Review About the Biodiversity of Pill Clams (Bivalvia, Sphaeriidae) in the Confines of the World, the Argentinean Patagonia

Abstract

This study aims at updating the diversity and distribution of Sphaeriidae in Argentine Patagonia, with a particular emphasis on the Santa Cruz Province. Samples were collected between 2015 and 2023 across diverse habitats, including rivers, lakes, lagoons, and Patagonian wetlands, and this was complemented by data obtained from a comprehensive literature review and a revision and improvement of major malacological collections. Both manual and sieve‐based collection methods were used to obtain specimens from different habitats. From 121 records analyzed, 101 records were identified to species level, including four species of

Pisidium

and two of

Sphaerium

.

Pisidium magellanicum

and

Pisidium patagonicum

were the most frequently recorded species.

Sphaerium patagonicum

demonstrated the broadest distribution, ranging from northern Neuquén to southern Tierra del Fuego. Santa Cruz Province had the highest number of records (57), followed by Chubut (24), with Río Negro and Tierra del Fuego having the fewest records. We report the first record of

Pisidium chilense

in Neuquén Province, providing new evidence of its presence in Argentine Patagonia. These findings advance our knowledge of Sphaeriidae distribution in Patagonia and highlight gaps in coverage, particularly in less‐sampled regions.