This dataset contains the digitized treatments in Plazi based on the original journal article Varela-Hernández, Fernando, Riquelme, Francisco, Guerrero, Roberto J. (2023): A Miocene ant species of the genus Forelius Emery, 1888 (Hymenoptera: Formicidae: Dolichoderinae) from Mexico. Palaeontologia Electronica (a 36) 26 (3): 1-9, DOI: 10.26879/1294, URL: http://dx.doi.org/10.26879/1294ABSTRACTThe first fossil ant species of the New World genus Forelius (Formicidae: Dolichoderinae) is described. The type material is a Miocene amber inclusion from the Montecristo mine near Simojovel, Chiapas, southwestern Mexico. The new species is named Forelius chenpauch sp. nov. It differs from its congeners by having a unique combination of characters: antennal scapes reaching the posterior margin of the head; pronotum with six erect hairs; mesonotum with four erect hairs; propodeum with four erect hairs; front and dorsum of head, dorsum of pronotum, dorsum of mesonotum and propodeum covered with a fine striation. Forelius chenpauch sp. nov. has a rounded spiracle, which could be considered a plesiomorphic character closely related to the Forelius group from the north of the Amazon basin. Accordingly, the current divergence estimates of Forelius as a single genus from the Leptomyrmex + Forelius + Dorymyrmex clade (ca. 27 Ma) and the occurrence of Forelius chenpauch sp. nov. in the fossil record (ca. 23 Ma), may suggest that the rounded spiracle is a plesiomorphic state probably widespread since the Miocene from southern Mexico to northern South America.Fernando Varela-Hernández. Laboratorio de Sistemática Molecular, Escuela de Estudios Superiores del Jicarero, Universidad Autónoma del Estado de Morelos, C. P. 62909, Jojutla, Morelos, México. Corresponding author. fernando.varela@uaem.mxFrancisco Riquelme. Laboratorio de Sistemática Molecular, Escuela de Estudios Superiores del Jicarero, Universidad Autónoma del Estado de Morelos, C. P. 62909, Jojutla, Morelos, México. Corresponding author. francisco.riquelme@uaem.mxRoberto J. Guerrero. Universidad del Magdalena, Santa Marta, Magdalena, Colombia, rguerrero@unimagdalena.edu.coKeywords: ant fossil; amber- Lagerstätte; Chiapas amber; Leptomyrmecini tribe; new speciesSubmission: 14 April 2023. Acceptance: 3 September 2023.https://zoobank.org/ 62019DB5-8F62-4276-994C-8867124393A6