Herein, we describe a new cryptic snake species of the genus Xenopeltis from Central Highlands of Vietnam: Kon Plông District, Kon Tum Province based both on morphological and molecular data. Xenopeltis intermedius sp. nov. is distinguished from the two known species by a combination of the following morphological characters. Xenopeltis intermedius sp. nov. differs from X. unicolor and X. hainanensis by the number of ventrals and subcaudals. The skull is less elongated than in X. unicolor and somewhat more elongate than in X. hainanensis. X. intermedius demonstrates differences in size, shape proportions and relief of the parietal bone and the number of teeth from X. hainanensis and X. unicolor. We provide a COI-based estimation of diversity of the genus Xenopeltis. Genetic divergence (p-distance) between Xenopeltis sp. nov. from Kon Tum Province, Central Highlands region of Vietnam, and two other congeners was 5.7% (for X. hainanensis) and 12.9% (for X. unicolor). The new species is currently known only from one locality from Central Highland and was recorded from 1500 to 2500 m a.s.l. in the evergreen polydominant forests in the mountainous regions of Kon Tum Province. This is the third species of Xenopeltis from Vietnam.

The utility of DNA Barcoding for species identification and discovery has catalyzed a concerted effort to build the global reference library; however, many animal groups of economical or conservational importance remain poorly represented. This study aims to contribute DNA barcode records for all ground squirrel species (Xerinae, Sciuridae, Rodentia) inhabiting Eurasia and to test efficiency of this approach for species discrimination. Cytochrome c oxidase subunit 1 (COI) gene sequences were obtained for 97 individuals representing 16 ground squirrel species of which 12 were correctly identified. Taxonomic allocation of some specimens within four species was complicated by geographically restricted mtDNA introgression. Exclusion of individuals with introgressed mtDNA allowed reaching a 91.6% identification success rate. Significant COI divergence (3.5–4.4%) was observed within the most widespread ground squirrel species (Spermophilus erythrogenys, S. pygmaeus, S. suslicus, Urocitellus undulatus), suggesting the presence of cryptic species. A single putative NUMT (nuclear mitochondrial pseudogene) sequence was recovered during molecular analysis; mitochondrial COI from this sample was amplified following re-extraction of DNA. Our data show high discrimination ability of 100 bp COI fragments for Eurasian ground squirrels (84.3%) with no incorrect assessments, underscoring the potential utility of the existing reference librariy for the development of diagnostic ‘mini-barcodes’.

The edible frog, Pelophylax esculentus, is a hybrid form that reproduces via clonal propagation of only one of the parental genomes through generations of hybrids while the genome of other parental species is eliminated during gametogenesis. Such reproductive ability requires hybrids to coexist with one of the parental species or rarely both parental species causing the formation of so‐called population systems. Population systems and reproductive biology of water frogs from the east of the range remained partially unexplored. In this study, we investigated the distributions, population systems, genetic structure, types of gametes, and morphological variability of water frogs of the genus Pelophylax from the northeastern parts of their ranges (Mari El Republic and adjacent territories, Russia). We examined 1,337 individuals from 68 localities using morphological traits combined with DNA flow cytometry and a multilocus approach (fragments of a nuclear and two mitochondrial genes). We revealed five types of population systems: “pure” populations of the parental P. ridibundus (R) and P. lessonae (L), mixed populations of parental species (R‐L) along and with their hybrids (R‐E‐L), as well as mixed populations of P. lessonae and P. esculentus (L‐E). However, the “pure” hybrid (E) and the mixed P. ridibundus and P. esculentus (R‐E) population systems were not found. All hybrids studied by DNA flow cytometry were diploid. Analysis of gametogenesis showed that the majority of hybrid males, as well as hybrid females from the L‐E system, produced gametes with the P. ridibundus genome. However, in the R‐E‐L system, hybrid females were usually sterile. The reproduction of hybrids in such systems is primarily based on crosses of P. esculentus males with P. lessonae females. Molecular analysis showed the presence of mitochondrial and nuclear DNA introgression of the Anatolian marsh frog (P. cf. bedriagae) into both P. ridibundus and P. esculentus. The observations of alleles and haplotypes of P. cf. bedriagae in P. ridibundus and P. esculentus individuals from the same localities suggest de novo formation of local hybrids. However, the presence of the Balkan marsh frog (P. kurtmuelleri) haplotypes in local hybrids supports the hypothesis regarding the migration of old hemiclonal lineages from glacial refugia. Finally, the diagnostic value of various morphological characteristics was discussed.