Synopsis of the Amphibians of Equatorial Guinea based upon the Authors’ Field Work and Spanish Natural History Collections Author Sánchez-Vialas, Alberto Museo Nacional de Ciencias Naturales (MNCN-CSIC), C / José Gutiérrez Abascal, 2. 28006, Madrid, Spain; Author Calvo-Revuelta, Marta Museo Nacional de Ciencias Naturales (MNCN-CSIC), C / José Gutiérrez Abascal, 2. 28006, Madrid, Spain; Author Castroviejo-Fisher, Santiago Laboratorio de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS). Av / Ipiranga, 6681, Prédio 40, sala 110, 90619 - 900, Porto Alegre, Brazil; * Corresponding author: IDlR (iriva @ mncn. csic. es) Author De, Ignacio Museo Nacional de Ciencias Naturales (MNCN-CSIC), C / José Gutiérrez Abascal, 2. 28006, Madrid, Spain; text Proceedings of the California Academy of Sciences 2020 2020-03-31 66 8 137 230 journal article 295393 10.5281/zenodo.11105986 4c7b4d3d-1fbe-4f48-8cb2-002e928eae42 0068-547X 11105986 Hyperolius olivaceus Peters, 1876 Photo figure 17A TYPE LOCALITY .— “Limbareni am Ogowe”, Lambaréné , Gabon . DISTRIBUTION .— This species ranges from the coastal region of Gabon and Republic of Congo to southwestern Equatorial Guinea , where it has been recorded in Río Muni , at lake Atoc, Monte Alén ( De la Riva 1994 ). There are no records of this species from Bioko ( Map 17B ). COMMENTS .— Hyperolius olivaceus (formerly considered as a subspecies of H. cinnamomeoventris Bocage, 1886 ) forms part of the H. cinnamomeoventris species complex. Bell et al. (2015) identified distinct evolutionary lineages within this complex across most part of its distribution and revealed that H. cinnamomeoventris represents a paraphyletic taxon. Subsequently, in order to resolve the taxonomy of the group, Bell et al. (2017) elevated the subspecies H. cinnamomeoventris olivaceus to full species status for the lineages inhabiting the Gabon region and south of the Congo River, which likely includes Río Muni populations (as considered herein). Hyperolius olivaceus is the sister species to a clade formed by the insular Hyperolius thomensis Bocage, 1886 , H. molleri (Bedriaga, 1892) and H. drewesi Bell, 2016 ( Bell et al. 2017 ). SPECIMENS EXAMINED .— Nine specimens . Engong (Aconibe-Asoc), 01 May 1987 ( EBD 25089–25093 , EBD 25071 , 25073–25075 ) .