Merodoras nheco, new genus and species from Rio Paraguay basin, Brazil (Siluriformes, Doradidae), and nomination of the new subfamily Astrodoradinae

Abstract

Merodoras nheco, new genus and species of Doradidae (Siluriformes) is described from Rio Paraguay basin, Brazil. The new genus belongs to the new subfamily Astrodoradinae, a monophyletic group formally named herein that includes, besides Merodoras, Amblydoras, Anadoras, Astrodoras, Hypodoras, Physopyxis, and Scorpiodoras. This group is diagnosed by the possession of: lacrimal serrated and participating in the orbital margin, four to seven pleural ribs; spines on the postcleithral process; postero-inferior portion of the coracoid exposed. Merodoras nheco, new species, is distinguished from other doradids by the unique combination of the following characteristics: 1) tips of retrorse spines on the midlateral scutes ventrally oriented in adults; 2) incomplete lateral line, with only a few midlateral scutes anteriorly; 3) pectoral girdle entirely exposed ventrally, with the opening of the arrector ventralis inferior reduced to a small fossae on the anterior edge of the coracoid; 4) caudal fin truncate; 5) dorsal-fin spine smooth, without serrae on both faces; 5) lacrimal serrated; 6) lateral ethmoid serrated. Merodoras nheco inhabits the "Pantanal Matogrossense," a flooded portion of the upper Rio Paraguay basin in western Brazil. Copyright © 2007 Magnolia Press.