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At least 253 records · Page 14Linked to original sources
PubMed1999

A case of rapid diversification in the neotropics: phylogenetic relationships among Cranioleuca spinetails (Aves, Furnariidae).

Relationships among the 18-19 species of spinetails of the genus Cranioleuca are difficult to establish. Attempts based on traditional taxonomic characters have failed because of a high degree of homoplasy. Most morphological characters vary independently, producing leap-frog patterns of variation along the Eastern Brazilian Andean track, and behavior and vocalizations vary little. We use mtDNA sequence data from the cyt b and ND2 genes in an attempt to clarify relationships within the genus. We show (i) that Cranioleuca represents a recent burst of speciation and (ii) that a set of species thought by Maijer and Fjeldså (1997) to form a natural group is in fact a paraphyletic assemblage which also includes humid forest species with different pigmentations and vocalizations. However, synapomorphic variation in the sequences is not sufficient to unambiguously resolve the relationships within the genus. Several species (C. baroni, C. antisiensis, C. pyrrhophia, C. albiceps) show more than one haplotype, without any obvious correlation between genetic and geographic or morphological variation, and the different species do not always show reciprocal monophyly in haplotype diversity. Nevertheless, low genetic differentiation characterizes not only allopatric taxa but also some forms which are essentially sympatric, supporting species rank for the former. Our data suggest a recent diversification and proliferation possibly linked to Pleistocene climatic variation and its consequent vegetational shifts, at least in the Andean species.

Animals↗
PubMed2001

Phylogeny and evolution of the neotropical rodent genus Calomys: inferences from mitochondrial DNA sequence data.

Field mice of the genus Calomys are small, mostly granivorous rodents common to several habitats in South America. To date, phylogenies for the genus have been proposed on the basis of morphological, chromosomal, and biochemical data, often with contradictory results due to incomplete species sampling or methodological shortcomings. In this paper, we propose relationships among 10 species of Calomys based on the complete cytochrome b gene sequence. Our analyses show that Calomys is constituted by two major clades, one mostly associated with mountain habitats with subsequent invasions to lowland habitats and another with species restricted to lowland habitats both north and south of the Amazon basin. The evolution of the genus was likely accompanied by a reduction of chromosome diploid numbers that occurred independently in each of the two evolutionary lineages. A "clock" calibrated on the split between Auliscomys and Loxodontomys suggests that the almost nonexistent fossil record for the genus greatly underestimates divergence times among its species.

Animals↗
PubMed1984

Anion-exchange separation for neotropical trypanosomes: a preliminary trial and a description of Trypanosoma devei from the tamarin Saguinus midas niger.

Anion-exchange separation trials using DEAE-cellulose columns were performed with blood from two single species of marsupial and edentate, three species of rodent and single species of carnivore, primate, cayman and lizard. Trypanosoma cruzi was isolated from Didelphis marsupialis, Dasypus novemcinctus and Coendou sp. T. (Megatrypanum) devei was isolated from the tamarin Saguinus midas niger and the mensural characters of the organism were redescribed. Anion-exchange separation was considered to be a valuable procedure for the taxonomist searching for new or little-known trypanosomes.

Animal Population Groups↗
PubMed1993

Fatty acid profiles of major food sources of howler monkeys (Alouatta palliata) in the neotropics.

Wild howler monkeys (Alouatta palliata) get most of their calories from carbohydrates (65%) and fats (18%) of native tropical plants, but little is known about their intake of individual fatty acids. The fatty acid composition of several natural food sources of howler monkeys collected in Panama was determined by gas-liquid chromatography. The predominant fatty acids were palmitic (30%), linoleic (23%), alpha-linolenic (16%) and oleic (15%). Fatty acids with less than 16, and more than 18, carbon chains were uncommon (0-7%). Although total saturated fatty acids were high in some specific food sources (22-54% of total fatty acids and 8 energy %), most of the calories from fat in the animals' diets are derived from mono- and polyunsaturated fatty acids (9.75 energy %). All food sources had significant amounts of the omega-3 fatty acid, alpha-linolenic acid (2.9 energy %). In terms of human diets, the howler monkey's fat consumption would not be considered atherogenic. Unless these animals show a particular adverse susceptibility to dietary fat, it is unlikely that their fat intake is the primary cause of the low, but significant, incidence of atherosclerosis that develops in these animals in the wild state.

Alouatta↗
PubMed1987

Ascorbic acid content of neotropical plant parts available to wild monkeys and bats.

The ascorbic acid content of foliage available to wild primates and bats in Panama (in transition between wet and dry seasons) was lower than that of temperate zone foliage but higher than that of most fruits and vegetables. Intakes of ascorbic acid (mg/kg b.wt/day) by wild primates and frugivorous bats in Panama are much greater than that of most human populations.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Assessing habitat utilization by neotropical primates: a new approach.

This study aims to ascertain habitat utilization, in relation to forest structural variation, by a multi-species group of primates in tropical lowland rainforest in Southeast Peru during dry season. A new approach to assessing habitat utilization was used. Habitat variation was described by structural and indicator variables collected in quadrats along transects through a study area within Terra Firme and Floodplain forest. Variables were grouped into 'factors' accounting for most of the variation by means of a Principal Components Analysis (PCA). Presence or absence of the primates within the quadrats, assessed by repeat transect surveys, was taken to indicate habitat preferences. Discrimination between the habitat and forest structure in areas of primate presence as opposed to absence was carried out by means of Discriminant Function Analysis (DFA). This highlighted patterns in most utilized habitat. Vertical utilization of the forest was also assessed along with presence in bamboo and general activity on encounter. Suggestions of habitat preference and utilization are made for each of the six sympatric species studied, based on significantly discriminating habitat factors, vertical stratification on encounter and relationships with bamboo. Saguinus fuscicollis and Cebus moloch appeared as habitat generalists. Cebus apella, Saimiri sciureus, and Aotus spp., exhibited varying degrees of preference for habitat factors suggesting disturbed forest, Cebus albifrons was more generalistic but with a possible association with primary, naturally disturbed forest. C. apella was encountered in Terra Firme forest significantly more than in Floodplain. For S. sciureus, C. moloch, and C. apella, upper understory was the most utilized forest layer, for C. albifrons, middle canopy and for S. sciureus and Aotus spp., lower understory. Both positive and negative relationships with bamboo were highlighted. Significant positive relationships between Aotus spp., and bamboo suggest dense bamboo stands provide important daytime resting sites for this nocturnal species. C. moloch was also shown to utilize bamboo whereas S. fuscicollis appeared to actively avoid it. High levels of conformity with past studies in terms of habitat utilization patterns described for the species studied supports the conclusion that the methods used in this study provide an effective means of assessing primate habitat utilization within complex habitat.

Animals↗
PubMed1998

Complete mitochondrial genome of a neotropical fruit bat, Artibeus jamaicensis, and a new hypothesis of the relationships of bats to other eutherian mammals.

The complete mitochondrial genome was obtained from a microchiropteran bat, Artibeus jamaicensis. The presumptive amino acid sequence for the protein-coding genes was compared with predicted amino acid sequences from several representatives of other mammalian orders. Data were analyzed using maximum parsimony, maximum likelihood, and neighbor joining. All analyses placed bats as the sister group of carnivores, perissodactyls, artiodactyls, and cetaceans (e.g., 100% bootstrap value with both maximum parsimony and neighbor joining). The data strongly support a new hypothesis about the origin of bats, specifically a bat/ferungulate grouping. None of the analyses supported the superorder Archonta (bats, flying lemurs, primates, and tree shrews). Our hypothesis regarding the relationship of bats to other eutherian mammals is concordant with previous molecular studies and contrasts with hypotheses based solely on morphological criteria and an incomplete fossil record. The A. jamaicensis mitochondrial DNA control region has a complex pattern of tandem repeats that differs from previously reported chiropteran control regions.

Animals↗