Preliminary analysis of non-pollen palynomorphs (NNP’s) record of the Palo Pintado Formation (Upper Miocene), Salta Province, NW Argentina.

FARREL, EZEQUIEL ; MAUTINO, LILIAN RENÉ; LARA, MARIA BELÉN; JIMENEZ, V.; PALAZZESI, LUIS

Salta

Encuentro; Reunión de Comunicaciones de la Asociación Paleontológica Argentina.; 2022

ASOCIACIÓN PALEONTOLÓGICA ARGENTINA

The non-pollen palynomorphs (NPP´s) include a large variety of microscopic organisms (e.g., testate amoebae, algae, rotifers, cyanobacterias, plant tissues, fungal hyphae, arthropod remains), originated in a wide range of environments, ecological niches and climates. These organic-walled microfossils are resistant to corrosion and frequently are found within palynological preparations during pollen analysis. Generally, the NPP´s studies are scarce, receiving little attention, although they can provide useful information particularly when integrating multi-proxy data to reconstruct past landscapes (e.g., multidisciplinary studies). The Palo Pintado Formation (Angastaco Basin, Upper Miocene), Salta province, NW Argentina, is well-known by its diverse paleontological record that include macroflora (e.g., woods, leaves, fruits, seeds), microflora (palynomorphs), plant-insect interactions, vertebrate (e.g., fishes and turtle scutes, cranial and postcranial elements of amphibians, mandibular remains of caimans), and invertebrate (bivalves) remains. Besides its high content of spores and pollen, the palynological samples prepared have given abundant organic matter with a mixed microfossil (NPP´s). Therefore, in this contribution, we present a preliminary analysis on NPP’s recorded at Quebrada El Estanque and Quebrada del Horno localities, Palo Pintado Formation. The samples were treated with standard palynological laboratory techniques and subsequently, observed and photographed using a Leica DM500 microscope attached to a Leica ICC50 W digital camera. The palynological and non-pollen palynomorphs samples are housed in the paleontological collection “Dr. Rafael Herbst” at the Universidad Nacional del Nordeste (UNNE), under acronym CTES-PMP. A total of 10 palynological samples (CTES-PMP 1714, 1721, 1975, 1992, 1993, 2031, 2034, 2067, 2117, 3717, 3718) were selected according to their abundant organic matter content and excellent preservation. The Palo Pintado NNP’s record include fungal remains (hyphaes and spores: Inapertisporites sp., Massarinaceae: Tetraploa sp., Didymellaceae: Epicoccum sp., Halosphaeriaceae: cf. Cirrenalia sp., Sclerodermataceae: cf. Scleroderma, Pleosporaceae: Curvularia sp., Microthyriaceae: Microthyriacites sp., Pleosporaceae: cf. Alternaria), phytoclasts (cuticle, angiosperms vessel with simple pitts and xylem ray tissues remains), and zooclasts (insect scales, setae/hairs, arthropod mouthparts, and rotifer eggsBrachionus sp.). To these NPP´s record we must add previously described algae Hydrodictyaceae: Pediastrum simplex, Pediastrum boryanum; Zygnemataceae: Lecaniella korsoddensis, Lecaniella irregularis, Mougeotia laetevirens, and Ovoidites grandis). In addition to provide additional information for paleoenvironmental and climate reconstructions, the NPP’s recorded in Palo Pintado outcrops enrich our knowledge about palaeocommunities developed on different environments associated to floodplains (e.g., low mobility rivers, lagoons, overbanks, gravel bars) under stable and hot-humid climatic conditions during the Late Miocene times.