The current specimen consists of a partial skull and fragments of a long, slender snout reminiscent of that of a false gharial, demonstrating that it was a piscivore in life.

It was originally tentatively placed within a group of Australian crocodilians now known as the Mekosuchinae, although this has been frequently disputed, with other authors instead suggesting it may have been a more basal crocodyloid or a type of gavialid.

Harpacochampsa was named on the basis of several bones, primarily of the skull, discovered at the Bullock Creek fossil site in the Northern Territory of Australia.

As a whole, the snout tip is relatively deep for its width, the cross-section resembling a flipped D towards the back of the preserved bone with a flat palate and sloping lateral edges.

The nares are slightly longer than wide and set far forward on the snout, almost entirely surrounded by the premaxillae except for a small area to which the nasal bones contribute.

Several other characters of the skull table are generally similar to gharials as well, such as the relation between fenestra and the surrounding squamosals and parietal bones and the shape of the orbito-temporal artery.

However, given the sparse material and uncertain internal relationships within Eusuchia, including the position of Tomistoma, the authors were hesitant to specify its exact placement with certainty.

[5] A second longirostrine mekosuchine would eventually be described in 2016 in the form of Ultrastenos, however phylogenetic analysis conducted at the time found that the inclusion of Harpacochampsa in the family does cause noise in the resulting phylogeny.

Australosuchus clarkae Volia athollandersoni Baru darrowi Mekosuchus sanderi Lastly, although the gavialoid affinities of Harpacochampsa have traditionally been dismissed, some research still suggest that the taxon is best placed within Gavialoidea alongside tomistomines as a basal grade within the clade.