Given the question: Information: - The Triassic is a geologic period and system which spans 50.9 million years from the end of the Permian Period million years ago (Mya), to the beginning of the Jurassic Period Mya. The Triassic is the first period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic was named in 1834 by Friedrich von Alberti, after the three distinct rock layers ("tri" meaning "three") that are found throughout Germany and northwestern Europered beds, capped by marine limestone, followed by a series of terrestrial mud- and sandstonescalled the "Trias". - A caiman is an alligatorid crocodilian belonging to the subfamily Caimaninae, one of two primary lineages within Alligatoridae, the other being alligators. - Birds (Aves), also known as avian dinosaurs, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds. - Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Late Permian (roughly 250 million years ago). It was defined by Jacques Gauthier (1994) as the clade stemming from the last common ancestor of Proterosuchidae and Archosauria; Phil Senter (2005) defined it as the most exclusive clade containing "Proterosuchus" and Archosauria. These reptiles, which include members of the family Proterosuchidae and more advanced forms, were originally superficially crocodile-like predatory semi-aquatic animals about 1.5meters (5ft) long, with a sprawling elbows-out stance and long snouts. Unlike the bulk of their therapsid contemporaries, the proterosuchids survived the catastrophe at the end of the Permian, perhaps because they were opportunistic scavengers or because they could retreat into water to find respite from an overheated climate. Any such scenarios are hypothetical; what is clearer is that these animals were highly successful in their new environment, and evolved quickly. Within a few million years at the opening of the Triassic, the proterosuchids had given rise to the Erythrosuchidae (the first sauropsids to totally dominate their environment), which in turn were the ancestors of the small agile Euparkeriidae, from which a number of successfully more advanced families the archosaurs proper evolved rapidly to fill empty ecological niches in the devastated global system. The Archosauria includes crocodylians, birds, and their extinct relatives. - Therapsida is a group of synapsids that includes mammals and their ancestors. Many of the traits today seen as unique to mammals had their origin within early therapsids, including having their four limbs extend vertically beneath the body, as opposed to the sprawling posture of other reptiles. The earliest fossil attributed to Therapsida is "Tetraceratops insignis" from the Lower Permian. - Erythrosuchidae (meaning "red crocodiles") are a family of large basal archosauriform carnivores that lived from the later Early Triassic (Olenekian) to the early Middle Triassic (Anisian). - Reptiles are tetrapod (four-limbed vertebrate) animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. The study of these traditional reptile orders, historically combined with that of modern amphibians, is called herpetology. - Crocodylomorpha is a group of archosaurs that includes the crocodilians and their extinct relatives. - Euparkeriidae is a family of small basal archosauromorph carnivores which lived from the Early Triassic to the Middle Triassic (Anisian). While most other early archosauriforms walked on four limbs, euparkeriids were probably facultative bipeds that had the ability to walk on their hind limbs at times. The only definitive member of Euparkeriidae is the species "Euparkeria capensis", which was named by paleontologist Robert Broom from the Karoo Basin of South Africa in 1913 and is known from several nearly complete skeletons. The family name was first proposed by German paleontologist Friedrich von Huene in 1920; Huene classified euparkeriids as members of Pseudosuchia, a traditional name for crocodilian relatives from the Triassic (Pseudosuchia means "false crocodiles"). Recent phylogenetic analyses place Euparkeriidae as a basal group of Archosauriformes, a position outside Pseudosuchia and close to the ancestry of both crocodile-line archosaurs and bird-line archosaurs (which include dinosaurs and pterosaurs). However, they are probably not direct ancestors of archosaurs. - The Crocodylidae family of crocodylians includes the true crocodiles which are the members of the subfamily Crocodylinae and the "Tomistoma" genus. Currently, the family includes two subfamilies, Crocodylinae and Tomistominae, with the latter being a subject of controversy whether it is a crocodile or belongs to the family Gavialidae. Further genetic analysis has to be done to come to a final conclusion. - Crocodiles (subfamily Crocodylinae) or true crocodiles are large aquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, all of whose members are considered true crocodiles, is classified as a biological subfamily. A broader sense of the term crocodile, Crocodylidae that includes "Tomistoma", is not used in this article. The term crocodile here applies only to the species within the subfamily of Crocodylinae. The term is sometimes used even more loosely to include all extant members of the order Crocodilia, which includes "Tomistoma", the alligators and caimans (family Alligatoridae), the gharials (family Gavialidae), and all other living and fossil Crocodylomorpha. - Diapsids ("two arches") are a group of amniote tetrapods that developed two holes (temporal fenestra) in each side of their skulls about 300 million years ago during the late Carboniferous period. The diapsids are extremely diverse, and include all crocodiles, lizards, snakes, tuatara, turtles, and dinosaurs (both avian and non-avian). Although some diapsids have lost either one hole (lizards), or both holes (snakes and turtles), or have a heavily restructured skull (modern birds), they are still classified as diapsids based on their ancestry. At least 7,925 species of diapsid reptiles exist in environments around the world today (nearly 18,000 when birds are included). - In biology, a species (abbreviated sp., with the plural form species abbreviated spp.) is the basic unit of biological classification and a taxonomic rank. A species is often defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is often problematic. For example, in a species complex, the boundaries between closely related species become unclear or disappear altogether. Other ways of defining species include similarity of DNA, morphology, or ecological niche. The presence of locally adaptive traits may further subdivide species into infraspecific taxa such as subspecies. - Gavialidae is a family of reptiles within the order Crocodilia. Gavialidae have conventionally consisted of only one surviving species, the gharial ("Gavialis gangeticus"), which is native to India and Nepal. Many extinct species are also known. The false gharial ("Tomistoma schlegelii") has usually been thought to be a member of the family Crocodylidae based on several characters including skull morphology, but has sometimes been viewed as a member of this family due to general similarities in morphology and habit. However, numerous molecular studies have consistently shown the two species to be very closely related, supporting the view that they are in the same family. - In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoological names with "-inae". - Proterosuchidae is an early , possibly paraphyletic , assemblage of basal archosauriformes whose fossils are known from the Latest Permian and the Early Triassic of Europe , Asia , Africa , Australia and possibly South America . The name comes from Greek - ( '' first '' ) and ( '' crocodile '' ) . - The Crocodilia (or Crocodylia) are an order of mostly large, predatory, semiaquatic reptiles. They appeared 83.5 million years ago in the Late Cretaceous period (Campanian stage) and are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria. Members of the order's total group, the clade Pseudosuchia, appeared about 250 million years ago in the Early Triassic period, and diversified during the Mesozoic era. The order Crocodilia includes the true crocodiles (family Crocodylidae), the alligators and caimans (family Alligatoridae), and the gharial and false gharial (family Gavialidae). Although the term 'crocodiles' is sometimes used to refer to all of these, a less ambiguous vernacular term for this group is crocodilians. - An alligator is a crocodilian in the genus "Alligator" of the family Alligatoridae. The two living species are the American alligator ("A. mississippiensis") and the Chinese alligator ("A. sinensis"). In addition, several extinct species of alligator are known from fossil remains. Alligators first appeared during the Paleocene epoch about 37 million years ago. - Proterosuchus is an extinct genus of Early Triassic archosauriform reptiles. Remains have been found from South Africa and China. The genus "Chasmatosaurus" is a junior synonym of "Proterosuchus", as all species of "Chasmatosaurus", including "C. aleandri", "C. vanhoepeni", and "C. yuani", have been reassigned to "Proterosuchus". "Elaphrosuchus" has also been synonymized with "Proterosuchus". The type species of "Proterosuchus" is "P. fergusi". The Chinese species is "P. yuani". - Latin (Latin: ) is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets. - The family Alligatoridae of crocodylians includes alligators and caimans. - Archosaurs are a group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct non-avian dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most recent common ancestor of living birds and crocodilians. It includes two main clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Ornithosuchia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Given the information above, choose from the list below the object entity that exhibits the relation 'taxon rank' with the subject 'proterosuchidae'. Choices: - branch - class - family - form - genus - group - order - series - species - subfamily
The answer is:
family