Kalthifrons is an extinct monospecific genus of mekosuchine crocodylian known from the Pliocene Tirari Formation of Australia. More specifically, Kalthifrons was recovered from the Mampuwordu Sand Member, which underlies the younger sediments of the Pompapillina Member. This is significant, as the latter preserves some of the earliest records of the genus Crocodylus in Australia, which would eventually go on to replace mekosuchines. It is currently unclear whether or not the Tirari Crocodylus directly outcompeted Kalthifrons or simply moved into the region after the niche was left empty by the extinction of the local mekosuchines. Should the later be the case, then Kalthifrons may have simply been the victim of global cooling and aridification. A point in favour of the competition hypothesis is that both Kalthifrons and the Tirari Crocodylus have broadly similar skull forms, with both being interpreted as generalist semi-aquatic predators much like many of today's crocodiles. Though far from large, Kalthifrons was nonetheless bigger than many other mekosuchines such as Trilophosuchus and Mekosuchus. The genus is monotypic, meaning it contains only a single species, Kalthifrons aurivellensis.

The remains of Kalthifrons were discovered on the western shores of Lake Palankarinna in South Australia's Lake Eyre Basin. The holotype (specimen SAM P35062), consisting of a cranium and two mandibular rami, was recovered from the Mampuwordu Sand Member of the Pliocene Tirari Formation. The fossil was discovered upside down, causing the area of the palate to be exposed to the elements and thus damaging it significantly. On top of this weathering of the surface, the fossil underwent significant compression during preservation, causing it to appear much flatter than it would have in life. The Golden Fleece Locality, where the fossils were discovered, also yielded a variety of isolated remains, mostly consisting of teeth, osteoderms and vertebrae. While the lack of overlap means that none can be definitely proven to have been those of Kalthifrons, the fact that the locality is thought to have been a mass death site has been used to argue that they likely represent a single species. As a result of this, the material was tentatively referred to Kalthifrons.

The generic name derives from the Dieri word for "spear" (kalthi) and frons, meaning forehead, a name chosen in reference to the animal's elongated frontal process. The species epithet is a combination of the Latin "aurum" for gold and "vellus" meaning fleece, chosen to reflect the locality where the fossil has been discovered.

Kalthifrons possessed a relatively short and roughly triangular skull that broadly resembles that of today's crocodiles, indicating that it was a generalist predator. Additionally, the snout is described as platyrostral, effectively meaning that it was flattened. However, the precise degree to which this applies is difficult to determine as the holotype skull was badly crushed during preservation, greatly exaggerating its form in profile view. Adam Yates and Neville Pledge speculate that the skull of Kalthifrons may have been moderately deep, making it similar to that of Baru, given that the former preserves a distinct swelling above the fifth maxillary tooth that would be absent in an animal with a very deep (altirostral) skull similar to Quinkana.

The tip of the snout appears to have been differently proportioned in Kalthifrons when compared to other mekosuchines. The premaxillae are narrow and the external nares are longer than they are wide, contrasting with those of its closest relatives. The nares themselves are almost entirely surrounded by the premaxillae, save for a small section where the nasal bones contribute. The region where the premaxilla transitions to the maxilla is marked by a prominent notch where the jaw is constricted to make space for the fourth tooth of the lower jaw, something commonly seen in crocodilians. While this condition can be observed in a variety of mekosuchines, it does help distinguish Kalthifrons from Australosuchus, as in the latter the fourth dentary tooth slides into a nearly enclosed hole in the bone rather than an open notch. Behind this notch, the maxillae swell laterally, forming a boss around the location where the fifth maxillary tooth would sit. The eyesockets, also known as orbits, are located comparably far towards the front to the skull, at least relative to other crocodilians. This condition is similar to that found in Baru darrowi, and is present due to the fact that the front of the orbits forms a narrow point that extends up until the eleventh tooth of the maxilla. The orbits are also noted for being large, with their individual diameters being much greater than the distance between them. Overall the orbits have an uneven shape, with the anterior segment being pointed, while the main part of the orbits is more circular in shape. This shape is partially caused by how the prefrontals contribute to the orbital margin, as these bones form prominent flanges that extend into the orbits. The lacrimal bones, which are situated before the prefrontals, are elongated and irregularly triangular in shape. Thick ridges extend from the lacrimal's contribution to the orbits until the pointed tip of the bones. These ridges are the result of a distinct change in slope, unlike in the Saltwater Crocodile, which has preorbital ridges raised above the rest of the skull. In general, the ridges seen on Kalthifrons resemble those of Baru wickeni.

The most characteristic feature of Kalthifrons, and the one it was named for, is its frontal bone. As is typical for crocodilians, the frontal is divided into two segments, the posterior one of them is broad and makes up the space between the eyesockets and part of the skull table. The anterior process meanwhile is generally long and slender, however, in Kalthifrons this is taken to an extreme as the anterior process extends much further down the rostrum as is typical, accounting for about 64% of the frontal's entire length. Additionally, the space between the eyes is much wider than in Australosuchus, owing to the greater width of the posterior section of the frontal.

The skull table is flat and trapezoid in shape with elliptical supratemporal fenestrae similar to those found in Trilophosuchus. The fenestrae are widely spaced, much wider than each fenestra is long, with the interfenestral bar being formed entirely by the parietal. The massive distance between the fenestrae is unusual for mekosuchines and only one other species is noted for having similar proportions, that being an unspecified species of Baru from the Alcoota fossil site. Though small, the fenestrae are largely unobscured by the surrounding bones overhanging it, with only the parietal slightly overhanging the rear-most corner of the fenestrae. The supraoccipital, though exposed on the dorsal surface like in the majority of mekosuchines, is narrow, and only makes up a small part of the skull table. The supraoccipital is described as semilunate in shape, whereas it is triangular in most other mekosuchines.

Since the mandibular remains found alongside the holotype skull are poorly preserved, little information could be gathered from them. The most notable aspect of the mandible is that the flat underside is offset from the side by a nearly 90° bend. This is most similar to mandibles that have been referred to Quinkana.