The genus is distinguishable by the combination of these ziphodont teeth and a deep, altirostral skull that is sometimes compared to those of sebecosuchians and planocraniids, leading some early researchers to mistakenly assign Quinkana to said groups.

The precise reasons for Quinkana's disappearance are unknown, but it is hypothesized that another period of intense aridification gradually dried up the river basins and destroyed the forests that the crocodilian inhabited, leading it to go extinct alongside much of Australia's megafauna.

This rostrum was noted for its unusual form, with a much deeper snout compared to extant crocodilians and toothsockets indicative of ziphodont teeth, a combination of traits previously unknown from Australia.

[3][4] These discoveries caught the attention of paleontologist Ralph Molnar, who described Quinkana as a genus in 1981 based primarily on the rostrum from the Chillagoe caves, though he also dealt with much of the more fragmentary material including the Chinchilla jugal and teeth from the Darling Downs region.

[7] Shortly after this, in 1994, Quinkana timara was named by paleontologist Dirk Megirian as a second species within the genus, although the timing of events meant that he could not properly address the newly erected Mekosuchinae in the main text of his publication.

The holotype (QM F23220), a fragment of the maxilla, was uncovered in 1991 by Mackness at the Dick's Mother Lode Quarry in the Charters Towers Region of northeast Queensland, a locality that would have been intermediate in time between those of the two previously named taxa.

Partly for this reason, the diagnosis that had been established by previous works for Quinkana was altered the most significantly by Willis and Mackness, removing features such as the prominent knobs before the eyes as they are not preserved in their taxon.

Among the more notable later finds was the discovery of a ziphodont tooth in the Late Pleistocene King Creek catchment of the eastern Darling Downs, an otherwise well sampled locality known for its abundant material of Megalania.

[9] A late Pleistocene tooth (QM F57032) was found in 2013 in the Kings Creek site of southeastern Queensland and shares similarities with teeth traditionally assigned to Quinkana fortirostrum, though the holotype of said species is actually toothless.

The snout of Quinkana fortirostrum is noticeably deep and angular, its proportions somewhat resembling much older fossil crocodylomorphs such as the planocraniids that existed during the Paleogene across the northern hemisphere and the sebecosuchians that were primarily found in South America from the Cretaceous to the Miocene.

Willis and Mackness also discuss the matter, arguing that the fact that the contact between maxilla and jugal on the inner side of the skull sits before the eyes means the external suture must have been located even further to the front.

In addition to the narial rim surrounding the animal's nostrils and the highly sculpted nasal bone, some species of Quinkana also feature a distinct crest located across the maxilla and sometimes premaxilla.

Lateral festooning was likewise not well developed, which means that when viewed from above skulls of Quinkana did not have the sinuous outline like other crocodilians, which is marked by the presence of multiple constrictions and expansions of the maxillae.

Initially, this notion was rejected for Quinkana fortirostrum on account of the narrowing maxilla,[5] however as Megirian points out the lack of space for an additional tooth could have been compensated for by the ectopterygoid bone.

[8] The precise size reached by species of the genus Quinkana is a matter of debate, but generally hard to determine both due to the absence of significant postcranial remains and the fragmentary nature of most known material.

In a 2018 tip dating study by Lee & Yates, morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data were used simultaneously to established the inter-relationships within Crocodylia.

Below, the left cladogram shows the placement of Quinkana within Mekosuchinae according to their study, placing it as a derived member of the group most closely related to small dwarf forms such as Mekosuchus and Trilophosuchus.

[23][24] Another study dealing with the postcranial anatomy of mekosuchines was published by Stein and colleagues in 2017, specifically examining the shoulder girdle and hips of these animals based on fossils found across Australia.

Stein and colleagues note that this derived state, primarily achieved by the more enclosed acetabulum and expanded iliac crest, would match the cursorial habits and terrestrial lifestyle often inferred based on the cranial material.

Crocodilian specialist Christopher Brochu for example maintains that the hooves of planocraniids were an anatomical feature rather than the result of taphonomy, with members of said group still being considered to have been largely terrestrial.

[28] Q. babarra appeared in the Bluff Downs Local Fauna alongside an undetermined species of Crocodylus and a mekosuchine possibly referrable to Paludirex, while non-crocodilian predators include the marsupial Thylacoleo, giant snakes and large monitor lizards.

[9] The environment of this region has previously been suggested to have been similar to today's Kakadu National Park, featuring a well developed aquatic ecosystem surrounded by vine thickets and rainforest.

[21] At King Creek Quinkana is known to have coexisted with Megalania and a wide range of potential prey items including Protemnodon, Macropus titan and other kangaroos, Diprotodon and Troposodon, though it is noted that it was likely rare in eastern Queensland relative to other parts of Australia.

While the herbivore fauna is composed of diprotodontids, kangaroos, palorchestids, wombats and the emu, carnivores are represented by Thylacoleo, two species of monitor lizards (including Megalania) and three crocodilians, once again showing how multiple members of the latter group seemingly coexisted alongside each other.

[12] Overall, the range of Quinkana, whether it was terrestrial or not, appears to have been closely linked to freshwater systems, in particular those surrounded by riparian woodland and vine forests,[29][22] typically sharing this environment with a plethora of other crocodilians.

[10][12][26] This would match the circumstances of its extinction as well, as researchers have noted that the disappearance of Quinkana coincides with an abrupt burst of aridification that lead to the drying of various river systems and the subsequent collapse of the local woodlands.

While this is thought to have prompted a major faunal turnover, with taxa such as Paludirex and Kalthifrons filling the niches of Baru and kin, this burst of aridification does not appear to have affected Quinkana greatly.

The fossil of the South Walker Creek site were given particular attention by Hocknull and colleagues in 2020, who studied the locality in an attempt to better understand the extinction of Megafauna in eastern Australia (then part of the continent Sahul).

[21] Sobbe, Price and Knezour for example describe the process of aridification as destroying the closed woodlands and vine scrublands that previously covered the landscape and leading to an expansion of open grasslands, which were oftentimes subject to prolonged periods without rain.

They argue that this progress may have begun as early as the beginning of the Pleistocene, with the team noting a marked decline in Quinkana material in the eastern Darling Downs following the end of the Pliocene.