Crocodylus robustus was named by Grandidier and Vaillant (1872) [Osteolaemine crocodylid with a prominent triangular crest at the posterolateral corner of each squamosal and a pair of oval bosses on the frontal between the orbits. Supratemporal fenestrae constricted, with no dorsal fossae. Nasals form thin processes that penetrate the narial rim, but premaxillae approach each other closely behind external naris. Surangular–angular suture intersects external mandibular fenestra at the posteriormost end laterally and does not pass anteriorly along the ventral margin of the fenestra (reversal of derived feature in crocodylids). Circular boss on medial surface of splenial. Vaulted premaxillary and maxillary palate surfaces. Shares everted choanal margin (choanal ‘neck’) and lateral extension of squamosal on to quadrate ramus with other osteolaemines; shares broad supraacetabular buttress and altirostral skull with Osteolaemus.]. Its type specimen is MCZ 1006 (neotype), a skull, and it is a 3D body fossil. Its type locality is Ambolisatra, which is in a Holocene terrestrial horizon in Madagascar.

It was recombined as Voay robustus by Brochu (2007); it was considered a nomen dubium by Jouve et al. (2008), Puértolas et al. (2011).