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We incorporated new data to re-evaluate the biogeographical patterns in the Mexican Transition Zone (MTZ) through the recognition of congruence in the geographic distributions of Mexican passalids (Coleoptera : Passalidae). We used three different approaches to parsimony analysis of endemicity (PAE): (1) the use of specific distribution data; (2) the application of a null model of significant co-occurrence to the specific distribution data; and (3) the use of predicted potential distributions through ecological niche modelling. Overall, these approaches sharpened the delimitation of distributions in three general zones. General zone (GZone) 1 includes species of restricted distribution in the state of Chiapas; the grid cells that make up this zone lie mainly in the Chiapas biogeographical province. GZone 2 includes species of restricted distribution located mainly in the states of Veracruz, Puebla, Hidalgo and Queretaro; the grid cells of this zone lie mainly in the Sierra Madre Oriental province. GZone 3 includes species with restricted distribution occurring mainly in the states of Guerrero and Oaxaca; the grid cells of this zone lie mainly in the Sierra Madre del Sur biogeographical province. The patterns of distributional congruence found in this study revealed three important distributional zones for the passalid species within the MTZ highly coincident with patterns proposed by Halffter.

Aim The Mexican Transition Zone (MTZ) is an area where the Nearctic and Neotropical biogeographical regions overlap, generating high species richness and endemism. The objective of this study was to analyse if potential changes in the composition and the geographical location of areas of endemism (AEs) for beetles and mammals during the Last Glacial Maximum (LGM), the mid‐Holocene (MH) or the Last Interglacial (LIG) have influenced the definition of the MTZ in the present. Location Mexico and Central America. Methods Ecological niche models (ENM) were generated describing the current distribution of 218 species associated with the MTZ and then transferred to three periods into the past. A parsimony analysis of endemicity (PAE) was run to identify current AEs. The transferred models of each set of species that form the current AEs were used to assess if the geographical ranges of the species’ ecological niches changed over time, or whether they remained stable supporting the validation of the AEs during three past recent periods (LGM, MH and LIG). Results Two current AEs were detected that persisted geographically during the three past periods (LGM, MH and LIG). Main conclusions The results show that some AEs change through time as a response of climate, whereas others remained stable. Thus, the MTZ could be considered as a dynamic zone at least over the last 130,000 years. The climate analysis of the AEs allows them to be recognized either as true spatio‐temporal units, or as temporarily restricted patterns of co‐distribution resulting from changes in climate over time.

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