Trematode infection of the second intermediate hosts can lead to changes in their fitness and, as a result, a change in the invasion rate of animal communities. It is especially pronounced during the invasion of parasite species that reduce activity due to the manipulation of hosts through the changes of their morphology and physiology. One of these cases is an anomaly P syndrome hotspot found in some populations of water frogs and toads in Europe caused by the trematode Strigea robusta metacercariae. The occurrence of pathogen and their participation in ecosystems are intrigues questions in the anomaly P phenomenon, as well as the role of planorbid snails that serve as the first intermediate hosts for many trematode species. Herein, we focused on trematodes spectra from planorbid snails and amphibians from the anomaly P hosts with the aim to undetected interactions between the pathways of parasites. Emerging cercariae of 6802 planorbid snails of dominant species ( Planorbarius corneus , Planorbis planorbis , and Anisus spp.) were detected by both morphological and molecular methods in seven waterbodies in Privolzhskaya Lesostep Nature Reserve (Russia). A total of 95 sequences of 18 species were received, and 48 sequences were unique and did not present in any genetic databases. The 18 species of trematodes from snails and 14 species of trematodes from amphibian hosts ( Pelophylax ridibundus ; Ranidae; Anura) were detected. Three species ( Echinostoma nasincovae , Tylodelphys circibuteonis and Australapatemon burti ) was new for the trematode fauna of the Middle Volga River region and Russia as a whole. Eleven species of parasitic flatworms have amphibians in their life cycles and nine species used amphibians as metacercariae hosts: Echinostoma nasincovae , E . miyagawai , Echinoparyphium recurvatum , Tylodelphys circibuteonis , Neodiplostomum spathula , Paralepoderma cloacicola , Macrodera longicollis , Strigea robusta , and Strigea strigis . The occurrence of trematode species from planorbid mollusks and frogs were compared.
The dataset contains information on amphibian occurrence in the Volga river basin and adjacent territories, located most part on the Russian plain of European Russia. Dataset is based on its own studies that were conducted in the years 1996-2020.
Here we present the first new data about the mysterious «anomaly P» of green frogs (genus Pelophylax) in about 50 years. We established that the gastropod Planorbarius corneus could be an intermediate host (or vector) of the infectious agent of the anomaly P. Symmetrical cases of polydactyly, the anomaly «cross» and heavy cases of the anomaly P, which were previously found in natural populations in the European part of Russia and recently obtained in laboratory, can be caused by this infectious agent. As the most probable cause, we assume a species of trematodes, for which the first intermediate host is P. corneus, from which they infest tadpoles of green frogs.
Abstract The Lindholm rock lizard, Darevskia lindholmi , is the only member of the genus Darevskia whose range is restricted solely to Europe, representing a local endemism found only in the Crimean Mountains. In our study, we investigated the cytochrome b gene (mtDNA) of 101 D. lindholmi sequences from 65 Crimean localities, representing its entire range. We found that D. lindholmi is highly genetically structured, and its range is divided into populations belonging to three mitochondrial lineages. The Lindholm rock lizard populations inhabiting the middle part of the Crimean Mountains (further referred to as the Central lineage) are sharply differentiated from the other two lineages (the Common and the Southwestern lineages), which are present in most of the species range. The genetic distance between the Central lineage and the other two taken together is 4.6%, according to our results, suggesting that the divergence occurred during the Early Pleistocene. The narrowly distributed Southwestern lineage and the widespread Common lineage, on the other hand, are differentiated by 1%. Field observations on the representatives of the main evolutionary groups show that their ecology is also different: the Central lineage is a mesophilic and cold-resistant form, while the other two closely related lineages are more xerophilic and thermophilic. Results of the potential ranges modeling and ecological niche analysis confirm that the genetic lineages occupy different niches of the Crimea. Furthermore, the area of inhabitation of the Central lineage splits the western and eastern parts of the Common lineage range, while the Southwestern lineage is restricted along the coast of the southwestern coast of the peninsula. The long-term co-existence of deeply divergent sister mitochondrial lineages in a relatively small (circa 7,000 km 2 ) isolated mountain system serves as a mesocosm for understanding the speciation process. Our data suggest that the Central lineage warrants further taxonomic investigation.
The anomaly P in green frogs was firstly found in 1952 in France by French writer and scientist Jean Rostand. Mild form of anomaly P manifestation includes polydactyly, while complex morphological transformations affect the fore and hindlimbs and include combinations of traits: polydactyly, brachymely, hind limb flexion, small additional limbs, bone outgrowths, tumors and edema in the hind limbs. Rostand experimentally showed that this anomaly is not inherited and is caused by some environmental factors. It was recorded only in Western Palearctic green frogs of the genus Pelophylax and was absent in other amphibian species, despite their syntopic occurrence. The severe cases of anomaly P were not found for a long time by researchers and were re-discovered after half a century since its last observation. A new record was made in 2016 in the central part of Russia in the Privolzhskaya Lesostep’ nature reserve. The morphological features of the anomalous frogs in the study area turned out to be similar to those described by Rostand. Symmetric polydactyly, brachymely, hind limb flexion, edema of hind limbs, small additional limbs in thighs, outgrowths, and concomitant anomalies – mandibular hypoplasia, unmoved hind limb, open opercular chamber. The frequency of occurrence of the anomaly in the studied population reached 24.7% (n = 384). Moreover, the “severe forms” of the anomaly P were noted in 4.7% of cases, and the “light” (polydactyly) in 20.0%. Growing tadpoles together with freshwater mollusks allowed us to obtain the anomaly P in the laboratory. It was revealed that the mollusks Planorbarius corneus are the intermediate hosts (vectors) for the “infectious agent” of this anomaly. As the most possible cause of the anomaly, the infection by trematodes species is considered.
Knowledge about the distribution of living organisms on Earth is very important for many areas of biological science and understanding of the surrounding world. However, much of the existing distributional data are scattered throughout a multitude of sources, such as taxonomic publications, checklists and natural history collections and often, bringing them together is difficult. A very successful attempt to solve this problem is the GBIF project, which allows a huge number of researchers to publish data in one place in a single standard. Our dataset represents a significant addition to the occurrences of amphibians in the Volga, Don riverine basins and adjacent territories.The dataset contains up-to-date information on amphibian occurrences in the Volga river basin and adjacent territories, located for the most part on the Russian plain of European Russia. The dataset is based on our own studies that were conducted in the years 1996-2020. The dataset consists of 5,030 incident records, all linked to geographical coordinates. A total of 13 amphibian species belonging to nine genera and six families have been registered within the studied territory, although the distribution of amphibian species in this region of Russia has not yet been fully studied. This is especially relevant with the spread of cryptic species that can only be identified using molecular genetic research methods.The main purpose of publishing a database is to make our data available in the global biodiversity system to a wide range of users. The data can be used by researchers, as well as helping the authorities to manage their territory more efficiently.All occurrences are published in GBIF for the first time. Most of the data are stored in field diaries and we would like to make it available to everyone by adding it in the global biodiversity database (GBIF).
Cases of polydactyly in natural populations of amphibians have attracted great interest from biologists. At the end of the 1940s, the French biologist Jean Rostand discovered a polymorphic syndrome in some water frog (Anura: Pelophylax) populations that included polydactyly and some severe morphological anomalies (he called it 'anomaly P'). The cause of this anomaly remains unknown for 70 years. In a previous study, we obtained anomaly P in the laboratory in tadpoles of water frogs that developed together with molluscs Planorbarius corneus (Mollusca: Gastropoda) collected in the field. We thus proposed the 'trematode hypothesis', according to which the infectious agent responsible for anomaly P is a trematode species.Metacercariae from tadpoles with anomaly P were identified using ITS2 gene sequencing as Strigea robusta (Trematoda: Strigeidae). To verify teratogenic features of the species, cercariae of S. robusta were tested for the possibility to cause anomalies. Identification of cercariae species was made using morphological and molecular methods (sequencing of ITS2 and 28S rRNA). The tadpoles were exposed to parasites at four doses of cercariae (control, low, medium and high) and divided into two groups: "early" (at 25-27 Gosner stages) and "late" (at 29-34 Gosner stages) exposure.A total of 58 (72.5%) tadpoles survived until metamorphosis under the dose-dependent experiment with the trematode S. robusta. Differences in the survival rates were observed between the exposed and unexposed tadpoles both in the group of "early" tadpoles and "late" tadpoles. The exposure of tadpoles to the cercariae of S. robusta induced anomaly P in 82% of surviving tadpoles. The severe forms developed only in "early" stages under all doses of cercariae exposure. Polydactyly predominantly developed in the "late" stages; under a light exposure dose, polydactyly also developed in "early" tadpoles. Laboratory-hatched tadpoles reared together with infected snails had different rates of survival and complexity of deformations associated with the period of coexistence.The experiments with direct cercariae exposure provide compelling evidence that S. robusta leads to anomaly P in tadpoles of water frogs. The manifestation of anomaly P turned out to be dependent on the stage of development, cercariae dose, and the location of the cysts.
The “anomaly P” was described in Palearctic water frogs of the genus Pelophylax by Jean Rostand as complex morphological anomalies of water frogs, including polydactyly, brachymely, hind limb oedema, bone outgrowths, spikes, flexions and additional limbs in the inguinal region. In 2016, the anomaly P syndrome was rediscovered in central Russia, confirming the hypothesis concerning its wider distribution. Here, three new records of this syndrome in two species of western Palearctic water frog from Russia are described.
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.
Для особо охраняемых природных территорий (ООПТ) отмечается высокий уровень биологического разнообразия, в том числе и у земноводных.Большой интерес вызывает группа европейских зеленых лягушек, характеризующаяся уникальным характером генетического и экологического взаимодействия в процессе гибридогенного воспроизводства.Приведены результаты исследований 2000-2018 гг.в пяти заповедниках (Мордовский, Присурский, Жигулевский, Волжско-Камский, Приволжская лесостепь) и четырех национальных парках (Смольный, Самарская Лука, Чаваш Вармане, Бузулукский бор).Изучаемые заповедники и национальные парки расположены в зоне перекрывания ареалов прудовой (Pelophylax lessonae) и озерной (P.ridibundus) лягушек, т.е.в районе потенциального распространения съедобной лягушки (P.esculentus), мероклонального гибрида, произошедшего от скрещивания указанных выше двух родительских видов.Выявлено, что озерная лягушка обитает во всех обследованных заповедниках и национальных парках, тогда как прудовая только в семи, а съедобная в пяти ООПТ.При изучении молекулярно-генетической изменчивости были использованы два маркера: для митохондриальной ДНК -фрагмент первой субъединицы гена цитохромоксидазы (COI), а для ядерной ДНК -интрон 1 гена сывороточного альбумина (SAI-1).Установлено, что в Среднем Поволжье у озерной лягушки встречаются митотипы и аллели двух криптических форм -«западной» (P.ridibundus) и «восточной» (P.cf.bedriagae).На ООПТ у этого вида были выявлены четыре из шести возможных комбинаций гаплотипов и аллелей по митохондриальной и ядерной ДНК, характерных для этих двух форм.Съедобная лягушка, обитающая на ООПТ, представлена только одним генотипом из четырех, обнаруженных в регионе.Популяционные системы зеленых лягушек на ООПТ представлены шестью типами.Здесь преобладают одновидовые популяции, включающие только озерную (n = 16; 41.0%) или прудовую (n = 10; 25.6%) лягушек.Среди смешанных популяционных систем чаще других отмечался тип, в котором представлены все три вида лягушек (n = 6; 15.4%).Реже встречаются системы, состоящие из двух видов: озерная и прудовая лягушки (n = 3; 7.7%), съедобная и прудовая (n = 3; 7.7%), озерная и съедобная (n = 1; 2.6%). Ключевые слова:
