The eastern oyster Crassostrea virginica is a commercially and ecologically important organism found throughout the western North Atlantic and Gulf of Mexico. Morphological differences in shell shape of eastern oysters are known to arise from environmental, genetic, and husbandry-related factors. Here, live eastern oysters were collected from 17 sites along the U.S. Gulf of Mexico coast from Texas to Florida to examine morphological differences among geographic samples. Six morphological metrics were recorded for each individual, and four different composite ratios commonly used to describe oyster shape (fan, cup, volume ratio, and weight ratio) were calculated. Principal component analysis was used to demonstrate geographic differences in ordinated shape ratios, correlating roughly with eastern (Florida), northern (Alabama, Louisiana, north Texas), and western (south Texas) samples. In Texas, differences in shape were correlated with previously described genetic population boundaries, indicating that populations north versus south of Aransas Bay had different overall shell shapes. On a broader scale, shell shape variation correlated roughly with previously described genetic population boundaries throughout the Gulf of Mexico as well as tide depth (intertidal versus subtidal reefs). Among the various factors that might act as drivers of shell shape, individual variation is important, but population structure and tide height are also significant predictor variables of shape in this species.

中文翻译：

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整个墨西哥湾东部牡蛎 Crassostrea virginica 的形态学评估

东部牡蛎Crassostrea virginica是一种在北大西洋西部和墨西哥湾中发现的具有商业和生态重要性的生物。已知东部牡蛎壳形状的形态差异是由环境、遗传和饲养相关因素引起的。在这里，从德克萨斯州到佛罗里达州的美国墨西哥湾沿岸的 17 个地点收集了活的东部牡蛎，以检查地理样本之间的形态差异。每个个体记录了六个形态指标，并计算了常用来描述牡蛎形状的四种不同的复合比例（扇形、杯形、体积比和重量比）。主成分分析用于证明协调形状比率的地理差异，与东部（佛罗里达州）、北部（阿拉巴马州、路易斯安那州、德克萨斯州北部）和西部（德克萨斯州南部）样本大致相关。在德克萨斯州，形状的差异与先前描述的遗传种群边界相关，表明阿兰萨斯湾北部和南部的种群具有不同的整体外壳形状。在更广泛的范围内，贝壳形状的变化与之前描述的整个墨西哥湾的遗传种群边界以及潮汐深度（潮间带与潮下礁）大致相关。在可能作为贝壳形状驱动因素的各种因素中，个体差异很重要，但种群结构和潮汐高度也是该物种形状的重要预测变量。贝壳形状变化与之前描述的整个墨西哥湾的遗传种群边界以及潮汐深度（潮间带与潮下礁）大致相关。在可能作为贝壳形状驱动因素的各种因素中，个体差异很重要，但种群结构和潮汐高度也是该物种形状的重要预测变量。贝壳形状变化与之前描述的整个墨西哥湾的遗传种群边界以及潮汐深度（潮间带与潮下礁）大致相关。在可能作为贝壳形状驱动因素的各种因素中，个体差异很重要，但种群结构和潮汐高度也是该物种形状的重要预测变量。