New contributions on the paleobiogeography of linguliform brachiopods from Ordovician of the Precordillera Argentina

LAVIÉ, FERNANDO J.; BENEDETTO, J. L.

Congreso; Online Annual Meeting of IGCP 635; 2020

In the last decade, several analyzes on the biogeographic distribution of Ordovicianlinguliform brachiopods have been carried out (e.g. Popov et al., 2013; Holmer et al.,2016). In the present study, we reassess the biogeographic affinities of the Middleand Upper Ordovician linguliform genera recorded globally, including new data fromthe Precordillera of western Argentina (Cuyania terrane). Clustering analyzes andPCoA (Principal Coordinate Analysis) were performed using the Dice and Raup-Crickindices in two sets of taxa, one including the genera present in the Middle Ordovicianand the other those present in the Upper Ordovician (both excluding endemicgenera). Results obtained in this paper based on linguliform brachiopods mostlymatch with the patterns observed in other benthic groups from Cuyania (mainlyrhynchonelliformean brachiopods). During the Darriwilian, many of the genera fromthe Precordillera show clear Laurentian and Baltic affinities, sharing with theseregions at least 13 genera (excluding cosmopolitan and widely distributed taxa).Additionally, there are several genera in common with the Kazakhstanian terranes.Another remarkable feature is the appearance in the Precordillera of some endemictaxa, which also have been recorded in the Famatina Range, on the western marginof Gondwana. By the Late Ordovician, however, despite the scarcity of data at theglobal scale (Popov et al., 2013), many genera become restricted to Laurentia andare absent in the Argentine Precordillera. This pattern may be due to the fact that atthis time the Cuyania terrane was already close to the western margin of Gondwana(the so-called ?pre-accretion stage?, Benedetto et al., 1999).