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In order to test hypotheses about the phylogenetic relationships among living genera of New World monkeys, 1.3 kb of DNA sequence information was collected for two introns of the glucose-6-phosphate dehydrogenase (G6PD) locus, encoded on the X chromosome, for 24 species of New World monkeys. These data were analyzed using a maximum parsimony algorithm. The strict consensus of the three most-parsimonious gene trees that result shows support for the following clades: a pitheciine clade including Callicebus within which Chiropotes and Cacajao are sister taxa, an Alouatta-atelin clade within which Brachyteles is the sister taxon of Lagothrix and which is sister to another clade containing the callitrichines, and a callitrichine/Aotus/Cebus/Saimiri clade. Within the callitrichines, Callimico is the sister taxon of Callithrix. Cebus and Saimiri form a clade. These results are broadly consistent with previously published DNA sequence analyses of platyrrhine phylogeny and provide additional support for groupings provisionally proposed in those earlier studies. Nevertheless, questions remain as to the relative phylogenetic placement of Leontopithecus and Saguinus, the branching order within the Aotus/Cebus/Saimiri/callitrichine clade, and the placement of the pitheciine clade relative to the atelines and the callitrichines.  相似文献   

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Examination of some collections from several late Miocene Turkish localities allows us to describe and definitely identify for the first time several species of spiral-horned antelopes in this country:Palaeoreas lindermayeri, Protragelaphus skouzesi, Prostrepsiceros zitteli andNisidorcas sp. During the first part of the late Miocene, several endemic species are restricted to central Anatolia, while more widespread taxa appear in the later part of this period, suggesting a decrease in provinciality of this area.  相似文献   

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Numerous dental remains of Nannopithex zuccolae, n. sp., from the terminal early Eocene locality of Prémontré (Aisne), France, show the lower anterior dentition to be similar to that of other Nannopithex. Similarities include enlarged I1, reduced I2, reduced lower canine, loss of P2, small P3 and large P4. Upper molars, P3 and P4 all present primitive characters, making this species the most primitive as well as the oldest known microchoerid.  相似文献   

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Stipa adamii M. Nobis sp. nov. (Poaceae), endemic to Kazakhstan, is described and illustrated. The species belongs to the section Smirnovia Tzvel. and is distributed in the central Karatau Mountains (western Tian‐Shan). It is morphologically close to Stipa karataviensis Roshev. but is easily distinguishable by longer glumes, lemmas, awns and the callus. The awn is scabrous in the lower part and the callus is bearded in S. adamii whereas both organs are glabrous in S. karataviensis. Characters distinguishing S. karataviensis and S. adamii are presented in a table, together with photographs of the callus. The analysis of morphological characters of the taxa provides new information on their variability. A key to the species of Stipa sect. Smirnovia occurring in Kazakhstan, typification of the name S. manrakica and synonymization of the name S. saurica as a syn. nov. are included.  相似文献   

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Ascunce MS  Hasson E  Mudry MD 《Genetica》2002,114(3):253-267
Nucleotide sequence variation at the mitochondrial cytochrome c oxidase subunit II gene (COII) was analyzed in 27 New World monkey specimens, nine newly reported herein. The study involved comparisons among platyrrhines and also between platyrrhines and catarrhines. The analysis of the frequencies of transitions and transversions at each codon position showed transitional saturation at third codon position. Neighbor-Joining trees obtained from genetic distances estimated by means of Kimura's (1980) two-parameter model showed poor resolution of phylogenetic relationships among platyrrhine genera. Rates of nucleotide substitutions were largely homogeneous except in the genus Saimiri that showed low numbers of unique substitutions suggesting the maintenance of ancestral or plesiomorphic states of platyrrhine mt DNA nucleotide characters probably due to its large population sizes as compared to other platyrrhines.  相似文献   

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Dr. Gary Alton Dudley was a modern pioneer in the study of muscle. His work encompassed almost 30 years of study with dramatic discoveries in the areas of muscle physiology, resistance training, and spinal cord injury and therapy. The greater understanding of muscle fiber changes with training, as well as novel experiments using magnetic resonance imaging and single fiber analyses, allowed for many discoveries in the areas of resistance training and detraining, the roles of electrical stimulation in training muscle, the compatibility of different exercise modes, and the characteristics of and treatment interventions for spinal cord injury. His work and insights will provide future investigators a knowledge base from which to work for both basic and applied research in muscle and exercise physiology.  相似文献   

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External and internal head structures of adults of Orchymontiinae, Prosthetopinae, Hydraeninae and Ochthebiinae were studied and those of Ochthebius semisericeus and Limnebius truncatellus are described in detail. The results are evaluated with respect to their relevance for a reconstruction of hydraenid phylogeny and also compared with structural features found in adults of other staphyliniform families. The monophyly of Hydraenidae is supported by the presence of a plate‐like, trilobed premento‐hypopharyngeal extension, an unusual origin of m. tentoriohypopharyngalis, dorsal tentorial arms firmly fused with the head capsule, modified basal antennomeres, and palpigers connected by a transverse sclerotized bar. Orchymontiinae are monophyletic and the basal sister group of the remaining Hydraenidae. The presence of a ventral transverse genal bulge and of a pubescent antennal club with more than two antennomeres (reversal in some prosthetopines: e.g. Mesoceration abstrictum) are possible apomorphies of Hydraenidae excluding Orchymontiinae. Prosthetopinae are probably monophyletic and the sister group of Ochthebiinae + Hydraeninae. The latter clade is characterized by a distinct cupula formed by antennomere VI, a loose five‐segmented pubescent antennal club, and a modified antennal musculature. The presence of an unusual tentorio‐pharyngeal dilator is a shared derived feature of Ochthebiinae and the genus Davidraena. The monophyly of Ochthebiinae was confirmed and Ochtheosus is the sister group of the remaining ochthebiine genera, which are characterized by a perforated wall‐like structure formed by the posterior tentorial arms. The absence of this tentorial modification and the fimbriate galea are plesiomorphies retained in Ochtheosus. Calobius differs strongly from other subgenera of Ochthebius and a generic status may be appropriate. The monophyly of Hydraeninae is not supported. Hydraena was confirmed as a clade and Laeliaena and Limnebius are sister groups. The latter genus is characterized by several autapomorphies. The basal position of Orchymontiinae and Prosthetopinae suggests a Gondwanan origin of Hydraenidae and a primary preference for life in running water. Important evolutionary changes of head structures are complex transformations of the antennae and related structures. Yet, the use of the antennae as accessory breathing organs is not a groundplan feature of the family. The results of this study strengthen the case of staphylinoid affinities of Hydraenidae.  相似文献   

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Ovaries of the giant silkmoth Samia cynthia Drury have been studied histologically and histochemically during diapause, adult development, and after injury to the diapause animal. In addition to cellular changes involved in follicular growth and vitellogenesis, changes in the intermediate layer cells are very striking, showing a distinct pattern during ovarian development and after injury. Two types of granules, one periodic acid-Schiff (PAS) positive, the other paraldehyde-fuchsin (PF) positive, change in their number and distribution in the intermediate cells during development and after injury. The PAS-positive granules appear during the first one-third of development, increase in number and size until the tenth day, then gradually dwindle in number and size, and disappear in the adult cells. The PF-positive granules, present in moderate numbers in the diapause animal, decrease in number until the tenth day of adult development, then reappear, and are present again in adult intermediate cells. After injury to a diapause pupa, intermediate cells show a greatly increased number of PF-positive granules, but none that are PAS-positive. The PAS-positive granules are a neutral or mildly acidic mucosubstance, and may correspond to lysosomal activity, while the PF-positive granules may be a neurosecretory-like substance or the product of hormone-dependent protein synthesis, since the patterns of granule distribution in the intermediate cells seem to reflect both general metabolic and hormone-related events.  相似文献   

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The anatomical and taxonomic knowledge of some groups of Glyptodontidae (Mammalia, Cingulata) is still very poor. In addition, a strict typological/morphological taxonomic criterion was used in recognizing many taxa, especially during the second half of the 19th century and the first of the 20th century. This particular situation resulted in a clear overestimation diversity, mainly with respect to the South American glyptodonts. In this scenario, this paper analyzes the taxonomic status of some Glyptodontinae through a precise comparative study with well characterized taxa. The main results show that the genera Pseudothoracophorus Castellanos (P. depressus) and Chlamydotherium Lund, one species of the genus “Boreostracon” Simpson (B. corondanus), and one species of the genus Glyptodon Owen (G. falkneri), actually represents juvenile specimens referable to Glyptodon Owen; the genus Neothoracophorus Ameghino (N. elevatus) could be related either to Glyptodon Owen or Glyptotherium Osborn. Another species, Heteroglyptodon genuarioi, presents an almost identical morphology compared with the recognized species of Glyptodon (e.g. G. munizi and G. reticulatus). In this sense, the diagnostic characters described for Glyptodon perforatus Ameghino, a taxon with biostratigraphic relevance since it is characteristic of the Lujanian Age/Stage (late Pleistocene-early Holocene), are also present in other species of Glyptodon, especially G. reticulatus and G. clavipes, very frequent taxa in southern South America.  相似文献   

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The ultrastructure of the walls of the tubuli of larvae of two Chironomus species living in lakes and four species from small ponds were studied, in order to decide whether the function of the tubuli is primarily a respiratory one or not.Data suggest a reinforcement of the concept of a respiratory function and a hypothesis is discussed which might explain the differences found between the tubuli of lake- and pond-dwelling species.  相似文献   

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Mites of the genus Veigaia are common gamasid inhabitants of forest litter. They engage in the peculiar reproductive strategy of podospermy which, along with other morphological and behavioral adaptations, involves modification of the chelicerae of the relatively rare males into gonopods. Each movable digit is provided with an appendage (spermatodactyl) that is involved in sperm transfer. We describe the gross anatomy, fine structure, and functional morphology of the mouthparts of a male Veigaia species and give ultrastructural details for the corniculi, laciniae, preoral cavity, labrum, pharynx, and movable and fixed digits. The fine structure of the spermatodactyl is illustrated here for the first time in detail. A semischematic reconstruction of the gnathosoma and spermatodactyl is provided. The spermatodactyl is totally fused with the movable digit and a sperm transfer duct runs along its entire length. This duct starts at the adaxial base of the movable digit, continues inside the digit into the tube of the spermatodactyl, and finally opens at the distal abaxial surface of the spermatodactyl. Several sensory structures associated with the spermatodactyl probably provide the male with mechanical and chemical clues.  相似文献   

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