Cryptic Species Diversity and Phylogenetic Relationship in the Rust Genus Chrysomyxa from China

Chrysomyxa rusts are fungal pathogens widely distributed in the Northern hemisphere, causing spruce needle and cone rust diseases, and they are responsible for significant economic losses in China. Taxonomic delimitation and precise species identification are difficult within this genus because some characters often overlap in several species. Adequate species delimitation, enhanced by the use of DNA-based methodologies, will help to establish well-supported species boundaries and enable the identification of cryptic species. Here, we explore the cryptic species diversity in the rust genus Chrysomyxa from China. Species delimitation analyses are conducted using a distance-based method (ABGD) and three tree-based methods (GMYC, bPTP, and mPTP) based on combined LSU and ITS sequences of over 60 specimens. Although there is some incongruence among species delimitation methods, two new species and three putative cryptic species are identified. The key to 20 Chrysomyxa species distributed in China is presented. These results suggest that a significant level of undiscovered cryptic diversity is likely to be found in Chrysomyxa from China. Future studies should consider multiple analytical methods when dealing with multi-locus datasets.

Molecular phylogeography reveals multiple Pleistocene divergence events in estuarine crabs from the tropical West Pacific

Due to the lack of visible barriers to gene flow, it was a long-standing assumption that marine coastal species are widely distributed, until molecular studies revealed geographically structured intraspecific genetic differentiation in many taxa. Historical events of sea level changes during glacial periods are known to have triggered sequential disjunctions and genetic divergences among populations, especially of coastal organisms. The Parasesarma bidens species complex so far includes three named plus potentially cryptic species of estuarine brachyuran crabs, distributed along East to Southeast Asia. The aim of the present study is to address phylogeography and uncover real and hidden biological diversity within this complex, by revealing the underlying genetic structure of populations and species throughout their distribution ranges from Japan to West Papua, with a comparison of mitochondrial COX1 and 16S rRNA gene sequences. Our results reveal that the P. bidens species complex consists of at least five distinct clades, resulting from four main cladogenesis events during the mid to late Pleistocene. Among those clades, P. cricotum and P. sanguimanus are recovered as monophyletic taxa. Geographically restricted endemic clades are encountered in southeastern Indonesia, Japan and China respectively, whereas the Philippines and Taiwan share two clades. As individuals of the Japanese clade can also be found in Taiwan, we provide evidence of a third lineage and the occurrence of a potential cryptic species on this island. Ocean level retreats during Pleistocene ice ages and present oceanic currents appear to be the main triggers for the divergences of the five clades that are here addressed as the P. bidens complex. Secondary range expansions converted Taiwan into the point of maximal overlap, sharing populations with Japan and the Philippines, but not with mainland China.

Discovery of a Cryptic Species, Erysiphe Salicina Sp. Nov., and Reconstruction of The Phylogeny of Powdery Mildews On Populus and Salix Spp.

Recently performed phylogenetic-taxonomic analyses of species belonging to Erysiphe sect. Uncinula on willows (Salix spp.) demonstrated a much higher diversity than previously assumed. Phylogenetic analyses and morphological examinations of Chinese Erysiphe collections on Salix abscondita (= S. raddeana), S. sinica and S. taraikensis, all belonging to Salix subgen. Vetrix sect. Vetrix, revealed an additional cryptic species in sister position to the E. salicis clade, which is described as Erysiphe salicina. The new species clearly distinguished from all allied species in morphological and genetical results. The phylogeny of the new species and closely related species on Populus and Salix spp. (Salicaceae) was reconstructed and discussed using a combined alignment of the internal transcribed spacer (ITS) regions and 28S rDNA sequences. The present phylogenetic analyses suggest that the recently described E. salicicola (on Salix gracilistyla in South Korea) has to be reduced to synonymy with E. salicis var. salicis-gracilistylae (º Uncinula salicis-gracilistylae).

Sex-specific distribution and classification of Wolbachia infections and mitochondrial DNA haplogroups in Aedes albopictus from the Indo-Pacific

The arbovirus vector Aedes albopictus (Asian tiger mosquito) is common throughout the Indo-Pacific region, where most global dengue transmission occurs. We analysed population genomic data and tested for cryptic species in 160 Ae. albopictus sampled from 16 locations across this region. We found no evidence of cryptic Ae. albopictus but found multiple intraspecific COI haplotypes partitioned into groups representing three Asian lineages: East Asia, Southeast Asia and Indonesia. Papua New Guinea (PNG), Vanuatu and Christmas Island shared recent coancestry, and Indonesia and Timor-Leste were likely invaded from East Asia. We used a machine learning trained on morphologically sexed samples to classify sexes using multiple genetic features and then characterized the w AlbA and w AlbB Wolbachia infections in 664 other samples. The w AlbA and w AlbB infections as detected by qPCR showed markedly different patterns in the sexes. For females, most populations had a very high double infection incidence, with 67% being the lowest value (from Timor-Leste). For males, the incidence of double infections ranged from 100% (PNG) to 0% (Vanuatu). Only 6 females were infected solely by the w AlbA infection, while rare uninfected mosquitoes were found in both sexes. The w AlbA and w AlbB densities varied significantly among populations. For mosquitoes from Torres Strait and Vietnam, the w AlbB density was similar in single-infected and superinfected ( w AlbA and w AlbB) mosquitoes. There was a positive association between w AlbA and w AlbB infection densities in superinfected Ae. albopictus . Our findings provide no evidence of cryptic species of Ae. albopictus in the region and suggest site-specific factors influencing the incidence of Wolbachia infections and their densities. We also demonstrate the usefulness of SNPs as sex-specific mosquito markers. The results provide baseline data for the exploitation of Wolbachia -induced cytoplasmic incompatibility (CI) in dengue control.

Three cryptic Anaplecta (Blattodea, Blattoidea, Anaplectidae) species revealed by female genitalia, plus seven new species from China

Morphological characteristics, including male and female genitalia, combined with DNA barcodes were used to identify 470 Anaplecta specimens sampled from China. Ten Anaplecta species are new to science, including three cryptic species: A. paraomei Zhu & Che, sp. nov., A. condensa Zhu & Che, sp. nov., and A. longihamata Zhu & Che, sp. nov., which are distinguished mainly by their female genitalia. The other seven new species are as follows: A. bicruris Zhu & Che, sp. nov., A. spinosa Zhu & Che, sp. nov., A. ungulata Zhu & Che, sp. nov., A. anomala Zhu & Che, sp. nov., A. serrata Zhu & Che, sp. nov., A. bombycina Zhu & Che, sp. nov., and A. truncatula Zhu & Che, sp. nov. This study illustrates that differences in female genitalia can be used to distinguish among species of Anaplecta. The female genitalia of 19 Chinese Anaplecta species are described and illustrated in this paper.

Split distribution, biogeography and morphological and genetic diversity of the Iberobathynellini Tribe in the family Parabathynellidae (Crustacea, Malacostraca, Bathynellacea)

The “Iberobathynella group”, or Iberobathynellini tribe, is a complex of six genera consisting of 33 nominal species and several cryptic species with an amphiatlantic distribution (in Europe, North Africa and North America). A modern systematic revision of this group of subterranean crustaceans is presented here. A phylogenetic and biogeographic study using morphological and molecular data (mitocondrial coi and nuclear 18S) was carried out and allowed to a) re-evaluate the taxonomic status and validity of previously erected subtribes, genera and subgenera that show congruence in the data; b) assess whether the identified mitochondrial lineages represent cryptic species; c) provide a plausible phylogenetic hypothesis for the relationships within Iberobathynellini and with the other two genera of the family Parabathynellidae that inhabit North America and Europe (Montanabathynella and Parabathynella, respectively); d) propose a plausible temporal and historical framework (paleobiogeographic scenario) for the diversification and evolution of the Iberobathynellini tribe based on the current distribution of morphotypes and their estimated times of divergence. Our results show that in parabathynellids, molecular and morphological divergences are not always congruent. Subtribe and subgenus are invalid categories so they must be eliminated. Paraiberobathynella genus needs to be revisited. The molecular dating results support the early divergence of the Iberobathynellini Tribe (Upper Cretaceous, around 78 Mya) and the vicariance by plate tectonics as main factor to explain the amphi-Atlantic distribution shown by this ancient subterranean crustacean group. Since there are species morphologically very similar to I. magna and I. imuniensis, but genetically different, we can ensure the existence of at least three cryptic species. Texanobathynella is undoubtedly a valid genus distinct from Iberobathynella. Montanabathynella and Parabathynella are two well-differentiated genera closely related to the Iberobathynellini tribe.

Harmozica zangezurica (Gastropoda, Pulmonata, Hygromiidae) - a cryptic species of land molluscs from southern Armenia

Additional material collected in September 2019 made it possible to clarify the range of conchological variability of Harmozica zangezurica recently described from the Syunik region of Armenia, which largely overlaps with that of Harmozica pisiformis thus rendering impossible the reliable identification of empty shells. At the same time the stability has been proven of a diagnostic feature of H. zangezurica - very long vaginal appendages whose length is approximately equal to the total length of the penis and epiphallus. This character allows reliable distinguishing of H. zangezurica not only from the conchologically similar species H. pisiformis , but also from other representatives of the genus Harmozica . Some data on the ecology and life cycle of H. zangezurica were obtained.