The Pyrenean desman
Is it a rat??? Is it a platypus??? No!!! It’s the Pyrenean desman!
Known by the scientific society as Galemys pyrenaicus, this little and ―it has to be said― weird animal, belongs to the Talpidae family (that is, the mole family). Now, prepare yourself because I’m going to introduce you to one of my favourite words: Eulipotyphla. It sounds funny, doesn’t it? The term Eulipotyphla refers to a group of mammals that underwent a rapid diversification just after the Cretaceous-Paleogene boundary1 and includes members of the Talpidae family along with hedgehogs, shrews and solenodons (Fig. 1).
This species can be found in non-polluted mountain rivers in the northern half of the Iberian Peninsula. Nowadays, this species is endangered because of habitat loss and fragmentation, presence of pollutants and predation by non-native invasive species. Desmans are small semi-aquatic animals with a furry compact body, long tail, and peculiar flat trunk-like nose (Fig. 2). They show nocturnal habits and prey on aquatic invertebrates. Little is known about its ecology and behaviour. Due to the nocturnal habits and its habitat requirements, they are extremely difficult to spot. For this reason, any evidence about them is considered a treasure. I am going to be clear here, when a researcher finds a desman’s poo, feels like the luckiest human in the entire world. I will tell you why: DNA can be extracted from excrements to obtain very valuable information. Researchers have employed this methodology to reveal the presence of this animal in different areas2, but also to obtain information about its diet3.
Figure 1. Diversification of Eulipotyphla1
Figure 2. Artist impression of Galemys pyrenaicus4.
Now, I will reveal a little secret, I have experienced that poo-happiness. One of my best friends is a researcher who studies genetic material from insectivorous animals. I had the chance to go with him during one of his field campaigns. On that expedition, we had to walk upstream in the water with lanterns, carefully inspecting each space behind the rocks and waterfalls in search of desmans’ excrements. Our mission was successful, we found excrements of different aquatic animals. He taught me how to differentiate between them based on the consistency, colour and composition (so yummy, I know). One of those little excrements seemed to belong to our peculiar friend, so we put the sample into an Eppendorf tube and added alcohol to preserve it. Could this sample belong to a Pyrenean desman? We didn’t know yet, but, at that moment, I felt extremely (and weirdly) proud of carrying such a valuable sample in one of my pockets. The sample is now in his laboratory, waiting to be examined. After the genetic test, my friend will be able to disclose if we achieved our mission to get close to one of the rarest extant animals in Europe.
Additional information and references
1 Jun J. Sato, Tessa M. Bradford, Kyle N. Armstrong, Stephen C. Donnellan, Lazaro M. Echenique-Diaz, Gerardo Begué-Quiala, Jorgelino Gámez-Díez, Nobuyuki Yamaguchig, Son Truong Nguyen, Masaki Kita, Satoshi D. Ohdachi. Post K-Pg diversification of the mammalian order Eulipotyphla as suggested by phylogenomic analyses of ultra-conserved elements. Molecular Phylogenetics and Evolution. 2019, 141: 1-14.
2 Pere Aymerich, Francesca Casadesús, Joaquim Gosálbez. Distribució de Galemys pyrenaicus (Insectivora, Talpidae) a Catalunya. Orsis. 2001, 16: 93-110.
3 François Gillet, Marie-Laure Tiouchichine, Maxime Galan, Frédéric Blanc, Mélanie Némoz, Stéphane Aulagnier, Johan R. Michaux. A new method to identify the endangered Pyrenean desman (Galemys pyrenaicus) and to study its diet, using next generation sequencing from faeces. Mammalian Biology. 2015, 50: 205-209.
4 Enciclopedia Virtual de los Vertebrados Españoles. Galemys pyrenaicus.( in Spanish) Museo Nacional de Ciencias Naturales http://www.vertebradosibericos.org/mamiferos/galpyr.html
– Escoda, L, Castresana, J. The genome of the Pyrenean desman and the effects of bottlenecks and inbreeding on the genomic landscape of an endangered species. Evol Appl. 2021; 14: 1898–1913. https://doi.org/10.1111/eva.13249
– Desmán (Galemys pyrenaicus) en la Península Ibérica (in Spanish). Ministerio para la Transición Ecológica y el Reto Demográfico. https://www.miteco.gob.es/es/biodiversidad/temas/conservacion-de-especies-amenazadas/vertebrados/desman_peninsula_iberica.html
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