Gonatocaris decora (Clarke, 1901) is an unusual, highly ornamented Silurian phyllocarid from the Pittsford Shale Member of the Vernon Formation, Salina Group of New York, that has been allied with Emmelezoe in the past due to the possession of an ‘optic tubercle.’ The systematic positions of Gonatocaris and Emmelezoe have been difficult to assess due to the lack of complete remains, attributions based on spurious characters, and missing and unfigured specimens. Relatively recent collections of Gonatocaris decora, along with a relocation of the original type material of Emmelezoe, have allowed a reexamination of all relevant genera and a more robust systematic placement for G. decora. Characters of generic importance for Gonatocaris include a greatly elongated abdomen; an acute angle of the ventral carapace margin separating distinct anteroventral and posteroventral margins from each other; and distinctive, multiscale horizontal ridge-like ornament of the carapace valves. Growth was found to be isometric. Experimental work done using a model of the scale-like ornament and multiple grain sizes of substrate indicates that cuticle ornament may have served to increase friction between the animal and a fine sand substrate, although resistance to predation is the currently favored hypothesis. Because Gonatocaris species are currently known only from the eastern margin of Laurentia and northern South China, it is likely that this genus was nektonic. Accumulations of similarly sized carapaces and other disarticulated sclerites in shallow-water settings may indicate spawning events following molting en masse.

中文翻译：

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志留纪叶蛉科 Gonatocaris 的重新描述、古地理和实验古生态学

蛔虫（克拉克，1901 年）是一种不寻常的、高度装饰的志留纪叶状体，来自纽约萨利纳组弗农组的皮茨福德页岩成员，与埃梅莱佐过去因藏有“视结节”。系统的立场性腺菌属和埃梅莱佐由于缺乏完整的遗骸、基于虚假特征的归属以及缺失和未确定的标本，因此难以评估。比较近期的收藏蛔虫，以及原始类型材料的重新定位埃梅莱佐, 允许重新检查所有相关属和更强大的系统放置G. 装饰. 具有一般重要性的字符性腺菌属包括一个大大拉长的腹部；腹甲壳边缘的锐角，将不同的前腹和后腹边缘分开；以及独特的多尺度水平脊状甲壳瓣装饰。发现增长是等距的。使用鳞片状装饰物模型和多种颗粒大小的基质进行的实验工作表明，角质层装饰物可能有助于增加动物与细砂基质之间的摩擦力，尽管目前流行的假设是对捕食的抵抗力。因为性腺菌属目前仅在Laurentia东部边缘和华南北部发现该种，该属很可能是nektonic。在浅水环境中类似大小的甲壳和其他脱节的硬骨的积累可能表明在集体蜕皮后发生产卵事件。