The worldwide distribution and extensive genetic diversity of the whitefly,Bemisia tabaci,has long been recognized.However,the levels of separation within B.tabaci and the nomenclature of the various ...genetic groups have been a subject of debate.Recent phylogenetic analyses indicate that B.tabaci is a complex composed of 28 morphologically indistinguishable species.In this article,we first review the debate and difficulties associated with B.tabaci＇s taxonomy and systematics,and argue for the need to apply the biological species concept in order to elucidate B.tabaci＇s systematics.We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B.tabaci.Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs,and observations on mating behaviour have been conducted for seven species pairs.Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species.We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility.Finally,we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B.tabaci groups and propose future research directions on the systematics of this complex.
In this chapter, we review and update current knowledge about the evolution, systematics, and biogeography of the Triatominae (Hemiptera: Reduviidae)-true bugs that feed primarily on vertebrate ...blood. In the Americas, triatomines are the vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Despite declining incidence and prevalence, Chagas disease is still a major public health concern in Latin America. Triatomines occur also in the Old World, where vector-borne T. cruzi transmission has not been recorded. Triatomines evolved from predatory reduviid bugs, most likely in the New World, and diversified extensively across the Americas (including the Caribbean) and in parts of Asia and Oceania. Here, we first discuss our current understanding of how, how many times, and when the blood-feeding habit might have evolved among the Reduviidae. Then we present a summary of recent advances in the systematics of this diverse group of insects, with an emphasis on the contribution of molecular tools to the clarification of taxonomic controversies. Finally, and in the light of both up-to-date phylogenetic hypotheses and a thorough review of distribution records, we propose a global synthesis of the biogeography of the Triatominae. Over 130 triatomine species contribute to maintaining T. cruzi transmission among mammals (sometimes including humans) in almost every terrestrial ecoregion of the Americas. This means that Chagas disease will never be eradicated and underscores the fact that effective disease prevention will perforce require stronger, long-term vector control-surveillance systems.
Despite recent advances in molecular phylogenetic studies, deep evolutionary relationships in Cyperaceae are still not entirely resolved. Reduction of floral morphology and complex inflorescences ...pose difficulties to unravel relationships based on morphology alone. One of the most phylogenetically informative structures in Cyperaceae are the embryos. The utility of embryo characters and types in Cyperaceae systematics is reviewed in a molecular phylogenetic context using a DNA supermatrix incorporating sequences from five plastid (
mat
K,
ndh
F,
rbc
L,
rps
16,
trn
L-F) and two nuclear ribosomal (ETS, ITS) regions. The phylogenetic hypothesis presented includes the most extensive sampling of the family to date. Fourteen qualitative morphological embryo characters were coded, ancestral state reconstructions were performed, and the embryo of each sampled genus was classified in a typological system based on key morphological features. Embryo morphology provides a valuable source of independent data for Cyperaceae systematics that can be used to place species with unknown affinities, when molecular data is not available, or when results of analyses are inconclusive or conflicting. Integrating embryo data will remain critical for future higher level studies of Cyperaceae evolution and classification.
We present a new cosmological probe for galaxy clusters, the halo sparsity. This characterizes halos in terms of the ratio of halo masses measured at two different radii and carries cosmological ...information encoded in the halo mass profile. Building on the work of Balmes et al., we test the properties of the sparsity using halo catalogs from a numerical N-body simulation of (2.6 Gpc h−1)3 volume with 40963 particles. We show that at a given redshift the average sparsity can be predicted from prior knowledge of the halo mass function. This provides a quantitative framework to infer cosmological parameter constraints using measurements of the sparsity of galaxy clusters. We show this point by performing a likelihood analysis of synthetic data sets with no systematics, from which we recover the input fiducial cosmology. We also perform a preliminary analysis of potential systematic errors and provide an estimate of the impact of baryonic effects on sparsity measurements. We evaluate the sparsity for a sample of 104 clusters with hydrostatic masses from X-ray observations and derive constraints on the cosmic matter density m and the normalization amplitude of density fluctuations at the 8 Mpc h−1 scale, 8. Assuming no systematics, we find m = 0.42 0.17 and 8 = 0.80 0.31 at 1 , corresponding to . Future cluster surveys may provide opportunities for precise measurements of the sparsity. A sample of a few hundred clusters with mass estimate errors at the few percent level can provide competitive cosmological parameter constraints complementary to those inferred from other cosmic probes.
Current status of annelid phylogeny Weigert, Anne; Bleidorn, Christoph
Organisms diversity & evolution,
06/2016, Letnik:
16, Številka:
2
Journal Article
Recenzirano
Annelida is an ecologically and morphologically diverse phylum within the Lophotrochozoa whose members occupy a wide range of environments and show diverse life styles. The phylogeny of this group ...comprising more than 17,000 species remained controversial for a long time. By using next-generation sequencing and phylogenomic analyses of huge data matrices, it was finally possible to reach a well-supported and resolved annelid backbone tree. Most annelid diversity is comprised in two reciprocal monophyletic groups, Sedentaria and Errantia, which are named after the predominant life style of their members. Errantia include Aciculata (Phyllodocida + Eunicida) and Protodriliformia, which is a taxon of interstitial polychaetes. Sedentaria comprise most of the polychaete families formerly classified as Canalipalpata or Scolecida, as well as the Clitellata. Six taxa branch as a basal grade outside of this major radiation: Oweniidae, Magelonidae, Chaetopteridae, Sipuncula, Amphinomida, and Lobatocerebrum. Oweniidae and Magelonidae form a monophyletic group which we name Palaeoannelida, which constitutes the sister taxon of the remaining annelids. The early splits of annelid phylogeny date back to the Cambrian. The new annelid phylogeny highlights the variability and lability of annelid body plans, and many instances of simplifications of body plan as adaptations to new life styles can be found. Therefore, annelids will be an appropriate model to understand major transitions in the evolution of Bilateria in general. Evolutionary developmental studies are one way to investigate macroevolutionary transition in annelids. We briefly summarize the state of developmental model organisms in Annelida and also propose new candidates on the background of the phylogeny.
Opisthobranchia have experienced an unsettled taxonomic history. At the moment their taxonomy is in state of dramatic flux as recent phylogenetic studies have revealed traditional Opisthobranchia to ...be paraphyletic or even polyphyletic, allocating some traditional opisthobranch taxa to other groups of Heterobranchia, e.g. Pulmonata. Here we review the history of Opisthobranchia and their subgroups, explain their traditionally proposed relationships, and outline the most recent phylogenetic analyses based on various methods (morphology, single gene and multiple gene analyses, as well as genomic data). We also present a phylogenetic hypothesis on Heterobranchia that, according to the latest results, represents a consensus and is the most probable one available to date. The proposed phylogeny supports the Acteonoidea outside of monophyletic Euthyneura, the basal euthyneuran split into Nudipleura (Nudibranchia plus Pleurobranchoidea) and the recently established taxon Tectipleura. The latter divides into the Euopisthobranchia, containing most of the major traditional opisthobranch clades, and the Panpulmonata, with a mix of the former opisthobranch, putative allogastropod and pulmonate taxa. This “new euthyneuran tree” rejects the traditional taxa Opisthobranchia and Pulmonata, and, in particular, has profound implications for preconceived textbook scenarios of opisthobranch and pulmonate evolution, which must now be reconsidered. In the absence of systematic barriers, research communities—which have traditionally investigated marine and non-marine heterobranchs separately—need to interact and finally merge for the sake of science.
Process mining allows analysts to exploit logs of historical executions of business processes to extract insights regarding the actual performance of these processes. One of the most widely studied ...process mining operations is automated process discovery. An automated process discovery method takes as input an event log, and produces as output a business process model that captures the control-flow relations between tasks that are observed in or implied by the event log. Various automated process discovery methods have been proposed in the past two decades, striking different tradeoffs between scalability, accuracy, and complexity of the resulting models. However, these methods have been evaluated in an ad-hoc manner, employing different datasets, experimental setups, evaluation measures, and baselines, often leading to incomparable conclusions and sometimes unreproducible results due to the use of closed datasets. This article provides a systematic review and comparative evaluation of automated process discovery methods, using an open-source benchmark and covering 12 publicly-available real-life event logs, 12 proprietary real-life event logs, and nine quality metrics. The results highlight gaps and unexplored tradeoffs in the field, including the lack of scalability of some methods and a strong divergence in their performance with respect to the different quality metrics used.
Coded distributed computing is used to mitigate the adverse effect of slow workers on the computation time in distributed computing systems. However, using error-correction codes results in encoding ...and decoding delays. In this work, we consider a systematic maximum-distance separable (MDS) coded matrix-vector multiplication problem with multi-message communication (MMC), where the master assigns multiple sub-tasks to each worker. In this setup, we show that the received systematic outputs can be used to reduce the decoding time by implementing a proper decoding algorithm. To further reduce the decoding time, we use the MMC property that sub-tasks are executed sequentially to propose an allocation of the systematic sub-tasks that significantly increases the number of received systematic outputs. Our results further demonstrate that the reduction in the decoding time is even more significant in applications that require only a partial recovery. In these applications, it suffices to complete a certain percentage of the computation, and using our approach, we show that decoding may be completely avoided.
The family Simuliidae includes more than 2000 species of black flies worldwide. Their morphological uniformity creates difficulty for species identification, which limits our knowledge of their ...ecology and vectorial role. We investigated the systematics of black flies in a semi-arid area of the Iberian Peninsula, an ecologically harsh environment for these organisms. Sampling adult black flies in three different habitats (by means of CDC traps) and in avian nest boxes and collecting immature stages in high-salinity rills provided a representative sample of the component species. A combination of approaches, including morphological, chromosomal, and molecular (based on the mitochondrial cytochrome C oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) genes) revealed five species: four common species (Simulium intermedium, S. petricolum, S. pseudequinum, and S. rubzovianum) and the first European record for S. mellah. Barcoding gap and phylogenetic analyses revealed that ITS2 is a key marker to identify the species, whereas the COI marker does not provide enough resolution to identify some species or infer their phylogenetic relationships. Morphological and chromosomal features are also provided to identify S. mellah unequivocally. Our study highlights the need for integrated studies of black flies in ecologically extreme habitats to increase our knowledge of their distribution, ecology, and potential risks for public health.
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