RESUMO
PREMISE OF STUDY: Flowering traits can sometimes be overemphasized in taxonomic classifications. The fused and completely differentiated papilionate floral organs in the neotropical legume trees Vatairea and Vataireopsis were traditionally used in part to ascribe these genera to the tribe Dalbergieae. In contrast, the free and mostly undifferentiated floral parts of Luetzelburgia and Sweetia fit the circumscription of the "primitive" Sophoreae. Such divergent floral morphologies thought to divide deep phylogenetic lineages indeed may be prone to episodic transformation among close papilionoid relatives. METHODS: We sampled 26 of 27 known species of Luetzelburgia, Sweetia, Vatairea, and Vataireopsis in parsimony and Bayesian phylogenetic analyses of nuclear ribosomal ITS/5.8S and six plastid (matK, 3'-trnK, psbA-trnH, trnL intron, rps16 intron, and trnD-T) DNA sequence loci. KEY RESULTS: The analyses of individual and combined data sets strongly resolved the monophyly of each of Luetzelburgia, Sweetia, Vatairea, and Vataireopsis. Vataireopsis was resolved as sister to the rest and the morphologically divergent Luetzelburgia and Vatairea were strongly resolved as sister clades. Floral morphology was generally not a good predictor of phylogenetic relatedness. CONCLUSIONS: Luetzelburgia, Sweetia, Vatairea, and Vataireopsis are unequivocally resolved as the "vataireoid" clade. Fruit and vegetative traits are found to be more phylogenetically conserved than many floral traits. This explains why the identity of the vataireoids has been overlooked or confused. The evolvability of floral traits may also be a general condition among many of the early-branching papilionoid lineages.
Assuntos
DNA de Cloroplastos/química , Fabaceae/genética , Flores/anatomia & histologia , Filogenia , Evolução Biológica , DNA Intergênico/química , Fabaceae/anatomia & histologia , Fabaceae/químicaRESUMO
The perceptual deficit hypothesis for schizophrenia is based on more general models of normal human visual perception, which have traditionally postulated that objects must compete for attention and processing space in the visual system. Recent evidence suggests that susceptibility of schizophrenics to the Müller-Lyer (ML) illusion may be a marker of vulnerability, detectable in prodromic patients, but disappearing with the progression of the illness. This illusion consists of overestimating the length of a straight line with converging arrowheads at the ends, while underestimating those with diverging arrowheads. Although the ML illusion has been shown to occur in touch as well as vision, it is not known whether abnormal contextual suppression extends to other sensory modalities in schizophrenics. Another challenge consists in verifying whether different visual parameters of the illusion which favor the magnocellular and parvocellular systems would have diverse ML illusion effects in schizophrenia. In this review we present data showing the degree of illusion in capuchin monkeys (Cebus spp.), a possible animal model for schizophrenia. To this end, a computer program was developed to conduct experiments in humans and non-human primates, allowing the display of illusory figures, manipulation of the stimuli's exposure time, interval between stimuli and number of trials. In the non-primate experiments, the visual illusion test based on achromatic ML illusion figures indicated the presence of the ML illusory effect in 10 capuchin monkeys. These results suggest that Cebus might be a good model for the experimental study of schizophrenia.
Assuntos
Ilusões Ópticas/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatologia , Animais , Humanos , Esquizofrenia/patologiaRESUMO
Visual illusions are formed by differences between the perception of one figure and its real physical characteristics. The Müller-Lyer illusion is the best known and most studied geometric illusion, consisting in the subject's judgment between two parallel lines that have the same size, one flanked with outward-pointing arrowheads, and the other with inward-pointing arrowheads. These arrowheads act as inductors that make the lines to be perceived as having different sizes, inward-pointing stimuli being estimated as longer. This study aimed to investigate the Müller-Lyer illusion in capuchin monkeys (Cebus apella), a New World primate not yet investigated for this illusion. For this purpose, stimuli were presented on a touch screen monitor. Ten adult subjects (five females and five males) were used. Before the tests, they were trained to discriminate between two physically different lines with and without arrowheads. The longer lines were always the positive (rewarded) stimuli. Regarding the Müller-Lyer Illusion test, all monkeys, unrespective of gender, demonstrated susceptibility to the illusion, by choosing preferentially the line with inward-pointing arrowheads. In order to determine the degree of the illusion, a point of subjective equality test (PSE) was performed. The PSE without arrowheads values were lower than the PSE with arrowheads. Thus, it was demonstrated that capuchin monkeys were susceptible to the Müller-Lyer illusion, once the perception of the lines' size was influenced by the presence of the arrowheads and by their orientation.
Assuntos
Cebus/fisiologia , Discriminação Psicológica/fisiologia , Ilusões/fisiologia , Julgamento/fisiologia , Animais , Comportamento Animal , Feminino , Masculino , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodosRESUMO
Large-field trichromacy is a general feature of protanope and deuteranope humans, provided that the stimuli size extends to an 8 degrees visual angle. In this study we compared the performance of five male and three female tufted capuchin monkeys (Cebus apella) in discriminating pairs of Munsell color papers. Human subjects were also studied in two-choice discrimination tests, using the same stimuli and apparatus employed for the monkeys. The results show that although the dichromatic humans showed improved discrimination with larger versions of the stimuli, the dichromatic monkeys exhibited the same performance for both stimuli sizes. Thus, Cebus apella apparently do not present large-field trichromacy-at least for the conditions in the present experiments.