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We tested the efficacy of DNA barcodes in identifying mayfly species primarily from the northeastern United States and central Canada. We sequenced a 630-base-pair segment of the mitochondrial gene, cytochrome c oxidase 1 (COI), from 1 individual of each of 80 species to create a reference sequence profile. We used these reference sequences to identify 70 additional specimens representing 32 of the species that were in the profile. DNA barcodes correctly identified 69 of the 70 test specimens. The sole exception was an individual identified morphologically as Maccaffertium modestum that showed deep genetic divergence from other M. modestum specimens. Mean sequence divergence within species was 1%, whereas mean divergence among congeneric species was an order of magnitude greater (18%). We conclude that DNA barcoding can provide a powerful tool for mayfly species identification. © 2005 by The North American Benthological Society.
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We observed 16 instances of caching behavior by Northern Saw-whet Owls in southern Connecticut between 30 October and 29 March over a 23-year period 1982 to 2004. Caches consisted of a single prey item in 13 instances and two prey items in three instances. Prey was cached either directly beneath the owl or from 5-28 cm distant, always on the same branch on which the owl was roosting. Observations of cached prey marked in the morning suggested that it was consumed after 14:30 in the afternoon of the same day. Such a delay indicated a true cache rather than delayed feeding.
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Newly recorded archaeological sites at Gona (Afar, Ethiopia) preserve both stone tools and faunal remains. These sites have also yielded the largest sample of cutmarked bones known from the time interval 2.58-2.1 million years ago (Ma). Most of the cutmarks on the Gona fauna possess obvious macroscopic (e.g., deep V-shaped cross-sections) and microscopic (e.g., internal microstriations, Herzian cones, shoulder effects) features that allow us to identify them confidently as instances of stone tool-imparted damage caused by hominid butchery. In addition, preliminary observations of the anatomical placement of cutmarks on several of the recovered bone specimens suggest that Gona hominids may have eviscerated carcasses and defleshed the fully muscled upper and intermediate limb bones of ungulates-activities that further suggest that Late Pliocene hominids may have gained early access to large mammal carcasses. These observations support the hypothesis that the earliest stone artifacts functioned primarily as butchery tools and also imply that hunting and/or aggressive scavenging of large ungulate carcasses may have been part of the behavioral repertoire of hominids by c. 2.5 Ma, although a larger sample of cutmarked bone specimens is necessary to support the latter inference. (c) 2004 Elsevier Ltd. All rights reserved.
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Published evidence of Oldowan stone exploitation generally supports the conclusion that patterns of raw material use mere determined by local availability. This is contradicted by the results of systematic studies of raw material availability and use among the earliest known archaeological sites from Gona, Afar, Ethiopia. Artifact assemblages from six Pliocene archaeological sites were compared with six random cobble samples taken from associated conglomerates that record pene-contemporaneous raw material availability. Artifacts and cobbles were evaluated according to four variables intended to capture major elements of material quality: rock type, phenocryst percentage, average phenocryst size, and groundmass texture. Analyses of these variables provide evidence of hominid selectivity for raw material quality. These results demonstrate that raw material selectivity was a potential component of Oldowan technological organization from its earliest appearance and document a level of technological sophistication that is not always attributed to Pliocene hominids. (c) 2004 Elsevier Ltd. All rights reserved.
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Comparative biomolecular studies suggest that the last common ancestor of humans and chimpanzees, our closest living relatives, lived during the Late Miocene-Early Pliocene 1,2. Fossil evidence of Late Miocene-Early Pliocene hominid evolution is rare and limited to a few sites in Ethiopia 3-5, Kenya 6 and Chad 7. Here we report new Early Pliocene hominid discoveries and their palaeoenvironmental context from the fossiliferous deposits of As Duma, Gona Western Margin (GWM), Afar, Ethiopia. The hominid dental anatomy (occlusal enamel thickness, absolute and relative size of the first and second lower molar crowns, and premolar crown and radicular anatomy) indicates attribution to Ardipithecus ramidus. The combined radioisotopic and palaeomagnetic data suggest an age of between 4.51 and 4.32 million years for the hominid finds at As Duma. Diverse sources of data (sedimentology, faunal composition, ecomorphological variables and stable carbon isotopic evidence from the palaeosols and fossil tooth enamel) indicate that the Early Pliocene As Duma sediments sample a moderate rainfall woodland and woodland/grassland., (C) 2005 Nature Publishing Group
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In this article, I explore the ideological underpinnings of the Indian government's language policies in the school setting, and I investigate why they fail to be compelling to residents of Banaras, a city in North India. The multiple language markets that exist in India are incommensurate and subvert the government's language policies in multiple ways. By exploring the uneven quality of these markets, this article illustrates the especially complicated dilemmas in which postcolonial nation-states are implicated.
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