Heterochronic events in the ontogeny of Columba livia, Coturnix coturnix, and Gallus gallus domesticus ¤ Eventos heterocrónicos en la ontogenia de Columba livia, Coturnix coturnix y Gallus gallus domesticus Eventos heterocrônicos na ontogenia da Columba livia, Coturnix coturnix e Gallus gallus domesticus SummaryBackground: a series of events take place in a precise spatial and temporal context during the development of any organism. Typically, certain ontogenetic processes are consistent with the proper completion of previous events. Objective: to identify possible heterochronic events that may relate to altricial and precocious development patterns. Methods: we analyzed the ontogeny of three species of birds with two different development models: Columba livia (semialtricial 2), Coturnix coturnix, and Gallus gallus domesticus (precocial 2). The starts and endings of thirteen morphological events were compared, from hour 16 of incubation to the time of hatching. Results: while no differences in the sequence of developmental events were found, the events of the maturation stage in the altricial kind started earlier compared to the precocial species. Ontogenetic acceleration events in C. livia and C. coturnix explain how these species reach a level of morphological development similar to that of G. gallus domesticus, but with shorter incubation period. Conclusion: the results provide information not considered in the literature of the specialty about heterochronic events in early developmental stages of poultry.

ABSTRACT. Reproductive aspects of Dendropsophus sanborni (Anura, Hylidae) in northeastern Argentina. The aim of this investigation was to characterize reproductive aspects of Dendropsophus sanborni (Schmidt, 1944) (Anura, Hylidae) in the northwest of Corrientes province, in northeastern Argentina. The reproductive cycles of males and females, the existence of sexual dimorphism and the male's vocalization period were analyzed. Samplings were made from September 2011 to August 2012. Dendropsophus sanborni showed a prolonged reproductive pattern because reproductive activity was observed during most part of the year. Calling males were recorded all months except in July. The spermatogenic cycle can be characterized as potentially continuous. In males, snout-vent length was significantly correlated with mean testicular volume. The species showed sexual dimorphism in body mass, with females larger than males. Post-ovulatory females were found from March to June and most females had oocytes at different stages of maturity, with abundant post-vitellogenic oocytes from August to December. KEYWORDS.Reproduction, vocalizations, gonads. RESUMEN. Aspectos reproductivos deDendropsophus sanborni (Anura, Hylidae) en el nordeste de la Argentina. El objetivo del presente estudio fue caracterizar aspectos reproductivos de Dendropsophus sanborni (Schmidt, 1944) (Anura, Hylidae) en la región noroeste de la provincia de Corrientes, al Nordeste de Argentina. Para esto, se analizó el ciclo gonadal de machos y hembras, la existencia de dimorfismo sexual y el periodo de vocalización de los machos. Los muestreos se efectuaron desde Septiembre de 2011 hasta Agosto de 2012. Dendropsophus sanborni exhibe un patrón reproductivo prolongado, dado que la actividad reproductiva ocurre durante gran parte del año. Se registraron machos en actividad de vocalización durante todos los meses excepto en julio. El ciclo espermatogénico puede ser caracterizado como potencialmente continuo. En los machos hubo correlación significativa entre la longitud hocico-cloaca y el volumen testicular medio. La especie presentó dimorfismo sexual en relación a la masa corporal, siendo las hembras mayores que los machos. Se encontraron hembras post-ovulatorias desde Marzo a Junio y una mayor proporción de hembras con ovocitos en diferentes estados de maduración, con abundantes ovocitos post-vitelogénicos, en los meses de Agosto a Diciembre.

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The objective of this study was to characterize the external morphology of Salvator meriane embryos in different stages of embryonic development and establish a relationship with the ultrastructure of the shell from oviductal transit to hatching. A total of 120 embryos were analyzed to describe their external morphology, and 78 eggs were used for the analysis of the shell. For embryonic development, the series was established according to the total length of the body. We established 40 embryonic stages from the primitive streak. In the early stages, the external morphological features are the C-shaped body, the maxillary, and mandibular fusion processes with the frontal process and the fusion of the forelimb with the digital plate. In the middle stages, the eyelid appears, and there are claws on the toes, cornification of fingers, and the onset of pigmentation. The last stage of embryonic development is characterized by the beginning of the formation of the scales, appear the toenails, and finalize the entire pigmentation. Regarding the relationship that exists with the ultrastructure of the egg during development, it was possible to observe a marked change in the composition of the shell and well-marked compaction during embryonic development, which may be related to the transport of calcium during embryonic ossification. Our results allowed us to show the complete sequence of embryonic development, determining the laying stage for this species. It was possible to establish a relationship with the ultrastructure of the eggshell from the oviductal transit to the moment of hatching.

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