The Rediscovery of the Viscacha

Living in a megadiverse country such as Ecuador entails two major responsibilities: the conservation and the study of its biological richness. These are complex and complementary tasks; neither can function effectively without the other. We cannot conserve what is unknown, and we cannot study what has not been conserved. In Ecuador, we have become accustomed to adding new species to our fauna. In the case of mammals, this is an ongoing endeavor carried out by the Comisión de Biodiversidad of the Asociación Ecuatoriana de Mastozoología, which has produced semiannual updates for the past 15 years, with new records incorporated in every revision (e.g., Tirira, 2011a; Tirira et al., 2026). The discovery of new mammalian genera is less common, although it remains part of the normal process of advancing biological knowledge. Far more exceptional is the discovery of a new family. Yet this is precisely what occurred in 2006, when the presence of a viscacha was reported in Loja Province, a record that represented the addition of a new mammalian family to the fauna of Ecuador (Werner et al., 2006). A few months before the publication of that report, I received a telephone call from one of its authors, Rodrigo Hidalgo, a mathematics teacher at Eloy Alfaro National High School in Cariamanga and the person credited with discovering this finding for science. During our conversation, Rodrigo told me about the existence of a mammal inhabiting Cerro El Ahuaca, less than two kilometers from his workplace. He explained that this mammal is absent from all available references on the fauna of Ecuador. When he described its characteristics, he also mentioned its local name, arnejo, because local residents believed it to be something intermediate between a squirrel (ardilla) and a rabbit (conejo, in Spanish). At the end of the conversation, I remained somewhat skeptical, wondering whether this might be yet another instance in which local people reported the existence of a “new species” that ultimately proved to be no more than a variation or interpretation of a known form. That skepticism disappeared in 2006 with the publication documenting the discovery of a viscacha in Ecuador. It was the first representative of the family Chinchillidae recorded in the country and was identified as Lagidium cf. peruanum (Werner et al., 2006). This finding was only the beginning of a series of new questions. How had a species reached southern Ecuador when its closest known relatives at the time occurred in central Peru, more than 500 kilometers to the south (GBIF, 2026)? More intriguingly, was this one of the already recognized species of the genus Lagidium, or could it represent something entirely new to science? In 2007, independent genetic analyses conducted in two laboratories—one in Quito and the other in Santiago, Chile—confirmed that the Ecuadorian population represented a new species to science (Paz y Miño, 2007; Spotorno, 2007). However, the most remarkable aspect of this discovery was yet to emerge. With the formal description of the new viscacha under the scientific name Lagidium ahuacaense, genetic evidence demonstrated that the species occupied a basal position within the phylogenetic tree of the genus (Ledesma et al., 2009). This finding indicated that the Ecuadorian form was evolutionarily the oldest among all known viscachas and that the populations currently inhabiting Peru, Bolivia, Argentina, and Chile were descendants of the Ecuadorian lineage. As mentioned at the outset, this discovery represents only the first cornerstone of what it means to live in a megadiverse country. We now knew that a representative of the family Chinchillidae inhabited Ecuador; however, at that time the species was known solely from its type locality: Cerro El Ahuaca, 2 km from the city of Cariamanga in Loja Province. This situation raised considerable concern because its distribution was restricted to less than 1 km², and its population was estimated to comprise only about 200 individuals (Hidalgo & Tirira, 2011). Consequently, the species was categorized as Critically Endangered in the subsequent two editions of the Libro Rojo de los mamíferos de Ecuador (Tirira, 2011b, 2021). Over the following 15 years, I heard reports of additional records of the Ecuadorian viscacha (R. Hidalgo and R. Cisneros-Vidal, pers. comm.), although no formal publications documented these observations. For this reason, the lead article in the present issue of Mammalia aequatorialis, authored by Daniel Sarango-Peláez and colleagues, is of particular significance. Their study documents 15 new localities, substantially expanding the known distribution of the species and providing a much clearer understanding of its area of occupancy and habitat preferences. Nevertheless, the threats affecting most of the newly documented sites, together with the isolation of the colonies and their apparent lack of connectivity, remain a source of concern. These circumstances underscore the urgent need for a reassessment of the species’ conservation status and the development of an effective action plan for its protection. This issue of Mammalia aequatorialis is further complemented by a diverse collection of articles and scientific notes ranging from ethnozoological topics, such as a study of the Kichwa classification system for mammals in Pastaza Province, to reports of genetic disorders in bats, including cases of piebaldism documented in Orellana Province. Several contributions focus on medium- and large-sized mammals, including a study of their diversity in the upper elevations of Antisana National Park and records of tapirs from the eastern slopes of the Ecuadorian Andes. Carnivores are represented by four specialized studies: an analysis of strategies to promote coexistence among people, Andean bears, and pumas in Imbabura Province; and documentation of noteworthy records for Lycalopex sechurae, Leopardus wiedii, and Otaria byronia. In addition, for the first time, the journal includes a contribution from Paraguay reporting novel records of three mammal species from the southern portion of that country. The present issue concludes with two short communications describing Areas of Importance for Bat Conservation (AICOMs, by its Spanish acronym) in the provinces of Guayas and Manabí. This nongovernmental conservation strategy, led by the Red Latinoamericana y del Caribe para la Conservación de Murciélagos (RELCOM), seeks to highlight areas of particular importance for the conservation of these mammals. This is our second issue of 2026. The contributions presented herein undoubtedly enrich our understanding of Neotropical mammal diversity and further emphasize the importance of continued research and conservation efforts throughout the region.