Hemiconcavodonta is known solely from late Ordovician, Caradoc epoch, fossils found in South America.

[1] Hemiconcavodonta minuta is a bivalve which was first described in 1999 by Teresa M. Sánchez from fossils from sediments of the late Middle Ordovician, Caradocian-aged Don Braulio Formation.

The formation outcrops on the flank of Sierra de Villicum in the Argentina precordillera.

[1] As a member of Concavodontinae, the hinge displays the chevroning of teeth typical of the subfamily.

However the placement of the umbo and anterior adductor muscle plus tooth size in the solitary fossil do not match H. minuta and thus Sánchez did not place the specimen into H.