The Fossil Calibration Database—A New Resource for Divergence Dating

Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important—often least appreciated—step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be difficult for nonspecialists to formulate. The dynamic nature of the fossil record (e.g., new discoveries, taxonomic revisions, updates of global or local stratigraphy) requires that calibration data be updated continually lest they become obsolete. Here, we announce the Fossil Calibration Database (http://fossilcalibrations.org), a new open-access resource providing vetted fossil calibrations to the scientific community. Calibrations accessioned into this database are based on individual fossil specimens and follow best practices for phylogenetic justification and geochronological constraint. The associated Fossil Calibration Series, a calibration-themed publication series at Palaeontologia Electronica, will serve as a key pipeline for peer-reviewed calibrations to enter the databas

The Fossil Calibration Database, A New Resource for Divergence Dating

Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important, and often least appreciated, step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be difficult for non- specialists to formulate. The dynamic nature of the fossil record (e.g., new discoveries, taxonomic revisions, updates of global or local stratigraphy) requires that calibration data be updated continually lest they become obsolete. Here, we announce the Fossil Calibration Database (http://fossilcalibrations.org), a new open- access resource providing vetted fossil calibrations to the scientific community. Calibrations accessioned into this database are based on individual fossil specimens and follow best practices for phylogenetic justification and geochronological constraint. The associated Fossil Calibration Series, a calibration-themed publication series at Palaeontologia Electronica, will serve as one key pipeline for peer-reviewed calibrations to enter the database

Brachial plexus block: Comparison of two different doses of clonidine added to bupivacaine

Background: The role of clonidine as an adjuvant to local anesthetic agents in brachial plexus block (BPB) has been extensively studied. However, till date there has been no consensus about the ideal dose of clonidine for this purpose. This study was carried out to evaluate two doses of clonidine-1 and 2 g/kg, added to 0.5% bupivacaine, with regard to onset and duration of sensorimotor blockade, hemodynamic effects, postoperative analgesia, and adverse effects. Materials and Methods: Sixty adult patients undergoing upper limb surgeries were randomly allocated into two groups. Thirty patients received 1 g/kg clonidine (group I) and the rest received 2 g/kg clonidine (group II) added to 30 mL of 0.5% bupivacaine through nerve stimulator-guided supraclavicular BPB. The onset and duration of sensorimotor blockade, hemodynamic variables, duration of analgesia, level of sedation, and adverse effects was assessed. Results: The onset of sensorimotor block was earlier in group II (9.9 ± 4.1 min for sensory block and 13.2 ± 6.7 min for motor block) than in group I (15.9 ± 6.8 min for sensory block and 18.5 ± 7.8 min for motor block). The duration of analgesia was also prolonged in patients receiving the higher dose (21.0 ± 2.96 h vs. 14.9 ± 3.0 h). Although hemodynamics remained comparable in both the groups, incidence of hypotension and bradycardia was higher in group II as compared to group I. The sedation was clinically and statistically more in group II patients (43% vs. 17%). Conclusion: Higher dose of clonidine in BPB hastens the onset, prolongs the duration of sensorimotor blockade and postoperative analgesia without significant hemodynamic alterations. It also causes more sedation, which although ensures patient comfort in most cases, but might be undesirable in certain situations

Topological support and data quality can only be assessed through multiple tests in reviewing Blattodea phylogeny

International audienc

Phytotoxicity of a medicinal plant, Anisomeles indica, against Phalaris minor and its potential use as natural herbicide in wheat fields

Anisomeles indica (Catmint; Lamiaceae) is an aromatic plant with a wide range of medicinal properties. In the search of new methods of weed management, we assessed A. indica for potential inhibitory activity against P. minor and other weeds of the wheat crop. A. indica leaf and root powder applied as mulch at 1 and 2 t ha-1 significantly reduced the emergence and growth of P. minor and other weeds of wheat crop similar to herbicide, without any negative effect on the wheat growth and yield. At 2 t ha-1 dose of root powder mulch of A. indica, there was an enhancement in the grain yield of wheat and suppression of weeds under natural field conditions. The study concludes that mulch of A. indica, a medicinal plant, holds good promise for use as a natural herbicide for managing weeds in wheat fields

Extremely low genetic diversity in a circumpolar dragonfly species, Somatochlora sahlbergi (Insecta: Odonata: Anisoptera)

We present the first empirical treatment of the northernmost breeding dragonfly, Somatochlora sahlbergi. We sequenced populations from United States, Canada, Finland, Sweden and Norway for cytochrome oxidase I (COI) and D2 region of 28s. We found that, despite geographic barriers across its vast arctic range, S. sahlbergi is a single species. Not only does it appear to interbreed across its entire range, there also seems to be almost no variation among European and North American populations in their COI gene fragment (the barcode gene), which is usually extremely variable. We further found that characters thought to be diagnostic for the larvae of S. sahlbergi were absent in our European samples. We review and re-describe the habitat of this species based on new findings from recent field observations. Finally, we report for the first time the likely presence of this species in Japan. We hope our findings will encourage further study of this species and other under-studied insect taxa that inhabit the remote Arctic

Comparative phylogeography uncovers evolutionary past of Holarctic dragonflies

Here, we investigate the evolutionary history of five northern dragonfly species to evaluate what role the last glaciation period may have played in their current distributions. We look at the population structure and estimate divergence times for populations of the following species: Aeshna juncea (Linnaeus), Aeshna subarctica Walker, Sympetrum danae (Sulzer), Libellula quadrimaculata Linnaeus and Somatochlora sahlbergi Trybom across their Holarctic range. Our results suggest a common phylogeographic pattern across all species except for S. sahlbergi. First, we find that North American and European populations are genetically distinct and have perhaps been separated for more than 400,000 years. Second, our data suggests that, based on genetics, populations from the Greater Beringian region (Beringia, Japan and China) have haplotypes that cluster with North America or Europe depending on the species rather than having a shared geographic affinity. This is perhaps a result of fluctuating sea levels and ice sheet coverage during the Quaternary period that influenced dispersal routes and refugia. Indeed, glacial Beringia may have been as much a transit zone as a refugia for dragonflies. Somatochlora sahlbergi shows no genetic variation across its range and therefore does not share the geographic patterns found in the other circumboreal dragonflies studied here. Lastly, we discuss the taxonomic status of Sympetrum danae, which our results indicate is a species complex comprising two species, one found in Eurasia through Beringia, and the other in North America east and south of Beringia. Through this study we present a shared history among different species from different families of dragonflies, which are influenced by the climatic fluctuations of the past. Copyright 2021 Kohli et al.Funsing: Manpreet Kohli received funding from the Systematic Research Fund, 2017 funded by Linnaean Society of London. Manpreet Kohli also received funds from Theodore Roosevelt Memorial Fund, 2017 funded American Museum of Natural History. Thomas J Simonsen, Marie Djernæs and Kent Olsen received funding from the research fund under the Danish Ministry for Culture (grant: FORM.2015-0023), 15 June Foundation (grant: 2015-A-89), The SYNTHESYS program under the EU Commission (grant: SE-TAF-5543). Jessica Ware received funding from National Science Foundation grant #1564386.</p