Peloso et al. (2014) synonymized the genus Syncope Walker, 1973 with Chiasmocleis Méhely, 1904, thus creating an instance of homonymy between Chiasmocleis carvalhoi (Nelson, 1975) (formerly in the genus Syncope) and Chiasmocleis carvalhoi Cruz,Caramaschi & Izecksohn, 1997. To solve the problem Peloso et al. (2014) renamed the latter species (i.e., the junior homonym) as C.lacrimae.
Silveira et al. (2010) reported the first record of Elachistocleis ovalis (Schneider, 1799), and also of the genus Elachistocleis Parker, 1927, for the state of Rio de Janeiro, based on a specimen from the municipality of Itaperuna. Caramaschi (2010) considered E. ovalis a nomen dubium, and identified all specimens of Elachistocleis examined by him from the state of Rio de Janeiro (including the specimen reported by Silveira et al., 2010) as E. cesarii, a species that had just been revalidated by Toledo et al. (2010) for specimens from the state of São Paulo. Thus, the species of Elachistocleis occurring in Rio de Janeiro is currently referred to E.cesarii.
The records of Stereocyclops incrassatus Cope, 1870 in the state of Rio de Janeiro are currently considered to represent S. parkeri (see Frost, 2017). Previously in the synonymy of S.incrassatus (see Carvalho, 1948), S. parkeri was treated as a valid taxon by Bokermann (1966) without comment, and this has been followed by most subsequent authors since then (e.g., Izecksohn & Carvalho‑e‑Silva, 2001; Haddad et al., 2013).