The evolutionary history of the extinct ratite moa and New Zealand Neogene paleogeography

Abstract

The ratite moa (Aves: Dinornithiformes) were a speciose group of massive graviportal avian herbivores that dominated the New Zealand (NZ) ecosystem until their extinction Ϸ600 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.ancient DNA ͉ Oligocene Drowning ͉ Dinornithiformes ͉ phylogeny ͉ taxonomy

Multiple nuclear genes and retroposons support vicariance and dispersal of the palaeognaths, and an Early Cretaceous origin of modern birds

“…The upper limit of our estimate coincides with the rebound and re-emergence of the New Zealand land mass around 23 Ma. This is much earlier than the 5.8 Ma proposed by Bunce et al [53] based on mitochondrial sequences. The timing of the moa radiation is consistent with a terrestrial biota that has undergone a severe bottleneck owing to habitat loss followed by a subsequent diversification as the environment expanded.…”

Ancient DNA reveals extreme egg morphology and nesting behavior in New Zealand’s extinct moa

“…Moa samples from natural sites typically ranged in age from approximately 1,300 to 19,000 y BP. For example, moa bones recovered from Makirikiri and Pyramid Valley swamps and Honeycomb Hill cave (Oparara) dated from 1,296 ± 28 y BP to 18,901 ± 192 y BP (2,6,8,16).…”

“…Extinct members include the elephant bird of Madagascar as well as approximately 10 species of moa (1)(2)(3)(4). Moa were flightless and were particularly diverse in both size and in morphology (1,2,(4)(5)(6)(7)(8). For example, members of the genus Dinornis were characterized by large body size, weighing as much as 250 kg, with extreme sexual dimorphism in which females were approximately twice the size of males (2,5).…”

“…In contrast, individuals of the coastal moa Euryapteryx curtus weighed as little as 9 kg (4) and females were approximately 20% larger than males. As a group, moa represented one of the most dramatic examples of morphological radiation in the history of vertebrates (1,2,6) and have been of international interest since originally described by Richard Owen in 1839 (9). This remarkable ratite group vanished soon after the settlement of New Zealand by Polynesians late in the 13th century (8,10).…”

Ancient DNA microsatellite analyses of the extinct New Zealand giant moa (Dinornis robustus) identify relatives within a single fossil site

“…Nine species of moa are currently recognised (Bunce et al, 2009), all of which were large browsing ratites endemic to New Zealand. They became extinct as a result of overhunting and habitat destruction shortly after Polynesians settled in the thirteenth century (Anderson, 1989;Holdaway and Jacomb, 2000;Allentoft et al, 2014;Holdaway et al, 2014).…”