Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They represented the dominant group of crocodilians in the region during most of the Cenozoic. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Late Pleistocene in Australia and within the Holocene in the Pacific islands of Fiji, New Caledonia and Vanuatu.
Baru, sometimes referred to as the cleaver-headed crocodile, is an extinct genus of Australian mekosuchine crocodilian. Its fossils have been found from various Late Oligocene and Miocene localities from across the Northern Territory and Queensland, indicating that Baru was a common species during the late Paleogene and early Neogene. Three species are recognized, B. darrowi, B. iylwenpeny, and B. wickeni.
Mekosuchus is a genus of extinct Australasian mekosuchine crocodilian. Species of Mekosuchus were generally small-sized, terrestrial animals with short, blunt-snouted heads and strong limbs. Four species are currently recognized, M. inexpectatus, M. whitehunterensis, M. sanderi and M. kalpokasi, all known primarily from fragmentary remains.
Trilophosuchus is an extinct genus of mekosuchine crocodilian from Australia. Its fossils have been found at the Ringtail Site in the Riversleigh World Heritage Area and date to the Miocene epoch. Additional remains have also been found at the older Hiatus Site and extend its range into the Oligocene. Like the closely related Mekosuchus, it is thought to have had a short and blunt snout and large eyes that generally resembles today's dwarf crocodiles. It also shares similarities with several much older crocodylomorph groups and is commonly thought to have been more terrestrial than any crocodilian living today. Only a single species has been described, the type species T. rackhami.
Australosuchus is an extinct monospecific genus of crocodylian belonging to the subfamily Mekosuchinae. The type and only known species Australosuchus clarkae lived during the Late Oligocene and the Early Miocene in the Lake Eyre Basin of South Australia. It was described in 1991 by Paul Willis and Ralph Molnar from fossil material discovered at Lake Palankarinna.
Paludirex is an extinct genus of mekosuchine crocodylian from the Pliocene and Pleistocene of Australia. A large and robust semi-aquatic ambush hunter capable of attaining lengths of up to 5 m (16 ft), it was likely the top predator of Australia's waterways prior to the appearance of modern saltwater crocodiles. Two species are known, the smaller Paludirex gracilis and the larger Paludirex vincenti. A third as of yet unnamed species may have also existed.
Kambara is an extinct genus of mekosuchine crocodylian that lived during the Eocene epoch in Australia. It is generally thought to have been a semi-aquatic generalist, living a lifestyle similar to many of today's crocodiles. Four species are currently recognised, the sympatric Kambara murgonensis and Kambara implexidens from sediments near Murgon, the poorly preserved Kambara molnari from the Rundle Formation and the youngest of the four, Kambara taraina, also from the Rundle Formation. Kambara were medium-sized crocodilians, with mature specimens generally reaching lengths from 3–4 m (9.8–13.1 ft).
Iberosuchus is a genus of extinct sebecosuchian mesoeucrocodylian found in Western Europe from the Eocene. Remains from Portugal was described in 1975 by Antunes as a sebecosuchian crocodilian. This genus has one species: I. macrodon. Iberosuchus was a carnivore, unlike the crocodilians today, they are not aquatic and are instead terrestrial.
Volia is an extinct monospecific genus of mekosuchine crocodylian closely related to Mekosuchus and Trilophosuchus. Volia is known from a collection of largely fragmentary remains including skull bones and limbs recovered from the Voli Voli and Wainibuku Caves on Viti Levu (Fiji), with similar remains having been found on Naigani. It was around 2–3 metres (7–10 ft) long, making it the largest predatory animal on the island and subsequently most likely the apex predator of the Pleistocene ecosystems of Fiji. It may have fed on giant iguanas, flightless birds or even fish. Like its closest relatives, it may have been more terrestrial than today's crocodiles.
Harpacochampsa is a poorly known Early Miocene crocodilian from the Bullock Creek lagerstätte of the Northern Territory, Australia. 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.
Asiatosuchus is an extinct genus of crocodyloid crocodilians that lived in Eurasia during the Paleogene. Many Paleogene crocodilians from Europe and Asia have been attributed to Asiatosuchus since the genus was named in 1940. These species have a generalized crocodilian morphology typified by flat, triangular skulls. The feature that traditionally united these species under the genus Asiatosuchus is a broad connection or symphysis between the two halves of the lower jaw. Recent studies of the evolutionary relationships of early crocodilians along with closer examinations of the morphology of fossil specimens suggest that only the first named species of Asiatosuchus, A. grangeri from the Eocene of Mongolia, belongs in the genus. Most species are now regarded as nomina dubia or "dubious names", meaning that their type specimens lack the unique anatomical features necessary to justify their classification as distinct species. Other species such as "A." germanicus and "A." depressifrons are still considered valid species, but they do not form an evolutionary grouping with A. grangeri that would warrant them being placed together in the genus Asiatosuchus.
Bergisuchus is an extinct genus of small sebecosuchian mesoeucrocodylian known primarily from the Eocene Messel Pit in Germany. Few fossils of Bergisuchus have been discovered, only a single incomplete snout, a few partial lower jaws and some teeth. Despite being fragmentary, the jaw bones are enough to indicate that Bergisuchus had a short, deep, narrow snout and serrated teeth, quite unlike the broad flat snouts of modern crocodylians.
Euthecodon is an extinct genus of long-snouted crocodile. It was common throughout much of Africa during the Neogene, with fossils being especially common in Kenya, Ethiopia, and Libya. Although superficially resembling that of gharials, the long snout was a trait developed independently from that of other crocodilians and suggests a diet of primarily fish. Euthecodon coexisted with a wide range of other crocodiles in the areas it inhabited before eventually going extinct during the Pleistocene.
Sebecus is an extinct genus of sebecid crocodylomorph from Eocene of South America. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by two species, the type S. icaeorhinus and S. ayrampu. Several other species have been referred to Sebecus, but were later reclassified as their own genera.
Astorgosuchus is an extinct monospecific genus of crocodilian, closely related to true crocodiles, that lived in Pakistan during the late Oligocene period. This crocodile may have reached lengths of up to 8 m (26 ft) and is known to have preyed on many of the large mammals found in its environment. Bite marks of a large crocodile have been found on the bones of juvenile Paraceratherium, however if these were left by Astorgosuchus cannot be said with certainty. The genus contains a single species, Astorgosuchus bugtiensis, which was originally named as a species of Crocodylus in 1908 and was moved to its own genus in 2019.
"Baru" huberi is a species of mekosuchine Crocodilian from the Miocene of Australia. Although initially named as a member of the genus Baru, both phylogenetic analysis and additional discoveries of related forms have shown that this species belonged to a distinct mekosuchine lineage more closely related to Mekosuchus and Trilophosuchus. Consequently, several researchers have argued that it should be placed in its own genus, which has yet to be named.
Gunggamarandu is an extinct monospecific genus of tomistomine crocodilian from Pliocene-Pleistocene aged deposits in the Darling Downs of Australia. Gunggamarandu represents the first tomistomine known from Oceania and it is also the southernmost known tomistomine to date. The type, and only known, species is Gunggamarandu maunala, which was described by Jorgo Ristevski et al. in 2021.
Ultrastenos is an extinct genus of Australian mekosuchine crocodilian first described in 2016. The type species Ultrastenos willisi was discovered at Riversleigh in northwestern Queensland, Australia, and lived during the Late Oligocene era. Following its discovery, it was speculated that Ultrastenos was a slender-snouted animal similar to modern gharials or freshwater crocodiles and that it may have inhabited forest pools and fed on small vertebrates like frogs and lizards. This is based on the peculiar shape of its mandible, which is wide towards the base of the head but constricts rapidly, leading into a narrow and gracile rostrum. Assuming that the holotype skull belonged to an adult individual, Ultrastenos may have been a rather small animal, approximately the size of a modern freshwater crocodile. However, Ultrastenos is only known from very fragmentary remains and thus among the most enigmatic mekosuchines. In a 2023 study multiple authors argue that the fragmentary nature of the animal means that further studies are required to truly test the hypothesis proposed in its original description, especially following the discovery of what is thought to have been a close relative.
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.
Antecrocodylus is a genus of crocodilian from the middle Miocene of Chiang Muan and Mae Moh, Thailand. The holotype consists of the back of the skull and an associated mandible. While far from complete and heavily damaged, the material highlights how little is known about the crocodylid fauna of Miocene Asia. Furthermore, Antecrocodylus was recovered as the basalmost member of Crocodylidae, having diverged before osteolaemines and crocodylines split from one another. This may suggest that it could provide significant information regarding the origins and evolution of modern crocodiles.
