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

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of basal archosauriform known from remains unearthed from the

Arcadia Formation The Arcadia Formation and its sub-unit, the Tampa Member, are Late Oligocene geologic formations in North Florida, United States. It is part of the Hawthorn Group. Age Period (geology), Period: Paleogene to Neogene Epoch (geology), Epoch: Early ...

( 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 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...

of the Crater, Southwest of Rolleston, south central

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

, Australia. It was named after

Kali Kali (; sa, काली, ), also referred to as Mahakali, Bhadrakali, and Kalika ( sa, कालिका), is a Hindu goddess who is considered to be the goddess of ultimate power, time, destruction and change in Shaktism. In this tra ...

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

type species In 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 species that contains the biological type specime ...

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 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) rather than lepidosaurs (such as tuataras, liz ...

known in Australia.

Description

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

of ''Kalisuchus'' is a partial left

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates 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. T ...

, 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 * Medi ...

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 only ...

''. 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 archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, bird ...

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'', 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 spec ...

''. 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, t ...

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 archosauriforms. The maxillary morphology of ''Kalisuchus'' seems intermediate between the semiaquatic crocodile-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 about 3 meters.

Classification

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

''. However, Ezcurra (2016) found that Proterosuchidae was a mostly paraphyletic 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 Prehistoric archosauriforms Early Triassic reptiles Mesozoic reptiles of Australia Fossil taxa described in 1979 Prehistoric reptile genera