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In order to place a newly discovered species Antigracilus costatus gen. sp. n. from the Lower Cretaceous Yixian Formation (China) and to assess previously unplaced fossil taxa, we investigated the relationships of extant and extinct lineages of Histeridae based on three data sets: (i) 69 morphological characters belonging to 48 taxa (representing all 11 subfamilies and 15 of 17 tribes of modern Histeridae); (ii) partitioned alignment of 6030 bp from downloaded nucleotide sequences (28S, CAD, COI, 18S) of 50 taxa (representing 10 subfamilies and 15 of 17 tribes of modern Histeridae); and (iii) a combined morphological and molecular dataset for 75 taxa. Phylogenetic analyses of the morphology and combined matrices recovered the new Lower Cretaceous taxon as a sister group to remaining Histeridae and it is placed in Antigracilinae subfam. n. Antigracilinae constitutes the earliest record of Histeridae from the Lower Cretaceous Yixian Formation (â¼125 Myr), backdating the minimum age of the family by 25 Myr from the earliest Cenomanian (~99 Myr) to the Barremian of the Cretaceous Period. Our molecular phylogeny supports Histeridae to be divided into seven different clades, with currently recognised subfamilies Abraeinae (sensu lato), Saprininae, Chlamydopsinae, and Histerinae (sensu lato) recovered as monophyletic, while Dendrophilinae, Onthophilinae, and Tribalinae are polyphyletic taxa. The Burmese amber species Pantostictus burmanicus Poinar & Brown is placed as a sister group to the tribe Plegaderini (Abraeinae) and was assigned as a new tribe Pantostictini trib. n. Both molecular and combined phylogenies recovered the subfamilies Trypanaeinae and Trypeticinae deeply within the subfamily Abraeinae (sensu lato), and they are downgraded into Trypanaeini stat. n. and Trypeticini stat. n.
Assuntos
Besouros/classificação , Besouros/genética , Abdome/anatomia & histologia , Animais , Besouros/anatomia & histologia , Besouros/ultraestrutura , Evolução Molecular , Extremidades/anatomia & histologia , Fósseis , Cabeça/anatomia & histologia , Masculino , Microscopia Eletrônica de Varredura , Boca/anatomia & histologia , Boca/ultraestrutura , Filogenia , Tórax/anatomia & histologia , Tórax/ultraestruturaRESUMO
BACKGROUND: Southern Appalachian forests are dominated by second-growth vegetation following decades of intensive forestry and agricultural use, although some old-growth patches remain. While it's been shown that second-growth areas may exhibit comparable species richness to old-growth in the area, the extent to which populations of arthropods in second-growth areas have persisted vs. recolonized from other areas remains unexamined. The implications for conservation of both classes of forest are significant. Here we analyze population diversity and relatedness across five old-growth and five second-growth populations of flightless, leaf litter-inhabiting beetles in the genus Eurhoptus (Coleoptera: Curculionidae: Cryptorhynchinae). Our main goal is asking whether second-growth areas show diminished diversity and/or signals of recolonization from old-growth sources. RESULTS: Population genetic and phylogenetic analyses do not reveal any consistent differences in diversity between the old-growth and second-growth populations examined. Some second-growth populations retain substantial genetic diversity, while some old-growth populations appear relatively depauperate. There is no phylogenetic indication that second-growth populations have recolonized from old-growth source populations. CONCLUSIONS: Most populations contain substantial and unique genetic diversity indicating long-term persistence in the majority of sites. The results support substantial resilience in second-growth populations, though the geographic scale of sampling may have hindered detection of recolonization patterns. Broad scale phylogeographic patterns reveal a deep break across the French Broad River basin, as has been reported in several other taxa of limited dispersal abilities. In Eurhoptus this break dates to ~ 2-6 Ma ago, on the older end of the range of previously estimated dates.
Assuntos
Voo Animal , Florestas , Gorgulhos/crescimento & desenvolvimento , Animais , Região dos Apalaches , Teorema de Bayes , Biodiversidade , Filogenia , Filogeografia , Dinâmica Populacional , Gorgulhos/classificação , Gorgulhos/genéticaRESUMO
In the eastern United States, 74 species of Anillini in two genera have been described, with most belonging to Anillinus Casey. Until now, no systematic framework has existed for this large genus, hampering integrative studies. Using DNA sequences from 101 Nearctic species, we present a well-resolved molecular phylogeny supporting a sound systematic framework. Sixteen species groups of Appalachian Anillinus are diagnosed, in part using newly recognized variation in the number of modified male protarsi and the state of the spermathecal duct. We present the first descriptions of Nearctic anilline larvae, which possess none of the synapomorphies of previously described anilline larvae. Within Anillinus, two major clades are mostly consistent with setation of the right paramere: a "hairy clade" with more than four setae, and a "quadrisetose clade." Throughout the phylogeny, microhabitat use varies within each clade, and several endogean lineages are phylogenetically isolated. Our work increases the South Carolina fauna by nearly five-fold. Nine new species are described, Serranillusmonadnock sp. nov., Anillinuscastaneus sp. nov., Anillinuschoestoea sp. nov., Anillinusdentatus sp. nov., Anillinusjancae sp. nov., Anillinusmica sp. nov., Anillinusmicamicus sp. nov., Anillinusseneca sp. nov., and Anillinussimplex sp. nov. Several species are newly reported from South Carolina, bringing the total to 20 described species representing seven species groups. Two endemic groups inhabit deep clay soils in the Piedmont and possess unique male sexual characters. The Anillini are a unique component of Nearctic biodiversity, with great potential as a model system for studies of biogeography, secondary male sexual modification, and endogean adaptations.
RESUMO
The fauna of Diplura, the two-pronged bristletails (Hexapoda), of the southern Appalachians has received little focused systematic attention. Existing literature suggests the fauna to comprise around a dozen species. Based on a broader DNA barcode-based survey of high elevation litter arthropods in the region, we suggest the fauna to be much richer, with automated species delimitation methods hypothesising as many as 35 species, most highly restricted to single or closely proximate localities. Such a result should not be very surprising for such small, flightless arthropods, although it remains to be seen if other markers or morphology support such high diversity. The region still remains sparsely sampled for these more cryptic elements of the arthropod fauna and much larger numbers of species undoubtedly remain to be discovered.
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The Pseudoscorpiones fauna of North America is diverse, but in regions like the southern Appalachian Mountains, they are still poorly documented with respect to their species diversity, distributions and ecology. Several families have been reported from these mountains and neighbouring areas. Here we analyse barcoding data of 136 specimens collected in leaf litter, most of them from high-elevation coniferous forest. We used ASAP as a species delimitation method to obtain an estimation of the number of species present in the region. For this and based on interspecific genetic distance values previously reported in Pseudoscorpions, we considered three different genetic Kimura two-parameter distance thresholds (3%/5%/8%), to produce more or less conservative estimates. These distance thresholds resulted in 64/47/27 distinct potential species representing the families Chthoniidae (33/22/12 species) and Neobisiidae (31/25/15) and at least six different genera within them. The diversity pattern seems to be affected by the Asheville Depression, a major biogeographic barrier in this area, with a higher diversity to the west of this geographic feature, particularly within the family Neobisiidae. The absence of representatives from other families amongst our studied samples may be explained by differences in their ecological requirements and occupation of different microhabitats.
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Species of the genus Lathrobium Gravenhorst (Coleoptera: Staphylinidae: Paederinae) from North America north of Mexico are reviewed and 41 species are recognized. Morphology and mitochondrial COI sequence data were used to guide species designations in three flightless lineages endemic to the southern Appalachian Mountains, a biologically diverse region known for cryptic diversity. Using a combination of phylogeny, algorithm-based species delimitation analyses, and genitalic morphology, five new cryptic species are described and possible biogeographic scenarios for their speciation hypothesized: L.balsamense Haberski & Caterino, sp. nov., L.camplyacra Haberski & Caterino, sp. nov., L.islae Haberski & Caterino, sp. nov., L.lividum Haberski & Caterino, sp. nov., L.smokiense Haberski & Caterino, sp. nov. Five additional species are described: L.absconditum Haberski & Caterino, sp. nov., L.hardeni Haberski & Caterino, sp. nov., L.lapidum Haberski & Caterino, sp. nov., L.solum Haberski & Caterino, sp. nov., and L.thompsonorum Haberski & Caterino, sp. nov. Two species are transferred from Lathrobium to Pseudolathra Casey: Pseudolathraparcum (LeConte, 1880), comb. nov. and Pseudolathratexana (Casey, 1905), comb. nov. Twenty-six names are reduced to synonymy. Lectotypes are designated for 47 species. Larvae are described where known, and characters of possible diagnostic value are summarized. Species diagnoses, distributions, illustrations of male and female genitalia, and a key to Lathrobium species known from the Nearctic region (including several introduced species) are provided.
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We describe a second species of Nearctomeris Wesener, 2012, a genus of pill millipede endemic to the southern Appalachians, based on morphological and molecular evidence. The fauna of Glomerida in America is characterized by its low diversity, and Nearctomerissmokysp. nov. is only the fifth species of the order known from the eastern United States. Our phylogenetic analyses based on COI sequences recover a tentatively monophyletic lineage including both eastern American genera Onomeris Cook, 1896 and Nearctomeris, with a common ancestor in the Late Cretaceous to Mid Eocene and extant diversity within genera dating back to the Miocene. Our results suggest that the observed low diversity of the group in the eastern US is likely caused by extinction events, but it is also possible that new species are yet to be found. We provide new records for Nearctomerisinexpectata Wesener, 2012, Onomerisunderwoodi Cook, 1896 and O.australora Hoffman, 1950; the latter is here reported for the first time from South Carolina. We also present DNA barcoding data for all species of Glomerida present in the US that are not yet publicly available.
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The beetle fauna of the California Channel Islands is here enumerated for the first time in over 120 years. We provide an annotated checklist documenting species-by-island diversity from an exhaustive literature review and analysis of a compiled dataset of 26,609 digitized specimen records to which were added over 3,000 individual specimen determinations. We report 825 unique species from 514 genera and 71 families (including 17 new family records) comprising 1,829 species-by-island records. Species totals for each island are as follows: Anacapa (74); San Clemente (197); San Miguel (138); San Nicolas (146); Santa Barbara (64); Santa Catalina (370); Santa Cruz (503); and Santa Rosa (337). This represents the largest list of species published to date for any taxonomic group of animals on the Channel Islands; despite this, we consider the checklist to be preliminary. We present evidence that both inventory and taxonomic efforts on Channel Islands beetles are far from complete. Rarefaction estimates indicate there are at least several hundred more species of beetles yet to be recorded from the islands. Despite the incomplete nature of existing records, we found that species diversity is highly correlated with island area. We report 56 species which are putatively geographically restricted (endemic) to the Channel Islands, with two additional species of questionable endemic status. We also report 52 species from the islands which do not natively occur in the southern California region.
Assuntos
Besouros , Poríferos , Animais , California , Ilhas Anglo-Normandas , Lista de ChecagemRESUMO
The close association between bacteria and insect hosts has played an indispensable role in insect diversity and ecology. Thus, continued characterization of such insect-associated-microbial communities is imperative, especially those of saprophagous scarab beetles. The bacterial community of the digestive tract of adults and larvae of the cetoniine scarab species Cotinis nitida is characterized according to life stage, gut structure, and sex via high-throughput 16S rRNA gene amplicon sequencing. Through permutational ANOVAs of the resulting sequences, bacterial communities of the digestive system are shown to differ significantly between adults and larvae in taxon richness, evenness and relatedness. Significant bacterial community-level differences are also observed between the midgut and hindgut in adult beetles, while no significant host-sex differences are observed. The partitioning between bacterial communities in the larval digestive system is shown through significant differences in two distinct hindgut regions, the ileum and the expanded paunch, but not between the midgut and ileum portion of the hindgut region. These data further corroborate the hypothesis of strong community partitioning in the gut of members of the Scarabaeoidea, suggest hypotheses of physiological-digestive association, and also demonstrate the presence of a seemingly unusual non-scarab-associated taxon. These findings contribute to a general portrait of scarabaeoid digestive tract bacterial communities while illuminating the microbiome of a common new world cetoniine of the Gymnetini-a tribe largely neglected in scarab and beetle microbiome and symbiosis literature.
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Thirteen new species of Euconnus Thomson (Staphylinidae: Scydmaeninae: Glandulariini) are described from the southern Appalachian Mts, USA: Euconnusmegalops sp. nov., E.vexillus sp. nov., E.cumberlandus sp. nov., E.vetustus sp. nov., E.adversus sp. nov., E.astrus sp. nov., E.cultellus sp. nov., E.falcatus sp. nov., E.cataloochee sp. nov., E.kilmeri sp. nov., E.draco sp. nov., E.tusquitee sp. nov., and E.attritus sp. nov. These share a number of morphological characters with the Old World subgenus Cladoconnus Reitter, representing a diversification of species distinct from anything previously known from the western hemisphere. Most of the species occur at higher elevations, some at the tops of the region's highest mountains, and a few are single-peak endemics. No females of these species are winged, and in several species neither sex is winged. A preliminary phylogeny suggests the wingless species represent a clade within a clade of wing-dimorphic species.
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For the first time, an extant histerid genus Anapleus Horn, 1873 is described from a specimen found in mid-Cretaceous Kachin amber. Anapleus kachinensis sp. nov. Although the genus Anapleus has not been precisely defined by synapomorphies, the new species shares numerous features with extant species while differing in comparatively few external characteristics. Anapleus kachinensis represents the first record of an extant histerid genus from Cretaceous deposits and provides further evidence of the ancient origin of the genus.
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BACKGROUND: Comparative phylogeography of sympatric sibling species provides an opportunity to isolate the effects of geography and demographics on the evolutionary history of two lineages over the same, known time scale. In the current study, we investigated the phylogeographic structure of two zopherid beetle species, Phloeodes diabolicus and P. plicatus, where their ranges overlap in California's Transverse Ranges. RESULTS: Although P. diabolicus and P. plicatus share similar habitats with largely overlapping distributions, the results of this study revealed different evolutionary histories for each species since divergence from their most recent common ancestor. In general, P. plicatus had higher genetic diversity, and more among population isolation than P. diabolicus. The mismatch distributions indicated that one major difference between the two species was the timing of population expansion. This result was consistent with genetic patterns revealed by the Phist values and genetic diversity. Lastly, there were no parallel genetic breaks at similar geographic barriers between the species. CONCLUSIONS: Our data revealed that differential demographics rather than geography were responsible for the genetic patterns of the two species.
Assuntos
Besouros/genética , Evolução Molecular , Variação Genética , Filogenia , Animais , Azlocilina , California , Besouros/classificação , Ecossistema , Genética Populacional , Geografia , Modelos Genéticos , Análise de Sequência de DNARESUMO
Nucleotide sequences from 16S rRNA and cytochrome c oxidase subunit I (COI) were used to examine phylogenetic relationships and evolution of beetles from the tribe Hololeptini (Coleoptera: Histeridae: Histerinae) that inhabit necrotic tissue of columnar cacti in the Sonoran Desert. Phylogenetic and morphological analyses revealed the presence of seven separate lineages, three representing species in the genus Iliotona, including I. beyeri stat. nov., and four species belonging to the genus Hololepta (sensu lato). The possible roles of historical vicariance and host plant associations on the evolution of the Hololeptini from the Sonoran Desert are discussed.
Assuntos
Besouros/classificação , Evolução Molecular , Filogenia , Animais , Arizona , Teorema de Bayes , California , Besouros/genética , DNA Mitocondrial/genética , Clima Desértico , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genes de Insetos , Haplótipos , Funções Verossimilhança , México , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Forty-nine new species of Neotropical Exosternini are described in this work, representing the newly recognized Phelister blairi species group, within the large, heterogeneous taxon Phelister. Eight previously described species are also assigned to this group. Relationships within are indicated with several informal subgroups: P. blairi subgroup: (P. blairi Hinton, 1935, P. erwini sp. nov., P. fimbriatus sp. nov., P. stellans sp. nov., P. sparsus sp. nov., P. pretiosus sp. nov., P. trigonisternus Marseul, 1889, P. globosus sp. nov., P. serratus sp. nov., P. geminus sp. nov., P. parana sp. nov., P. asperatus sp. nov., P. uniformis sp. nov., P. miscellus sp. nov., P. inbio sp. nov., P. sculpturatus Schmidt, 1893, P. tunki sp. nov., P. praedatoris Reichensperger, 1939, P. ifficus sp. nov., P. genieri sp. nov., P. marginatus sp. nov., P. vazdemelloi sp. nov., P. dilatatus sp. nov., P. spectabilis sp. nov., P. pervagatus sp. nov.); P. amazoniae subgroup: (P. morbidus sp. nov., P. annulatus sp. nov., P. sphaericus sp. nov., P. geijskesi Kanaar, 1997, P. fraternus sp. nov., P. conjunctus sp. nov., P. chabooae sp. nov., P. striatinotum Wenzel & Dybas, 1941, P. notandus Schmidt, 1893, P. amazoniae (Lewis, 1898) comb. nov., P. arcuatus sp. nov.); P. gregarius subgroup: (P. gregarius sp. nov., P. praecisus sp. nov., P. rudis sp. nov., P. incongruens sp. nov., P. congruens sp. nov., P. praesignis sp. nov.); P. umens subgroup: (P. umens sp. nov., P. almeidae sp. nov., P. chicomendesi sp. nov., P. microdens sp. nov., P. matatlantica sp. nov.); P. curvipes subgroup: (P. curvipes sp. nov., P. vilavelha sp. nov.); P. rio subgroup: (P. rio sp. nov., P. semotus sp. nov., P. uncinatus sp. nov., P. inscriptus sp. nov.); incertae sedis - unplaced to subgroup: (P. incertus sp. nov., P. okeefei sp. nov., P. blairoides sp. nov., P. pirana sp. nov.). Lectotypes are designated for the following species: P. trigonisternus Marseul, P. sculpturatus Schmidt, P. praedatoris Reichensperger, P. notandus Schmidt, and Discoscelis amazoniae Lewis. Preliminary phylogenetic analyses of the broader Neotropical Exosternini do not support the monophyly of the P. blairi group, nor of all of these subgroups, but the majority do fall within one large clade (which is potentially paraphyletic with respect to some other Neotropical exosternine genera). More work on the phylogeny and taxonomy of this diverse fauna is needed.
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The ant-loving beetle genus Panabachia Park 1942 is a poorly studied beetle lineage from the new world tropics. We recently collected Panabachia from several previously unrecorded locations in the páramo biome of the high Ecuadorian Andes, with males exhibiting great morphological variation in the distribution of the foveae and depressions in the pronotum, as well as aspects of the male genitalia. Here, we employ phylogenetic and species delimitation methods with mitochondrial (COI) and nuclear protein-coding (wingless) gene sequences to examine the concordance of morphological characters and geography with hypothesized species boundaries. Three methods of species delimitation (bPTP, GMYC and Stacey) were used to estimate the number of species, and divergence times between putative species using molecular clock calibration. Phylogenetic analysis revealed two parallel radiations, and species delimitation analyses suggest there are between 17 and 22 putative species. Based on clade support and concordance across species delimitation methods we hypothesize 17 distinct clusters, with allopatric speciation consistent with most geographic patterns. Additionally, a widespread species appears to be present in northern páramo sites, and some sister species sympatry may indicate other diversification processes have operated on certain lineages of Panabachia. Divergence time estimates suggest that Panabachia originated in the Miocene, but most species analyzed diverged during the Pliocene and Pleistocene (5.3-0.11 Mya), contemporaneous with the evolution of páramo plant species.
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The Phelisterhaemorrhous species group is established here, revising the seventeen included species, four of which are described as new. This group is named for and contains the type species of Phelister, so represents a core around which a modern concept of the dumping-ground genus Phelister may be developed. The group includes several common and well-known species in the Americas, including some of the only Phelister to exhibit distinctive coloration. Several of these are typically found in cattle dung, and have likely expanded beyond their native ranges as cattle spread throughout the Americas. The group contains the following species: Phelisterhaemorrhous Marseul, 1854, Phelisteraffinis J.E. LeConte, 1859, Phelisterparallelisternus Schmidt, 1893, Phelistermobilensis Casey, 1916, Phelisterbrevistriatus Casey, 1916, Phelistersonorae sp. nov., Phelisterwarneri sp. nov., Phelisterpuncticollis Hinton, 1935, Phelistersubrotundus (Say, 1825), Phelisterrouzeti (Fairmaire, 1850), Phelisterrufinotus Marseul, 1861, Phelisterthiemei Schmidt, 1889, Phelisterparecis sp. nov., Phelisterbryanti sp. nov., Phelistervernus (Say, 1825), Phelisterchilicola Marseul, 1870, and Phelisterbruchi Bickhardt, 1920. We also designate the following new synonymies: Phelisterhaemorrhous Marseul (= Phelisterrubicundus Marseul, 1889, syn. nov.); Phelistersubrotundus (= Phelistercontractus Casey, 1916, syn nov.); Phelisterrouzeti (Fairmaire) (= Phelisterfairmairei Marseul, 1861; syn. nov., = Phelisterwickhami Casey, 1916, syn. nov.); Phelisterrufinotus Marseul, 1861 (= Epierusmarseulii Kirsch, 1873, syn. nov.); and Phelisterthiemei Schmidt, 1889 (= Phelisterstercoricola Bickhardt, 1909, syn. nov.).
RESUMO
BACKGROUND: Páramo is a tropical alpine ecosystem present in the northern Andes. Its patchy distribution imposes limits and barriers to specialist inhabitants. We aim to assess the effects of this habitat distribution on divergence across two independently flightless ground beetle lineages, in the genera Dyscolus and Dercylus. METHODS: One nuclear and one mitochondrial gene from 110 individuals from 10 sites across the two lineages were sequenced and analyzed using a combination of phylogenetics, population genetic analyses, and niche modeling methods. RESULTS: The two lineages show different degrees of population subdivision. Low levels of gene flow were found in Dyscolus alpinus, where one dominant haplotype is found in four out of the six populations analyzed for both molecular markers. However, complete population isolation was revealed in species of the genus Dercylus, where high levels of differentiation exist at species and population level for both genes. Maximum entropy models of species in the Dercylus lineage show overlapping distributions. Still, species distributions appear to be restricted to small areas across the Andes. CONCLUSION: Even though both beetle lineages are flightless, the dispersal ability of each beetle lineage appears to influence the genetic diversity across fragmented páramo populations, where Dyscolus alpinus appears to be a better disperser than species in the genus Dercylus.
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The genus Eurhoptus LeConte, 1876 is revised for America north of Mexico. Eight species are recognized including E.pyriformis LeConte, 1876, E.sordidus (LeConte, 1876), E.curtus (Hamilton, 1893), resurrected name, and five new species as follows: E.rileyi new species (type locality, Texas, Hidalgo County, Bentsen Rio Grande State Park), E.imbricatus new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.cariniventris new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.occidentalis new species (type locality, Texas, Brewster County, Big Bend National Park), and E.aenigmaticus new species (type locality, Alabama, Winston County, Bankhead National Forest). Descriptions or redescriptions, and images of taxonomically important structures are presented for all species. A key to the eight species is included.
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We describe a new genus and species of Histeridae from Upper Cretaceous Burmese amber, Amplectister tenax Caterino & Maddison, gen. & sp. n. This species represents the third known Cretaceous histerid, which, like the others, is highly distinct and cannot easily be placed to subfamily. It exhibits prosternal characters in common with Saprininae, but other characters appear inconsistent with this possibility. The abdominal venter is strongly concave, and the hind legs are enlarged and modified for grasping. We hypothesize that this represents the earliest example in Histeridae of modifications for phoresy on social insects.
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The Transverse Ranges in southern California have been identified as having a prominent phylogeographic role. Numerous studies have identified distinct north-south and/or east-west lineage breaks involving the Transverse Ranges. However, in evaluating their findings, most authors have regarded this complex system somewhat simplistically. In this study we more deeply investigate these breaks using two approaches: first we examine the phylogeographic history of Sepedophilus castaneus (Coleoptera: Staphylinidae) and then implement a comparative phylogeography approach applying Brooks parsimony analysis to the topologies of nine additional taxa. Phylogenetic analysis, nested clade analysis, and AMOVAs for S. castaneus agree that there is a major lineage break between the eastern and western Transverse Ranges, localized between the Sierra Pelona and the San Gabriel Mountains. The comparative phylogeographic analysis supports a generally strong concordance of area relationships with geographic proximity. It is notable, however, that the Transverse Ranges as a group do not show phylogenetic cohesion, but rather they are split into three main regions: an eastern region (San Gabriel, San Bernardino, and San Jacinto Mountains), a central region (central Transverse Ranges and Sierra Pelona) that is often grouped with the Tehachapi and Sierra Nevada populations, and a western region (northwestern Transverse Ranges and Santa Ynez Mountains) that is consistently grouped with coast range areas to the north. The lineage break between east and west Transverse Ranges is attributable to the presence of a marine embayment in what is now the Santa Clara River valley 5-2.5 million years ago.