Loricata is a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of archosaur reptiles that includes

crocodilians Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living re ...

and some of their Triassic relatives, such as ''

Postosuchus ''Postosuchus'', meaning "Crocodile from Post", is an extinct genus of rauisuchid reptiles comprising two species, ''P. kirkpatricki'' and ''P. alisonae'', that lived in what is now North America during the Late Triassic. ''Postosuchus'' is a ...

'' and ''

Prestosuchus ''Prestosuchus'' (meaning "Prestes crocodile") is an extinct genus of pseudosuchian in the group Loricata, which also includes '' Saurosuchus'' and '' Postosuchus''. It has historically been referred to as a " rauisuchian", and was the defining ...

''. More specifically, Loricata includes

Crocodylomorpha Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, cro ...

(the persistent archosaur subset which crocodilians belong to) and most "

rauisuchians "Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians t ...

", a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

grade Grade most commonly refers to: * Grade (education), a measurement of a student's performance * Grade, the number of the year a student has reached in a given educational stage * Grade (slope), the steepness of a slope Grade or grading may also ref ...

of large terrestrial pseudosuchians which were alive in the Triassic period and ancestral to crocodylomorphs. Loricata is one branch of the group

Paracrocodylomorpha Paracrocodylomorpha is a clade of pseudosuchian archosaurs. The clade includes the diverse and unusual group Poposauroidea as well as the generally carnivorous and quadrupedal members of Loricata, including modern crocodylians. Paracrocodylomorpha ...

; the other branch is the clade

Poposauroidea Poposauroidea is a clade of advanced pseudosuchians (archosaurs closer to crocodilians than to dinosaurs). It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as ''Qianosuchus'' and ''Lotosaurus''. How ...

, an unusual collection of strange "rauisuchians" including bipedal, herbivorous, and sail-backed forms. The vast majority of typical "rauisuchians", which were usually quadrupedal predators, occupy basal (early-branching) rungs of Loricata leading up to crocodylomorphs.

History and Classification

Loricata was initially named in a completely different context by

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

naturalist

Blasius Merrem Blasius Merrem (4 February 1761 – 23 February 1824) was a German naturalist, zoologist, ornithologist, mathematician, and herpetologist. In 1804, he became the professor of political economy and botany at the University of Marburg. Early li ...

in his 1820 ''Versuch eines Systems der Amphibien''. Merrem considered it to be one of three groups of Pholidota (reptiles), the other two being Testudinata (

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

s) and

Squamata Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...

(

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

s and

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

s). Loricata was an early name for the order that includes

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 even more loosely to inclu ...

alligator An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...

s, and

gharial The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...

s. That order is now referred to as

Crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

(or

Crocodylia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...

), the crocodilians. The name Loricata gained a new

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

definition in 2011. In his study of early archosaur phylogeny,

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Sterling J. Nesbitt Sterling Nesbitt (born March 25, 1982, in Mesa, Arizona) is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Department of ...

defined it as the most inclusive

containing ''

Crocodylus niloticus ''Crocodylus'' is a genus of true crocodiles in the family Crocodylidae. Taxonomy The generic name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti in 1768. ''Crocodylus'' contains 13–14 extant (living) species and 5 extinct species ...

'' (the Nile crocodile), but not ''

Poposaurus gracilis ''Poposaurus'' (" Popo Agie reptile") is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail ...

'', '' Ornithosuchus longidens'', or '' Aetosaurus ferox,'' all of which were extinct species of Triassic archosaurs closer to crocodilians than to dinosaurs. Nesbitt considered the following features to be

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

(distinguishing features) of Loricata: * Four teeth in the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

(the toothed bone at the tip of the snout). * A ridge on the surface of the lower branch of the

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal The quadratojugal is a skull bone present in many vertebrates, including ...

(the multi-pronged bone forming the upper rear corner of the skull). * A projection on the squamosal which encroaches the

infratemporal fenestra An infratemporal fenestra, also called the lateral temporal fenestra or simply temporal fenestra, is an opening in the skull behind the orbit in some animals. It is ventrally bordered by a zygomatic arch. An opening in front of the eye sockets ...

(the boxy hole on the side of the skull behind the eye socket) * A tall, narrow orbit (

eye socket In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of ...

). * A ridge for the attachment of the ''iliofibularis'' muscle positioned halfway down the length of the

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is ...

(outer shin bone). * A distinct gap on the

calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. St ...

(heel bone) between the articulation for the fourth distal tarsal bone and the tip of the calcaneal tuber. * A projection at the base of the fifth

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...

of the foot which is separated from the end of the bone by a concave gap. Nesbitt's phylogenetic analysis placed

and an array of "

rauisuchia "Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilia ...

ns" within Loricata.

Rauisuchidae Rauisuchidae is a group of large (up to or more) predatory Triassic archosaurs. There is some disagreement over which genera should be included in Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed wheth ...

was found to be a small

, forming the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of Crocodylomorpha.

Prestosuchidae Prestosuchidae (in its widest usage) is a polyphyletic grouping of carnivorous archosaurs that lived during the Triassic. They were large active terrestrial apex predators, ranging from around in length. They succeeded the Erythrosuchidae as the ...

, on the other hand, was reconfigured into a

, forming a series of more basal loricatans. Loricata is the sister taxon of

, a group of unusual Triassic rauisuchians. Below is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

of Loricata from Nesbitt (2011): França, Langer and Ferigolo (2011) found that, when added to Nesbitt's analysis (2011), '' Decuriasuchus'' was recovered as the basalmost loricatan. Its addition influenced the phylogenetic placement of ''

Ticinosuchus ''Ticinosuchus'' is an extinct genus of suchian archosaur from the Middle Triassic (Anisian - Ladinian) of Switzerland and Italy. Description One of only a handful of fossil reptiles that have been found in Switzerland, ''Ticinosuchus'' (mea ...

'' as well; in Nesbitt's original analysis it was recovered outside Loricata, but when ''Decuriasuchus'' was included in the analysis, ''Ticinosuchus'' was recovered as a basal member of Loricata. Prior to 2011, poposauroids were sometimes viewed as closer relatives of crocodylomorphs than rauisuchids and "prestosuchids "were. The clade

was named in 1993 to include poposaurids and crocodylomorphs. Although Paracrocodylomorpha was originally designated to exclude rauisuchids and "prestosuchids", Nesbitt (2011) found that most members of those groups are closer to crocodylomorphs than poposauroids are. Thus, Paracrocodylomorpha was redefined into a two-pronged group, one prong containing poposauroids and the other (i.e., Loricata) including crocodylomorphs, rauisuchids, and "prestosuchids". Loricata is considered to be a subgroup of Paracrocodylomorpha according to this redefinition. A clade called Paracrocodyliformes was erected in 2007 in which rauisuchids and prestosuchids were more closely related to Crocodylomorpha, and poposauroids were the most basal group. This usage is similar to Loricata.

References

{{Taxonbar, from=Q13362187 Paracrocodylomorphs Olenekian first appearances Fossil taxa described in 1820 Extant Early Triassic first appearances