Anomalie P

Welcome to my website about the anomaly P
and other morphological anomalies in amphibians!


The thing cannot be described – there is no language for such abysms of shrieking and immemorial lunacy, such eldritch contradictions of all matter, force, and cosmic order.

- H.P. Lovecraft, The Call of Cthulhu


In the 1950s, famous French writer and biologist Jean Rostand (1894-1977) discovered morphological anomalies of an unknown etiology in water frogs of the genus Pelophylax, which he named “Anomalie P”. The anomaly P is the morphological deformations of water frogs that have light and severe forms of manifestation.

The light form of the anomaly is symmetrical polydactyly. Specimens suffering from severe forms of the anomaly have symmetrical brachymely, polydactyly, hind limb edema, bone outgrowths, spikes, flexions, and additional limbs in the inguinal region.

Dubois A. Rostand’s anomaly P in Palaearctic green frogs (Pelophylax) and similar anomalies in amphibians // Studies on Anomalies in Natural Populations of Amphibians. Mertensiella, 2017. 25: 49–56.

Svinin A.O., Ermakov O.A., Litvinchuk S.N., and Bashinskiy I.V. The anomaly P syndrome in green frogs: the history of discovery, morphological features and possible causes // Proceedings of the Zoological Institute RAS, 2020. 324(1): 108–123 [In Russian with English summary]



The Rostand’s anomaly P, in comparison with deformities caused by trematode Ribeiroia ondatrae (see Johnson's Lab), had no additional full limbs and can have small autopod elements in inguinal regions only. The most important difference is symmetry of bilateral traits: number of structures and their shapes usually same on both sides of the body.

The study of anomaly P was discontinued after Jean Rostand and did not resume for almost 50 years. In 2016, we found first severe cases of anomaly P in the Khopyor River drainage (Central Russia).

Svinin A.O., Bashinskiy I.V., Neymark L.А., Katsman E.A., and Osipov V.V. Morphological Deformities in Anuran Amphibians from the Khoper River Valley in the “Privolzhskaya Lesostep’” Nature Reserve and Adjacent Territories // The Second International conference “Amphibian and reptiles anomalies and pathology: methodology, evolutionary significance, monitoring and environmental health”, KnE Life Sciences, 2018: 150–155.

Svinin A.O., Bashinskiy I.V., Litvinchuk S.N., Neymark L.A., Osipov V.V., Katsman E.A., Ermakov O.A., Ivanov A.Y., Vedernikov A.A., Drobot G.P., and Dubois A. First record of the Jean Rostand’s “anomaly P” in the marsh frog, Pelophylax ridibundus, in central Russia // Alytes, 2019. 37: 31–45

And two years later we described new localities from Russia where severe cases of anomaly P was observed in two species of western Palearctic water frogs.

Svinin A.O., Bashinskiy I.V., Osipov V.V., Neymark L.A., Ivanov A.Yu, Ermakov O.A., and Litvinchuk S.N. New records of the anomaly P syndrome in two water frog species (Pelophylax ridibundus and P. lessonae) in Russia // Herpetozoa, 2019. 32: 277-281.



The frequency of anomaly P occurrence 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) form were noted in 20.0%.

Jean Rostand suggested that the anomaly P could be caused by some infectious agent transmitted by fish, which he hypothesized to be a teratogenic virus with a temporary effect on limb development.

We found that the mollusk Planorbarius corneus could be an intermediate host of the infectious agent of the anomaly P: symmetrical cases of polydactyly and severe cases of the anomaly P were obtained in the laboratory when tadpoles reared together with mollusk. As the most probable cause, we assume a species of trematodes, for which the first intermediate hosts are planorbid snails.

Svinin A. O., Bashinskiy I.V., Litvinchuk S.N., Neymark L.A., Ivanov A.Y., Ermakov O.A., Vedernikov A.A., and Dubois A. Planorbarius corneus is an intermediate host of the infectious agent of Rostand’s “anomaly P” in green frogs // Russian Journal of Herpetology, 2019. 26(6): 349 – 353.
The direct experiments with exposure to certain cercariae doses provide compelling evidence that Strigea robusta (Trematoda: Strigeidae) 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.

Svinin A.O., Bashinskiy I.V., Litvinchuk S.N., Ermakov O.A., Ivanov A.Yu., Neymark L.A., Vedernikov A.A., Osipov V.V., Drobot G.P., and Dubois A. Strigea robusta causes polydactyly and severe forms of Rostand’s anomaly P in water frogs // Parasites & Vectors 13 (381).
The anomaly P for a long time considered to be specific for water frogs of the genus Pelophylax. We described polydactyly and heavy forms of the anomaly P syndrome in toads of the genera Bufo and Bufotes, as a result of exposure to S. robusta cercariae. All anomalies in the toads were similar to those observed in water frogs.

Svinin A.O., Matushkina K.A., Dedukh D.V., Bashinskiy I.V., Ermakov O.A., Litvinchuk S.N. Strigea robusta (Digenea: Strigeidae) infection effects on the gonadal structure and limb malformation in toad early development // Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 2022. 1-12. Published Online
In both infected and uninfected tadpoles, we did not found differences in stages of gonadal development. Infected tadpoles exhibited similar to uninfected tadpoles distribution of diplotene oocytes and gonocytes throughout the ovary.

Moreover, we did not detect any difference in distribution of heterochromatin epigenetic modifications within germ cells and somatic cells in gonads of infected and uninfected tadpoles. In both groups, immunostaining against H3K9me3 showed accumulation on the periphery of cell nuclei as well as inside the nucleus on the periphery of nucleoli.

 Svinin A.O., Matushkina K.A., Dedukh D.V., Bashinskiy I.V., Ermakov O.A., Litvinchuk S.N. Strigea robusta (Digenea: Strigeidae) infection effects on the gonadal structure and limb malformation in toad early development // Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 2022. 1-12. Published Online

No limb anomalies were observed in syntopic amphibian species: Bombina bombina, Pelobates vespertinus, Rana arvalis and Lissotriton vulgaris.

This possible specificity of the action is of great interest, and the aim of our next work was to test the effect of S. robusta on tadpoles of brown frogs in the laboratory experiments.

The survival rate of tadpoles varied from 36 to 93%; 57% on average for R. arvalis and 77% for R. temporaria. Despite the presence of cysts in developing tadpoles, none of the experimental specimens showed anomalies. Thus, the specificity of the effect, previously assumed on the observations in nature, was confirmed in experiments.

 Svinin A.O. Effect of Strigea robusta (Digenea: Strigeidae) metacercariae on development of brown frog tadpoles // 13th European Multicolloquium of Parasitology, Belgrade, Serbia. October 12-16, 2021. p. 265.

Undoubtedly, records of abnormal tadpoles of Bufo bufo near Yailu from Lake Teletskoye is belonging to the records of severe cases of the anomaly P in toads, and these findings are the first and unique report of heavy cases of the anomaly P in toads (Yakovlev, 1984).

Yakovlev, V. A. (1984). Amphibians and reptiles of Altai Nature Reserve (PhD thesis), 161.

Even though we have demonstrated the ability of tadpoles to become infected and to show the anomaly P phenotype, there is a deficit of anomaly P severe forms observations in natural populations of amphibians. The study of interactions between phenology of spring migrations of birds, time of breeding of amphibians, and development of their larvae, lifespan features of mollusks, from the one side, and trematodes lifecycle features, from another, will help to answer on question about mosaic distribution of the anomaly P hotspots observed in nature.

The research was supported by the Russian Science Foundation grant № 21-74-00079 https://rscf.ru/en/project/21-74-00079/

Website @RANARIUM

Contacts
E-mail: ranaesc@gmail.com
Dr. Anton O. Svinin
Ph.D., researcher
Laboratory of Ecological Genetics and Metagenomics
Institute of Environmental and Agricultural Biology (X-BIO)
University of Tyumen
23 Lenina St., 625003 Tyumen, Russia