| the phylogeny and life cycle of two species of profilicollis (acanthocephala: polymorphidae) in marine hosts off the pacific coast of chile. | resolving complex life cycles of parasites is a major goal of parasitological research. the aim of this study was to analyse the life cycle of two species of the genus profilicollis, the taxonomy of which is still unstable and life cycles unclear. we extracted individuals of profilicollis from two species of crustaceans (intermediate hosts) and four species of seagulls (definitive hosts) from sandy-shore and estuarine habitats along the south-east pacific coast of chile. mitochondrial dna analys ... | 2016 | 27667136 |
| comparing the retinal structures and functions in two species of gulls (larus delawarensis and larus modestus) with significant nocturnal behaviours. | ring-billed gulls (larus delawarensis) and gray gulls (larus modestus) are two species active both by day and night. we have investigated the retinal adaptations that allow the diurnal and nocturnal behaviours of these two species. electroretinograms and histological analyses show that both species have a duplex retina in which cones outnumber rods, but the number of rods appears sufficient to provide vision at night. their retinas respond over the same scotopic dynamic range of 3.4logcdm(-2), w ... | 2006 | 16647740 |
| reduced oxygen diffusion across the shell of gray gull (larus modestus) eggs. | gray gulls, larus modestus, nest 1500 m above sea level in northern chile's atacama desert, one of the driest in the world. their eggshell gas permeability, one third of that found in other larus species, is an adaptation that reduces water loss, but at the expense of oxygen diffusion into the air cell with resultant hypoxia and reduced metabolic rate. this contrasts with characteristics found in birds nesting at very high altitudes where oxygen diffusion across the egg shell is maximized at the ... | 2000 | 15696681 |
| phylogenetic relationships within the laridae (charadriiformes: aves) inferred from mitochondrial markers. | gulls (aves: laridae) constitute a recent and cosmopolite family of well-studied seabirds for which a robust phylogeny is needed to perform comparative and biogeographical analyses. the present study, the first molecular phylogeny of all larids species (n=53), is based on a combined segment of mtdna (partial cytochrome b and control region). we discuss our phylogenetic tree in the light of previous suggestions based on morphological, behavioral, and plumage characters. although the phylogeny is ... | 2005 | 16054399 |