230 research outputs found
A new species and a new record of Nesticus from southeastern Brazil (Araneae: Nesticidae)
Incorporating topological and age uncertainty into event-based biogeography of sand spiders supports paleo-islands in galapagos and ancient connections among neotropical dry forests
Event-based biogeographic methods, such as dispersal-extinction-cladogenesis, have become increasingly popular for attempting to reconstruct the biogeographic history of organisms. Such methods employ distributional data of sampled species and a dated phylogenetic tree to estimate ancestral distribution ranges. Because the input tree is often a single consensus tree, uncertainty in topology and age estimates are rarely accounted for, even when they may affect the outcome of biogeographic estimates. Even when such uncertainties are taken into account for estimates of ancestral ranges, they are usually ignored when researchers compare competing biogeographic hypotheses. We explore the effect of incorporating this uncertainty in a biogeographic analysis of the 21 species of sand spiders (Sicariidae: Sicarius) from Neotropical xeric biomes, based on a total-evidence phylogeny including a complete sampling of the genus. Using a custom R script, we account for uncertainty in ages and topology by estimating ancestral ranges over a sample of trees from the posterior distribution of a Bayesian analysis, and for uncertainty in biogeographic estimates by using stochastic maps. This approach allows for counting biogeographic events such as dispersal among areas, counting lineages through time per area, and testing biogeographic hypotheses, while not overestimating the confidence in a single topology. Including uncertainty in ages indicates that Sicarius dispersed to the Galapagos Islands when the archipelago was formed by paleo-islands that are now submerged; model comparison strongly favors a scenario where dispersal took place before the current islands emerged. We also investigated past connections among currently disjunct Neotropical dry forests; failing to account for topological uncertainty underestimates possible connections among the Caatinga and Andean dry forests in favor of connections among Caatinga and Caribbean + Mesoamerican dry forests. Additionally, we find that biogeographic models including a founder-event speciation parameter (“+J”) are more prone to suffer from the overconfidence effects of estimating ancestral ranges using a single topology. This effect is alleviated by incorporating topological and age uncertainty while estimating stochastic maps, increasing the similarity in the inference of biogeographic events between models with or without a founder-event speciation parameter. We argue that incorporating phylogenetic uncertainty in biogeographic hypothesis-testing is valuable and should be a commonplace approach in the presence of rogue taxa or wide confidence intervals in age estimates, and especially when using models including founder-event speciation.Fil: Fiorini de Magalhaes, Ivan Luiz. Universidade Federal de Minas Gerais; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Santos, Adalberto J.. Universidade Federal de Minas Gerais; BrasilFil: Ramirez, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin
New synonymies and a revalidation in the spider genera Eustala and Micrathena (Araneae: Araneidae)
Sistemas aquosos bifásicos uma ferramenta sustentável para a extração de ácido clavulânico a partir de diferentes fontes
O ácido clavulânico (AC) é um inibidor de β-lactamases que tem vindo a ser largamente utilizado na área médica. Embora seja de extrema importância, o desenvolvimento de processos alternativos de produção e purificação é ainda insignificante, sendo fundamental o estudo de técnicas de extração mais biocompatíveis, como os Sistemas Aquosos Bifásicos (SABs). Assim, este trabalho objetivou o estudo de Sistemas Aquosos Bifásicos baseados em polímeros como uma ferramenta alternativa para a extração de AC. Foram testados dois SPAB compostos por Polietileno Glicol (PEG) com massa molecular (M) de 4000 g/mol e Poliacrilato de Sódio de 8000 g/mol, nos quais foi alterado o eletrólito indutor da formação de fases, em particular, sulfato de sódio (Na2SO4,) e cloreto de sódio (NaCl). Ademais, este trabalho visou também avaliar a eficiência de extração do AC, bem como compreender o efeito dos contaminantes no processo de migração. Para tal, foi avaliada a extração do AC a partir de três fontes distintas: solução pura (99,9%); solução comercial (60%); diretamente a partir do sobrenadante de um meio fermentando de Streptomyces clavuligerus. Os resultados obtidos demonstraram que independentemente da fonte inicial do AC, ambos os SABs poliméricos promoveram uma partição preferencial do AC para a fase rica em PEG, sendo o coeficiente de partição maior nos sistemas com Na2SO4 do que com NaCl. Após identificar a grande capacidade de partição de AC, o SAB com PEG/NaPA/Na2SO4 foi também utilizado para avaliar a partição de proteínas presente no meio fermentado, sendo também obtida uma preferencial partição destas para a fase rica em PEG. Assim, apesar da baixa capacidade de purificação de AC frente a proteínas contaminantes, os SABs estudados demonstraram que podem ser uma técnica alternativa sustentável e bastante econômica para uma etapa inicial de clarificação/concentração de bioprodutos a partir de caldos fermentados
A stable liquid–liquid extraction system for clavulanic acid using polymer-based aqueous two-phase systems
The partitioning of Clavulanic Acid (CA) in a novel inexpensive and stable aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied.
The aqueous two-phase systems are formed by mixing both polymers with a salt (NaCl or Na2SO4) and an aqueous solution of CA. The stability of CA on the presence of both polymers was investigated and
it was observed that these polymers do not degrade the biomolecule. The effect of PEG-molecular size, polymer concentrations on the commercial CA partitioning has been studied, at 25 C. The data showed that commercial CA was preferentially partitioned for the PEG-rich phase with a partition coefficient (KCA) between 1 and 12 in the PEG/NaPA aqueous two phase systems supplemented with NaCl and
Na2SO4. The partition to the PEG phase was increased in the systems with high polymer concentrations.
Furthermore, Na2SO4 caused higher CA preference for the PEG-phase than NaCl. The systems having a composition with 10 wt.% of PEG4000, 20 wt.% of NaPA8000 and 6 wt.% of Na2SO4 were selected as the
optimal ones in terms of recovery of CA from fermented broth of Streptomyces clavuligerus. The partitioning results (KCA = 9.15 ± 1.06) are competitive with commercial extraction methods of CA
(KCA = 11.91 ± 2.08) which emphasizes that the system PEG/NaPA/Na2SO4 can be used as a new process to CA purification/concentrationFinancial support is gratefully acknowledged from FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Sao Paulo, Brazil) and from CNPq (National Council for Scientific and Technological Development, Brasilia, Brazil) and CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior)
Guaraguaoonops.
13 p. : ill., map ; 26 cm.A new endemic goblin spider genus Guaraguaoonops is erected to include two new soft-bodied oonopid species from Brazil: the type species, G. hemhem, distributed in the states of Maranhão, Piauí, and Ceará, and G. humbom, known only from Piauí. These spiders are unique among oonopids and easily diagnosed by the flattened carapace with a porrect clypeus, modified lateral setae on the carapace in both sexes, and male with a sinuous, flattened distal cheliceral projection and palp with ventral conical tegular projection. These species probably occupy a soil cryptic habit and are found in dry sand of "cerrado" areas in northeastern Brazil
Predatoroonops.
68 p. : ill., maps ; 26 cm.The new endemic goblin spider genus Predatoroonops is erected for 17 new soft-bodied oonopid species from Brazil: Predatoroonops schwarzeneggeri, sp. nov., is the type species of the genus, P. poncho, sp. nov., P. billy, sp. nov., P. valverde, sp. nov., P. blain, sp. nov., P. maceliot, sp. nov., P. anna, sp. nov., P. rickhawkins, sp. nov., P. dutch, sp. nov., P. dillon, sp. nov., P. vallarta, sp. nov., P. phillips, sp. nov., P. yautja, sp. nov., P. peterharlli, sp. nov., P. mctiernani, sp. nov., P. chicano, sp. nov., and P. olddemon, sp. nov. Males of this new genus are easily diagnosed and separated from other Oonopinae genera by the extremely modified male chelicerae that frontally have median furrows and accentuated projections. The females can be recognized by the genitalia, which have a conspicuous posterior receptaculum, usually exposed between the epigastric folds. An auxiliary character for both sexes could be the presence of very long pairs of ventral spines with pronounced bases on the legs I and II tibiae and metatarsi. The genus is considered endemic and the species are recorded mainly from the Brazilian Atlantic Forest. An identification key is provided for all Predatoroonops species known to date
Goblin spider genus Neoxyphinus.
75 p. : ill., maps ; 26 cm.The Neotropical spider genus Neoxyphinus Birabén, 1953, is revised, comprising 10 species found from the West Indies to northern Argentina. The genus is characterized by a unique combination of characters, which include the presence of a set of low tubercles or large spikes on the posterior surface of carapace; male endites with an apical, retrolateral excavation bearing a subapical toothlike apophysis; palpal bulb strongly inflated; embolus compact, S-shaped, with large, round ejaculatory opening; epigynal atrium large, with angular lateral corners. The large, round ejaculatory duct may be a synapomorphy of the genus. The genus Hawkeswoodoonops Makhan and Ezzatpanah, 2011, is synonymized with Neoxyphinus and the two species included in that genus are considered as nomina dubia. The monotypic genus Decuana Dumitrescu and Georgescu, 1987, is also synonymized with Neoxyphinus and its type species, D. hispida Dumitrescu and Georgescu, 1987, is transferred to the genus and redescribed. Confirming a hypothesis raised in the literature, Dysderina termitophila Bristowe, 1938, is transferred to Neoxyphinus and recognized as the senior synonym of the type species N. ogloblini Birabén, 1953. Two other species are transferred from Dysderina to Neoxyphinus: D. keyserlingi Simon, 1907, here recognized as the senior synonym of D. rugosa Bristowe, 1938, and D. furtiva Chickering, 1968, of which the male is described for the first time. In addition to the redescription of N. termitophilus, n. comb., N. hispidus, n. comb., N. xyphinoides (Chamberlin and Ivie, 1942), N. keyserlingi, n. comb., and N. furtivus, n. comb., five new species are described: N. petrogoblin Abrahim and Ott, from the Amazon basin in Brazil, Colombia, Ecuador, and Peru; N. gregoblin Abrahim and Santos, from Venezuela; N. axe Abrahim and Brescovit, from Bahia, Brazil; N. boibumba Abrahim and Rheims, from Pará, Brazil; and N. barreirosi Abrahim and Bonaldo, from Brazil, Colombia, Guyana, and Venezuela. With the exception of N. boibumba, known only from males, all new species are described from both sexes
Twenty years, eight legs, one concept: Describing spider biodiversity in Zootaxa (Arachnida: Araneae)
Zootaxa published more than a thousand papers on Araneae from 2002 to the present, including descriptions of 3,833 new spider species and 177 new genera. Here we summarise the key contributions of Zootaxa to our current knowledge of global spider diversity. We provide a historical account of the researchers that have actively participated as editors, and recognize the more than 1,000 reviewers without whom none of this would have been possible. We conduct a simple analysis of the contributions by authors and geographic region, which allows us to uncover some of the underlying trends in current spider taxonomy. In addition, we examine some of the milestones in twenty years of spider systematic research in Zootaxa. Finally, we discuss future prospects of spider taxonomy and the role that Zootaxa and its younger sister journal Megataxa will play in it. We would like to dedicate this contribution to the memory of Norman I. Platnick, a crucial figure in the advancement of spider systematics.Fil: Jäger, Peter. Senckenberg Research Institute; AlemaniaFil: Arnedo, Miquel. Universidad de Barcelona; EspañaFil: Fernandes de Azevedo, Guilherme Henrique. San Diego State University; Estados UnidosFil: Baehr, Barbara. Queensland Museum; AustraliaFil: Bonaldo, Alexandre B.. Museu Paraense Emílio Goeldi; BrasilFil: Haddad, Charles R.. University of the Free State; SudáfricaFil: Harms, Danilo. Universitat Hamburg; AlemaniaFil: Hormiga, Gustavo. The George Washington University; Estados UnidosFil: Labarque, Facundo Martín. Universidade Federal do São Carlos; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Muster, Christoph. No especifíca;Fil: Ramirez, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Santos, Adalberto J.. Universidade Federal de Minas Gerais; Brasi
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