Calder Dale R, Johnson William S
Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6.; Email:
Department of Biological Sciences, Goucher College, 1021 Dulaney Valley Road, Towson, Maryland 21204, USA.; Email:
Zootaxa. 2015 Dec 2;4052(2):215-25. doi: 10.11646/zootaxa.4052.2.5.
The binomen Nemopsis gibbesii McCrady, 1859, originally applied to a species of hydromedusa and its supposed hydroid from South Carolina, USA, has been known for more than a century to encompass two species. The medusa stage is conspecific with that of Nemopsis bachei L. Agassiz, 1849, while the hydroid stage is referable to the genus Margelopsis Hartlaub, 1897. Both that hydroid, and the medusa stage now subjectively linked to it, are commonly assigned to M. gibbesii. With no type having ever been designated for McCrady's species, a lectotype is designated to stabilize nomenclature of the species and serve as the standard for application of the name. In the absence of type specimens, an illustration of the hydroid of N. gibbesii by McCrady is chosen as lectotype, thereby conserving the name Margelopsis gibbesii in its accustomed usage. Hydroids and medusae of the species are re-described from new material, the cnidome of both stages is characterized, and a taxonomic review is given. The hydroid stage is reported for the first time since its original description in the mid-19th century. Medusae of M. gibbesii are also seen infrequently, having been reported only six times earlier.
双名法命名的Nemopsis gibbesii McCrady，1859年最初用于指代一种来自美国南卡罗来纳州的水螅水母及其推测的水螅体，一个多世纪以来人们都知道它包含两个物种。水母体阶段与1849年L.阿加西命名的Nemopsis bachei的水母体阶段同种，而水螅体阶段则归属于1897年哈特劳布命名的Margelopsis属。那种水螅体以及现在主观上与之关联的水母体阶段，通常都被归为M. gibbesii。由于麦克拉迪所定物种从未指定过模式标本，现指定一个选模式标本以稳定该物种的命名，并作为该名称应用的标准。在没有模式标本的情况下，选择麦克拉迪绘制的N. gibbesii水螅体插图作为选模式标本，从而保留Margelopsis gibbesii这一名称的惯常用法。根据新材料对该物种的水螅体和水母体进行了重新描述，对两个阶段的刺胞动物群落进行了特征描述，并给出了分类学综述。自19世纪中叶首次描述以来，首次报道了该物种的水螅体阶段。M. gibbesii的水母体也很少见，此前仅被报道过六次。
