The palaemonid genus Sandyella includes S. tricornuta (Isla María Madre, Mexico), S. mclaughlinae, S. bicornuta, S. quadricornuta and S. sexicornuta (Clipperton Island, France). These species were first described in the genus Chacella based on collections of few individuals and limited to no ecological information. Sandyella was later erected to differentiate Chacella kerstitchi from Chacella tricornuta and Chacella mclaughlinae. The remaining three Chacella species (<3 mm cephalothorax length) were later also moved to Sandyella and distinguished mainly based on variation in the less than three protuberances on the cephalothorax and number of protuberances on the abdomen. Since their description from their type localities, only Sandyella tricornuta has been additionally recorded from Bahía de La Paz, Mexico. Collections done at 13 locations along the Gulf of California (2009–2010) yielded 2,905 specimens including representatives of all Sandyella species as epibionts of 57 black coral colonies Antipathes galapagensis, which prompted a closer taxonomic examination. Based on observations of live and preserved specimens, including type material, population cephalothorax size frequency and mitochondrial COI data, we inferred that all current Sandyella species (a) exhibit three protuberances on the cephalothorax; (b) cephalothorax length and number of protuberances appear to be progressive among species; (c) species exhibit high COI sequence similarity; and d) the five Sandyella species were observed cohabiting the same black coral colony. Therefore, we conclude that the five current Sandyella species are in fact distinct ontogenetic stages of a single species, S. tricornuta, and our results of a morphological Bayesian analysis led us conclude that this species belongs to the genus Sandyella rather than Chacella.

中文翻译：

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从 5 到 1： Sandyella 物种（Palaemonidae）是单个物种的不同个体发育阶段

palaemonid 属 Sandyella 包括 S. tricornuta（墨西哥玛丽亚马德雷岛）、S. mclaughlinae、S. bicornuta、S. quadricornuta 和 S. sexicornuta（法国克利珀顿岛）。这些物种首先在 Chacella 属中描述，基于少数个体的集合，并且仅限于没有生态信息。后来建立了 Sandyella 以将 Chacella kerstitchi 与 Chacella tricornuta 和 Chacella mclaughlinae 区分开来。其余三个 Chacella 物种（<3 毫米头胸部长度）后来也转移到 Sandyella，主要根据头胸部上少于三个突起和腹部突起数量的变化进行区分。由于它们是从它们的类型地点进行描述的，因此仅在墨西哥巴伊亚德拉巴斯 (Bahía de La Paz) 中还记录了三角三角藻。在加利福尼亚湾沿线的 13 个地点（2009-2010 年）收集了 2,905 个标本，其中包括所有 Sandyella 物种的代表，作为 57 个黑珊瑚群落 Antipathes galapagensis 的表皮生物，这促使进行了更仔细的分类学检查。根据对活体和保存标本的观察，包括类型材料、种群头胸大小频率和线粒体 COI 数据，我们推断所有当前的 Sandyella 物种 (a) 在头胸上表现出三个突起；(b) 头胸部的长度和突起的数量似乎在物种之间是渐进的；(c) 物种表现出高 COI 序列相似性；d) 观察到五种 Sandyella 物种与同一黑珊瑚群共存。所以，