First record of Moina dumonti Kotov , Elías-Gutiérrez & Granado-Ramírez , 2005 ( Branchiopoda : Anomopoda ) in Brazil

The cladoceran Moina dumonti Kotov, ElíasGutiérrez & Granado-Ramírez, 2005 (Anomopoda: Moinidae) was found in a hypereutrophic lagoon, Lagoinha, Rio de Janeiro, Brazil. It represents the first record of this species in Brazil and in the Southern Hemisphere; it also represents the first record of this species in a perennial lagoon. The reasons for the success of the species in Lagoinha are discussed.

Species of the family Moinidae are present in almost all biogeographic regions except in the Antarctic (Forró et al. 2008) and are most common in brackish or ephemeral environments that are commonly warm and nutrient rich (Petrusek 2002, Dumont et al. 2013, Padhye & Dumont 2014).According to Forró et al. (2008), approximately 60% of the species are endemic to their type localities.Results from genetic analysis also suggest that their diversity is greatly underestimated, at least in Eurasia (Petrusek et al. 2004, Bekker et al. 2016).To date, Moina dumonti Kotov, Elías-Gutiérrez & Granado-Ramirez, 2005 was recorded only at its type locality in Mexico and in Cuba (Kotov et al. 2005).The M. dumonti group is comprised by 2 closely related species that are characterized by a prominent pecten at the terminal claw: M. dumonti and M. hemanti Padhye & Dumont, 2014.The morphology of M. hemanti closely resembles M. dumonti, but differs in the number of filtering setae on the gnathobase of the second thoracic appendix (P2) (Padhye & Dumont 2014).Both species are similar in their ecology and were only recorded from temporary water bodies with low concentrations of dissolved oxygen (Kotov et al. 2005, Padhye & Dumont 2014).Moina hemanti is restricted to its type locality in India (Padhye & Dumont 2014).
During an inventory of the zooplankton community in an oligohaline and hypereutrophic lagoon (Lagoinha; 23°01ʹ24.80ʺS, 043°28ʹ17.93ʺW) located in the Chico Mendes Municipal Natural Park in the city of Rio de Janeiro, several specimens of M. dumonti were found.The lagoon is dominated by floating macro phytes of the genus Eichhornia Kunth that cover much of the water surface and has also Lemna minor L. in marginal areas.This waterbody is part of the lagoon system of Jacarepaguá, which also includes the lagoons of Jacarepaguá, Camorim, Tijuca and Marapendi (Soares 1999).The lagoon system is polluted by the inflow of rainwater drainage, untreated sewage, and wastes from various other sources.The park is known to be a refuge for the wildlife of large aquatic vertebrates, including populations of Capybaras (Hydrochoreus hydrochaeris) and the Broad-snouted Caiman (Caiman latirostris).
A semiannual survey of the zooplankton community and limnological features of the lagoon has been carried out since 2013.Specimens were collected by horizontal hauls and with buckets at subsurface.A plankton net (68 μm mesh) was used for sample filtration.The collected material was immediately fixed in buffered formaldehyde solution (4% of the total volume).Samples without the adding of fixative solution were also collected for the analysis of living organisms in the laboratory.The specimens were studied with a binocular microscope with attached digital camera.The limnological conditions of the water were evaluated with multiparametric probes (YSI 6600V2-4 and turbidity meter TU-2016 Lutron ® ).Five voucher specimens were deposited in the crustacean collection of the Museu Nacional, Universidade Federal do Rio de Janeiro (MNRJ28420).Another set of 3 vouchers are kept in the Elmoor-Loureiro collection, at the Universidade Católica de Brasília (EL02928).
In both sampling dates only parthenogenetic females were collected.Examined specimens (n = 56) had sizes ranging from 527.81 to 746.24μm, with a mean (± standard deviation) of 651.46μm (± 48.94).The specimens analyzed showed morphological characteristics of M. dumonti (Kotov et al. 2005): live animals are red (Fig. 1); ocellus present on the base of the antenna I (Fig. 2); denticles of the dorsal edge of the carapace organized into groups (Fig. 3); post-abdomen with a row of 6 triangular teeth and a bident tooth with the distal branch significantly larger than the basal branch (Fig. 4); antenna II with 2 coxal sensory setae of very different sizes (Fig. 5); basal segment of antenna II with a short distal spine on anterior face, and a long distal sensory setae on the posterior face (Fig. 6); presence of a setulate hook in the dorsal-most portion of the posterior margin of the valve (Fig. 7); gnathobase of P2 with 10 filtering setae (Fig. 8).According to Kotov et al. (2005), M. dumonti shows 3 to 5 spines in the basal pecten of terminal claw, but the specimens collected from Lagoinha showed a variation from 3 to 6 spines (Fig. 9).This is the only difference observed between these specimens and the original description (Kotov et al. 2005).
Moina dumonti has tolerance to low concentrations of dissolved oxygen (Kotov et al. 2005).Adaption to hypoxia together with possible reduced predation pressure under such conditions may be favoring M. dumonti in the Lagoinha.On the 2 occasions when M. dumonti was found, it dominated the zooplankton community in terms of relative abundance.Some limnological characteristics of the sampling location in Lagoinha lagoon were similar to those at the type locality (Kotov et al. 2005), such as shallow depth (0.20 m), oligohaline conditions (0.01%), high electrical conductivity (383 μS⸱cm -1 ), and low dissolved oxygen content (0.28 mg⸱L -1 ).
The present record expands the distribution of M. dumonti to South America (Fig. 10), and it is the first record of this species in a perennial lagoon (Table 1).Moina dumonti can be easily distinguished from congeneric species by its remarkable morphology, especially the basal pecten.It is difficult to explain the large gaps in the known distribution of populations of M. dumonti except that this species remains overlooked in other regions due insufficient sampling efforts.Despite the great richness and variety of existing inland aquatic ecosystems in the Neotropics, we need to consider the lack of sampling effort and scarcity of taxonomic studies on zooplankton communities in highly eutrophic ecosystems, such as shallow lagoons and temporary ponds.Shallow lagoons and temporary ponds rapidly dispersed in Neotropical waterbodies and was already reported in Brazilian waters by Elmoor-Loureiro et al. (2010) and Rietzler et al. (2014).The observation of male, ephippial eggs and sexual females, along with molecular analysis, could elucidate the relationship between the populations of M. dumonti from Brazil, Mexico and Cuba and the systematic position of Brazilian specimens.are commonly neglected in taxonomic studies compared to lakes and reservoirs.Because M. dumonti naturally occurs in such habitats, further studies may reveal new occurrences of cladoceran species, including M. dumonti.Cladoceran species can produce diapause eggs, which disperse easily over long distances attached to other species such as birds (Panov et al. 2004, Green et al. 2007) or to man-made apparatuses such as vehicles, industrial equipment, and footwear (Havel & Shurin 2004, Panov et al. 2004, Waterkeyn et al. 2010).Thus, it is possible that this may be another case of manmade dispersion as suggested for M. macrocopa (Straus, 1820) (Elías-Gutiérrez & Zamuriano-Claros 1994, Paggi 1997).Moina macrocopa

Figure 10 .
Figure 10.Previous registered localities of Moina dumonti (black squares) and new occurrence in Rio de Janeiro, Brazil (black triangle).

Table 1 .
Occurrences of M. dumonti *First record of M. dumonti in South America.