The tree of life of fishes is in a state of flux because we still lack a comprehensive phylogeny that includes all major groups. The situation is most critical for a large clade of spiny-finned fishes, traditionally referred to as percomorphs, whose uncertain relationships have plagued ichthyologists for over a century. Most of what we know about the higher-level relationships among fish lineages has been based on morphology, but rapid influx of molecular studies is changing many established systematic concepts. We report a comprehensive molecular phylogeny for bony fishes that includes representatives of all major lineages. DNA sequence data for 21 molecular markers (one mitochondrial and 20 nuclear genes) were collected for 1410 bony fish taxa, plus four tetrapod species and two chondrichthyan outgroups (total 1416 terminals). Bony fish diversity is represented by 1093 genera, 369 families, and all traditionally recognized orders. The maximum likelihood tree provides unprecedented resolution and high bootstrap support for most backbone nodes, defining for the first time a global phylogeny of fishes. The general structure of the tree is in agreement with expectations from previous morphological and molecular studies, but significant new clades arise. Most interestingly, the high degree of uncertainty among percomorphs is now resolved into nine well-supported supraordinal groups. The order Perciformes, considered by many a polyphyletic taxonomic waste basket, is defined for the first time as a monophyletic group in the global phylogeny. A new classification that reflects our phylogenetic hypothesis is proposed to facilitate communication about the newly found structure of the tree of life of fishes. Finally, the molecular phylogeny is calibrated using 60 fossil constraints to produce a comprehensive time tree. The new time-calibrated phylogeny will provide the basis for and stimulate new comparative studies to better understand the evolution of the amazing diversity of fishes.

Hypervirulent Klebsiella pneumoniae (hvKP) is traditionally defined by hypermucoviscosity, but data based on genetic background are limited. Antimicrobial-resistant hvKP has been increasingly reported but has not yet been systematically studied. K. pneumoniae isolates from bloodstream infections, hospital-acquired pneumonia, and intra-abdominal infections were collected from 10 cities in China during February to July 2013. Clinical data were collected from medical records. All K. pneumoniae isolates were investigated by antimicrobial susceptibility testing, string test, extended-spectrum ␤-lactamase (ESBL) gene detection, capsular serotypes, virulence gene profiles, and multilocus sequence typing. hvKP was defined by aerobactin detection. Of 230 K. pneumoniae isolates, 37.8% were hvKP. The prevalence of hvKP varied among different cities, with the highest rate in Wuhan (73.9%) and the lowest in Zhejiang (8.3%). Hypermucoviscosity and the presence of K1, K2, K20, and rmpA genes were strongly associated with hvKP (P < 0.001). A significantly higher incidence of liver abscess (P ‫؍‬ 0.026), sepsis (P ‫؍‬ 0.038), and invasive infections (P ‫؍‬ 0.043) was caused by hvKP. Cancer (odds ratio [OR], 2.285) and diabetes mellitus (OR, 2.256) appeared to be independent variables associated with hvKP infections by multivariate analysis. Importantly, 12.6% of hvKP isolates produced ESBLs, and most of them carried bla CTX-M genes. Patients with neutropenia (37.5% versus 5.6%; P ‫؍‬ 0.020), history of systemic steroid therapy (37.5% versus 5.6%; P ‫؍‬ 0.020), and combination therapy (62.5% versus 16.7%; P ‫؍‬ 0.009) were more likely to be infected with ESBL-producing hvKP. The prevalence of hvKP is high in China and has a varied geographic distribution. ESBLproducing hvKP is emerging, suggesting an urgent need to enhance clinical awareness, especially for immunocompromised patients receiving combination therapy. Over the past few decades, increasing rates of hypervirulent Klebsiella pneumoniae (hvKP) infection have been reported worldwide (1-4). Such strains are notorious for their capacity to cause serious and metastatic infections in young and healthy individuals, such as pyogenic liver abscesses and endophthalmitis (5). Hypermucoviscosity is an important in vitro parameter for identification of hvKP (6, 7). However, several controversies have arisen regarding the association of hypermucoviscosity phenotype and virulence (8, 9). Hypermucoviscosity-negative strains are more prone to cause severe infections and have a higher mortality rate in diabetic mice than hypermucoviscous K. pneumoniae (8). Our previous study also demonstrated that one of the five hypermucoviscous K. pneumoniae isolates showed high virulence in both in vitro and in vivo assays (9). Therefore, it is apparent that hvKP cannot be defined by string test alone (10). Aerobactin accounts for increased siderophore production and is a major virulence determinant and new defining trait for hvKP based on genetic background (11). Some advances have been made recently...

Zircon U‐Pb geochronological data on over 900 zircon grains for Cambrian to Silurian sandstone samples from the South China Block constrain the pre‐Devonian tectonic setting of, and the interrelationships between, the constituent Cathaysia and Yangtze blocks. Zircons range in age from 3335 to 465 Ma. Analyses from the Cathaysia sandstone samples yield major age clusters at ∼2560, ∼1850, ∼1000, and 890–760 Ma. Zircons from the eastern and central Yangtze sandstone samples show a similar age distribution with clusters at ∼2550, ∼1860, ∼1100, and ∼860–780 Ma. A minor peak at around 1450 Ma is also observed in the Cathaysia and central Yangtze age spectra, and a peak at ∼490 Ma represents magmatic zircons from Middle Ordovician sandstone in the eastern Yangtze and Cathaysia blocks. The Cambrian and Ordovician strata show a transition from a carbonate‐dominated succession in the central Yangtze Block, to an interstratified carbonate‐siliciclastic succession in the eastern Yangtze Block, to a neritic siliciclastic succession in the Cathaysia Block. Paleocurrent data across this succession consistently indicate directions toward the W‐NNW, from the Cathaysia Block to the Yangtze Block. Our data, together with other geological constraints, suggest that the Cathaysia Block constitutes a fragment on the northern margin of east Gondwana and both Cathaysia and east Gondwana constituted the source for the analyzed early Paleozoic samples. The similar age spectra for the Cambrian to Silurian sandstone samples from the Yangtze and Cathaysia blocks argue against the independent development and spatial separation of these blocks in the early Paleozoic but rather suggest that the sandstone units accumulated in an intracontinental basin that spanned both blocks. Subsequent basin inversion and Kwangsian orogenesis possibly at 400–430 Ma also occurred in an intracontinental setting probably in response to the interaction of the South China Block with the Australian‐Indian margin of east Gondwana.

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