Diplodon Cf. Colhuapiensis (Bivalvia - Hyriidae) in the Santa Cruz Formation (Early-Middle Miocene), at the Río Santa Cruz, Patagonia, Argentina. Stratigraphic and Paleoenvironmental Considerations

Abstract

The Santa Cruz Formation (Early-Middle Miocene) is one of the most widespread sedimentary units of the Argentine Patagonia. This unit contains an abundant and taxonomically diverse fossil vertebrate fauna, especially in mammals. Thus, the paleoecological and paleoenvironmental information derives mainly from the analysis of the vertebrate assemblages, as well as from the ichnological and paleobotanical evidence. The record of freshwater bivalves assigned to the species Diplodon cf. colhuapiensis Ihering, 1903 from the Santa Cruz Formation, collected in the locality of Barrancas Blancas (Estancia Santa Lucía), at Río Santa Cruz, allows us to infer the particular paleoenvironmental conditions setting during the deposition of the bearing levels. Considering this record, we propose that Diplodon, which was originally assigned to the "Sehuenense stage" (piso sehuenense of F. Ameghino), could have come from the Early-Middle Miocene of the Santa Cruz Formation. In this sense, the specimens referred to Diplodon cf. colhuapiensis suggest the existence of an established community of Hyriidae mollusks at the upper-middle levels of the Santa Cruz Formation. The presence of freshwater bivalves suggests that the depositional environment of this unit included the existence of water courses. The identification of the genus in the Santa Cruz Formation validates its presence in the Early Miocene and extends its southern distribution to the latitude of Río Santa Cruz (~ 50º S).

Stratigraphy and Depositional Environments of the Santa Cruz Formation (Early-Middle Miocene) Along the Río Santa Cruz, Southern Patagonia, Argentina

“…In this locality, besides the fossil vertebrate collection (Fernicola et al, 2019b), a level bearing the freshwater bivalve Diplodon sp. was found (Pérez et al, 2019).…”

From Pixels to Deposits: Porphyry Mineralization With Multispectral Convolutional Neural Networks

“…Number of study areas References Sudan 1 [39], [40], [41] Namibia 1 [42], [43], [44] Argentina 4 [45], [46], [47] , [48], [49], [50], [51], [52], [53], [54], [55], [56] Iran 4 [57], [58], [59], [60], [61], [62], [63], [64], [65] , [66], [67], [68], [69], [70] Pakistan 3 [71], [72], [73], [74], [75], [76] , [77], USA 5 [71], [78], [79], [80], [81], [82], [83] [84], [85], [86], [87] , [88], [89]…”

Náyades (Bivalvia - Hyriidae) en El “Conglomerado Osífero” (Mioceno Tardío), Entre Ríos, Argentina

“…It is true that Rhipidodonta Mörch, 1853, can also be included in this definition. Rhipidodonta was considered traditionally as a subgenus of Diplodon (e.g., Parodiz & Bonetto, 1963;Haas, 1969), but other authors, such as Simone Formation (Parodiz, 1969;Pérez et al, 2019), are more elongated, have a less prominent and less inflated umbo and their dorsal and ventral margins are straighter. In addition, no umbonal sculpture is known for these taxa.…”

“…Hyriidae Swainson, 1840 are represented in this continent by seven genera and approximately 249 species (Torres et al, 2018), distributed from equatorial latitudes to the southern lakes and rivers of Argentinean and Chilean Patagonia (see Ageitos de Castellanos, 1959;Bonetto, 1973). One of the most widespread genus is Diplodon Spix in Wagner, 1827 with many fossil and living species (see Torres et al, 2013Torres et al, , 2018Pérez et al, 2019). Present day, the greatest diversity of Diplodon is found in the relatively clear waters of the upper Paraná River (Torres et al, 2013).…”

“…In Argentina, Diplodon has a long temporal range, from the Middle Jurassic to the present (e.g., Ihering, 1903;Doello Jurado, 1927;Pilsbry & Olsson, 1935;Parodiz, 1969;Manceñido & Damborenea, 1984;Morton & Herbst, 2001;Parras & Griffin, 2013;Pérez et al, 2019). However, records of Diplodon in the Mesopotamian region are relatively scarce (Frenguelli, 1920;Herbst & Camacho, 1970;Morton & Jalfin, 1987;Morton & Sequeira, 1991;Morton, 2004).…”