Taphonomy of Death Assemblages of the Freshwater Bivalve Corbicula Fluminea (Müller, 1774) (Veneroidea) After Three and Four Decades in the Upper Río De Laplata, Uruguay

The invasive bivalve Corbicula fluminea has been known in the Río de la Plata for approximately 40 years. This decadal time lapse fill a gap in taphonomic studies. Our study is the second to investigate taphonomic modifications on valves of this species in Uruguay, expanding the temporal resolution of the first. We divided the valve into four sectors and recorded fragmentation, periostracum loss, and corrasion, categorizing these attributes into three severity levels. We also observed no attempts at bioerosion and bioencrustation. The central sector is the most frequent among all samples, and the posterior one is the least frequent. The differences in damage were tested using the X2 test, the Bonferroni correction, and an average taphonomic score. We evaluated the extent of taphonomic damage over time by comparing the average taphonomic score using Kendall’s tau. The tests revealed several statistically significant differences. The umbonal and posterior sectors are differently represented, with the 2008 sample being different in both cases. The central and anterior sectors do not exhibit differences. Fragmentation exhibits differences in all sectors except the anterior over the years; category 0 is the most represented in all years and sectors. Periostracum damage shows no statistically significant differences in sectors or years; category 2 is the most represented. Corrasion differs among the three samples, varying over the years in different sectors; category 2 is the most represented. In conclusion, there are statistically significant differences in the sectors represented and in fragmentation. However, no linear trend was observed over the years.