6,132 research outputs found

    A new species and new records of Aphodius Illiger (Coleoptera: Scarabaeidae: Aphodiinae) from mammal burrows in Nebraska

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    Direct sampling of rodent burrows in Nebraska resulted in the collection of 16 species of Aphodius Illiger previously unknown from the state, including specimens of four undescribed species. One of these species is described here as new: Aphodius viceversus new species recorded from Nebraska and Kansas. Other Aphodius species recorded from Nebraska for the first time include A. acuminatus Cartwright, A. anomaliceps Brown, A. carri Brown, A. criddlei Brown, A. kirni Cartwright, A. kiowensis Gordon and Salsbury, A. magnificens Robinson, A. neodistinctus Brown, A. peculiosus Schmidt, A. punctissimus Brown, A. thomomysi Brown, and A. leptotarsis Brown. Collecting information is summarized for each species

    A new genus for the Neotropical species of Aesalus Fabricius, with descriptions of eight new species (Coleoptera: Lucanidae: Aesalinae)

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    The Neotropical members of the genus Aesalus Fabricius (Coleoptera: Lucanidae: Aesalinae) are transferred to a new genus, Trogellus, due to their morphological dissimilarity and molecular divergence from the Old World species of Aesalus, and the new genus is revised. A neotype is designated for A. trogoides Albers and a lectotype for A. neotropicalis Bates. Aesalus smithi Bates is placed into synonymy with Aesalus trogoides, new synonymy. Two new combinations result from the transfer of species formerly in Aesalus: Trogellus trogoides from Mexico and Trogellus neotropicalis from Guatemala. In addition to the two known species, eight new species are described: T. catrachitus, T. chapinitus, T. hawksi, T. herrmanni, T. maesi, T. narizotus, T. ticiticus, and T. trifinius. This brings the total number of species of Central American aesalines to ten. A phylogeny of Aesalini based on two gene regions of ribosomal DNA is presented. Due to clear morphological differences and large molecular divergence between species groups, two additional new subgenera of Trogellus are proposed: Mayaesalus and Trogoides

    A new species of Parochodaeus Nikolajev from the southwestern United States (Coleoptera: Scarabaeoidea: Ochodaeidae)

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    A new species of Parochodaeus Nikolajev (Scarabaeoidea: Ochodaeidae) with extremely small adults is described from west Texas, P. pixius Paulsen. The species is compared with the sympatric P. biarmatus (LeConte), to which it is most similar in size

    Nomenclatural changes in the Nearctic Ochodaeinae and description of two new genera (Coleoptera: Scarabaeoidea: Ochodaeidae)

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    Generic placement of Nearctic species of Ochodaeinae has lagged behind changes in generic concepts in the group. In order to place Nearctic species into the appropriate genus-level taxa, several nomenclatural changes are made. The new generic name Xenochodaeus is proposed for species with an elongate, subparallel sulcus on the propygidium and a longitudinally impressed mentum. The genus contains 6 species. Xenochodaeus americanus (Westwood), new combination, is valid and is removed from synonymy with X. musculus (Say), new combination. A neotype is designated for Odontaeus musculus. Ochodaeus opacus LeConte is synonymized under X. americanus. Other new combinations include Xenochodaeus luscinus (Howden), X. planifrons (Schaeffer), X. simplex (LeConte), and X. ulkei (Horn). The new generic name Cucochodaeus is proposed for species having the propygidial sulcus absent, stridulatory peg absent, and possessing 9 antennomeres. The genus contains 1 species, C. sparsus (LeConte), new combination. Ochodaeus mandibularis Linell is placed into synonymy with C. sparsus. Ochodaeus gnatho Fall is transferred to the genus Codocera Eschscholtz, resulting in C. gnatho (Fall), new combination. Two new combinations result from Nearctic species transferred to Neochodaeus Nikolajev: N. repandus (Fall) and N. striatus (LeConte). Three Nearctic species are transferred to Parochodaeus Nikolajev, resulting in new combinations: Parochodaeus californicus (Horn), P. duplex (LeConte), and P. peninsularis (Horn). A lectotype is designated for Ochodaeus kansanus Fall, and that same specimen is designated as the neotype of Ochodaeus duplex (LeConte), objectively synonymizing O. kansanus with O. duplex. A checklist of Nearctic species and key to Nearctic genera are provided

    A second species of Lucanobium Howden and Lawrence from South America (Coleoptera: Lucanidae: Aesalinae)

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    The monotypic aesaline genus Lucanobium Howden and Lawrence (Coleoptera: Lucanidae) was previously known only from Venezuela. A second species is here described as new from French Guiana, extending the range of the genus approximately 1800 km to the southeast. The generic description of Lucanobium is updated with respect to the discovery of a second species

    The Ochodaeidae of Argentina (Coleoptera, Scarabaeoidea)

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    The Ochodaeidae (Coleoptera: Scarabaeoidea) of Argentina are revised. Previously, two species of Ochodaeinae were known from the country, both in the genus Parochodaeus Nikolajev: P. campsognathus (Arrow) and P. cornutus (Ohaus). An additional 7 species of Parochodaeus from Argentina are described here as new. In addition, Gauchodaeus patagonicus, new genus and new species in the subfamily Chaetocanthinae, is described. "is is the #rst record of the subfamily Chaetocanthinae in South America. Redescriptions, diagnoses, and maps are provided for each species. We also provide a key to genera and a key to species of Parochodaeus of Argentina. With this work, the number of ochodaeid species known from Argentina is increased from 2 to 10.Fil: Paulsen, M. J.. University of Nebraska; Estados UnidosFil: Ocampo, Federico Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

    Platyceroidini, a new tribe of North American stag beetles(Coleoptera: Lucanidae: Lucaninae)

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    The tribe Platyceroidini is created to accommodate two genera of North American stag beetles, Platyceroides Benesh and Platyceropsis Benesh (Lucanidae: Lucaninae). These genera are removed from the tribe Platycerini Mulsant

    DFT Calculations as a Tool to Analyse Quadrupole Splittings of Spin Crossover Fe(II) complexes

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    Density functional methods have been applied to calculate the quadrupole splitting of a series of iron(II) spin crossover complexes. Experimental and calculated values are in reasonable agreement. In one case spin-orbit coupling is necessary to explain the very small quadrupole splitting value of 0.77 mm/s at 293 K for a high-spin isomer

    Hyperuniformity with no fine tuning in sheared sedimenting suspensions

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    Particle suspensions, present in many natural and industrial settings, typically contain aggregates or other microstructures that can complicate macroscopic flow behaviors and damage processing equipment. Recent work found that applying uniform periodic shear near a critical transition can reduce fluctuations in the particle concentration across all length scales, leading to a hyperuniform state. However, this strategy for homogenization requires fine tuning of the strain amplitude. Here we show that in a model of sedimenting particles under periodic shear, there is a well-defined regime at low sedimentation speed where hyperuniform scaling automatically occurs. Our simulations and theoretical arguments show that the homogenization extends up to a finite lengthscale that diverges as the sedimentation speed approaches zero.Comment: 11 pages, 6 figure

    An automated and versatile ultra-low temperature SQUID magnetometer

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    We present the design and construction of a SQUID-based magnetometer for operation down to temperatures T = 10 mK, while retaining the compatibility with the sample holders typically used in commercial SQUID magnetometers. The system is based on a dc-SQUID coupled to a second-order gradiometer. The sample is placed inside the plastic mixing chamber of a dilution refrigerator and is thermalized directly by the 3He flow. The movement though the pickup coils is obtained by lifting the whole dilution refrigerator insert. A home-developed software provides full automation and an easy user interface.Comment: RevTex, 10 pages, 10 eps figures. High-resolution figures available upon reques
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