Rates of evolution in ancient DNA from Adélie penguins

Well-preserved subfossil bones of Adélie penguins, Pygoscelis adeliae, underlie existing and abandoned nesting colonies in Antarctica. These bones, dating back to more than 7000 years before the present, harbor some of the best-preserved ancient DNA yet discovered. From 96 radiocarbon-aged bones, we report large numbers of mitochondrial haplotypes, some of which appear to be extinct, given the 380 living birds sampled. We demonstrate DNA sequence evolution through time and estimate the rate of evolution of the hypervariable region I using a Markov chain Monte Carlo integration and a least-squares regression analysis. Our calculated rates of evolution are approximately two to seven times higher than previous indirect phylogenetic estimates.     

Ages of fossil penguins in new zealand

The age of a New Zealand specimen generally believed to represent the oldest known penguin, hitherto considered early Eocene (Heretaungan), has been restudied by the New Zealand Geological Survey and is early Miocene. The oldest known penguins are from the late Eocene. The reported great range of a single species, Palaeeudyptes antarcticus, from late Eocene to late Oligocene or early Miocene (Kaiatan to Waitakian) is not acceptable. Dating of some other specimens is less precise than previously reported.     

Paleognathous carinate birds from the early tertiary of north america

Fossils newly discovered in the Paleocene and early Eocene of western North America document some of the oldest birds known from nearly complete skeletons. These were medium-sized carinates with powers of sustained flight but which had a paleognathous palate like that of the flightless ostrich-like birds and the tinamous. The fossils provide additional evidence that the paleognathous palate is probably primitive and therefore should not be cited as a derived character state to define the ostrich-like birds as a monophyletic group.     

Environmental temperatures of tertiary penguins

Marine paleotemperatures, determined by oxygen isotope measurement, show that Australasian Tertiary penguins, including giant forms, lived in warm to tropical environments. Evolution from smaller species also occurred in warm environments. Mid-Tertiary fluctuations of sea temperature were controlled by alternating uplift and erosion of "Tasmantis," an unstable meridional landmass occupying and extending beyond the present position of New Zealand.     

Ratite eggshells from lanzarote, canary islands

Struthious and aepyornithoid eggshells from Tertiary calcareous sediments on Lanzarote prove the presence, until about 12 million years ago, of large flightless birds. The calcarenite horizon is recognized as an old land surface. Mesozoic sedimentary rocks in the basement of the volcanic islands of Lanzarote and neighboring Fuerteventura indicate that at least part of the Canary Archipelago is underlain by continental crust. Separation of the eastern Canaries from Africa raight have been by rifting, and a land connection might still have existed in the lower Pliocene.     

Prehistoric extinctions of pacific island birds: biodiversity meets zooarchaeology

On tropical Pacific islands, a human-caused "biodiversity crisis" began thousands of years ago and has nearly run its course. Bones identified from archaeological sites show that most species of land birds and populations of seabirds on those islands were exterminated by prehistoric human activities. The loss of birdlife in the tropical Pacific may exceed 2000 species (a majority of which were species of flightless rails) and thus represents a 20 percent worldwide reduction in the number of species of birds. The current global extinction crisis therefore has historic precedent.     

Laonastes and the "Lazarus effect" in recent mammals

The living Laotian rodent Laonastes aenigmamus, first described in early 2005, has been interpreted as the sole member of the new family Laonastidae on the basis of its distinctive morphology and apparent phylogenetic isolation from other living rodents. Here we show that Laonastes is actually a surviving member of the otherwise extinct rodent family Diatomyidae, known from early Oligocene to late Miocene sites in Pakistan, India, Thailand, China, and Japan. Laonastes is a particularly striking example of the "Lazarus effect" in Recent mammals, whereby a taxon that was formerly thought to be extinct is rediscovered in the extant biota, in this case after a temporal gap of roughly 11 million years.     

Pleistocene extinction of genyornis newtoni: human impact on australian megafauna

More than 85 percent of Australian terrestrial genera with a body mass exceeding 44 kilograms became extinct in the Late Pleistocene. Although most were marsupials, the list includes the large, flightless mihirung Genyornis newtoni. More than 700 dates onGenyornis eggshells from three different climate regions document the continuous presence of Genyornis from more than 100,000 years ago until their sudden disappearance 50,000 years ago, about the same time that humans arrived in Australia. Simultaneous extinction of Genyornis at all sites during an interval of modest climate change implies that human impact, not climate, was responsible.     

Amino Acid composition of planktonic foraminifera: a paleobiochemical approach to evolution

A unique, species-specific amino acid composition is identified with each of 16 species of planktonic Foraminifera isolated from the tops of deep-sea sediment cores. This amino acid pattern appears to directly reflect the genotype. The total amino acid content ranges from 2.0 to 4.2 micromoles per gram of calcified tissue or 0.02 to 0.04 percent by weight. Analyses of two Early Miocene species indicate that characteristic compositional differences are sufficiently well preserved over geologic time to determine phylogenetic affinities among extinct species living at least 18 million years ago.     

Miocene burrows of extinct bear dogs: indication of early denning behavior of large Mammalian carnivores

Partial skeletons of four species of extinct carnivores have been found in their dens excavated in the floodplain of an early Miocene ephemeral braided stream at Agate Fossil Beds National Monument, Nebraska. Bear dogs (Carnivora: Amphicyonidae) were the principal occupants; their den dimensions and body size are similar to those of living wolves and hyenas. Discovery of this predator community extends the record of denning behavior of large mammalian carnivores to the early Miocene, 20 million years ago.     

一例巴布亚企鹅胃穿孔手术及治疗

企鹅是一种好奇心很强的鸟类,且经常吞食异物。本文对一只巴布亚企鹅摄食尾羽后进行胃镜取出,胃内已穿孔的部位通过钛合金钳子固定后自行愈合的方法进行处置,通过后续治疗后,该企鹅食欲正常,健活动状态正常,痊愈。本文对于了解圈养巴布亚企鹅摄食异物后处置及治疗方案具有重要意义。     

A catastrophic death assemblage and paleoclimatic implications of pliocene seabirds of Florida

A deposit of fossil seabirds from the late Pliocene of Florida includes more than 130 skeletons of an extinct cormorant that is related phylogenetically to Recent species currently restricted to the eastern north Pacific. Evidence suggests the birds died in a single catastrophic event, perhaps a red tide. The fossil cormorant, along with other extinct seabirds and marine mammals, supports molluscan evidence for cold-water upwelling along the Florida Gulf Coast during the Pliocene. A decline in species richness of marine vertebrates throughout the Pliocene of Florida coincides with cessation of upwelling after emergences of the Panamanian Land Bridge.     

A 3.3-Ma impact in argentina and possible consequences

Enigmatic glassy materials (escorias) and red bricklike materials (tierras cocidas) occur at a restricted stratigraphic level (the top of the Chapadmalal Formation). Materials from one locality near Mar del Plata are attributed to a mid-Pliocene impact event with a radiometric and magnetostratigraphic age of 3.3 million years ago (Ma). An extinction of endemic fauna (including the glyptodonts and flightless cariamid birds) correlates with the unit containing the impact glasses. Moreover, the age of the glasses is coincident within dating uncertainties with a pulselike change in the oxygen isotope marine record in the Atlantic and Pacific Oceans just before the late Pliocene deterioration of the climate.     

Avian extinction and mammalian introductions on oceanic islands

The arrival of humans on oceanic islands has precipitated a wave of extinctions among the islands' native birds. Nevertheless, the magnitude of this extinction event varies markedly between avifaunas. We show that the probability that a bird species has been extirpated from each of 220 oceanic islands is positively correlated with the number of exotic predatory mammal species established on those islands after European colonization and that the effect of these predators is greater on island endemic species. In contrast, the proportions of currently threatened species are independent of the numbers of exotic mammalian predator species, suggesting that the principal threat to island birds has changed through time as species susceptible to exotic predators have been driven extinct.     

Ivory-billed woodpecker (Campephilus principalis) persists in continental North America

The ivory-billed woodpecker (Campephilus principalis), long suspected to be extinct, has been rediscovered in the Big Woods region of eastern Arkansas. Visual encounters during 2004 and 2005, and analysis of a video clip from April 2004, confirm the existence of at least one male. Acoustic signatures consistent with Campephilus display drums also have been heard from the region. Extensive efforts to find birds away from the primary encounter site remain unsuccessful, but potential habitat for a thinly distributed source population is vast (over 220,000 hectares).     

Life history of symbiont-bearing giant clams from stable isotope profiles

Stable isotopic and shell-growth banding studies of the symbiont-bearing giant clam Tridacna maxima reveal the existence of two growth phases related to sexual maturity that can be discerned in the shells of extinct and extant mollusks. The changeover from the first to second growth phase at an age of approximately 10 years is accompanied by a decrease in rate of calcification and suggests a reordering of energy priorities between biomineralization and reproduction. The carbon-13 to carbon-12 ratio of Tridacna maxima is systematically depleted relative to symbiont-barren mollusks, making it possible to determine the importance of algal-molluscan symbiosis to the functional morphology and paleoecology of mollusks in the geologic record.     

Paleoenvironment of the earliest hominoids: new evidence from the oligocene avifauna of egypt

Analysis of fossil birds from the Oligocene Jebel Qatrani Formation in the Fayum depression of Egypt, site of the oldest known hominoid primates, allows precise paleoenvironmental reconstruction of the climatic and biotic conditions that influenced some of the earliest stages of hominoid evolution. Unlike the fossil mammals of the Fayum, which belong largely to extinct groups, most of the birds are referable to living families, with some being close to modern genera. The avifauna consists mainly of aquatic species, with such forms as jacanas (Jacanidae) and shoebilled storks (Balaenicipitidae) indicating expanses of freshwater with dense floating vegetation. An avifauna closely analogous to that of the Fayum is found today only in a limited area of Uganda, north and west of Lake Victoria, a region of swampland bordered by forest and grasslands that presents marked faunal similarities to the environment inferred for the Egyptian Oligocene.     

Gender-specific reproductive tissue in ratites and Tyrannosaurus rex

Unambiguous indicators of gender in dinosaurs are usually lost during fossilization, along with other aspects of soft tissue anatomy. We report the presence of endosteally derived bone tissues lining the interior marrow cavities of portions of Tyrannosaurus rex (Museum of the Rockies specimen number 1125) hindlimb elements, and we hypothesize that these tissues are homologous to specialized avian tissues known as medullary bone. Because medullary bone is unique to female birds, its discovery in extinct dinosaurs solidifies the link between dinosaurs and birds, suggests similar reproductive strategies, and provides an objective means of gender differentiation in dinosaurs.     

Seed dispersal by weta

Weta are giant, flightless grasshoppers that are endemic to New Zealand. In the absence of native mammals, weta are thought to perform similar ecological functions. As such, they might be expected to be important seeds dispersers. However, insects are not known to consume fleshy fruits and to disperse seeds after gut passage. We conducted a series of observations and experiments to test whether weta form mutualistic partnerships with fleshy-fruited plants as seed dispersers, similar to small mammals elsewhere in the world. Results showed that weta are indeed effective seeds dispersers, providing an example of ecological convergence between unrelated organisms.     

Invasion and extinction in the west Indian ant fauna: evidence from the dominican amber

Of 37 genera and well-defined subgenera identified in the amber of the Dominican Republic (late Oligocene or early Miocene), 34 have survived somewhere in the New World tropics to the present, although the species studied thus far are extinct. Of the surviving genera and subgenera, 22 persist on Hispaniola. Fifteen genera and subgenera have colonized the island since amber times, restoring the number of genera and well-defined subgenera now present on Hispaniola to 37. A higher extinction rate has occurred in genera and subgenera that are either highly specialized or possess less colonizing ability, as evidenced by their restriction to the New World.