The genus Diaphanosoma (Diplostraca: Sididae) in Greece: morphological and molecular assessment.

For the genus Diaphanosoma Fischer (Cladocera) the species name D. brachyurum has been widely used for many decades to identify other species belonging to this genus. To clarify the diversity of the genus in Greek lakes in the present study, we morphologically and genetically identified the Diaphanosoma species occurring in eight lakes. Three hundred twenty-nine Diaphanosoma individuals were morphologically examined, while for the genetic analyses the mtDNA COI gene was sequenced in 48 individuals. Combining the morphological and genetic results, we verified the occurrence of D. mongolianum, D. orghidani and D. macedonicum in our study area. We could not confirm prior records of D. brachyurum and D. lacustris while we provide the molecular identity of D. macedonicum. Furthermore, we highlight the need to check whether the European D. mongolianum populations are characterised of mitochondrial discordance and hybridization as the individuals from the Asian type locality of the species. Our results support the importance of combining both approaches to correctly identify taxonomic species, despite the extra effort and cost during the sample analysis.

Rotifers from inland water bodies of continental Ecuador and Galápagos Islands: An updated checklist.

We present an updated checklist of the rotifer fauna from inland aquatic habitats in continental Ecuador and the Galápagos islands based on published rotifer records found in the literature. The checklist summarizes the status of the current taxonomic and faunistic knowledge on rotifers in Ecuador, updates the nomenclature, and reports the regions where each species has been found in the country. A total of 287 valid species (269 monogononts and 18 bdelloids was found. The Ecuadorian region with the highest number of records was Amazonia (228) followed by the Coastal region (139) and the Andes (121), whereas in the Galápagos Archipelago only 40 species have been recorded. Studies of the rotifer fauna of the areas are scarce and quite recent, pointing to important gaps in our knowledge on taxonomy and biogeography of Ecuadorian rotifers.

Reverse taxonomy applied to the Brachionus calyciflorus cryptic species complex: Morphometric analysis confirms species delimitations revealed by molecular phylogenetic analysis and allows the (re)description of four species.

The discovery and exploration of cryptic species have been profoundly expedited thanks to developments in molecular biology and phylogenetics. In this study, we apply a reverse taxonomy approach to the Brachionus calyciflorus species complex, a commonly studied freshwater monogonont rotifer. By combining phylogenetic, morphometric and morphological analyses, we confirm the existence of four cryptic species that have been recently suggested by a molecular study. Based on these results and according to an exhaustive review of the taxonomic literature, we name each of these four species and provide their taxonomic description alongside a diagnostic key.

Integrative Taxonomy Recognizes Evolutionary Units Despite Widespread Mitonuclear Discordance: Evidence from a Rotifer Cryptic Species Complex.

Mitonuclear discordance across taxa is increasingly recognized as posing a major challenge to species delimitation based on DNA sequence data. Integrative taxonomy has been proposed as a promising framework to help address this problem. However, we still lack compelling empirical evidence scrutinizing the efficacy of integrative taxonomy in relation to, for instance, complex introgression scenarios involving many species. Here, we report remarkably widespread mitonuclear discordance between about 15 mitochondrial and 4 nuclear Brachionus calyciflorus groups identified using different species delimitation approaches. Using coalescent-, Bayesian admixture-, and allele sharing-based methods with DNA sequence or microsatellite data, we provide strong evidence in support of hybridization as a driver of the observed discordance. We then describe our combined molecular, morphological, and ecological approaches to resolving phylogenetic conflict and inferring species boundaries. Species delimitations based on the ITS1 and 28S nuclear DNA markers proved a more reliable predictor of morphological variation than delimitations using the mitochondrial COI gene. A short-term competition experiment further revealed systematic differences in the competitive ability between two of the nuclear-delimited species under six different growth conditions, independent of COI delimitations; hybrids were also observed. In light of these findings, we discuss the failure of the COI marker to estimate morphological stasis and morphological plasticity in the B. calyciflorus complex. By using B. calyciflorus as a representative case, we demonstrate the potential of integrative taxonomy to guide species delimitation in the presence of mitonuclear phylogenetic conflicts.