New Species of Macroalgae from Tamengo Formation, Ediacaran, Brazil

Abstract

The Tamengo Formation (Corumbá Group) is an important Ediacaran stratigraphic unit in South America due to the presence of metazoan fossils and geochemistry data of carbonate rocks, with excellent geochronological delimitation (between 555–541 Ma) obtained by U–Pb dating on volcanic zircons. The present work shows three new species of macroalgae found as carbonaceous compressions and studied for their morphology and taxonomy. All new taxa are characterized as centric macroalgae; Tamengophyton espinosa sp. nov. is a fan-shaped alga with striated thalli, dichotomous branches, trichomes with perpendicular growth, and a connecting membrane. Ladariella hidria sp. nov. is formed by a set of striated and branched thalli in a cylindrical form with almond-shaped structures in the top. Ladariophyton veinosa sp. nov. is characterized by the main growth thallus and an enlarged longitudinal structure at the center. These new occurrences of macroalgae add to the largest life assemblages in the Neoproterozoic of South America, which contributes to documentation of the evolutionary history of macroalgae and the paleoecological settings of the Late Ediacaran.

Artifacts resembling Ediacaran or Cambrian fossils: how to identify them and avoid their generation

“…The Tamengo Formation is predominantly composed of dark-gray limestones (grainstones, wackestones and mudstones) and reddish to ochre siltstones and shales (Amorim et al, 2020). This unit contains fossils of Cloudina, Corumbella werneri, Paraconularia ediacarensis, macroalgae and ichnofossils (Gaucher et al, 2003;Adorno et al, 2017;Parry et al, 2017;Diniz et al, 2021;Leme et al, 2022). The main exposures of the Tamengo Formation are located on the right bank of the Paraguai River between Corumbá and Ladário in the Corcal quarry and in the Laginha quarry (Boggiani et al, 2010;Fig.…”

Sedimentary and tectonic breccias at the base of the Ediacaran Tamengo Formation (Corumbá Group): a comparative study

“…The Bocaina Formation marks the onset of carbonate sedimentation, with stromatolitic dolomudstone facies and phosphorite layers (Boggiani et al 1993, Fontaneta 2012, with a Doushantuo-Pertatataka-like acritarch fossil assemblage (Morais et al 2021). The Tamengo Formation comprises breccias, grainstones and wackestones interbedded with shales, with Cloudina and Corumbella skeletonized fossils (Hahn et al 1982, Hahn and Pflug 1985, Adorno et al 2017, Becker-Kerber et al 2017, Zaine and Fairchild 1985, acritarchs (Zaine 1991, Gaucher et al 2003, macroalgae (Diniz et al 2021) and vendotaenids (Becker-Kerber et al 2021). Lastly, the younger unit of the Corumbá Group is the Guaicurus Formation, characterized by a thick succession of organic-rich black shales (Boggiani et al 2010, Fazio et al 2019, Amorim et al 2020, with organic-walled microfossils (Gaucher et al 2003).…”

Microscopic and geochemical analyses of the Tonian Longfengshan biota from the Luotuoling Formation (Hebei Province, North China) with taphonomic implications

“…Recently, taphonomic experiments revealed that non-mineralized organisms such as polychaetes can be transported without major damage (Bath-Enright et al, 2017). With this in mind, transportation or reworking may have been involved in the preservation of the Longfengshan biota (Diniz et al, 2021).…”