Assembly of the eastern North American herpetofauna: new evidence from lizards and frogs

Darwin first recognized the importance of episodic intercontinental dispersal in the establishment of worldwide biotic diversity. Faunal exchange across the Bering Land Bridge is a major example of such dispersal. Here, we demonstrate with mitochondrial DNA evidence that three independent dispersal events from Asia to North America are the source for almost all lizard taxa found in continental eastern North America. Two other dispersal events across Beringia account for observed diversity among North American ranid frogs, one of the most species-rich groups of frogs in eastern North America. The contribution of faunal elements from Asia via dispersal across Beringia is a dominant theme in the historical assembly of the eastern North American herpetofauna

Dieta e dispersão de sementes por Cerdocyon thous (Linnaeus) (Carnívora, Canidae), em um fragmento florestal no Paraná, Brasil Diet and seed dispersal by Cerdocyon thous (Linnaeus) in a forest fragment in Paraná (Carnivora, Canidae)

Embora o cachorro-do-mato, Cerdocyon thous (Linnaeus, 1706), seja um Canidae relativamente comum, não há muita informação sobre sua dieta e seu papel como dispersor de sementes nos diferentes habitats onde ocorre. O objetivo deste trabalho foi o de reportar a dieta de C. thous e sua importância como dispersor e/ou predador de sementes, e ainda testar a taxa de germinação de sementes após passar pelo trato digestório do animal. O estudo foi realizado em um fragmento (680 ha) de Floresta Estacional Semidecidual, o Parque Estadual Mata dos Godoy, localizado na cidade de Londrina, Paraná, sul do Brasil. A metodologia consistiu de coletas de fezes de C. thous, as quais foram analisadas em laboratório para identificar os itens consumidos. Nos testes de germinação, as sementes foram dispostas para germinar em placas de Petri com algodão umedecido em água. Noventa e três amostras fecais com 219 itens de origem vegetal e animal foram registradas, sendo 36,52% contendo restos de pequenos roedores, 24,19% de gramíneas, 13,24% de aves, 10,47% de insetos, 6,39% de Syagrus romanzoffiana (Cham.) Glassm., 4,6% de outros itens de origem animal e 4,54% de outros itens de origem vegetal. Ainda, C. thous dispersou nove espécies de plantas, com relevante importância para a germinação de algumas sementes que passaram pelo trato digestório do animal, exceto para S. romanzoffiana, cujas sementes não germinaram nas condições de laboratório. Conclui-se que, C. thous apresentou uma dieta generalista e oportunista, sobrevivendo em áreas degradadas e antrópicas, e agindo como dispersor de sementes nestes locais.<br>Although the crab eating fox, Cerdocyon thous (Linnaeus, 1706), is a relatively common Canidae, there isn't much information about its diet and its role as a seed disperser in the different habitats where it occurs. The aim of this work was to report the diet of the C. thous and its importance as a seed disperser and / or a seed predator and to test the rate of germination of the seeds after passing through the digestive tract of the animal. The work was carried out in a 680 ha fragment of the Semidecidual Seasonal Forest in the Parque Estadual Mata dos Godoy, located in the city of Londrina-Paraná, south of Brazil. The methodology consisted of the collection of excrement of C. thous which were analyzed in laboratory for identification of consumed items and seeds. In germination tests, the seeds were placed to germinate in Petri dishes with wet cotton. Ninety-three animal feces samples, with 219 animal and vegetable items were registered, being 36.52% remaining portions of small rodents, 24.19% of grasses, 13.24% of birds, 10.47% of insects, 6.39% of Syagrus romanzoffiana (Cham.) Glassm., 4.6% of other items of animal origin and 4.54% of items vegetable origin. In addition, C. thous dispersed nine species of plants, with relevant importance to the germination of some seeds, which passed through the digestive tract, except for the most consumed of fruit, S. romanzoffiana, whith no seed germination at all in lab conditions. In conclusion, C. thous has a generalistc and opportunistc diet, surviving in degraded and anthropic areas and being able to act as a seed disperser