Lipanorthis Benedetto from the Tremadocian of NW Argentina reidentified as a dalmanellidine: Significance for the origin and early radiation of the punctate orthide brachiopods

The dalmanellidine brachiopods formed a diverse, abundant and long-lived group of Palaeozoic benthos, reaching their acme during the later Ordovician. The oldest members of the suborder occur in Arenig rocks, where both superfamilies, the Enteletoidea and Dalmanelloidea, are represented by relatively simple morphotypes. The reidentification of Lipanorthis Benedetto from the Tremadocian rocks of Argentina as a linoporellid significantly extends the record of the dalmanellidines into older strata. The relatively complex morphology of the recently described taxon and its marked morphological divergence from other Arenig dalmanellidine taxa suggest a significant pre-Ordovician record for the punctate orthide brachiopods.