Aim We test whether species of western Mediterranean aquatic Coleoptera of the 'Haenydra' lineage (Hydraenidae, Hydraena) originated through: (1) successive periods of dispersal and speciation, (2) range fragmentation by random vicariance, or (3) range fragmentation by geographic isolation owing to a general reduction of population density.Location Europe. MethodsTo discriminate between scenarios we use contrasting predictions of the relationship between phylogenetic and geographic distance. The phylogeny was based on 3 kb of four mitochondrial and two nuclear gene fragments of about half of the known species of 'Haenydra', including most western Mediterranean taxa. Divergences were estimated using a molecular clock. The relationship between phylogenetic and geographic distance was tested using bivariate plots, Mantel tests and comparison of the observed phylogeny with the one minimizing geographic distances between species, as measured using Euclidean minimum spanning trees (EMSTs). ResultsThe monophyly of 'Haenydra' was strongly supported, although its phylogenetic placement was not resolved. 'Haenydra' was estimated to be of late Miocene age, with most species originating during the Pleistocene. In two clades (Hydraena tatii and Hydraena emarginata clades) there was a significant association between geographic and phylogenetic distance, and the reconstructed phylogeny was identical to that obtained through the EMST, demonstrating a strong non-randomness of the geographic distribution of the species. In two other clades (Hydraena iberica and Hydraena bitruncata clades) there was no association between geographic and phylogenetic distance, and the observed phylogeny was not the one minimizing geographic distances. In one of the clades this seems to be due to a secondary, recent range expansion of one species (H. iberica), which erased the geographic signal of their distributions.Main conclusions We show that it is possible to obtain strong evidence of stasis of the geographic ranges of narrow-range endemic species through the study of their phylogenetic relationships and current distributions. In at least two of the studied clades, current species seem to have originated through the fragmentation of a more widely distributed species, without further range movements. A process of range expansion and fragmentation may have occurred repeatedly within the 'Haenydra' lineage, contributing to the accumulation of narrow-range endemics in Mediterranean Pleistocene refugia.

Ochthebiinae, with c. 650 species distributed worldwide, are the second most speciose subfamily of the aquatic beetle family Hydraenidae. They are ecologically the most diverse hydraenid subfamily, with terrestrial species as well as species in almost all types of aquatic habitats, including hypersaline waters. Ochthebiinae include the tribes Ochtheosini (four species in three genera) and Ochthebiini. We provide here the first comprehensive phylogeny of the tribe Ochthebiini, based on 186 species and four subspecies from most genera, subgenera and species groups. We obtained sequence data for a combination of mitochondrial and nuclear gene fragments including the 5 ′ and 3 ′ ends of the cytochrome c oxidase subunit 1, the 5 ′ end of 16S RNA plus the leucine tRNA transfer plus 5 ′ end of NADH dehydrogenase subunit I, and internal fragments of the large and small ribosomal units. The analyses with maximum likelihood (ML) and Bayesian probabilities consistently recovered a generally well supported phylogeny, with most currently accepted taxa and species groups as monophyletic. We provide a new classification of the tribe based on our phylogenetic results, with six genera: Meropathus Enderlein, Ochthebius Leach, Protochthebius Perkins, Prototympanogaster Perkins, Tympallopatrum Perkins and Tympanogaster Janssens. The genus Ochthebius is here divided into nine subgenera in addition to Ochthebius s.s.: (1) O. (Angiochthebius) Jäch & Ribera; (2) O. (Asiobates) Thomson; (3) O. (Aulacochthebius) Kuwert; (4) O. (Cobalius) Rey; (5) O. (Enicocerus) Stephens; (6) O. (Gymnanthelius) Perkins comb.n.; (7) O. (Gymnochthebius) Orchymont; (8) O. (Hughleechia) Perkins comb.n.; and (9) O. (Micragasma) Sahlberg. Within Ochthebius s.s., 17 species groups are proposed, five of them newly established (3, 9, 11, 13 and 16): (1sumatrensis; and (17) vandykei. We elevated to species rank two subspecies of Ochthebius: O. fallaciosus Ganglbauer stat.n. (former subspecies of O. viridis Peyron) and O. deletus Rey stat.rest. (former subspecies of O. subpictus Wollaston).

Aim To reconstruct the evolutionary history of a genus of freshwater beetle with a pan-Mediterranean distribution, to test classic hypotheses which proposed a Miocene origin for groups with high biodiversity in the Iberian and Anatolian peninsulas. Location Mediterranean basin.Methods We sequenced four mitochondrial and one nuclear gene from 51 specimens of 30 of the c. 60 extant species of Deronectes (Dytiscidae), all typical of mid-mountain streams from North Africa and Iberia over most of Europe to the Middle East. We used maximum likelihood, Bayesian probabilities with an a priori evolutionary rate and a dispersal-extinction-cladogenesis model to reconstruct their biogeographical history.Results Deronectes has two major lineages which originated in the mid Miocene; one including mostly eastern and another mainly western and central Mediterranean species. From these two areas, range expansions, mainly at the end of the Miocene and beginning of the Pliocene, resulted in the many species groups and some of the extant species of the genus. Most of the current diversity and distributions are, however, of Plio-Pleistocene origin, particularly in widespread European species.Main conclusions In line with traditional hypotheses, we found an ancient division between eastern and western Mediterranean lineages of Deronectes, likely resulting from the isolation of Europe west of the Alps from the Balkans and Anatolia during the early-middle Miocene. The history of the genus was strongly influenced by major geological and climatic events, with successive cycles of fragmentation and subsequent eastward and westward range expansions, resulting in a steady accumulation of species across the basin. Most of these range movements took place through the north side of the Mediterranean, with only local displacements in the south during the Messinian salinity crisis and a recent (Pleistocene) colonization of the Italian Peninsula, which remained largely submerged through most of the genus' evolutionary history.

Abstract. Aquatic Coleoptera in shallow lakes associated with the Canal de Castilla (Palencia Province, Spain) in the northern Ibe rian Meseta were sampled over the course of a year (spring 1998-winter 1999). These waterbodies are typical plateau wetlands with dense vegetation and vary in permanence and area (from 3.3 ha to 29.35 ha). Oxygen concentration, conductivity and pH were recorded at the time of sampling. Lake area, depth, water permanence and type of vegetation were also taken into account. Ninety two species were collected. Species richness was high in comparison with other wetlands in Spain. The assemblage structure was assessed in terms of three community parameters: richness, abundance and diversity (Shannon index). Their relationships with envi ronmental variables were explored using correlation coefficients. The assemblage composition was analysed by multivariate tech niques. First, the sites were classified by means of TWINSPAN. The presence of each species in the different TWINSPAN groups was used to assess their habitat preferences. Second, the sites and species were ordinated by Detrended Correspondence Analysis (DCA) using the CANOCO statistical package. Richness was significantly correlated with water permanence, conductivity and aquatic macrophyte cover. The first DCA axis was significantly correlated with water permanence and conductivity, but not with any of the other parameters. Conductivity was significantly inter-correlated with permanence. Therefore, water permanence and aquatic vegetation cover seem to be the main factors influencing richness, but only water permanence appears to determine species composition.

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