Middle Ordovician linguliformean microbrachiopods from western Argentina: new data and biogeographic implications

Abstract

New linguliform microbrachiopods from the Middle Ordovician are described and illustrated. This fauna was recovered from the uppermost beds of the San Juan Formation in two sections of the Central Precordillera (Argentina), which are accurately dated to the Lenodus pseudoplanus Zone (middle Darriwilian). The fauna consists of the obolid Luthieria diminuta n. gen. n. sp., and the acrotretids Eoconulus tucunucoensis n. sp., Conotreta andina Lavié, Serra, and Feltes, Scaphelasma zharykensis Popov, and Numericoma rowelli Holmer et al. This low-diversity lingulate association displays close similarities with coeval faunas that inhabited the Laurentia, Baltica, and Kazakhstanian regions, in agreement with evidence from other linguliform and rhynchonelliform brachiopods. UUID: http//zoobank.org/fe9acbb0-6654-4462-ba4d-ea2386ae79f6

Biostratigraphic and paleobiogeographic significance of the Darriwilian microfossils from the top of San Juan Formation in the Los Baños de Talacasto section, Central Precordillera (Argentina)

“…Moreover, based on Darriwilian Baltic signature of a number of linguliform and rhynchonelliform brachiopods from the Precordillera, Lavié and Benedetto (2016) infer that it was located in low-temperate latitudes like to Baltica. On the other hand, the acrotretids and other lingulid microbrachiopods from the San Juan Formation in the La Chilca section and La Brecha creek section display major similarities with those inhabiting low-latitude paleocontinents (Holmer et al, 2016;Lavié et al, 2021). Accordingly, the paleobiogeographic affinities shown by the Darriwilian conodont assemblage in the Los Baños de Talacasto section are in agreement with those observed in ostracods and other fauna.…”