770 resultados para taxonomic relationships
Resumo:
The Anarak, Jandaq and Posht-e-Badam metamorphic complexes occupy the NW part of the Central-East Iranian Microcontinent and are juxtaposed with the Great Kavir block and Sanandaj-Sirjan zone. Our recent findings redefine the origin of these complexes, so far attributed to the Precambrian-Early Paleozoic orogenic episodes, and now directly related to the tectonic evolution of the Paleo-Tethys Ocean. This tectonic evolution was initiated by Late Ordovician-Early Devonian rifting events and terminated in the Triassic by the Eocimmerian collision event due to the docking of the Cimmerian blocks with the Asiatic Turan block. The ``Variscan accretionary complex'' is a new name we proposed for the most widely distributed metamorphic rocks connected to the Anarak and Jandaq complexes. This accretionary complex exposed from SW of Jandaq to the Anarak and Kabudan areas is a thick and fine grain siliciclastic sequence accompanied by marginal-sea ophiolitic remnants, including gabbro-basalts with a supra-subduction-geochemical signature. New Ar-40/Ar-39 ages are obtained as 333-320 Ma for the metamorphism of this sequence under greenschist to amphibolite facies. Moreover, the limy intercalations in the volcano-sedimentary part of this complex in Godar-e-Siah yielded Upper Devonian-Tournaisian conodonts. The northeastern part of this complex in the Jandaq area was intruded by 215 +/- 15 Ma arc to collisional granite and pegmatites dated by ID-TIMS and its metamorphic rocks are characterized by Some Ar-40/Ar-39 radiometric ages of 163-156 Ma. The ``Variscan'' accretionary complex was northwardly accreted to the Airekan granitic terrane dated at 549 +/- 15 Ma. Later, from the Late Carboniferous to Triassic, huge amounts of oceanic material were accreted to its southern side and penetrated by several seamounts such as the Anarak and Kabudan. This new period of accretion is supported by the 280-230 Ma Ar-40/Ar-39 ages for the Anarak mild high-pressure metamorphic rocks and a 262 Ma U-Pb age for the trondhjemite-rhyolite association of that area. The Triassic Bayazeh flysch filled the foreland basin during the final closure of the Paleo-Tethys Ocean and was partly deposited and/or thrusted onto the Cimmerian Yazd block. The Paleo-Tethys magmatic arc products have been well-preserved in the Late Devonian-Carboniferous Godar-e-Siah intra-arc deposits and the Triassic Nakhlak fore-arc succession. On the passive margin of the Cimmerian block, in the Yazd region, the nearly continuous Upper Paleozoic platform-type deposition was totally interrupted during the Middle to Late Triassic. Local erosion, down to Lower Paleozoic levels, may be related to flexural bulge erosion. The platform was finally unconformably covered by Liassic continental molassic deposits of the Shemshak. One of the extensional periods related to Neo-Tethyan back-arc rifting in Late Cretaceous time finally separated parts of the Eocimmerian collisional domain from the Eurasian Turan domain. The opening and closing of this new ocean, characterized by the Nain and Sabzevar ophiolitic melanges, finally transported the Anarak-Jandaq composite terrane to Central Iran, accompanied by large scale rotation of the Central-East Iranian Microcontinent (CEIM). Due to many similarities between the Posht-e-Badam metamorphic complex and the Anarak-Jandaq composite terrane, the former could be part of the latter, if it was transported further south during Tertiary time. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
The species of Euglossa (Glossura) occuring in the Brazilian Atlantic forest were revised and an identification key to males and females is provided. The status of Euglossa annectans Dressler and E. stellfeldi Moure is reevaluated and the latter species is transferred from E. (Glossura) to E. (Glossurella). Here we also synonymize E. carinilabris Dressler under E. stellfeldi. Taxonomic notes are provided and relevant morphological features are illustred. Latitudinal color variation along the Brazilian Atlantic forest, found in two of the species studied here, is also presented and discussed.
Resumo:
The plant architecture hypothesis predicts that variation in host plant architecture influences insect herbivore community structure, dynamics and performance. In this study we evaluated the effects of Macairea radula (Melastomataceae) architecture on the abundance of galls induced by a moth (Lepidoptera: Gelechiidae). Plant architecture and gall abundance were directly recorded on 58 arbitrarily chosen M. radula host plants in the rainy season of 2006 in an area of Cerrado vegetation, southeastern Brazil. Plant height, dry biomass, number of branches, number of shoots and leaf abundance were used as predicting variables of gall abundance and larval survival. Gall abundance correlated positively with host plant biomass and branch number. Otherwise, no correlation (p > 0.05) was found between gall abundance with shoot number or with the number of leaves/plant. From a total of 124 galls analyzed, 67.7% survived, 14.5% were attacked by parasitoids, while 17.7% died due to unknown causes. Larvae that survived or were parasitized were not influenced by architectural complexity of the host plant. Our results partially corroborate the plant architecture hypothesis, but since parasitism was not related to plant architecture it is argued that bottom-up effects may be more important than top-down effects in controlling the population dynamics of the galling lepidopteran. Because galling insects often decrease plant fitness, the potential of galling insects in selecting for less architectural complex plants is discussed.
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A phylogenetic analysis is presented of subgenera and species-groups of Mischocyttarus de Saussure, the largest genus of social wasps. The analysis is based on 62 morphological and nest architecture characters, coded for 71 terminals representing much of the taxonomic diversity within the genus, plus three outgroup terminals representing other polistine tribes. The main conclusions about phylogenetic relationships within the genus are based on parsimony analysis under implied weights. Monophyly of Mischocyttarus is confirmed as well as that of most of the previously recognized subgenera: Mischocyttarus s. str., Clypeopolybia, Monogynoecus, Scytokeraia, Phi, Kappa, Megacanthopus and Omega sensu Richards (1978). Haplometrobius as conceived by Richards (1978) is not a monophyletic taxon, but some of its species-groups are monophyletic. The groups of M.artifex and M.cerberus are raised to subgenus level, and a new concept of Haplometrobius restricts it to the group of M.iheringi (the type species of this subgenus) in the sense of this work. The concept of subgenus Omega is widened to include the species-groups of M.surinamensis and M.prominulus. Besides the new subgeneric classification presented, limits and diagnoses of all species-groups of the subgenera Phi and Haplometrobius sensu Richards (1978) are discussed, and a new key for all subgenera and species-groups of Mischocyttarus is also presented.
Resumo:
I study a repeated buyer-seller relationship for the exchange of a givengood. Asymmetric information over the buyer's reservation price, which issubject to random shocks, may lead the seller to use a rigid pricing policydespite the possibility of making higher profits through price discriminationacross the different satates of the buyer's reservation price. The existence of a flexible price subgame perfect equilibrium is shown for the buyerssufficiently locked-in. When the seller faces a population of buyers whose degree of involvmentin the relatioship is unknown, the flexible price equilibrium is notnecessarily optimal. Thus tipically the seller will prefer to use therigid price strategy. A learning process allowing the seller to screenthe population of buyers is derived abd the existence of a switching pointbetween the two regimes (i.e. price rigidity and price felxibility) isshown.
Resumo:
The taxonomic placement and provenance of Hypopyra inconspicua Herrich-Schäffer (Lepidoptera, Thyrididae). Tanyodes inconspicua (Herrich-Schäffer) comb. nov. is transferred from Spirama Guenée (Noctuidae, Catocalinae) to Striglininae (Thyrididae), as a senior synonym of Ortogramma rufitibia R. Felder & Rogenhofer syn. nov. and Tanyodes ochracea Möschler syn. nov., and from the African to the Neotropical fauna.
Resumo:
A new species of soft scale insect from Mexico, Toumeyella fontanai Kondo & Pellizzari sp. nov. is des-cribed and illustrated. A taxonomic key to the species of scale insects of the genus Toumeyella Cockerell known in Mexico is provided.
Resumo:
Phylogeny and revision of the bee genus Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini), with comments on its female cephalic polymorphism. A taxonomic revision and a phylogeny for the species of Rhinocorynura are provided. Six species are recognized: R. briseis, R. crotonis, R. inflaticeps and R. vernoniae stat. nov., the latter removed from synonymy with R. inflaticeps, in addition to two newly described species, R. brunnea sp. nov. and R. viridis sp. nov. Lectotypes for Halictus crotonis Ducke, 1906 and Halictus inflaticeps Ducke, 1906 are hereby designated. Another available name included in Rhinocorynura, Corynuropsis ashmeadi Schrottky, 1909, is removed from the genus and treated as species inquerenda in Augochlorini. Rhinocorynura is monophyletic in the phylogenetic analysis and the following relationships were found among its species: (R. crotonis (R. briseis ((R. brunnea sp. nov. + R. viridis sp. nov.) (R. inflaticeps + R. vernoniae)))). Biogeographic relationships within the genus and comparisons with related taxa are presented. Females of all species exhibit pronounced variation in body size, in two of them, R. inflaticeps and R. vernoniae, with structural modifications possibly linked to division of labor. Identification key and illustrations for the species are provided.
Resumo:
Partial DNA sequences from two mitochondrial (mt) and one nuclear gene (cytochrome b, 12S rRNA, and C-mos) were used to estimate the phylogenetic relationships among the six extant species of skinks endemic to the Cape Verde Archipelago. The species form a monophyletic unit, indicating a single colonization of the islands, probably from West Africa. Mabuya vaillanti and M. delalandii are sister taxa, as indicated by morphological characters. Mabuya fogoensis and M. stangeri are closely related, but the former is probably paraphyletic. Mabuya spinalis and M. salensis are also probably paraphyletic. Within species, samples from separate islands always form monophyletic groups. Some colonization events can be hypothesized, which are in line with the age of the islands. C-mos variation is concordant with the topology derived from mtDNA.
Resumo:
It is shown how correspondence analysis may be applied to a subset of response categories from a questionnaire survey, for example the subset of undecided responses or the subset of responses for a particular category. The idea is to maintain the original relative frequencies of the categories and not re-express them relative to totals within the subset, as would normally be done in a regular correspondence analysis of the subset. Furthermore, the masses and chi-square metric assigned to the data subset are the same as those in the correspondence analysis of the whole data set. This variant of the method, called Subset Correspondence Analysis, is illustrated on data from the ISSP survey on Family and Changing Gender Roles.
Resumo:
A taxonomic key for the genera of Elmidae (Coleoptera, Byrrhoidea) occurring in Goiás State, Brazil, including new records and distributional notes. Despite their great diversity and high abundance in Neotropical aquatic environments, the fauna of Elmidae remains practically unknown in some areas and even entire biomes in this region. In this work we bring, for the first time, faunistic data for the Elmidae of central Brazil. The aim of this work was to inventory the Elmidae fauna in central, southwestern and southeastern Goiás State, Brazil and to produce a taxonomic key, at genus level, for adults from the studied region. The taxonomic key presented herein offers means for the identification of all the 13 genera known to occur in Goiás, 11 of them being new records for the State. Moreover, the number of named species registered for Goiás increased from one to nine.
Resumo:
On the taxonomic status of Nephochaetopteryx calida (Wiedemann) (Diptera, Sarcophagidae). Based on analysis of the holotype of Nephochaetopteryx calida (Wiedemann) it was concluded that this species does not belong to Nephochaetopteryx. The holotype is a female partly damaged and it was not possible to place it in one of Sarcophaginae genera, remaining as Sarcophaga calida Wiedemann, 1830, incertae sedis.
Resumo:
The taxonomic identity of the butterfly Heliconius melpomene f. pyritosa var. fumigata Zikán, 1937 (Nymphalidae: Heliconiinae) is discussed based on the discovery of the specimen based on which this name was assigned. The specimen is not a variation of Eueides tales surdus Stichel, 1903, as previously stated, but is in fact a variation of H. melpomene f. pyritosa, which is a synonym of Heliconius erato amalfreda Riffarth, 1901.