RESUMEN
Evaluating biodiversity and understanding the processes involved in diversification are noticeable conservation issues in fishes subject to large, sometimes illegal, ornamental trade purposes. Here, the diversity and evolutionary history of the Neotropical dwarf cichlid genus Apistogramma from several South American countries are investigated. Mitochondrial and nuclear markers are used to infer phylogenetic relationships between 31 genetically identified species. The monophyly of Apistogramma is suggested, and Apistogramma species are distributed into four clades, corresponding to three morphological lineages. Divergence times estimated with the Yule process and an uncorrelated lognormal clock dated the Apistogramma origin to the beginning of the Eocene (≈ 50 Myr) suggesting that diversification might be related to marine incursions. Our molecular dating also suggests that the Quaternary glacial cycles coincide with the phases leading to Apistogramma speciation. These past events did not influence diversification rates in the speciose genus Apistogramma, since diversification appeared low and constant through time. Further characterization of processes involved in recent Apistogramma diversity will be necessary.
Asunto(s)
Biodiversidad , Cíclidos/fisiología , Animales , Citocromos b/genética , Complejo IV de Transporte de Electrones/genética , Haplotipos/genética , Funciones de Verosimilitud , Filogenia , Reacción en Cadena de la Polimerasa , América del Sur , Especificidad de la Especie , Factores de TiempoRESUMEN
Con el objetivo de resolver algunas interrogantes sobre la anatomía interna de los incisivos inferiores respecto a la frecuencia de un segundo conducto radicular, fueron analizados in vitro 70 muestras. La metodología analizada fue el relleno de acrílico asociado a la descalcificación. Éste mediante replicas posibilita observar de manera tridimensional el sistema de conductos de las piezas a estudiar. Completada la descalcificación las muestras fueron analizadas, demostrando que el 29 por ciento de los incisos inferiores presentan un segundo conducto radicular, mejores hallazgos de segundos conductos con las técnicas radiográficas proximales y con el método de relleno de acrílico y que la mayoria de estos conductos se inician en el tercio medio desembocando en el mismo foramen.
With the objective to solve some questions on the internal anatomy of the mandibular incisorswith respected to the frequency of a second radicular canal, 70 samples. were analized in vitro. The used methodology was the stuffed method of of acrylic associated to the decalcification. This one by means of retorts makes possible to observe of three-dimensional way the system of canal of the pieces to study. Completed the decalcification the samples were analyzed, demonstrating that samples were analyzed, demostrating that 29 per cent of the mandibular incisors present/display a second radicular canal, better findings of seconds canals with the proximales X-rays techniques and with the method of stuffed of acrilycic and that most of these conduits begins in third means, ending at hte same foramen.