A New Genus and Species of Weakly Armored Catfish from the Upper Mazaruni River, Guyana (Siluriformes: Loricariidae)

Paulasquama callis is a new genus and species of partially deplated ancistrin loricariid from the Waruma River, a tributary of the upper Mazaruni River, in northwestern Guyana. Paulasquama differs from all other described hypostomines by lacking plates in an oval area lateral to the mesethmoid, by having small plates in the dorsal series below the dorsal fin (less than half the typical size of other loricariids), and by having a fleshy keel on the preadipose plate and slightly anterior. The opercle of Paulasquama is sickle-shaped as in basal ancistrins, but has a posterior connection to the hyomandibula as in derived members of the Ancistrus clade.