RESUMEN
Rapateaceae (16 genera, approximately 100 species) is largely restricted to the tepuis and sandplains of the Guayana Shield in northern South America, with Maschalocephalus endemic to West Africa. The family has undergone extensive radiation in flower form, leaf shape, habit, and habitat. To analyze the evolution of these distributions and traits, we derived a molecular phylogeny for representatives of 14 genera, based on sequence variation in the chloroplast-encoded ndhF gene. The lowland subfamily Rapateoideae is paraphyletic and includes the largely montane subfamily Saxofridericioideae as a monophyletic subset. Overall, the morphological/anatomical data differ significantly from ndhF sequences in phylogenetic structure, but show a high degree of concordance with the molecular tree in three of four tribes. Branch lengths are consistent with the operation of a molecular clock. Maschalocephalus diverges only slightly from other Monotremae: it is the product of relatively recent, long-distance dispersal, not continental drift--only its habitat atop rifted, nutrient-poor sandstones is vicariant. The family appears to have originated approximately 65 Mya in inundated lowlands of the Guayana Shield, followed by: (1) wide geographic spread of lowland taxa along riverine corridors; (2) colonization of Amazonian white-sand savannas in the western Shield; (3) invasion of tepui habitats with frequent speciation, evolution of narrow endemism, and origin of hummingbird pollination in the western Shield; and (4) reinvasion of lowland white-sand savannas. The apparent timing of speciation in the Stegolepis alliance about 6-12 Mya occurred long after the tepuis began to be dissected from each other as the Atlantic rifted approximately 90 Mya. Given the narrow distributions of most montane taxa, this suggests that infrequent long-distance dispersal combined with vicariance accounts for speciation atop tepuis in the Stegolepis alliance.
Asunto(s)
Adaptación Fisiológica , Evolución Molecular , Magnoliopsida/genética , NADH Deshidrogenasa/genética , Proteínas de Plantas , África Occidental , Animales , Aves , Ecología , Geografía , Germinación , Filogenia , América del SurRESUMEN
Anti-neutrophil cytoplasmic autoantibodies (ANCA) are usually determined during the diagnostic evaluation of systemic vasculitis and glomerulonephritis syndromes in adult patients, but few pediatric patients with ANCA have been reported. We describe five pediatric patients with ANCA and glomerulonephritis, with and without upper or lower respiratory tract disease. We compared these five patients and six previously described patients to affected adults; the spectrum of ANCA-associated disease appears to be similar in adults and children, but a female predominance may exist in the pediatric patients. Pediatric patients often had end-stage renal disease within 1 year after onset. We conclude that ANCA is a useful diagnostic tool in both pediatric and adult patients with systemic vasculitis and glomerulonephritis.