Late Cambrian (Furongian, Stage 10) linguliform brachiopods from the western margin of Gondwana, Cordillera Oriental, Argentina

A new and exceptionally diverse assemblage of late Cambrian (Furongian, Stage 10) linguliform brachiopods is described from the basal limestone layers of the Lampazar Formation, in the Quebrada Entre Ríos section (Sierra de Cajas, Jujuy Province, Argentina). This fauna, recovered from bioclastic-rich layers accumulated during storms in offshore environments in the Neoparabolina frequens argentina Zone, represents the first well-documented and most diverse Cambrian linguliform assemblage from the Central Andean Basin, west of Gondwana. It comprises the lingulids Lingulella sp. and Broeggeria sp., and the acrotretid Eurytreta cf. sarbinae. The first record of the genera Eoscaphelasma, Oaxaquiatreta, Olenekotreta and Dictyonina in South America includes Eoscaphelasma santaolallai sp. nov., Oaxaquiatreta argentina sp. nov., Olenekotreta? sp. and Dictyonina tetralobata sp. nov. Quantitative palaeobiogeographic analyses (cluster analysis and principal coordinates analysis) of this fauna indicate its closest affinities with contemporaneous assemblages from the peri-Gondwanan terranes of Oaxaquia (Mexico) and Alborz (Iran). The occurrence of Oaxaquiatreta supports the proximity of the Central Andean Basin to the Oaxaquia terrane along the Gondwanan margin. The record of widely distributed genera alongside more restricted taxa supports the existence of a dispersal route along the western margin of Gondwana during the late Furongian, which was likely to have been facilitated by ocean currents and peri-Gondwanan terrains acting as biotic bridges. This study significantly enhances our understanding of the diversity, composition and biogeographic connections of linguliform brachiopods during the Cambrian–Ordovician transition.

Papers in Palaeontology

Papers in Palaeontology

12

2056-2802

N/A

5

22