2026/07/29 by Patricia Pérez, Alejandra P. Pérez, María Cristina Marinone +3
Earth and Planetary Sciences · Environmental Science · #Aquatic Ecosystems and Phytoplankton Dynamics #Aquatic Invertebrate Ecology and Behavior #Geology and Paleoclimatology Research
paper · doi:10.1177/09596836261468284
openalex publication_date 2026/07/29 · openalex created_date 2026/07/31 · openalex updated_date 2026/07/31
Subfossil remains of Daphnia preserved in lake sediments provide valuable archives for reconstructing past limnological and environmental conditions. However, due to the fragility of their chitinous exoskeleton, members of the family Daphniidae are usually underrepresented in sediment records, limiting their paleoecological potential. In a high-altitude basaltic plateau of Argentine Patagonia, we recovered well-preserved head shields of Daphnia ( Daphnia ) commutata from lacustrine sediments dated to ca. 7000 cal yr BP. This finding represents the first record of Daphnia head shields in South America, expanding the scarce global evidence of their preservation. We include images and detailed descriptions of both extant and subfossil cephalic shields to support their recognition in other fossil records. The unusual integrity of these remains is likely linked to the combined influence of biological, environmental, and taphonomic factors. We hypothesize that the presence of multiple invertebrate predators capable of inducing defensive morphologies, together with the natural absence of fish and the cold, oligotrophic, and seasonally ice-covered conditions of the lake, enhanced the resistance and long-term integrity of the shields. These results provide observational evidence relevant to the taphonomy of Daphnia remains and highlight the potential of Patagonian plateau lakes as valuable archives for paleolimnological studies.