A new triradial species from the Neoproterozoic formations of the Chenachene region, north-east of the Taoudeni basin (south-western Algeria)

Abstract

Precambrian life remains enigmatic, the traces of life of this period discovered throughout the world, have been interpreted differently; the observations made in the Chenachene region will deepen the knowledge and enrich the debate on these fascinating organisms.The Chenachene area represents the north-eastern margin of the Taoudeni Basin, where the Reguibat Shield outcrops with Pleoproterozoic metamorphic, metasedimentary and granitic series, constituting the Eburnian basement of the Eglab, surmounted in major discontinuity by a Meso-Neoproterozoic and Paleozoic sedimentary cover little or no deformed. A trace fossil was collected in a coredrill from the Chenachene region, in the Cheikhia-Bir Amrane Group, with an absolute age obtained by Rb/Sr ranging from 775 to 650 Ma corresponding to the Cryogenian.The diagnosis of the collected specimen allows us to recognize similarities with the genus Rugoconites described by Glaessner and Wade in 1966 from Flinders Ranges, South Australia, with notable differences from the two species already described (R. enigmaticus and R. tenuirugosus), which allows us to present it as a new species: Rugoconites reguibatensis.The exceptional state of preservation of Rugoconites reguibatensis has permitted to characterize it and reconstitute it, presenting great morphological similarities with present-day jellyfish, this revive, once again, the debate on the Precambrian life and the disappearance of this fauna at the end of the Proterozoic.