Fifteen limnic ostracodes species have been recorded in the Alagamar Formation, Potiguar Basin: Cypridea araripensisSilva, 1978a; Cypridea? sp., Harbinia sinuata (Krömmelbein and Weber, 1971); Harbinia crepata n. sp., Harbinia dimorphica n. sp., Harbinia altaAntonietto et al., 2012; Paracypria? elongata n. sp., Ilyocyprimorpha berthoui (Colin and Dépêche, 1997); Ilyocypris? sp., Brasacypris subovatum n. sp., Candona? sp., Theriosynoecum colini n. sp., T. guzzoi n. sp., T. silvai (Silva, 1978b) diagnosis emended by Do Carmo et al. (2004b); and Darwinula martinsiSilva, 1978c diagnosis emended by Do Carmo et al. (2004b). Nine of these species have also been recorded outside of the Potiguar Basin, either in other Cretaceous basins in Brazil or coeval strata in western Africa. Despite the controversy about dating the local Alagoas Stage and the relatively large range of the Zone Harbinia spp. 201–218, the material studied in this paper belongs to the interval corresponding to the well-defined palynological zone coded as P-270, which is mid-upper Aptian in age.