PETROBRASIA Krömmelbein, 1965

Type Species: Dolerocypris ? marfinensis Krömmelbein, 1962

Diagnosis: Carapace in lateral outline from a rounded triangle to rounded trapezoid or drop shaped. Anterior margin broadly rounded, posterior margin decidedly narrowly rounded, narrowing strongly almost to a point; dorsal margin highly curved; ventral margin always more or less distinctly indented in anterior third. Carapace in dorsal view moderately to slimly biconvex. Carapace surface embellished with more or less fine or also more definite little ridges, in some cases linked together like a mesh, which run more or less clearly parallel to the lengthways margins. Some species presumably completely smooth. In the case of sculpted species, a shell area between the dorsum and muscle field remains more or less free from sculpture.