A new protacanthopterygian fish from the Upper Cretaceous (Turonian) of the Pelotas Basin, southern Brazil

The Turonian age in the Pelotas Basin is represented by the Atlântida Formation, which consists mainly of marine dark shales and siltstones with intervening layers of carbonates. It has yielded a neritic fish assemblage that includes lamniform, pycnodontid, cladocyclid, clupeomorph, basal euteleostean, dercetid, enchodontid and holocentrid remains. In this assemblage there is a small fish, here described as Parawenzichthys minor gen. et sp. nov. It is characterized by having a low and elongate body, prominent snout, drop-shaped nasal, smooth dermal bones, toothless jaws, a mandible-suspensorium joint placed at the posterior portion of the orbit, very small pleural ribs, and at least 50 smooth vertebrae. Although superficially very similar to Santanasalmo elegans, known from the Albian of the Araripe Basin, it is separated by a combination of features of skull and, particularly, in the caudal endoskeleton. The first uroneural shows reduced anterior outgrowth and is fused to the compound centrum (first preural + ural centra), and the second uroneural is very long. There are six hypurals, the first of which is the largest. Taking into account the presence of derived conditions in the skull and caudal endoskeleton, the fish is assigned to Protacanthopterygii, sharing certain derived features with the argentinoid Wenzichthys congolensis from the non-marine Lower Cretaceous of Gabon (Africa).