Bryozoans offer one of the few systems in which competitive interactions for living space can be studied in the fossil record. Here, we describe the outcome of competitive overgrowths in a 3‐million‐year‐old bryozoan palaeocommunity encrusting shells of the bivalve Anomia simplex from the lower Tamiami Formation in Florida (upper Pliocene, Piacenzian). We found that win–lose overgrowths are more common than stand‐offs in interspecific encounters, while stand‐offs are more common than win–lose overgrowths in intraspecific encounters. We observed more intraspecific encounters and fewer interspecific interactions than expected under a null hypothesis, suggesting that bryozoans of the same species are likely to be clustered. For some species, intraspecific encounters are more likely to result in the apparent fusion of the two colonies, with the development of rows of kenozooids along the contact edge, probably reflecting relatively low dispersal. We also identified some clear winners and some clear losers. A negative correlation was found between the number of colonies observed and the probability of winning for a species, resulting in a dominance of loser species in the assemblage, a pattern previously described as typical for early colonizers of hard substrates. Our results also confirm the finding of earlier studies that having large zooids and, subordinately, multilayered growth are key traits for success in overgrowth competition, with angle of encounter also having an effect for both poor and good competitors that take advantage of ‘attacking’ colonies of other species from the rear and the flank.

中文翻译：

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冒犯“敌人”：减轻来自美国佛罗里达州近300万年前的古群落竞争结果中的固有劣势

苔藓虫提供了为数不多的可以在化石记录中研究生存空间竞争性相互作用的系统之一。在这里，我们描述了有竞争力的过度生长的在3万年前的老苔藓palaeocommunity结壳双壳类的壳成果命名障碍单纯来自佛罗里达的下塔米米组（上新世，Piacenzian）。我们发现，在种间遭遇中，输赢过度比僵局更为普遍，而在种内遭遇中，僵局比输赢过度更为普遍。我们观察到比原假设下的预期要多的种内遭遇和更少的种间相互作用，这表明相同物种的苔藓虫很可能会聚集。对于某些物种而言，种内相遇更可能导致两个菌落的明显融合，沿接触边缘的成排类生物体的发展，可能反映了相对较低的分散性。我们还确定了一些明显的赢家和一些明显的输家。在观察到的菌落数量与获胜物种的概率之间存在负相关关系，导致组合中的失败者物种占优势，这是先前描述为硬质底物早期定居者的典型模式。我们的研究结果还证实了较早的研究发现，大型动物群和从属的多层生长是过度生长竞争成功的关键特征，相遇的角度也对利用“进攻”殖民地的贫穷和善良竞争者都产生影响后部和侧面的其他物种。