''Kalisuchus'' ('Kali's crocodile') was a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of basal

archosauriform Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemming from the last common anc ...

known from remains unearthed from the Arcadia Formation ( Rewan Group) of the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

of the Crater, Southwest of Rolleston, south central

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. It was named after

Kali Kali (; , ), also called Kalika, is a major goddess in Hinduism, primarily associated with time, death and destruction. Kali is also connected with transcendental knowledge and is the first of the ten Mahavidyas, a group of goddesses who p ...

, the Hindu goddess of destruction, a reference to the very fragmentary nature of its remains. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

of ''Kalisuchus'' is ''K. rewanensis,'' which refers to the Rewan Group. The Arcadia formation is dated to the Induan age at the very beginning of the Triassic, making ''Kalisuchus'' one of the oldest

archosauromorphs Archosauromorpha (Greek language, Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) than to Lepidosauria, lepidosaurs ( ...

known in Australia.

Description

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Kalisuchus'' is a partial left

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

, QM F8998. Although many other fragmentary bones from the Arcadia Formation were referred to the genus, the lack of overlap between these bones and the holotype makes these referrals dubious. One of the referred bones, QM F9521, was originally believed to be an unusual

jugal The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy ...

but was subsequently interpreted as a right

pterygoid Pterygoid, from the Greek for 'winglike', may refer to: * Pterygoid bone, a bone of the palate of many vertebrates * Pterygoid processes of the sphenoid bone ** Lateral pterygoid plate ** Medial pterygoid plate * Lateral pterygoid muscle * Medial ...

similar to that of

erythrosuchids Erythrosuchidae (meaning "red crocodiles" in Greek) are a family of large basal archosauriform carnivores that lived from the later Early Triassic (Olenekian) to the early Middle Triassic (Anisian). Naming The family Erythrosuchidae was named by ...

and ''

Sarmatosuchus ''Sarmatosuchus'' is an extinct genus of archosauriform reptile found in sediments of Middle Triassic age and known from the single species ''Sarmatosuchus otschevi''. It is one of the earliest stem-archosaur species known. The holotype and onl ...

''. The anterior process of the maxilla is very short, similar to that of erythrosuchids. The ascending process is tall and vertical, creating a front edge of the

antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with Archosauriformes, archosauriforms, first appearing during the Triassic Period. Among Extant ...

which is only gently concave, as opposed to the strongly concave edge in other basal archosauriforms. The ascending process also thins transversely towards the tip. Similar to proterosuchids and ''

Fugusuchus ''Fugusuchus'' is an extinct genus of archosauriform, probably the basal-most member of the family Erythrosuchidae. The genus is known from a single fossil from the middle Early Triassic Heshanggou Formation in Shanxi, China. The partial skel ...

'', there is no antorbital fossa separating the antorbital fenestra from the rest of the maxilla. The maxilla as a whole curves outwards very slightly, although to a lesser extent than in ''

Proterosuchus ''Proterosuchus'' is an extinct genus of archosauriform reptiles that lived during the Early Triassic. It contains three valid species: the type species ''P. fergusi'' and the referred species ''P. alexanderi'' and ''P. goweri''. All three spe ...

''. The lower edge of the medial (inside) surface of the maxilla is convex, while the palatal process is strongly downturned at the front. Although most of the

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

are poorly preserved, those which can be identified are unusually ankylothecodont (placed in deep sockets and fused to the bone), but also compressed, recurved, and serrated on the rear edge and the distal part of the front edge, as in most other

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

archosauriforms. The maxillary morphology of ''Kalisuchus'' seems intermediate between the semiaquatic

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term "crocodile" is sometimes used more loosely to include ...

-like proterosuchids and the robust terrestrial erythrosuchids. The strongly downturned palatal process of the maxilla may have been evidence for a strongly downturned snout, as in proterosuchids, and it may have had a similar niche and biology. Its body length is estimated at 3 meters.

Classification

Thulborn (1979) considered it a proterosuchid closely related to ''

''. However, Ezcurra (2016) found that Proterosuchidae was a mostly

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

group of basal archosauriforms. Although the presence of

interdental plate The interdental plate refers to the bone-filled mesial-distal region between the teeth. The word "''interdental''" is a combination of "''inter''" + "''dental''" (meaning "''between the teeth''") which originated in approximately 1870. In paleobi ...

s in QM F8998 made Ezcurra consider ''Kalisuchus'' to be more advanced than proterosuchids, the large number of tooth sockets (14) preserved in the maxilla forced ''Kalisuchus'' to be excluded from the clade containing more advanced archosauriforms, such as the erythrosuchids.

References

Long, J.A., ''Dinosaurs of Australia and New Zealand'', UNSW Press 1998 {{Taxonbar, from=Q2595501 Archosauriformes Early Triassic reptiles Mesozoic reptiles of Australia Fossil taxa described in 1979 Prehistoric reptile genera