Two new Inosperma (Inocybaceae) species with unexpected muscarine contents from tropical China

An accurate identification of poisonous mushrooms and the confirmation of the toxins involved are both of great importance in the treatment of mushroom poisoning incidents. In recent years, cases of mushroom poisoning by Inosperma spp. have been repeatedly reported from tropical Asia. It is urgent to know the real species diversity of Inosperma in this region. In the present study, we proposed two new Inosperma species from tropical Asia, namely I. muscarium and I. hainanense. They were described based on morphology and multilocus phylogeny. Detailed descriptions, color photographs and the discussion with other closely related species of the two new taxa were provided. In addition, a comprehensive muscarine determination of these two new species using ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) approach has been performed. Results showed that these two species were muscarine positive, with a content of 16.03 ± 1.23 g/kg in I. muscarium and a content of 11.87 ± 3.02 g/kg in I. hainanense, much higher than the known species I. virosum. Recovery of muscarine ranged from 93.45% to 97.25%, and the average recovery is 95.56%.

Mazosia hainanensis sp. nov. from tropical China

A new species, Mazosia hainanensis, is described from Hainan, China. It is most similar to M. pseudobambusae but differs by its yellowish green thallus and smaller ascospores (14–18.5 × 3–4 μm). An analysis of its relationships based on molecular phylogeny is given. A key to the Mazosia species recorded in China is also presented.

Buchwaldoboletus xylophilus and Phlebopus portentosus, two non-ectomycorrhizal boletes from tropical China

Buchwaldoboletus xylophilus and Phlebopus portentosus (Boletales) are two non-ectomycorrhizal boletes, which are widely reported in tropical Asia. However, there is little information available about the taxonomy of these two boletes. Here, B. xylophilus and P. portentosus are redescribed based on morphology and molecular phylogenetic analyses of DNA sequences from nuclear 28S rDNA (28S), nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), translation elongation factor 1-α gene (TEF1) and the RNA polymerase II second largest subunit gene (RPB2). Detailed descriptions, color photos of fresh basidiomata, and line-drawings of microscopic features of the two taxa are presented.

Application of COI Primers 30F/885R in Rotifers to Regional Species Diversity in (Sub)Tropical China

Rotifers are the most diverse group in freshwater zooplankton and play an important role in food webs and ecosystems. DNA barcoding has become a useful approach to investigate species diversity at local and regional scales, but its application is still limited by efficient primers for the group. To test a pair of primers 30F/885R recently designed for rotifers, we applied them to investigating regional species diversity in the freshwater of South China. We sequenced the cytochrome c oxidase subunit I (COI) gene of rotifers collected from the investigated 23 reservoirs in a large river basin and obtained 145 COI sequences from 33 species in 14 genera. The mean PCR success rate for all tested species was 50%. The 145 sequenced mtCOI in this study covered 33 of 64 identified morphological taxa, including most of the common species in the basin. The intraspecific genetic distance was calculated with a K2P model for 24 rotifer species occurring in the quantitative samples, in which 15 rotifers, such as Keratella cochlearis and Brachionus calyciflorus, had a genetic distance higher than 5%. The high intraspecific genetic differentiation indicates that cryptic species are probably common in (sub)tropical China.

Baorangia duplicatopora (Boletaceae, Boletales), a new bolete from tropical China

Baorangia duplicatopora is described as a new species from Hainan Province, a tropical region of China. It is morphologically characterized by large to very large basidiomata with a dull rose red, rose pink to purplish red pileus, compound pores, pileus context near hymenophore and stipe context staining blue when injured, a red stipe, and cheilocystidia wider than those of other Baorangia species. Phylogenetic analyses of DNA sequences from part of the 28S gene, the nuc rDNA internal transcribed spacer (ITS) region, and part of the translation elongation factor 1-α gene (TEF1) also confirmed that B. duplicatopora forms an independent lineage within Baorangia. Detailed descriptions, color photographs of fresh basidiomata, and line drawings of microscopic features of the new species are presented. A key to species of Baorangia in the world is also provided.

Response of Mangrove Development to Air Temperature Variation Over the Past 3000 Years in Qinzhou Bay, Tropical China

Mangroves, a blue carbon ecosystem between land and ocean in the (sub)tropics, are sensitive to changes in climate and the sea level. It is imperative to reconstruct the historical dynamics of their development to predict the fate of mangrove ecosystems in the backdrop of rapid global changes. This study analyzes records of the sources of organic matter from sediment core Q43 of Qinzhou Bay in tropical China by using the endmember mixing model based on stable organic carbon isotopes and C/N ratio. Mangrove-derived organic matter (MOM) is regarded as a reliable indicator for reconstructing the historical development of mangroves. The variations in MOM in Qinzhou Bay over the past ∼3,000 cal yr BP indicate that mangrove forests underwent two periods of flourishment: ∼2,200–1,750 cal yr BP and ∼1,370–600 cal yr BP, as well as three periods of deterioration: ∼3,000–2,200 cal yr BP, ∼1,750–1,370 cal yr BP, and ∼600–0 cal yr BP. Of factors that might have been influential, changes in the relative sea level and the regional hydrological environment (e.g., seawater temperature, salinity, and hydrodynamic conditions) did not appear to have notable effects on mangrove flourishing/degradation. However, climate change, especially the variation in air temperature, formed the primary factor controlling mangrove development. The stages of mangrove flourishing/deterioration corresponded to the warm/cold periods of the climate, respectively. Noteworthy is that the rapid rise in air temperature during the Anthropocene warm period should have promoted mangrove development, but the increasing intensity of human activity has reversed this tendency leading to the degradation of mangroves.