| Journal: | The biologist |
| Database: | PERIÓDICA |
| System number: | 000373150 |
| ISSN: | 1994-9073 |
| Authors: | Marín Espinoza, G1 Ouellet, H2 Navarro Rodríguez, R3 |
| Institutions: | 1Universidad de Oriente, Departamento Biología, Cumaná, Sucre. Venezuela 2Fundación Grupo de Investigaciones Ornitológicas, Ciudad Guayana, Bolívar. Venezuela 3Urbanización Villa Olímpica, Cumaná, Sucre. Venezuela |
| Year: | 2010 |
| Season: | Oct-Dic |
| Volumen: | 57 |
| Number: | 4 |
| Pages: | 212-234 |
| Country: | Perú |
| Language: | Español |
| Document type: | Artículo |
| Approach: | Analítico, descriptivo |
| English abstract | Despite that no ring species have yet been convincingly demonstrated in the western hemisphere, Sporophila lineola/bouvronides/restricta complex may provide a plausible theoretical model in South America. There are at present three distinct forms, with varying proportions of sedentary and partially migratory “races”: S. lineola (L), S. bouvronides (B) and S. restricta (R). Two characters are most obviously subject to variation: the extent (or absence) of white on the crown, and the amount (or absence) of dark mottling or barring on the white underparts. L and B populations occur sympatrically and seasonally, with one of them breeding (B) and the other non-breeding (L) and possessing subtly different song patterns. Interestingly, R is a stable “race” confined to the northwestern corner of South America (i.e., NE Colombia). In addition, there is a highly variable population exhibiting a combination of characters (hybrids?) reported between breeding areas B (e.g., Venezuela) and breeding areas L (e.g., SE Brazil). Moreover, the total extent of the breeding range of the L population is nearly unknown; similarly, where B populations spend the non-breeding season is not yet known. Likewise, we don't know if R populations migrate. If so, it may represent an incipient ring species pattern. Indeed, our hypothesis is consistent with southern american biogeographical history, involving isolation mechanisms. In the first phase, an ancestral species was split into two populations (due to andean uplift), one to the north (R) and the other to the east; secondarily, Pliocene times would have subdivided L (subequatorial breeding) and B (supraequatorial breeding). With the advent of pleistocenic and holocenic regressions and climatic fluctuations, the successive secondary contacts permitted L and B interconnections, involving both ethological (e.g., the cromo-vocalic gradual differentiation) and seasonal isolating mechanisms |
| Disciplines: | Biología |
| Keyword: | Aves, Ecología, Evolución y filogenia, Sporophila, Emberizidae, América del Sur |
| Keyword: | Biology, Birds, Ecology, Evolution and phylogeny, Sporophila, Emberizidae, South America |
| Full text: | Texto completo (Ver PDF) |
