Assuntos
Evolução Biológica , Extinção Biológica , Geografia , Paleógnatas/genética , Paleontologia , Animais , Biodiversidade , Calibragem , DNA Mitocondrial/genética , Especiação Genética , Dados de Sequência Molecular , Nova Zelândia , Paleógnatas/classificação , Filogenia , Fatores de TempoRESUMO
A Leslie matrix population model supported by carbon-14 dating of early occupation layers lacking moa remains suggests that human hunting and habitat destruction drove the 11 species of moa to extinction less than 100 years after Polynesian settlement of New Zealand. The rapid extinction contrasts with models that envisage several centuries of exploitation.