973 resultados para 270308 Microbial Systematics, Taxonomy and Phylogeny


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In this study, I investigated the reproductive biology of fish species from the family Characidae of the order Characiformes. I also investigated the relationship between reproductive biology and body weight and interpreted this relationship in a phylogenetic context. The results of the present study contribute to the understanding of the evolution of the reproductive strategies present in the species of this family. Most larger characid species and other characiforms exhibit a reproductive pattern that is generally characterized by a short seasonal reproductive period that lasts one to three months, between September and April. This is accompanied by total spawning, an extremely high fecundity, and, in many species, a reproductive migration. Many species with lower fecundity exhibit some form of parental care. Although reduction in body size may represent an adaptive advantage, it may also require evolutionary responses to new biological problems that arise. In terms of reproduction, smaller species have a tendency to reduce the number of oocytes that they produce. Many small characids have a reproductive pattern similar to that of larger characiforms. On the other hand they may also exhibit a range of modifications that possibly relate to the decrease in body size and the consequent reduction in fecundity. Examples of changes in the general reproductive pattern include the following: reduction in the size of mature oocytes; increase in fecundity; production of several batches of oocytes; an extended reproductive period or even continuous reproduction that allows individuals to reproduce more than once a year; high growth rates; rapid recruitment of juveniles; presence of more than one reproductive cohort that increases the sexually active population; and multiple independent development of insemination as a reproductive strategy. These changes are possibly associated with adaptive pressures that are related to the reduction in body size. In addition, such reproductive characteristics or novelties may reflect the phylogenetic history of a given species.

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Species of sandflies in the oswaldoi-group of the genus Lutzomyia occuring in Venezuela are reviewed. A new species, Lutzomyia saccai n. sp. is described. A distribution map and pictorial keys for males and females are provided with notes on biological and ecological data collected in Venezuela.

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Species of sandflies in the subgenuys Trichopygomyia of the genus Lutzomyia occurring in Venezuela are reviewd. A new species, Lutzomyia pinna n. sp. is described. A distribution map and a pictorial key for maleds are provided with remarks on the ecological data collected in Venezuela.

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Culex (Culex) maxi Dyar is described in the adult, pupal and larval stages, and the male genitalia and parts of the fourth-instar larva are illustrated. The larva is described for the first time. The paper includes a summary of available information on the taxonomy, bionomics and distribution of the species. The taxonomy and identification of the species are reviewed in light of current knowledge of the subgenus Culex in the New World.

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Chromosomal and biochemical investigations of shrews from the genus Crocidura from Crete and Turkey show that C. russula monacha Thomas, 1906 and C. caneae Miller, 1909 are both members of the species C. suaveolens Pallas, 1811. C. russula zimmermanni Wettstein, 1953. The population of C. suaveolens in Crete, whose presence on the island dates from at least 3500 years b.p. is biochemically very similar to those of C. suaveolens from Turkey. The same set of electrophoretic data suggests that C. suaveolens from Cyprus became isolated from main land populations much earlier. C. zimmermanni shows closer phylogenetic relationships with C. leucodon and C. suaveolens, than with C. russula. endemic in Crete, C. zimmermanni is syntopic with C, suaveolens at medium and high altitudes, but has been eliminated by the latter in the fertile lowland plains.

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Selostus: Suomen happamien sulfaattimaiden kansainvälinen luokittelu