Ancient Tethyan Vicariance and Long-Distance Dispersal Drive Global Diversification and Cryptic Speciation in the Red Seaweed Pterocladiella.

We investigated the globally distributed red algal genus Pterocladiella, comprising 24 described species, many of which are economically important sources of agar and agarose. We used DNA-based species delimitation approaches, phylogenetic, and historical biogeographical analyses to uncover cryptic diversity and infer the drivers of biogeographic patterns. We delimited 43 species in Pterocladiella, of which 19 are undescribed. Our multigene time-calibrated phylogeny and ancestral area reconstruction indicated that Pterocladiella most likely originated during the Early Cretaceous in the Tethys Sea. Ancient Tethyan vicariance and long-distance dispersal have shaped current distribution patterns. The ancestor of Eastern Pacific species likely arose before the formation of the formidable Eastern Pacific Barrier-a first confirmation using molecular data in red algae. Divergences of Northeast and Southeast Pacific species have been driven by the Central American Seaway barrier, which, paradoxically, served as a dispersal pathway for Atlantic species. Both long- and short-distance dispersal scenarios are supported by genetic relationships within cosmopolitan species based on haplotype analysis. Asymmetrical distributions and the predominance of peripatry and sympatry between sister species suggest the importance of budding speciation in Pterocladiella. Our study highlights the underestimation of global diversity in these crucial components of coastal ecosystems and provides evidence for the complex evolution of current species distributions.

Contrasting patterns of genetic structure and phylogeography in the marine agarophytes Gelidiophycus divaricatus and G. freshwateri (Gelidiales, Rhodophyta) from East Asia.

The evolutionary and population demographic history of marine red algae in East Asia is poorly understood. Here, we reconstructed the phylogeographies of two upper intertidal species endemic to East Asia, Gelidiophycus divaricatus and G. freshwateri. Phylogenetic and phylogeographic inferences of 393 mitochondrial cox1, 128 plastid rbcL, and 342 nuclear ITS2 sequences were complemented with ecological niche models. Gelidiophycus divaricatus, a southern species adapted to warm water, is characterized by a high genetic diversity and a strong geographical population structure, characteristic of stable population sizes and sudden reduction to recent expansion. In contrast, G. freshwateri, a northern species adapted to cold temperate conditions, is genetically relatively homogeneous with a shallow population structure resulting from steady population growth and recent equilibrium. The overlap zone of the two species roughly matches summer and winter isotherms, indicating that surface seawater temperature is a key feature influencing species range. Unidirectional genetic introgression was detected at two sites on Jeju Island where G. divaricatus was rare while G. freshwateri was common, suggesting the occurrence of asymmetric natural hybrids, a rarely reported event for rhodophytes. Our results illustrate that Quaternary climate oscillations have left strong imprints on the current day genetic structure and highlight the importance of seawater temperature and sea level change in driving speciation in upper intertidal seaweed species.

Continuous veno-venous hemofiltration for treatment of enterovirus 71-induced fulminant cardiopulmonary failure: a case report.

INTRODUCTION: Fulminant cardiopulmonary failure is a severe complication of hand, foot and mouth diseases due to enterovirus 71 infection, with a high mortality rate. The treatment is mainly supportive with aggressive cardiopulmonary resuscitation. We report the use of continuous veno-venous hemofiltration in a patient with pulmonary edema and shock due to enterovirus 71 infection. To the best of our knowledge, this is the first report of the use of continuous veno-venous hemofiltration to successfully treat a patient with fulminant cardiopulmonary failure due to enterovirus 71 infection. CASE PRESENTATION: A 36-month-old Asian girl presented to our hospital with pulmonary edema, refractory hypotension and severe cardiac dysfunction due to enterovirus 71 infection. In addition to the standard management and care, we performed continuous veno-venous hemofiltration to overcome refractory shock and our patient eventually made a full recovery. At a three-month follow-up, a full assessment revealed no neurological sequelae. CONCLUSIONS: In the management of patients with enterovirus 71-related fulminant cardiopulmonary failure, early continuous veno-venous hemofiltration may be considered as an alternative treatment to improve patient survival and to prevent severe neurological disabilities.