The subterranean genus Niphargus (Crustacea, Amphipoda) in the Middle East: A faunistic overview with descriptions of two new species

The Middle East is at the southeastern borderline of the range of the subterranean amphipod Niphargus. The review of new and published data identified two new species and set the guidelines for the future research in the area. The genus in this part of the world seems to be insufficiently studied. The taxonomic status of Niphargus valachicus, population identified as N. spoeckeri and some populations, identified as N. nadarini, need to be reviewed. According to present data, we expect the highest diversity in Western Turkey. The eventual new records of the genus in the Middle East can be expected from those areas where even the longest periods of drought in the recent geological history did not affect the water supply.     

ECOMORPHOLOGICAL CONVERGENCE OF CAVE COMMUNITIES

Extreme selective environments are commonly believed to funnel evolution toward a few predictable outcomes. Caves are well‐known extreme environments with characteristically adapted faunas that are similar in appearance, physiology, and behavior all over the world, even if not closely related. Morphological diversity between closely related cave species has been explained by difference in time since colonization and different ecological influence from the surface. Here, we tested a more classical hypothesis: morphological diversity is niche‐based, and different morphologies reflect properties of microhabitats within caves. We analyzed seven communities with altogether 30 species of the subterranean amphipod (crustacean) genus Niphargus using multivariate morphometrics, multinomial logit models cross‐validation, and phylogenetic reconstruction. Species clustered into four distinct ecomorph classes—small pore, cave stream, cave lake, and lake giants—associated with specific cave microhabitats and of multiple independent phylogenetic origins. Traits commonly regarded as adaptations to caves, such as antenna length, were shown to be related to microhabitat parameters, such as flow velocity. These results demonstrate that under the selection pressure of extreme environment, the ecomorphological structure of communities can converge. Thus, morphological diversity does not result from adaptive response to temporal and ecological gradients, but from fine‐level niche partitioning.     

Taxonomic,phylogenetic and ecological diversity of Niphargus (Amphipoda: Crustacea) in the Hölloch cave system (Switzerland)

Groundwater belongs to the spatially most extensive, but least explored freshwater systems. On a global scale, the species richness of several subterranean invertebrate taxa parallels species richness found in surface waters, while on a local scale species richness hardly exceeds 20 species. This results in a high contribution of groundwater ecosystems to regional β- and γ-diversity, and to a smaller degree to α-diversity, and deserves focused attention. In general, more species are to be found in large cave systems. The second largest cave system in Europe is Hölloch in Switzerland. In this paper we revised the taxonomic, phylogenetic and ecological diversity of the amphipod community in the Hölloch cave system. While previous records listed five geographically widespread species of the genus Niphargus for this cave system, we could not confirm the presence of any of those species, but rather found three highly distinct species new to science. In this paper we describe Niphargus styx sp. nov., Niphargus murimali sp. nov., and Niphargus muotae sp. nov., and suggest that previous records from that cave were probably misidentifications. Although amphipod species richness in this cave system seems to be lower than previously thought in terms of absolute numbers, the cave retained its regional and international importance in terms of nature conservation for multiple reasons. First, all newly described species are probably endemic to this cave system. Second, they are phylogenetically distantly related and exhibit moderate to high phylogenetic diversity. Third, the species, as inferred from their functional morphology, are also ecologically highly divergent. Based on geographic distribution of their nearest relatives, we hypothesize that the cave system was most likely independently colonized from North, West and South and that the pre-adapted ancestors occupied different ecological niches within the system.

http://zoobank.org/urn:lsid:zoobank.org:pub:A19309E5-C06B-4844-A4D8-7571F05F25C9     

Can heterochrony help explain the high morphological diversity within the genus Niphargus (Crustacea: Amphipoda)?

Postembryonic development of nine species of Niphargus (Crustacea: Amphipoda) was studied, with spine development and shifts in allometric growth being combined in developmental sequences that were compared across species. The developmental sequences show high diversity with respect to the position of individual events in the sequence, as well as a high frequency of events being inapplicable in some species. Within Niphargus, the highest degree of independence between events occurs mainly in early mid-aged instars, where the shifts in position are both the largest in magnitude and also the most frequent in occurrence. Constructive troglomorphic features of subterranean species were inferred to develop more because of accelerated growth rather than a delayed offset of growth. Shifts in both relative timing and growth rate appeared to have played a role in the evolution of sexually dimorphic elongated appendages. Growth patterns differed greatly between species for individual sexually dimorphic and troglomorphic traits, hinting at their possible independent origin. The independence between developmental events that was generally apparent might indicate the existence of an important genetic basis for the extreme intrageneric morphological variation arising from numerous highly variable body parts being combined in a ‘mosaic’ manner. Moreover, we suggest that the overall diversity of the genus might actually be underestimated in light of possible convergent features accompanied by ‘cryptic’ speciation. We conclude that both sequential and growth heterochrony appear to have played a key role in the evolution of Niphargus, the most diverse genus of freshwater amphipods. A preliminary list of heterochronic characters is provided.     

Comparative study of electron transport system activity and oxygen consumption of amphipods from caves and surface habitats

1. Respiratory electron transport system (ETS) activity and oxygen consumption were measured at 10 °C for the hypogean amphipods Niphargus stygius (from two epikarst locations) and N. krameri (from a sinking river in a cave) and the epigean amphipod Gammarus fossarum (inhabiting a spring and a river). 2. ETS activity and oxygen consumption were compared between caves and the two surface locations, and between hypogean and epigean amphipods. ETS activities were found not to differ between animals from different locations, or between epigean and hypogean amphipods. As expected, the oxygen consumption of N. krameri and N. stygius was lower than that of G. fossarum. 3. The high ratio between ETS activity and oxygen consumption (ETS/R ratio) showed that N. krameri and N. stygius possess high metabolic potential that can be exploited for energy recovery and rapid restoration of body reserves immediately following the appearance of favourable conditions (food and/or oxygen). In contrast, G. fossarum exhibited a low ETS/R ratio, indicating exploitation of a great proportion of the metabolic potential for standard metabolism. 4. Feeding in N. stygius increased oxygen consumption but not ETS activity, and thus fed N. stygius had a much lower ETS/R ratio than starved ones. 5. A relatively high metabolic potential (i.e. high ETS/R ratio) may be an adaptation to hypogean life in amphipods, in that it improves survival under poor food and/or oxygen conditions.     

Taxonomy and biogeography of <Emphasis Type="Italic">Niphargus steueri</Emphasis> (Crustacea: Amphipoda)

Niphargus steueri (Niphargidae) comprises a complex of four subspecies (N. s. steueri, N. s. kolombatovici, N. s. subtypicus, and N. s. liburnicus), the morphology and distribution of which have been poorly known until now. New diagnostic characters of the species and its four subspecies are presented and illustrated. The species is distributed along the major part of the Dinaric Karst, between Slovenia in the northwest and Bosnia and Herzegovina in the southeast. The distribution of the four subspecies approximately resembles the distribution of the evolutionary lineages of the subterranean amphibian Proteus anguinus and the Dinaric lineage of the cave shrimp Troglocaris agg. anophthalmus. Niphargus s. steueri is restricted to the Istran Peninsula; N. s. subtypicus is distributed in southeast Slovenia and northwest Croatia; N. s. liburnicus is known from two disjunctive localities, one on the island of Krk (Croatia) and the other in Gorizia (Italy); and N. s. kolombatovici is restricted to Dalmacija and Herzegovina. The somewhat variable putative synapomorphies of N. steueri probably suggest that the group is old and that the present distribution pattern is a result of historical events, possibly events in the Miocene Dinaride Lake system. Two populations of N. s. kolombatovici and one population of N. s. subtypicus deviate from the general distributional pattern and may belong to cryptic taxa that cannot be distinguished on the basis of morphology. Both hypotheses corroborate with the estimated times of divergence and with the number of independent lineages in the similarly distributed but unrelated stygobionts Proteus and Troglocaris.     

The effect of light on oxygen consumption in two amphipod crustaceans-the hypogean Niphargus stygius and the epigean Gammarus fossarum

The effects of light on the metabolic rates of the hypogean amphipod Niphargus stygius and the epigean amphipod Gammarus fossarum were compared by measuring oxygen consumption and respiratory electron transport system (ETS) activity. They were exposed to light intensities of 720 and 4700 lx at 10°C. Oxygen consumption increased significantly in N. stygius exposed to both low and high intensities of light, but no significant increase was observed in G. fossarum at either intensity. The increase of oxygen consumption in N. stygius was significantly greater at the higher light intensity. This indicates a stress response in which exploitation of half the metabolic potential for energy production in N. stygius during exposure to high light intensity constitutes an adverse effect on its metabolism, since this species usually uses less than 25% of its total metabolic potential for standard metabolic demands.     

A gradient of interstitial Niphargus rhenorhodanensis populations in two karst/floodplain transition zones of the French Jura

The Bou-Rouch technique was used to sample two small alluvial plains in two different karst areas. One was mainly supplied by karst water (Verna), the other by both karst and surface water (Pissoir).Physical and chemical characteristics varied with time (seasons) and location of sampling sites at both stations.The distribution of Niphargus rhenorhodanensis populations was influenced by the geographical characteristics of the outlets. Only a small number of individuals was found near the outlet and none in the floodplain when the outlet was located at a base-level (Verna). Individuals were more numerous and their presence constant at all sites and dates when the outlet was located at the overflow level of the massif (Pissoir).     

Revision of the genus Chalcasthenes Arrow (Coleoptera: Scarabaeidae: Dynastinae: Oryctoderini) from the Solomon Islands

The genus Chalcasthenes Arrow (Dynastinae: Oryctoderini), a scarab beetle genus endemic to the Solomon Islands, is reviewed. Based on examination of type specimens, the genus Strehlia Frey (Rutelinae: Rutelini: Parastasiina) is a new junior synonym of Chalcasthenes . The historical classification of these genera (either in the subfamily Dynastinae or Rutelinae) and character-based criteria for assigning the taxa to the Dynastinae are provided. We discuss character states that support the monophyly of members of the genus Chalcasthenes, comment on the distribution and biogeography of species in the genus and provide a key to species. The genus includes four species: Chalcasthenes divinus Endrödi, Chalcasthenes pulcher Arrow, Chalcasthenes squamigerus Frey new combination and Chalcasthenes styracoceros Jameson and Ratcliffe n. sp. Species hypotheses are corroborated based on evidence from Pleistocene geological reconstructions of the Solomon Islands, geographic variation of bird species in the region and development in scarab beetles.     

BSD: the Biodegradative Strain Database

The Biodegradative Strain Database (BSD) is a freely-accessible, web-based database providing detailed information on degradative bacteria and the hazardous substances that they degrade, including corresponding literature citations, relevant patents and links to additional web-based biological and chemical data. The BSD (http://bsd.cme.msu.edu) is being developed within the phylogenetic framework of the Ribosomal Database Project II (RDPII: http://rdp.cme.msu.edu/html) to provide a biological complement to the chemical and degradative pathway data of the University of Minnesota Biocatalysis/Biodegradation Database (UM-BBD: http://umbbd.ahc.umn.edu). Data is accessible through a series of strain, chemical and reference lists or by keyword search. The web site also includes on-line data submission and user survey forms to solicit user contributions and suggestions. The current release contains information on over 250 degradative bacterial strains and 150 hazardous substances. The transformation of xenobiotics and other environmentally toxic compounds by microorganisms is central to strategies for biocatalysis and the bioremediation of contaminated environments. However, practical, comprehensive, strain-level information on biocatalytic/biodegradative microbes is not readily available and is often difficult to compile. Similarly, for any given environmental contaminant, there is no single resource that can provide comparative information on the array of identified microbes capable of degrading the chemical. A web site that consolidates and cross-references strain, chemical and reference data related to biocatalysis, biotransformation, biodegradation and bioremediation would be an invaluable tool for academic and industrial researchers and environmental engineers.     

Root:soil adhesion in the maize rhizosphere: the rheological approach

This study was designed to investigate the strength of attachment of plant seedling roots to the soil in which they were grown. The study also assessed the effects of differing soil textures and differing soil matric potentials upon the strength of the root:soil attachment. A device for growing roots upon a soil surface was designed, and was used to produce roots which were attached to the soil. In order to quantify root:soil adhesion, roots of maize seedlings, grown on the soil surface, were subsequently peeled off using a universal test machine, in conjunction with simultaneous time-lapse video observation. To clarify the partitioning of energy in the root:soil peeling test, separate mechanical tests on roots, and on two adherent remoulded topsoil balls were also carried out. The seedling root was characterised by a low bending stiffness. The energy stored in bending was negligible, compared to the root:soil adhesion energy. The mechanical properties of two adherent remoulded topsoil balls were a decrease of the soil:soil adhesion energy as the soil:soil plastic energy increased. These two parameters were therefore interdependent. Using a video-camera system, it was possible to separate the different processes occurring during the root:soil peeling test, in particular, the seed:soil adhesion and the root:soil soil adhesion. An interpretation of the complex and variable force:displacement curves was thus possible, enabling calculation of the root:soil interfacial rupture energy. At a given suction (10 kPa), the results of the peeling test showed a clear soil texture effect on the value of the root:soil interfacial rupture energy. In contrast, for the same silty topsoil, the effect of the soil water suction on the value of the interfacial rupture energy was very moderate. The root:soil interfacial rupture energy was controlled mainly by a product of microscopic soil specific surface area and the macroscopic contact surface area between the root and the soil. Biological and physical interactions contributing to root:soil adhesion such as root:soil interlocking mechanics were also analysed and discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Molecular dynamics simulations of the Ras:Raf and Rap:Raf complexes

The protein Raf is an immediate downstream target of Ras in the MAP kinase signalling pathway. The complex of Ras with the Ras-binding domain (RBD) of Raf has been modelled by homology to the (E30D,K31E)-Rap1A:RBD complex, and both have been subjected to multiple molecular dynamics simulations in solution. While both complexes are stable, several rearrangements occur in the Ras:RBD simulations: the RBD loop 100-109 moves closer to Ras, Arg73 in the RBD moves towards Ras to form a salt bridge with Ras-Asp33, and Loop 4 of the Ras switch II region shifts upwards toward the RBD. The Ras:RBD interactions (including the RBD-Arg73 interaction) are consistent with available NMR and mutagenesis data on the Ras: RBD complex in solution. The Ras switch II region does not interact directly with the RBD, although indirect interactions exist through the effector domain and bridging water molecules. No large-scale RBD motion is seen in the Ras:RBD complex, compared to the Rap:RBD complex, to suggest an allosteric activation of Raf by Ras. This may be because the Raf kinase domain (whose structure is unknown) is not included in the model.     

Transposon mutagenesis of the anaerobic commensal, Bacteroides fragilis, using the EZ::TN5 transposome

Genetic analysis of Bacteroides fragilis (BF) is hindered because of the lack of efficient transposon mutagenesis methods. Here, we describe a simple method for transposon mutagenesis using EZ::TN5, a commercially available system that we optimized for use in BF638R. The modified EZ::TN5 transposon contains an Escherichia coli conditional origin of replication, a kanamycin resistance gene for E. coli, an erythromycin resistance gene for BF , and 19 basepair transposase recognition sequences on either ends. Electroporation of the transposome (transposon-transposase complex) into BF638R yielded 3.2 ± 0.35 × 10(3) CFU μg(-1) of transposon DNA. Modification of the transposon by the BF638R restriction/modification system increased transposition efficiency sixfold. Electroporation of the EZ::TN5 transposome results in a single-copy insertion of the transposon evenly distributed across the genome of BF638R and can be used to construct a BF638R transposon library. The transposon was also effective in mutating a BF clinical isolate and a strain of the related species, Bacteroides thetaiotaomicron. The EZ::TN5-based mutagenesis described here is more efficient than other transposon mutagenesis approaches previously reported for BF.     

Afp::mCherry, a red fluorescent transgenic reporter of the mouse visceral endoderm

Live imaging of genetically encoded fluorescent protein reporters is increasingly being used to investigate details of the cellular behaviors that underlie the large-scale tissue rearrangements that shape the embryo. However, the majority of mouse fluorescent reporter strains are based on the green fluorescent protein (GFP). Mouse reporter strains expressing fluorescent colors other than GFP are therefore valuable for co-visualization studies with GFP, where relative positioning and relationship between two different tissues or compartments within cells are being investigated. Here, we report the generation and characterization of a transgenic Afp::mCherry mouse strain in which cis-regulatory elements from the Alpha-fetoprotein (Afp) locus were used to drive expression of the monomeric Cherry red fluorescent protein. The Afp::mCherry transgene is based on and recapitulates reporter expression of a previously described Afp::GFP strain. However, we note that perdurance of mCherry protein is not as prolonged as GFP, making the Afp::mCherry line a more faithful reporter of endogenous Afp expression. Afp::mCherry transgenic mice expressed mCherry specifically in the visceral endoderm and its derivatives, including the visceral yolk sac, gut endoderm, fetal liver, and pancreas of the embryo. The Afp::mCherry reporter was also noted to be expressed in other documented sites of Afp expression including hepatocytes as well as in pancreas, digestive tract, and brain of postnatal mice.     

Re-examining the Manning hypothesis: androgen receptor polymorphism and the 2D:4D digit ratio

The ‘Manning hypothesis,’ the idea that small differences in the ratio of the lengths of the human second to fourth digits—the 2D:4D ratio—reflect differences in the level of fetal androgen exposure, has been highly influential in the biological and biobehavioral sciences. The ratio is widely used to investigate the involvement of fetal androgens in the differentiation of sexually dimorphic traits. The validity of such studies is based on the premise that individual differences in the size of the 2D:4D ratio mirror differences across individuals in developmental levels of androgen exposure in a dose-dependent manner. Despite its widespread adoption by researchers, clinical evidence has yet to confirm that individual gradation in the ratio denotes differences in testosterone action. Key support for the view that 2D:4D does, in fact, reflect fetal testosterone in a graded fashion is the finding, based on a single small-sample study, that the magnitude of 2D:4D covaries with a polymorphic repeat (CAG) sequence in exon 1 of the gene coding the androgen receptor, AR. In a larger independent sample, we reexamine this genetic association and fail to substantiate a correlation between AR CAG length and 2D:4D. Combined with other recent reports, these data question one of the fundamental pieces of evidence on which the Manning hypothesis rests and raise new issues regarding the extent to which 2D:4D is a valid reflection of differences in fetal testosterone action in normally developing individuals.     

Cladispa Baly: revision,biology and reassignment of the genus to the tribe Spilophorini (Coleoptera: Chrysomelidae: Cassidinae)

The genus, Cladispa Baly 1858, is transferred from the tribe Imatidiini (= Cephaloleiini Chapuis, 1875) to Spilophorini Chapuis, 1875 based on the review of type material, newly collected specimens and molecular phylogenetic analysis. The type species, C. quadrimaculata Baly, 1858, is redescribed, and two new species, C. amboroensis sp.n. from Bolivia (Santa Cruz Department) and C. ecuadorica sp.n. from Ecuador (Pastaza Province), are described and figured. The morphology of C. amboroensis sp.n. immature stages is broadly consistent with other Spilophorini. Field observations document that both C. quadrimaculata and C. amboroensis sp.n. are trophic specialists on Orchideaceae. Keys to Cladispa species and Spilophorini genera are provided. Trophic associations of other Cassidinae and Orchideaceae are discussed. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:42A1ECF3‐2030‐4938‐8F3D‐FE7EC36F303A     

The monophyly of the subfamily Perisphaeriinae (Dictyoptera: Blattaria: Blaberidae)

A new definition of the subfamily Perisphaeriinae is given on the basis of five synapomorphies described from male and female genitalia and head morphology. The subfamily comprises eighteen genera: Bantua , Compsagis , Cyrtotria , Derocalymma , Ellipsica , Elliptoblatta , Gymnonyx , Hostilia , Laxta , Neolaxta , Perisphaeria , Perisphaerus , Pilema , Platysilpha , Poeciloblatta , Pseudoglomeris , Trichoblatta , Zuluia . Two genera are newly assigned to the Perisphaeriinae: Laxta and Neolaxta . Four genera are removed from the Perisphaeriinae: Aptera , Blepharodera , Eustegasta , Isoniscus . One new generic synonymy is proposed: Pronaonota as a synonym of Pilema . The subfamily has a large geographical range including tropical Africa, the Arabian Peninsula, Asia and Australia.