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.

Strong differentiation between amphibian communities on two adjacent mountains in the Upper Rio Pastaza watershed of Ecuador, with descriptions of two new species of terrestrial frogs

We present the results of herpetological surveys in two adjacent mountains where the EcoMinga Foundation protects the cloud forest in the Upper Rio Pastaza watershed, in the Llanganates Sangay Ecological Corridor in Ecuador. A rapid assessment of the amphibian communities of the study sites reveals a diverse and heterogeneous composition, dominated by terrestrial frogs from the genus Pristimantis. We also identify a cryptic diversity with a significant number of candidate new species. We describe two new species of terrestrial frogs of the genus Pristimantis. Pristimantis maryanneaesp. nov. is characterised by not having tympanum externally visible and having 2–3 subconical tubercles in the upper eyelid; and Pristimantis burtoniorumsp. nov. is characterised by the presence of red colouration in hidden surfaces of the hind-limbs, tubercles on the upper eyelid, interorbital tubercle and a row of rounded tubercles along the snout to the tip and a pale red venter with dark brown mottled pattern. Our samples from the two Reserves do not share species between them, so the proportion of shared species seems to be relatively low. In addition, we highlight the importance of updating the knowledge of amphibians that are restricted to this important conservation region and comment about the threats and composition of the amphibian communities on the eastern slopes of the Upper Rio Pastaza watershed.

New records of water mites from the Balkans revealed by DNA barcoding (Acari, Hydrachnidia)

New records of water mites from Serbia, North Macedonia and Greece revealed by DNA barcoding are presented. DNA barcodes were recovered from 63 water mite specimens morphologically assigned to 32 species. One species Lebertia algeriensis Lundblad, 1942, is reported for the first time for the Balkans; four species, i.e. Lebertia fimbriata Thor, 1899, L. rivulorum K. Viets, 1933, Atractides stankovici Pešić & Gerecke, 2010, and Wettina lacustris Pešić & Smit, 2018 are new for North Macedonia; Monatractides madritensis (K. Viets, 1930) and Mideopsis roztoczensis Biesiadka & Kowalik, 1979 are new for Serbia; and Hygrobates mediterraneus Pešić, 2020 is new for Greece. Comparing sequences of our study with the available COI sequences we recognized five possible cases of cryptic diversity involving species clusters with more than 5% divergence indicating that these species need further study.

Phylogeny and Taxonomy on Cryptic Species of Forked Ferns of Asia

Cryptic species comprise two or more taxa that are grounded under a single name because they are more-or-less indistinguishable morphologically. These species are potentially important for detailed assessments of biodiversity, but there now appear to be many more cryptic species than previously estimated. One taxonomic group likely to contain many cryptic species is Dicranopteris, a genus of forked ferns that occurs commonly along roadsides in Asia. The genus has a complex taxonomical history, and D. linearis has been particularly challenging with many intra-specific taxa dubiously erected to accommodate morphological variation that lacks clear discontinuities. To resolve species boundaries within Dicranopteris, we applied a molecular phylogenetic approach as complementary to morphology. Specifically, we used five chloroplast gene regions (rbcL, atpB, rps4, matK, and trnL-trnF) to generate a well-resolved phylogeny based on 37 samples representing 13 taxa of Dicranopteris, spanning the major distributional area in Asia. The results showed that Dicranopteris consists of ten highly supported clades, and D. linearis is polyphyletic, suggesting cryptic diversity within the species. Further through morphological comparison, we certainly erected Dicranopteris austrosinensis Y.H. Yan & Z.Y. Wei sp. nov. and Dicranopteris baliensis Y.H. Yan & Z.Y. Wei sp. nov. as distinct species and proposed five new combinations. We also inferred that the extant diversity of the genus Dicranopteris may result from relatively recent diversification in the Miocene based on divergence time dating. Overall, our study not only provided additional insights on the Gleicheniaceae tree of life, but also served as a case of integrating molecular and morphological approaches to elucidate cryptic diversity in taxonomically difficult groups.

Designation of the neotype of Triatoma dimidiata (Latreille, 1811) (Hemiptera, Reduviidae, Triatominae), with full integrated redescription including mitogenome and nuclear ITS-2 sequences

The taxonomic status of Triatoma dimidiata (Latreille, 1811) is, by far, the most discussed within Triatominae. Molecular studies have recovered at least three independently evolving lineages in T. dimidiata across its range. The original description of T. dimidiata (as Reduvius dimidiatus) included few taxonomic characters, and no types were assigned. To define and describe the cryptic diversity within T. dimidiata sensu lato (s.l.), a neotype must be designated. For this purpose, all 199 specimens identified as T. dimidiata from the collections of the Smithsonian Institution – National Museum of Natural History and the American Museum of Natural History, ranging from Peru to Mexico, were studied. Only one specimen (from Tumbes, Peru) matched the combination of characters as listed in the original description, and it is herein formally designated as the neotype for T. dimidiata. The neotype is morphologically described and DNA sequences of its whole mitochondrial genome and the nuclear second internal transcribed spacer region (ITS2), commonly used in triatomine molecular systematics studies, are presented and compared to other publicly available sequences of T. dimidiata s.l. in GenBank. Our results suggest that T. dimidiata sensu stricto (s.s.) is somewhat rare and, therefore, unlikely to serve as a major vector of Chagas disease.