Late Pleistocene/Early Holocene sites in the montane forests of New Guinea yield early record of cassowary hunting and egg harvesting.

How early human foragers impacted insular forests is a topic with implications across multiple disciplines, including resource management. Paradoxically, terminal Pleistocene and Early Holocene impacts of foraging communities have been characterized as both extreme-as in debates over human-driven faunal extinctions-and minimal compared to later landscape transformations by farmers and herders. We investigated how rainforest hunter-gatherers managed resources in montane New Guinea and present some of the earliest documentation of Late Pleistocene through mid-Holocene exploitation of cassowaries (Aves: Casuariidae). Worldwide, most insular ratites were extirpated by the Late Holocene, following human arrivals, including elephant birds of Madagascar (Aepyornithidae) and moa of Aotearoa/New Zealand (Dinornithiformes)-icons of anthropogenic island devastation. Cassowaries are exceptional, however, with populations persisting in New Guinea and Australia. Little is known of past human exploitation and what factors contributed to their survival. We present a method for inferring past human interaction with mega-avifauna via analysis of microstructural features of archaeological eggshell. We then contextualize cassowary hunting and egg harvesting by montane foragers and discuss the implications of human exploitation. Our data suggest cassowary egg harvesting may have been more common than the harvesting of adults. Furthermore, our analysis of cassowary eggshell microstructural variation reveals a distinct pattern of harvesting eggs in late ontogenetic stages. Harvesting eggs in later stages of embryonic growth may reflect human dietary preferences and foraging seasonality, but the observed pattern also supports the possibility that-as early as the Late Pleistocene-people were collecting eggs in order to hatch and rear cassowary chicks.

Earth history and the passerine superradiation.

Avian diversification has been influenced by global climate change, plate tectonic movements, and mass extinction events. However, the impact of these factors on the diversification of the hyperdiverse perching birds (passerines) is unclear because family level relationships are unresolved and the timing of splitting events among lineages is uncertain. We analyzed DNA data from 4,060 nuclear loci and 137 passerine families using concatenation and coalescent approaches to infer a comprehensive phylogenetic hypothesis that clarifies relationships among all passerine families. Then, we calibrated this phylogeny using 13 fossils to examine the effects of different events in Earth history on the timing and rate of passerine diversification. Our analyses reconcile passerine diversification with the fossil and geological records; suggest that passerines originated on the Australian landmass ∼47 Ma; and show that subsequent dispersal and diversification of passerines was affected by a number of climatological and geological events, such as Oligocene glaciation and inundation of the New Zealand landmass. Although passerine diversification rates fluctuated throughout the Cenozoic, we find no link between the rate of passerine diversification and Cenozoic global temperature, and our analyses show that the increases in passerine diversification rate we observe are disconnected from the colonization of new continents. Taken together, these results suggest more complex mechanisms than temperature change or ecological opportunity have controlled macroscale patterns of passerine speciation.

A Passerine Bird's evolution corroborates the geologic history of the island of New Guinea.

New Guinea is a biologically diverse island, with a unique geologic history and topography that has likely played a role in the evolution of species. Few island-wide studies, however, have examined the phylogeographic history of lowland species. The objective of this study was to examine patterns of phylogeographic variation of a common and widespread New Guinean bird species (Colluricincla megarhyncha). Specifically, we test the mechanisms hypothesized to cause geographic and genetic variation (e.g., vicariance, isolation by distance and founder-effect with dispersal). To accomplish this, we surveyed three regions of the mitochondrial genome and a nuclear intron and assessed differences among 23 of the 30 described subspecies from throughout their range. We found support for eight highly divergent lineages within C. megarhyncha. Genetic lineages were found within continuous lowland habitat or on smaller islands, but all individuals within clades were not necessarily structured by predicted biogeographic barriers. There was some evidence of isolation by distance and potential founder-effects. Mitochondrial DNA sequence divergence among lineages was at a level often observed among different species or even genera of birds (5-11%), suggesting lineages within regions have been isolated for long periods of time. When topographical barriers were associated with divergence patterns, the estimated divergence date for the clade coincided with the estimated time of barrier formation. We also found that dispersal distance and range size are positively correlated across lineages. Evidence from this research suggests that different phylogeographic mechanisms concurrently structure lineages of C. megarhyncha and are not mutually exclusive. These lineages are a result of evolutionary forces acting at different temporal and spatial scales concordant with New Guinea's geological history.

SPECIATION IN NORTH AMERICAN CHICKADEES: I. PATTERNS OF mtDNA GENETIC DIVERGENCE.

We surveyed mitochondrial DNA haplotype divergence within and between populations of six species of North American chickadees (Parus, Subgenus Poecile) with the following results. (1) Genotype diversities (range 0.3 to 0.7) and low nucleotide diversities (range 3 to 27 × 10-4 ) within populations were typical of known vertebrates. (2) The two widespread, northern species (atricapillus and hudsonicus) exhibit little mtDNA genetic differentiation throughout their previously glaciated continental distributions, most likely because of recent, postglacial range expansions. (3) Newfoundland populations of atricapillus and maritime province (Newfoundland plus Nova Scotia) populations of hudsonicus have distinct mtDNA haplotypes which differ from continental haplotypes by single restriction site changes. (4) Haplotypes of the southeastern U.S. species P. carolinensis divide into eastern and western sets which have diverged by three percent. This heretofore unrecognized, divided population structure may correspond to the Tombigbee River/ Mobile Bay disjunction known in some other vertebrate taxa. (5) Allopatric populations of the southwestern species sclateri and gambeli exhibit divergences of one and three percent respectively. (6) Prevailing interspecific divergence distances of three to seven percent suggest speciation early in the Pleistocene rather than during late (e.g., Wisconsin) glaciations. (7) Phylogenetic analyses suggest that North American taxa include two clades, hudsonicus-rufescens-sclateri versus carolinensis-atricapillus-gambeli and that carolinensis and atricapillus are not sister species.