Allopatric divergence and genetic diversity of recent Aphanius Iberus and fossil Prolebias Meyeri (Teleostei, Cyprinodontidae) from southwest and western Europe, as indicated by otoliths

Otoliths of three Recent Spanish Aphanius iberus populations are described and illustrated by SEM pictures for the first time. Based on random samples taken from each population, we found distinctive differences in otoliths b etween-populations. We suggest that these differences reflect allopatric di vergence and, for the population from Lebrija, beginning endemism. Our data support previous studies on populations of A. iberus based on crossbreedin g analyses and various molecular methods: In addition, we found different l evels of variability of otoliths within a population. We suppose, that a lo w (or high) level of such variability may be connected with a low (or high) genetic diversity within the population studied. Furthermore; we describe and illustrate otoliths of Aphanius apodus which is possibly extinct in its natural habitats. Its otoliths clearly differ from those of A. iberus and suggest a spatial separation for at least 2-3 Ma (Pliocene). In addition to the Recent species, otoliths of the fossil Prolebias meyeri of early Mioce ne age were studied from three localities in southern France and Germany. T hese P. meyeri populations span over 2 Ma within the Lower Miocene, from 23 .8 Ma to 21.8 Ma. However, variability of otoliths between the three fossil populations indicates an allopatric divergence but no speciation. Otolith variability within a P. meyeri population seems to decline with time and is lowest in the youngest population of 21.8 Ma which represents the last rec ord of this species (except for a relic fauna of probably 19 Main the Hanau Basin in Germany). (C) Editions scientifiques et medicales Elsevier SAS.