Developmental Variability and Heterochronic Variation in Poeciliid Fishes

9307245施特劳斯异时性是个体发育(发育)时间的改变，导致结构相对于祖先条件的发育速度加快或减慢，为创造物种之间的形态多样性提供了重要的发育机制。这项研究涉及到对几个不同谱系的角鱼的形态和发育变异性的详细研究。角鱼是生活在美洲中部的一群活的淡水鱼。将研究发育的各个方面，包括异速生长梯度(大小/形状关系)、标准化条件下的绝对和相对生长速度，以及骨化和其他离散个体发育事件的相对时间。不同物种的总体模式将在系统发育框架内进行解释。这项研究的意义在于，它将有助于更详细地了解池鱼的发育，这些结果也可以与其他鱼类类群相关。这项研究还提供了与特征的大小和形状以及发育时间相关的形态变化模式的宝贵信息。最后，这项研究将利用这一有趣的鱼类群体来开发分析程序，可以用来检查其他生物的生长和发育。***

9307245 Strauss Heterochrony, the alteration of timing within ontogeny (development) resulting in accelerated or retarded developmental rates of structures with respect to ancestral conditions, provides an important developmental mechanism for creating morphological diversity among species. This research involves a detailed examination of patterns of morphological and developmental variability in several divergent lineages of poeciliid fishes, a group of livebearing freshwater fishes occurring throughout Middle America. Various aspects of development will be examined including allometric growth gradients (size/shape relationships), absolute and relative growth rates under standardized conditions, and the relative timings of ossification and other discrete ontogenetic events. The overall patterns seen for different species will be interpreted within a phylogenetic framework. %%% The significance of this research is that it will contribute to a more detailed knowledge of the development of poeciliid fishes, and these results can be related to other fish groups. The research also provides valuable information on patterns of morphological change associated with the size and shape of characteristics as well as the timing of development. Finally, this research will utilize this interesting group of fish to develop analytical procedures that can be used to examine growth and development in other organisms. ***