Searching needles in a (big) haystack: multidisciplinary studies about extreme environment terrestrial snails from the high Central Argentinian Andes

DELAGNOLLA, F.; MIRANDA, M. J.; CUEZZO M.G.; VITALE, N.; VEGA, I.

San Pablo

Congreso; EBRAM & CLAMA 2023; 2023

Asociacion Latinoamericana de Malacologia

Searching needles in a (big) haystack: multidisciplinary studies about extreme environment terrestrial snails from the high Central Argentinian AndesFederico Dellagnola1,2,3*; Maria Jose Miranda4,5; Gabriela Cuezzo5; Nydia Vitale6; Israel Vega1,2,31Instituto de Fisiología, Universidad Nacional de Cuyo; 2Instituto de Histología y Embriología de Mendoza (IHEM-CONICET); 3Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo; 4Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán; 5Instituto de Biodiversidad Neotropical (IBN-CONICET), 6Centro para la Conservación de la Biodiversidad (CCB-MM) *fdellagnola@fcm.uncu.edu.arFrom Spring 2019 to date, we developed a malacological survey in the Central Andes from Argentina, a vast mountainous area with an abrupt topology and several parallel mountain ranges. To date, ~300 kilometres of routes and 207 sites (ranging from 1346-4291 m.a.l.s.) were revisited in three geographical unities which differ in climatological and ecological traits, i.e. Eastern and Central Precordillera, and Cordon del Plata (Cordillera Frontal). Specimens of some Bostryx species occurred between 1907-3827 m.a.l.s., being taxonomically reviewed with the description of a new species found at Lomas Blancas peak (Cordon del Plata range). All species were described, some for the first time, using novel conchological and anatomical information. Radula, jaw and pallial organs were similar among species. The distinctive morphological characters were the shell shape, size and teleoconch sculpture; the genitalia differed in shape and relative proportion of organs, such as the bursa copulatrix duct, vagina, flagellum and vas deferens. Molecular analyses (mtCOXI, mt16S and ITS2) suggested differences between geographical populations, some of which would be extremely small in number as in spatial distribution; these differences were seen in both DNA-based trees and ITS2 RNA secondary structure. Some ecological traits (altitude, terrain, exposition, soil, plants/lichen richness and coverage) were analysed, the most snail richness associated with exposed, highest ridges with a slope of 25-45% and scarcely developed mixed soils, being keys to the presence of lichens cover of >25% in bare rock. In the Cordon del Plata (the most diverse unity in snail species), the cold season displayed low air temperatures (daily mean ~0°C) with high variability in minimum temperature and snow coverage; however, the soil temperature and relative humidity were constant in the summery season. This multidisciplinary approach suggests the existence of a hidden diversity of patchy populations that occurs in fragile extreme high-mountain ecosystems.Keywords: Bostryx; New species, Anatomy, Molecular markers; Endangered species, Climate change impact.Acknowledgements: We thank Gonzalo Dell agnola and Margarita Mante (Adventure Andes Team) for guided expeditions and logistic support.