Thermal niche evolution and geographical range expansion in a species complex of western Mediterranean diving beetles

[Background] Species thermal requirements are one of the principal determinants of their ecology and biogeography, although our understanding of the interplay between these factors is limited by the paucity of integrative empirical studies. Here we use empirically collected thermal tolerance data in combination with molecular phylogenetics/phylogeography and ecological niche modelling to study the evolution of a clade of three western Mediterranean diving beetles, the Agabus brunneus complex.[Results] The preferred mitochondrial DNA topology recovered A. ramblae (North Africa, east Iberia and Balearic islands) as paraphyletic, with A. brunneus (widespread in the southwestern Mediterranean) and A. rufulus (Corsica and Sardinia) nested within it, with an estimated origin between 0.60-0.25 Ma. All three species were, however, recovered as monophyletic using nuclear DNA markers. A Bayesian skyline plot suggested demographic expansion in the clade at the onset of the last glacial cycle. The species thermal tolerances differ significantly, with A. brunneus able to tolerate lower temperatures than the other taxa. The climatic niche of the three species also differs, with A. ramblae occupying more arid and seasonal areas, with a higher minimum temperature in the coldest month. The estimated potential distribution for both A. brunneus and A. ramblae was most restricted in the last interglacial, becoming increasingly wider through the last glacial and the Holocene.[Conclusions] The A. brunneus complex diversified in the late Pleistocene, most likely in south Iberia after colonization from Morocco. Insular forms did not differentiate substantially in morphology or ecology, but A. brunneus evolved a wider tolerance to cold, which appeared to have facilitated its geographic expansion. Both A. brunneus and A. ramblae expanded their ranges during the last glacial, although they have not occupied areas beyond their LGM potential distribution except for isolated populations of A. brunneus in France and England. On the islands and possibly Tunisia secondary contact between A. brunneus and A. ramblae or A. rufulus has resulted in introgression. Our work highlights the complex dynamics of speciation and range expansions within southern areas during the last glacial cycle, and points to the often neglected role of North Africa as a source of European biodiversity.This work was supported by an FPI grant to AH-G and projects CGL2007-61665 and CGL2010-15755 from the Spanish government to IR. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

Geographic variation in acclimation responses of thermal tolerance in South African diving beetles (Dytiscidae: Coleoptera)

Understanding sources of variation in animal thermal limits is critical to forecasting ecological responses to climate change. Here, we estimated upper and lower thermal limits, and their capacity to respond to thermal acclimation, in several species and populations of diving beetles (Dytiscidae) from diverse geographic regions representative of variable climate within South Africa. We also considered ecoregions and latitudinal ranges as potential predictors of thermal limits and the plasticity thereof. For upper thermal limits, species showed significant variation and limited acclimation-related plasticity. Lower thermal limits responded to acclimation in some cases and showed marked variation among species that could be explained by taxonomic affiliation and ecoregion. Limited acclimation ability in the species included in this study suggest plasticity of thermal limits will not be a likely buffer for coping with climate change. From the present results for the Dytiscidae of the region, it appears the group may be particularly susceptible to heat and/or drought and may thus serve as useful indicator species of ecosystem change. Understanding how these climate-related impacts play out at different spatial and temporal scales will have profound implications for conservation management and functional responses, especially important in a region already showing a trend for warming and drying

Hydrochus smaragdineus Fairmaire 1879

<i>Hydrochus smaragdineus</i> Fairmaire, 1879 <p> <i>Hydrochus angustatus bicolor</i> Rey, 1885 <b>syn.n.</b></p> <p> <b>Material studied.</b> Lectotype (of <i>Hydrochus angustatus bicolor</i> Rey, 1885), male (Muséum d’Histoire Naturelle, Lyon): “ Hydrochus / bicolor Rey [male symbol] / mus. Lyon. [red handwritten label]”; “Museon Den Haag / Hydrochus [male symbol] / bicolor Rey [hdw] / det. A. L. van Berge / Henegouwen 1986”; “ lectotype. Van Berge / Henegouwen 1985 [red label, hdw]”.</p> <p> <b>Remarks.</b> The study of the lectotype of <i>H. angustatus bicolor</i> revealed that its aedeagus is identical to that of <i>H. smaragdineus</i> Fairmaire (in the interpretation of Valladares, 1995), and thus it has to be considered a subjective junior synonym and not a subspecies of <i>Hydrochus angustatus</i> Germar, 1824.</p>Published as part of <i>Hidalgo-Galiana, Amparo, Jäch, Manfred A. & Ribera, Ignacio, 2010, Hydrochus farsicus sp. n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae), pp. 61-64 in Zootaxa 2344</i> on page 64, DOI: <a href="http://zenodo.org/record/193349">10.5281/zenodo.193349</a&gt

Hydrochus farsicus Hidalgo-Galiana, Jäch & Ribera, 2010, new species

Hydrochus farsicus, new species Figs 1–2 Type locality. Sepidan, Province of Fars, Iran. Type material. Holotype (NMW): “ 2 - IRAN Fars, 13.8. 1998 / 6km W Sepidan / rd. Sepidan-Yasuj / brook (Cheshmeh Saran) / leg. Elmi & Fery (# 2098)” and holotype label. Aedeagus glued on the same card. Base of aedeagus slightly damaged. Paratypes (NMW): Two females with the same data as holotype, plus paratype labels. Diagnosis. The only reliable characters to identify this new species are those of the male genitalia (Fig. 2). Other putative morphological characters may be shared with still undescribed, closely related species and are thus not reliable for an unambiguous identification. Description. Habitus as in Fig. 1. Elytra and body appendages brown, except apex of maxillary palpi and base of mandibles darker; head black; pronotum brown with central area darker; surface with light bluish or greenish metallic reflections. Ventral side evenly dark brown, except for head black. Head with deep, coarse evenly distributed punctures, intermixed with smaller punctures with short whitish setae; four small tubercles between eyes. Pronotum elongate, subcylindrical, wider anteriorly; with seven depressions, three anterior, rounder and four posterior, more elongate; lateral posterior depressions smaller, reaching posterior margin of pronotum. Punctation and pubescence as on head. Elytra subparallel-sided, slightly wider posteriorly; with 10 longitudinal striae formed by deep, regularly aligned punctures. Humeral region of elytra prominent. Tibiae with a regular dense row of setae in upper apical part; femora with evenly distributed small setae. Ventral surface covered with short, thick and dense pubescence, surface strongly microrecticulate, cells small and with a shagreen-like aspect. Medial line of ventrites, medial area of metaventrite, and two lateral areas in the metaventrite glabrous or with less dense pubescence. Ventrites with a strong transverse medial ridge, almost forming a carina. Aedeagus as in Fig. 2, 0.98 mm long, 0.3 mm wide; robust, parameres and median lobe asymmetrical: apex of left paramere with an asymmetrical triangular expansion; apex of right paramere sinuated, not expanded. Apex of median lobe expanded, poorly sclerotized, with a small flagellum. Variation. Length 3.2–3.4 mm; maximum width 1.0– 1.3 mm. Without apparent secondary sexual dimorphism. Distribution. Only known from the type locality. Remarks. The morphology of the aedeagus of H. farsicus resembles that of some Iberian species (Hydrochus ibericus Valladares, Díaz & Delgado and H. angusi Valladares), although it may also be related to the group of H. elongatus (Schaller), with a more eastern distribution (Hidalgo-Galiana et al., in preparation). Mart et al. (2009) recorded H. ibericus from Turkey, but unfortunately they did not figure the aedeagus and did not give details of the material used for comparison. Etymology. Named after the Iranian province of Fars, from where this species was collected.Published as part of Hidalgo-Galiana, Amparo, Jäch, Manfred A. & Ribera, Ignacio, 2010, Hydrochus farsicus sp. n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae), pp. 61-64 in Zootaxa 2344 on pages 61-63, DOI: 10.5281/zenodo.19334

Hydrochus farsicus sp.n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae)

The family Hydrochidae (or subfamily Hydrochinae for some authors) includes one recognised genus (Hydrochus Leach) with more than 200 species and a worldwide distribution (Hansen, 1999; Short & Hebauer, 2006). The West Mediterranean is among the most diverse areas for the genus in the Palearctic Region, with 12 species known from Spain and Morocco, including several endemic species described recently (Hansen, 2004). On the contrary, in the East Mediterranean and the Middle East few species are known so far, although some undescribed species from Turkey are deposited in the Naturhistorisches Museum Wien (NMW). No species of Hydrochus has ever been recorded from Iran (Hansen, 2004). Other groups of aquatic Coleoptera (e.g. Dytiscidae, Nilsson, 2004 or Hydraenidae, Jäch, 2004) display a more balanced distribution of species, and include a high number of Turkish or Iranian endemics. The situation in Hydrochus may be due to lack of knowledge, as the undescribed specimens in the NMW and some recent works (Incekara et al., 2004; Mart et al., 2009) may suggest, but it may be that in Turkey and the Middle East the genus Hydrochus is generally less speciose than in the West Mediterranean. In this paper two species of Hydrochus are recorded from Iran, one of which is described as new. In addition, some taxonomic notes on other Palearctic species are provided

Hydrochus farsicus sp. n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae)

Hidalgo-Galiana, Amparo, Jäch, Manfred A., Ribera, Ignacio (2010): Hydrochus farsicus sp. n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae). Zootaxa 2344: 61-64, DOI: 10.5281/zenodo.19334

Hydrochus nodulifer Reitter 1897

Hydrochus nodulifer Reitter, 1897 Material studied. One male (Coll. Pütz, Eisenhüttenstadt, Germany): IRAN: Prov. Gilan, Siahkal County, Elburz Mts., S-Slope, Deylaman-Barresar road, sifted, 1688 m, 36 º 51 '07''N, 49 º 49 ' 67.3 ''E, 07.VI. 2008, leg. A. Pütz “IR08- 25 ”. Remarks. First record for Iran. This species was described from “Elisabethpol” [= Ganja (or Ganca), Azerbaijan] (Reitter, 1897). A lectotype was designated by Shatrovskij (1993), who also figured the aedeagus. Hydrochus nodulifer has also been recorded from Eastern Anatolia and the Black Sea Area of Turkey (Mart et al., 2009).Published as part of Hidalgo-Galiana, Amparo, Jäch, Manfred A. & Ribera, Ignacio, 2010, Hydrochus farsicus sp. n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae), pp. 61-64 in Zootaxa 2344 on page 63, DOI: 10.5281/zenodo.19334

Protein expression parallels thermal tolerance and ecologic changes in the diversification of a diving beetle species complex

International audienc