Chydorus nitidulus ( Sars,1901 )

Chydorus nitidulus ( Sars,1901) View in CoL

( Fig. 3 View Figure 3 )

Material examined. 1 ind. ( CZ-UFRPE 18008 ), Camucim Forest Protected Area, São Lourenço da Mata, Pernambuco, 8°02’24.8”S 35°11’48.5”W ( WGS84 ), 09 May 2018, colls. R.F. de Oliveira and F.A. Santos; 12 ind. ( CZ-UFRPE 18010 ), 2 ind. ( CZ-UFRPE 18034 ), Camucim Forest Protected Area , São Lourenço da Mata , Pernambuco, 8°02’18.2’’S 35°12’2.97’’W ( WGS84 ), 09 and 11 May 2018, colls. R.F. de Oliveira and F.A. Santos GoogleMaps .

Specimens. The specimens of C. nitidulus show characters similar to their latest descriptions ( Elmoor-Loureiro, 1997). In Fig. 3a View Figure 3 , the body structure of a parthenogenetic female is represented, with oval body and postabdomen exposed.Arrow indicates the naked and elongated labral keel, which is diagnostic for this species. Details of postabdomen are typical, showing terminal claw chitinized and curved, with two basal spines of different sizes ( Fig. 3b View Figure 3 ). Valves have one denticle in the posteroventral corner ( Fig. 3c View Figure 3 ).

Ecology and habitat. Parthenogenetic females of C. nitidulus were recorded in environments limnologically distinct from those of M. dumonti , although both species were collected in stations dominated by Lemna . The specimens sampled in the present study occurred in ponds with both degraded and preserved riparian vegetation, which show high turbidity (132 ± 96.55 NTU), low oxygenation (3.57 ± 2.73 mg L- 1) and low a- chlorophyll concentration (14.24 ± 13.76 µg L- 1).

Distribution. Chydorus nitidulus is a Neotropical species, previously recorded in Venezuela (Rey and Vásquez, 1886; Vásquez and Rey, 1989), Argentina ( Paggi, 1972), Brazil ( Elmoor-Loureiro, 1997), Mexico ( Elías-Gutiérrez et al., 2006),and Colombia ( Fuentes-Reinés, 2014; Fuentes-Reinés et al., 2019). In Brazil, this species was mainly recorded in the hydrographic regions of Amazonia (AM), Paraguay (PG), Paraná (PR), São Francisco (SF), East (AL), South (SA) and Southeast Atlantic (SE), and Tocantins /Araguaia(TA) (see Fig. 1 View Figure 1 and Tab.1, for references). Thus, this study expands the distribution of C. nitidulus to the Oriental Northeast Atlantic hydrographic region (NOr) and to Atlantic forest ponds in Northeastern Brazil.