A NEW RECORD OF BRYOGRAPTUS KJERULFI (GRAPTOLITHINA) FROM THE JUJUY PROVINCE: BIOSTRATIGRAPHIC AND PALEOECOLOGIC SIGNIFICANCE

HERRERA SÁNCHEZ, NEXXYS C.; TORO, BLANCA A.; MUÑOZ, DIEGO F.; LO VALVO, GERARDO A.

Buenos Aires

Congreso; XII Congreso de la Asociación Paleontológica Argentina; 2021

Asociación Paleontológica Argentina

Centro de Investigaciones en Ciencias de la Tierra repository, allows confirming the early?upper Tremadocian age of the deposits exposed at the Corte del Ferrocarril section, Jujuy Province. The characteristic pendent habit in lateral view, the slender stipes with slightly undulating dorsal side, but without visible dissepiments connecting them; and the thecal style with a moderate inclination of the ventral walls, scarce overlapping, and considerable high spacing are in agreement with previous taxonomic revisions of Bryograptus kjerulfi. This species is restricted to the eponymous biozone at northwestern Argentina and it is widely described in many Early Ordovician sections located in the Salta Province (Cuesta de la Pedrera, Parcha, Santa Victoria, Floresta, and Miraflores), whereas it was previously mentioned only for the Angosto del Moreno section in the Jujuy Province. This study expands the regional correlation of the bearer deposits corresponding to the Rupasca Member of the Santa Rosita Formation, based on the occurrence of B. kjerulfi which also constitutes a key taxon for precise global correlations. From the paleoecological point of view, it is widely accepted that the global distribution of this species is restricted to intermediate to high paleolatitudes. In addition, the current analysis indicates the tolerance of B. kjerulfi to a higher energy environment than the previously proposed one. This confirms the expansion of the habitat distribution of the species from the outer shelf to the upper offshore paleoenvironment.