Misplaced Pages

#278721

22-514: Aramidae is a bird family in the order Gruiformes . The limpkin ( Aramus guarauna ) is the only living member of this family, although other species are known from the fossil record, such as Aramus paludigrus from the Middle Miocene and Badistornis aramus from Oligocene. Gruiformes Some 5–10 living, see article text. The Gruiformes ( / ˈ ɡ r uː ɪ f ɔːr m iː z / GROO -ih-for-meez ) are an order containing

44-453: A node-based clade definition , for example, could be "All descendants of the last common ancestor of species X and Y". On the other hand, polyphyletic groups can be delimited as a conjunction of several clades, for example "the flying vertebrates consist of the bat, bird, and pterosaur clades". From a practical perspective, grouping species monophyletically facilitates prediction far more than does polyphyletic grouping. For example, classifying

66-452: A classification is discouraged. Monophyletic groups (that is, clades ) are considered by these schools of thought to be the only valid groupings of organisms because they are diagnosed ("defined", in common parlance) on the basis of synapomorphies , while paraphyletic or polyphyletic groups are not. From the perspective of ancestry, clades are simple to define in purely phylogenetic terms without reference to clades previously introduced:

88-455: A considerable number of living and extinct bird families , with a widespread geographical diversity. Gruiform means "crane-like". Traditionally, a number of wading and terrestrial bird families that did not seem to belong to any other order were classified together as Gruiformes. These include 15 species of large cranes , about 145 species of smaller crakes and rails , as well as a variety of families comprising one to three species , such as

110-418: A lot of', and φῦλον ( phûlon ) 'genus, species', and refers to the fact that a polyphyletic group includes organisms (e.g., genera, species) arising from multiple ancestral sources. Conversely, the term monophyly , or monophyletic , employs the ancient Greek adjective μόνος ( mónos ) 'alone, only, unique', and refers to the fact that a monophyletic group includes organisms consisting of all

132-421: A newly discovered grass in the monophyletic family Poaceae , the true grasses, immediately results in numerous predictions about its structure and its developmental and reproductive characteristics, that are synapomorphies of this family. In contrast, Linnaeus' assignment of plants with two stamens to the polyphyletic class Diandria, while practical for identification, turns out to be useless for prediction, since

154-571: Is dependent on the inclusion of one or two specific loci in the analyses. One locus, i.e., mitochondrial DNA , contradicts the strict monophyly of Coronaves (Morgan-Richards et al. 2008), but phylogeny reconstruction based on mitochondrial DNA is complicated by the fact that few families have been studied, the sequences are heavily saturated (with back mutations) at deep levels of divergence, and they are plagued by strong base composition bias. The kagu and sunbittern are one another's closest relatives. It had been proposed (Cracraft 2001) that they and

176-541: The Heliornithidae , the limpkin , or the Psophiidae . Other birds have been placed in this order more out of necessity to place them somewhere ; this has caused the expanded Gruiformes to lack distinctive apomorphies . Recent studies indicate that these "odd Gruiformes" are if at all only loosely related to the cranes, rails, and relatives ("core Gruiformes"). There are only two suprafamilial clades (natural groups) among

198-462: The Gruiformes based on large DNA–DNA hybridization distances to other supposed Gruiformes. However, it was not until the work of Paton et al. (2004) and Fain and Houde (2004, 2006) that the correct placement of buttonquails within the shorebirds (order Charadriiformes) was documented on the basis of phylogenetic analysis of multiple genetic loci. Using 12S ribosomal DNA sequences, Houde et al. (1997) were

220-445: The Gruiformes, e.g., Ergilornithidae, Phorusrhacidae, Messelornithidae, Eogruidae, Idiornithidae, Bathornithidae, to name just a few (see below). Though some of these are superficially 'crane-like' and the possibility exists that some may even be related to extant families traditionally included in the Gruiformes, there are no completely extinct families that can be confidently assigned to core-Gruiformes. The traditional order Gruiformes

242-535: The ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping. Other examples of polyphyletic groups are algae , C4 photosynthetic plants , and edentates . Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes. Researchers concerned more with ecology than with systematics may take polyphyletic groups as legitimate subject matter;

SECTION 10

#1732875966279

264-768: The birds traditionally classified as Gruiformes. Rails ( Rallidae ), flufftails ( Sarothruridae ), finfoots and sungrebe ( Heliornithidae ), adzebills ( Aptornithidae ), trumpeters ( Psophiidae ), limpkin ( Aramidae ), and cranes ( Gruidae ) compose the suborder Grues and are termed "core-Gruiformes". These are the only true Gruiformes. The suborder Eurypygae includes the kagu (Rhynochetidae) and sunbittern (Eurypygidae). These are not even remotely related to Grues. The families of mesites or roatelos ( Mesitornithidae ), button-quails ( Turnicidae ), Australian plains-wanderer ( Pedionomidae ), seriemas ( Cariamidae ), and bustards ( Otididae ) each represent distinct and unrelated lineages. Many families known only from fossils have been assigned to

286-402: The descendants of a unique common ancestor. By comparison, the term paraphyly , or paraphyletic , uses the ancient Greek preposition παρά ( pará ) 'beside, near', and refers to the situation in which one or several monophyletic subgroups are left apart from all other descendants of a unique common ancestor. In many schools of taxonomy , the recognition of polyphyletic groups in

308-500: The first to present molecular genetic evidence of gruiform polyphyly , although apparently they were not convinced by it. However, on the basis of numerous additional sequence data, it has been shown decisively that the traditionally recognized Gruiformes consist of five to seven unrelated clades (Fain and Houde 2004, Ericson et al. 2006, Hackett et al. 2008). Fain and Houde (2004) proposed that Neoaves are divisible into two clades, Metaves and Coronaves, although it has been suggested from

330-403: The known families and that may occupy a more basal position: Other even more enigmatic fossil birds and five living families are occasionally suggested to belong into this order, such as the proposed Late Cretaceous family Laornithidae and the following taxa: Polyphyly For example, the biological characteristic of warm-bloodedness evolved separately in the ancestors of mammals and

352-400: The presence of exactly two stamens has developed convergently in many groups. Species have a special status in systematics as being an observable feature of nature itself and as the basic unit of classification. It is usually implicitly assumed that species are monophyletic (or at least paraphyletic ). However, hybrid speciation arguably leads to polyphyletic species. Hybrid species are

374-792: The recently extinct adzebills (family Aptornithidae) from New Zealand constitute a distinct Gondwanan lineage. However, sunbittern and kagu are believed to have diverged from one another long after the break-up of Gondwanaland and the adzebills are in fact members of the Grues (Houde et al. 1997, Houde 2009). The seriemas and bustards represent distinct lineages within neoavian waterbirds. Psophiidae – trumpeters (3 species) Aramidae – limpkin Gruidae – cranes (15 species) Rallidae – rails, crakes and coots (152 species) Heliornithidae – finfoots (3 species) Sarothruridae – flufftails (15 species) Gruiformes When considered to be monophyletic, it

396-448: The similarities in activity within the fungus group Alternaria , for example, can lead researchers to regard the group as a valid genus while acknowledging its polyphyly. In recent research, the concepts of monophyly, paraphyly, and polyphyly have been used in deducing key genes for barcoding of diverse groups of species. The term polyphyly , or polyphyletic , derives from the two Ancient Greek words πολύς ( polús ) 'many,

418-528: The start that Metaves may be paraphyletic (Fain and Houde 2004, Ericson et al. 2006, Hackett et al. 2008). Sunbittern, kagu, and mesites all group within Metaves but all the other lineages of "Gruiformes" group either with a collection of waterbirds or landbirds within Coronaves. This division has been upheld by the combined analysis of as many as 30 independent loci (Ericson et al. 2006, Hackett et al. 2008), but

440-499: The traditional Gruiformes. They recognized that the Australian plains-wanderer (family Pedionomidae) was actually a member of the shorebirds (order Charadriiformes) based on skeletal characters. This was confirmed by Sibley and Ahlquist (1990) based on DNA–DNA hybridization and subsequently by Paton et al. (2003), Paton and Baker (2006) and Fain and Houde (2004, 2006). Sibley and Ahlquist furthermore removed button-quails (Turnicidae) from

462-479: Was assumed that Gruiformes was among the more ancient of avian lineages. The divergence of "gruiforms" among "Metaves" and "Coronaves" is proposed to be the first divergence among Neoaves, far predating the Cretaceous–Paleogene extinction event c. 66 mya (Houde 2009). No unequivocal basal gruiforms are known from the fossil record. However, there are several genera that are not unequivocally assignable to

SECTION 20

#1732875966279

484-451: Was established by the influential German avian comparative anatomist Max Fürbringer (1888). Over the decades, many ornithologists suggested that members of the order were in fact more closely related to other groups (reviewed by Olson 1985, Sibley and Ahlquist 1990). For example, it was thought that sunbittern might be related to herons and that seriemas might be related to cuckoos. Olson and Steadman (1981) were first to correctly disband any of

#278721