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29-727: Proterosuchidae is an early family of basal archosauriforms whose fossils are known from the Late Permian and the Early Triassic . The highest diversity of genera is known from European Russia , but fossils are also known from South Africa , India , China , Australia , Brazil and possibly Argentina . The name comes from Greek πρότερο- ("first") and σοῦχος (" crocodile "). They were slender, medium-sized (about 1.5 m (4 ft 11 in) long, largest specimens reached 3.5–4 m (11–13 ft)), long-snouted and superficially crocodile-like animals, although they lacked

58-409: A correlation does not make a given case predicable, so ancestral characters should not be imputed to the members of a less species-rich basal clade without additional evidence. In general, clade A is more basal than clade B if B is a subgroup of the sister group of A or of A itself. In the context of large groups, the term "basal" is often used loosely to refer to positions closer to

87-623: A majority of proterosuchids outside of Proterosuchus and Sarmatosuchus as belonging to a distinct subfamily , the Chasmatosuchinae , defined as "the most inclusive clade containing Chasmatosuchus rossicus , but not Proterosuchus fergusi , " Chasmatosaurus " yuani , Proterosuchus alexanderi , Proterosuchus goweri , Erythrosuchus africanus , or Alligator mississippiensis (the American alligator)". Chasmatosuchinae contains many Triassic proterosuchids in addition to

116-698: A mix of archaic and apomorphic (derived) features that have only been sorted out via comparison with other angiosperms and their positions within the phylogenetic tree (the fossil record could potentially also be helpful in this respect, but is absent in this case). The cladogram below is based on Ramírez-Barahona et al. (2020), with species counts taken from the source indicated. Amborellales (1 species) Nymphaeales (about 90 species) Austrobaileyales (about 95 species) Magnoliids (about 9,000 species) Chloranthales (about 80 species) Monocots (about 70,000 species) Ceratophyllales (about 6 species) Eudicots (about 175,000 species) Within

145-1143: A monophyletic Proterosuchidae containing only Archosaurus and the species of Proterosuchus , however some species (e.g. Chasmatosuchus spp, Vonhuenia friedrichi ) are too fragmentary to resolve whether they also fall into Proterosuchidae. Tasmaniosaurus , Fugusuchus , Sarmatosuchus , Cuyosuchus and the "Long Reef proterosuchid" (SAM P41754) on the other hand were recovered confidently outside of Proterosuchidae. Prolacertidae SAM-PK-591 " Ankistrodon indicus " (dubium) " Blomosuchus georgii " (dubium) Tasmaniosaurus triassicus Chasmatosuchus magnus Chasmatosuchus rossicus Gamosaurus lozovskii Chasmatosuchus vjushkovi Vonhuenia friedrichi Archosaurus rossicus Proterosuchus fergusi Proterosuchus alexanderi Proterosuchus goweri Proterosuchus yuani Eorasaurus olsoni Kalisuchus rewanensis Fugusuchus hejiapanensis Sarmatosuchus otschevi Cuyosuchus huenei SAM P41754 Uralosaurus magnus Guchengosuchus shiguaiensis other erythrosuchids Eucrocopoda The following phylogeny for

174-476: A proterosuchid, a 2016 cladistic analysis by Ezcurra et al . recovered it as a non-eucrocopodan archosauriform of uncertain position. However, a 2023 cladistic analysis of the Proterosuchidae, again by Ezcurra et al. , again recovered Vonhuenia as a proterosuchid, specifically as a basal member of the subfamily Chasmatosuchinae . The earliest known proterosuchid and archosauromorph, Archosaurus ,

203-503: A single common ancestor and proterosuchids as its only descendants. Instead, they are a chain of successively basal archosauriforms. Proterosuchidae sensu stricto is defined as "all taxa more closely related to Proterosuchus fergusi than to Erythrosuchus africanus , Crocodylus niloticus (the Nile crocodile ), or Passer domesticus (the house sparrow ). Below is a cladogram from Ezcurra (2016), that reexamined all historical members of

232-473: A sister group to Homininae and are the basal genus in the great ape family Hominidae as a whole. Orangutans ( Pongo spp.) Humans ( Homo sapiens ) Chimpanzees ( Pan spp.) Gorillas ( Gorilla spp.) Subfamilies Homininae and Ponginae are both basal within Hominidae, but given that there are no nonbasal subfamilies in the cladogram it is unlikely the term would be applied to either. In general,

261-405: A statement to the effect that one group (e.g., orangutans) is basal, or branches off first, within another group (e.g., Hominidae) may not make sense unless the appropriate taxonomic level(s) (genus, in this case) is specified. If that level cannot be specified (i.e., if the clade in question is unranked) a more detailed description of the relevant sister groups may be needed. As can be seen, the term

290-461: A trait generally viewed as ancestral among the apes. Given that the deepest phylogenetic split in a group is likely to have occurred early in its history, identification of the most basal subclade(s) in a widely dispersed taxon or clade can provide valuable insight into its region of origin; however, the lack of additional species in a clade is not evidence that it carries the ancestral state for most traits. Most deceptively, people often believe that

319-553: Is a basal clade of extant angiosperms , consisting of the most species, genus, family and order within the group that are sister to all other angiosperms (out of a total of about 250,000 angiosperm species). The traits of Amborella trichopoda are regarded as providing significant insight into the evolution of flowering plants; for example, it has "the most primitive wood (consisting only of tracheids ), of any living angiosperm" as well as "simple, separate flower parts of indefinite numbers, and unsealed carpels". However, those traits are

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348-476: Is also placed in Chasmatosuchinae but is thought to be more derived than Vonhuenia , suggesting that the ancestors of Vonhuenia diverged from other chasmatosuchines during the Late Permian . Vonhuenia was a small archosauriform that lived alongside amphibians like Tupilakosaurus and Luzocephalus , small reptiles like Phaanthosaurus , and the large-bodied dicynodont Lystrosaurus in

377-584: Is an extinct genus of proterosuchid , a basal archosauriform from the Early Triassic of Russia . Fossils have been found in the Vokhminskaya Formation , along the Vetluga River that are Induan in age, making Vonhuenia one of the earliest archosauriforms. The type species V. friedrichi , named in 1992, is based on material that was misassigned to the genus Chasmatosuchus by Ochev (1978). Although originally classified as

406-415: Is likely a source of the mis-use of the term. Other famous examples of this phenomenon are the oviparous reproduction and nipple-less lactation of monotremes , a clade of mammals with just five species, and the archaic anatomy of the tuatara , a basal clade of lepidosaurian with a single species. The flowering plant family Amborellaceae , restricted to New Caledonia in the southwestern Pacific,

435-515: Is not reflective of ancestral states or proximity to the common ancestor of extant species. In this example, orangutans differ from the other genera in their Asian range. This fact plus their basal status provides a hint that the most recent common ancestor of extant great apes may have been Eurasian (see below), a suggestion that is consistent with other evidence. (Of course, lesser apes are entirely Asiatic.) However, orangutans also differ from African apes in their more highly arboreal lifestyle,

464-418: Is unnecessary and misleading. The term is more often applied when one branch (the one deemed "basal") is less diverse than another branch (this being the situation in which one would expect to find a basal taxon of lower minimum rank). The term may be equivocal in that it also refers to the direction of the root of the tree, which represents a hypothetical ancestor; this consequently may inaccurately imply that

493-590: The great apes , gorillas (eastern and western) are a sister group to chimpanzees , bonobos and humans . These five species form a clade, the subfamily Homininae (African apes), of which Gorilla has been termed the basal genus. However, if the analysis is not restricted to genera, the Homo plus Pan clade is also basal. Humans ( Homo sapiens ) Bonobos ( Pan paniscus ) Chimpanzees ( Pan troglodytes ) Eastern gorillas ( Gorilla beringei ) Western gorillas ( Gorilla gorilla ) Moreover, orangutans are

522-418: The "Proterosuchia" (a polyphyletic historical group including proterosuchids and erythrosuchids ). The placement of fragmentary taxa that had to be removed to increase tree resolution are indicated by dashed lines (in the most derived position that they can be confidently assigned to). Taxa that are nomina dubia are indicated by the note "dubium". Bold terminal taxa are collapsed. Ezcurra (2016) recovered

551-515: The Proterosuchidae sensu stricto was recovered by Ezcurra et al (2023): Proterosuchus " Chasmatosaurus " yuani Vonhuenia Jaikosuchus Gamosaurus Chasmatosuchus Tsylmosuchus Samsarasuchus Archosaurus Ankistrodon Archosaurus Blomosuchus Chasmatosuchus Proterosuchus Vonhuenia [REDACTED] [REDACTED] Basal (phylogenetics) While there must always be two or more equally "basal" clades sprouting from

580-443: The armoured scutes of true crocodiles, and their skeletal features are much more primitive. The limbs are short and indicate a sprawling posture, like contemporary lizards but unlike most later archosaurs. Their most characteristic feature is a distinct down-turning of the premaxilla (the front of the upper jaw, which overhangs the lower jaw). The terminal Permian catastrophe , which killed off 95% of all types of life, cleared

609-504: The direction of migration away from the area of origin can also be inferred (as in the Amaurobioides and Noctilionoidea cases below). As with all other traits, the phylogeographic location of one clade that connects to the root does not provide information about the ancestral state. Examples where such unjustified inferences may have been made include: Vonhuenia friedrichi Vonhuenia (named after Friedrich von Huene )

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638-719: The extant taxa of a given rank within the clade; this is one reason the term basal is highly deceptive, as the lack of additional species in one clade is taken as evidence of morphological affinity with ancestral taxa. Additionally, this qualification does not ensure that the diversity of extinct taxa (which may be poorly known) is represented. In phylogenetics, the term basal cannot be objectively applied to clades of organisms, but tends to be applied selectively and more controversially to groups or lineages thought to possess ancestral characters, or to such presumed ancestral traits themselves. In describing characters, "ancestral" or " plesiomorphic " are preferred to "basal" or " primitive ",

667-403: The following case:   Basal clade #1  Non-basal clade #1  Non-basal clade #2    Non-basal clade #3 While it is easy to identify a basal clade in such a cladogram, the appropriateness of such an identification is dependent on the accuracy and completeness of the diagram. It is often assumed in this example that the terminal branches of the cladogram depict all

696-437: The latter of which may carry false connotations of inferiority or a lack of complexity. The terms ''deep-branching'' or ''early-branching'' are similar in meaning, and equally may misrepresent extant taxa that lie on branches connecting directly to the root node as having more ancestral character states. Despite the ubiquity of the usage of basal , systematists try to avoid its usage because its application to extant groups

725-457: The only Permian proterosuchid, Archosaurus ; this would suggest that an initial taxonomic diversification of the Proterosuchidae (including an initial taxonomic divergence between Proterosuchus and chasmatosuchines) had already occurred in the Permian. Recent studies consider Proterosuchidae to be at least a partially paraphyletic grouping, meaning that it does not form a true clade with

754-419: The root of every cladogram, those clades may differ widely in taxonomic rank , species diversity , or both. If C is a basal clade within D that has the lowest rank of all basal clades within D , C may be described as the basal taxon of that rank within D . The concept of a ' key innovation ' implies some degree of correlation between evolutionary innovation and diversification . However, such

783-423: The root than the majority, and in such cases, expressions like "very basal" can appear. A 'core clade' refers to the grouping that encompasses all constituent clades except for the basal clade(s) of the lowest rank within a larger clade, exemplified by core eudicots . No extant taxon is closer to the root than any other. A basal group in the stricter sense forms a sister group to the rest of the larger clade, as in

812-529: The sister group of a more species-rich clade displays ancestral features. An extant basal group may or may not resemble the last common ancestor of a larger clade to a greater degree than other groups, and is separated from that ancestor by the same amount of time as all other extant groups. However, there are cases where the unusually small size of a sister group does indeed correlate with an unusual number of ancestral traits, as in Amborella (see below). This

841-545: The world of all large therapsids and allowed the proterosuchids to become the top predators. Within the space of five million years the proterosuchids had evolved to fill a wide variety of terrestrial and semi-aquatic niches. The proterosuchids represent perhaps the earliest adaptive radiation of the archosaurs. They gave rise to the Erythrosuchidae some time in the Early Triassic. A 2023 study recovered

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