Genus Trygonorrhina Müller & Henle, 1838

Type species. Trygonorhina fasciata Müller & Henle, 1841 (by monotypy).

Description. Anterior nasal flaps fused to form a broad, rectangular nasal curtain, its lateral and posterior margins almost straight (recessible into internasal space and not overlapping mouth). Nostrils small and largely concealed beneath nasal curtain; internasal distance subequal nostril length posterior aperture absent. Anterior aperture small, suboval; anteriormost part of nasal curtain forming a broad fold-like valve, partly inside anterior aperture; lateral and posterior margins of anterior aperture bordered with narrow subcircular posterolateral nasal flap, extending medially beneath nasal curtain and almost to innermost corner of nostril as broad free lobe. Lower jaw straight to slightly convex with single posteriorly directed lateral groove at its angle; short oral groove near angle of jaw, but its extension not well formed on chin.

Species. T. dumerilii (Castelnau, 1873), T. fasciata Müller & Henle, 1841.