An annotated checklist of freshwater Copepoda (Crustacea, Hexanauplia) from continental Ecuador and the Galapagos Archipelago

Abstract

An annotated checklist of the free-living freshwater Copepoda recorded in different regions in Ecuador (including the Amazon, the Andes, the coastal region, and the Galapagos Islands) is here provided. We revised all published records, critically evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each one. A total of 27 taxa have been reported, including species and records at the generic level only. The species and taxa identified only up to the generic level belong to five families and 14 genera. The Cyclopoida is the most diverse group with 16 records belonging to species (or identified to the generic level only) and eight genera, followed by the Harpacticoida with six species, one identification to the generic level only, and four genera, and Calanoida with four species belonging to two genera. A total of 18 taxa are recorded for the Andes. Six have been recorded in the Amazon, two are recorded for the coastal region, and six for the Galapagos. One species is shared between the Amazon and the Andes. One species is shared between the coastal region and the Amazon. Seventeen are only reported from the Andes and four are only reported from the Amazon. At the current status of the knowledge, any attempt to analyze and generalize distributional patterns of copepods in Ecuador is premature due to the scarcity of available information, and evidently there is an urgent need for more extensive field collections. A few working hypothesis for future studies are identified.

Loss of a freshwater copepod species from El Junco Lake, Galápagos following the introduction and eradication of the Nile tilapia

“…Verification of this identification is still needed (Corgosinho et al, 2019) and a formal description is still awaited (E.N.d.S.S., personal communication). The diaptomid copepod species from El Junco Lake appears to be the only diaptomid species known to occur in the entire archipelago (Peck, 1994;Corgosinho et al, 2019).…”

“…Verification of this identification is still needed (Corgosinho et al, 2019) and a formal description is still awaited (E.N.d.S.S., personal communication). The diaptomid copepod species from El Junco Lake appears to be the only diaptomid species known to occur in the entire archipelago (Peck, 1994;Corgosinho et al, 2019). This diaptomid copepod species was not found in any of the collections made after 2006; thus, its disappearance is synchronous with the introduction and eradication of the Nile tilapia in the lake, and plausibly linked to it (Figure 2).…”

“…before the introduction of the Nile tilapia. An examination of the preserved samples from the Steinitz-Kannan collections shows only a few anomopods and a single diaptomid copepod taxon for this site (L opez et al, 2018;Corgosinho et al, 2019). This article reports the probable extinction of this diaptomid copepod species linked to the introduction and eradication of the non-native fish species O. niloticus in El Junco Lake.…”

Mastigodiaptomus galapagoensis n. sp. (Crustacea: Copepoda: Diaptomidae), a possibly extinct copepod from a crater lake of the Galápagos archipelago

“…Until now, no endemic freshwater zooplankters besides M. galapagoensis have been found in the archipelago, but all freshwater ecosystems (temporary or permanent) have not been thoroughly studied, particularly for zooplankton composition. So far, we know only the report on rotifers of Segers (1991) , a bachelor thesis Obando (2009) , and the checklists of cladocerans by Lopez et al (2018a) , rotifers by López et al (2020) and copepods ( Peck, 1994 ; Corgosinho et al, 2019 ). We consider doubtful the records of marine copepods ( Acrocalanus sp.…”

“…The first mention of the copepod was by Steinitz-Kannan (1979) , who noted its resemblance with Notodiaptomus amazonicus and observed that in July 1966, July 1977, and December 1978, there was a disproportionate large number of adults (up to 80% of the sampled population) compared to nauplii larvae and copepodites, presumably resulting from a slow turnover of the population. According to Corgosinho et al (2019) , this copepod population is the only calanoid species in inland waters of the archipelago and needs taxonomic verification. Recently, Dr. Miriam Steinitz-Kannan brought the existence of these copepods to the attention of Dr. Carlos López who examined the specimens from the 2004 collection and recruited Dr. Manuel Elías-Gutiérrez and Dr. Eduardo Suárez-Morales to aid with the taxonomic identification.…”