23-396: Macquaria is a genus of medium-sized, predatory temperate perches endemic to Australia . They are found in rivers and estuaries of the eastern part of the continent. The currently recognized species in this genus are: Some workers have found that the genus Macquaria is polyphyletic and that the two catadromous species Macquaria colonorum and M. novemaculeata are not
46-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
69-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
92-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
115-755: A single naturally occurring cyprinid species; unfortunately, the illegal introduction of carp has now established the family's presence in Australia.) A single genus occurs outside Australia, Percichthys in southern South America. A number of species are or have been important food species; some of these (e.g. the Murray cod, Maccullochella peelii peelii ) have become threatened through overfishing and river regulation, while others are now farmed to some extent. Some smaller species (e.g. Balston's pygmy perch , Nannatherina balstoni ) are popular in aquaria . The extremely rare Bloomfield River cod , Guyu wujalwujalensis ,
138-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
161-499: Is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade" was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case,
184-471: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
207-482: Is only found in a short stretch of the Bloomfield River in north Queensland . Clade In biological phylogenetics , a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as a monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In
230-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
253-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
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#1733117779022276-681: The taxonomical literature, sometimes the Latin form cladus (plural cladi ) is used rather than the English form. Clades are the fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over
299-521: The Chinese perches have been classified in the separate family Sinipercidae while the genus Percilia has been found not to be closely related to either that family or the Percichthyidae and has been placed in its own monotypic family Perciliidae . The following 8 genera are classified within the family Percichthyidae: Some workers have found that the genus Macquaria is polyphyletic and that
322-651: The closest relatives of the other two species in the genus and are placed in the genus Percalates in the monotypic family Percalatidae These authors also found that the Percichthyidae and the Percalatidae were part of one of three cladea within a new order , the Centrarchiformes in the Percomorpha . This Centrarchiformes -related article is a stub . You can help Misplaced Pages by expanding it . Temperate perch see text Gadopsidae The members of
345-581: The family Percichthyidae are known as the temperate perches . They belong to the order Perciformes , the perch-like fishes. The name Percichthyidae derives from the Latin perca for perch and Ancient Greek ἰχθύς, ichthys for fish. Potential percichthyid fossil remains are known from the Early Paleocene of the El Molino Formation of Bolivia; these remains have been described as resembling those of
368-457: The family Percichthyidae, while research using mitochondrial DNA suggests the species of the family Nannopercidae are in reality percichthyids, as well. Australia is unique in having a freshwater fish fauna dominated by percichthyids and allied families/species. This in contrast to Europe and Asia, whose fish faunas are dominated by members of the Cyprinidae carp family. (Australia does not have
391-581: The fossil Percichthys hondoensis from the Eocene of Argentina . One articulated specimen is known from the Paleocene portion of the formation, but other remains are known from the Maastrichtian beds of the formation, indicating that percichthyids could have potential Cretaceous origins. However, the condition of this material is unclear. Another fossil percichthyid, Percichthys lonquimayiensis from Chile ,
414-615: The greatest number of percichthyid species, where they are represented by the Australian freshwater cods ( Maccullochella spp.), which are Murray cod , Mary River cod , eastern freshwater cod , and trout cod , by the Australian freshwater blackfishes ( Gadopsis spp.), which are river blackfish and two-spined blackfish , and by the Australian freshwater perches which are golden perch , Macquarie perch ( Macquaria spp.), and Australian bass , and estuary perch ( Percalates spp.). Several other Australian freshwater species also sit within
437-546: The group consists of a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
460-590: The last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of the relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade"
483-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
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#1733117779022506-419: The two catadromous species Macquaria colonorum and M. novemaculeata are not the closest relatives of the other two species in the genus and are placed in the genus Percalates in the monotypic family Percalatidae These authors also found that the Percichthyidae and the Percalatidae were part of one of three clades within a new order , the Centrarchiformes in the Percomorpha . Australia has
529-792: Was initially dated to the Paleocene, but further studies have found it to be from the Miocene . The temperate perches are closely related to the temperate basses of the family Moronidae , and older literature treats the latter as belonging to the family Percichthyidae. Australian freshwater percichthyids were once placed in the marine grouper family, Serranidae , and the two families are thought to be closely related. Almost 40 species of percichthyids are now recognised, grouped in 11–12 genera . Most but not all are exclusively freshwater fishes. They are mainly found in Australia , but species are also found in southern South America ( Percichthys ). More recently
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