Galapagos Species Database

Female with total body length 1,328 µm (range 1,310–1,360 µm), from anterior end of cephalothorax to posterior end of anal somite, fourth pediger with large, conical dorsal process inserted off-central axis pointing out to right side. Urosome 3-segmented, including proximally expanded genital-double somite, short preanal and cylindrical anal somites

According to Elías-Gutiérrez et al., 2023, this is the first report of this Neotropical copepod genus outside its original biogeographic region, the third species of a diaptomid copepod reported from insular freshwater systems, the southernmost record of Mastigodiaptomus, and the only freshwater calanoid in the Galápagos. Additional studies are needed to understand if it arrived naturally or was introduced accidentally by humans. This copepod was described based on individuals recovered from a small, collection of plankton samples from El Junco lake, on San Cristóbal island. The samples were collected in 1966. This copepod was regularly reported (1966–2004) as abundant in the lake, but it was not found in subsequent plankton surveys, and its specific identity remained unknown. In 2020, it was declared extinct because of introduced fish predation and rotenone treatment against Tilapia, among others. The taxonomic examination of these specimens revealed an undescribed species of the freshwater diaptomid genus Mastigodiaptomus Light, 1939 (Gutiérrez et al., 2023).