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, the equivalent Latin term cladus is often used in taxonomical literature.
In biology, a taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping.
Hemiptera is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of piercing-sucking mouthparts. The name "true bugs" is often limited to the suborder Heteroptera.
Homoptera is a suborder of order Hemiptera that is considered by some taxonomists to be paraphyletic, and therefore deprecated (obsolete). It was therefore split into the suborders Sternorrhyncha, Auchenorrhyncha, and Coleorrhyncha. The earlier work was based on nuclear DNA, but more recent phylogenetic analysis using mitochondrial DNA suggest that Homoptera may be a monophyletic group after all, a sister group of Heteroptera. The cause of the disparity in the analyses is suggested to be the long branch attraction effect in phylogenetic analysis, due to rapidly evolving DNA regions.
Gasterosteoidei is a suborder of ray-finned fishes that includes the sticklebacks and relatives, the 5th edition of Fishes of the World classifies this suborder within the order Scorpaeniformes.
A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and are covered with hairs that facilitate the spreading of a secretion over their bodies that acts as a water repellent and carrier of pheromones. They undergo a partial metamorphosis, and have various host associations, varying from very generalized to very specific. Some species have a cosmopolitan distribution, or occur throughout the temperate and tropical regions. Some are pests or vectors of plant viruses and phytoplasmas. The family is distributed all over the world, and constitutes the second-largest hemipteran family, with at least 20,000 described species.
A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit.
The Gerromorpha comprise an infraorder of insects in the "true bug" order Hemiptera. These "typical" bugs are commonly called semiaquatic bugs or shore-inhabiting bugs. The Ochteroidea (infraorder Nepomorpha are also found in shore habitat, while the Gerromorpha are actually most often encountered running around on the water surface, being kept from sinking by surface tension and their water-repellent legs. Well-known members of the Gerromorpha are the namesake Gerridae.
Nepomorpha is an infraorder of insects in the "true bug" order (Hemiptera). They belong to the "typical" bugs of the suborder Heteroptera. Due to their aquatic habits, these animals are known as true water bugs. They occur all over the world outside the polar regions, with about 2,000 species altogether. The Nepomorpha can be distinguished from related Heteroptera by their missing or vestigial ocelli. Also, as referred to by the obsolete name Cryptocerata, their antennae are reduced, with weak muscles, and usually carried tucked against the head.
The Cimicomorpha are an infraorder of insects in the order Hemiptera, the true bugs. The rostrum and other morphology of all members apparently is adapted to feeding on animals as their prey or hosts. Members include bed bugs, bat bugs, assassin bugs, and pirate bugs.
The Pentatomomorpha comprise an infraorder of insects in the true bug order Hemiptera. It unites such animals as the stink bugs (Pentatomidae), flat bugs (Aradidae), seed bugs, etc. They are closely related to the Cimicomorpha.
The Peloridiidae or moss bugs are a family of true bugs, comprising eighteen genera and thirty-four species. They are small, ranging in length from 2 to 4 mm, rarely seen, peculiarly lumpy, flattened bugs found in Patagonia, New Zealand, eastern Australia, Lord Howe Island, and New Caledonia. Peloridiids are found amongst mosses and liverworts, commonly in association with southern beech forests. They have become known as moss bugs for their habit of feeding on mosses. Almost all Peloridiidae species are flightless, except one. Their present distribution suggests they have existed since before the breakup of Gondwana. They are the only living members of the suborder Coleorrhyncha, which first appeared in the Upper Permian, over 250 million years ago.
The Auchenorrhyncha suborder of the Hemiptera contains most of the familiar members of what was called the "Homoptera" – groups such as cicadas, leafhoppers, treehoppers, planthoppers, and spittlebugs. The aphids and scale insects are the other well-known "Homoptera", and they are in the suborder Sternorrhyncha.
The name Prosorrhyncha is a name for a suborder of Hemiptera, comprising a grouping of the traditional taxon "Heteroptera" plus its sister taxon, the family Peloridiidae. There is no agreement on the status of this taxon, as there are two competing classifications regarding this branch of the Hemiptera; while some hemipterists follow this classification, it has by no means been accepted universally. See the Heteroptera article for the detailed discussion, and a comparison of the two taxoboxes.
Cicadomorpha is an infraorder of the insect order Hemiptera which contains the cicadas, leafhoppers, treehoppers, and spittlebugs. There are approximately 35,000 described species worldwide. Distributed worldwide, all members of this group are plant-feeders, and many produce either audible sounds or substrate vibrations as a form of communication. The earliest fossils of cicadomorphs first appear during the Late Permian.
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a type, which can be a specimen or a taxon of lower rank, and a description in words. Phylogenetic nomenclature is currently regulated by the International Code of Phylogenetic Nomenclature (PhyloCode).
In biological classification, taxonomic rank is the relative level of a group of organisms in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While older approaches to taxonomic classification were phenomenological, forming groups on the basis of similarities in appearance, organic structure and behaviour, methods based on genetic analysis have opened the road to cladistics.
Paraneoptera or Acercaria is a superorder of insects which includes lice, thrips, and hemipterans, the true bugs. It also includes the extinct order Permopsocida, known from fossils dating from the Early Permian to the mid-Cretaceous.
Coleorrhyncha or Peloridiomorpha, also known as moss bugs or beetle bugs, are a suborder of Hemiptera and represent an ancient lineage of moss-feeding insects. They show some similarities to the Heteroptera but have been considered distinct. It has a single extant family, the Peloridiidae. They are 2 to 5 millimetres in length, and feed on moss and liverworts. They have wings in some species which are reduced in others but all species are flightless and live in damp moss habitats and are associated with the distribution of Nothofagus trees in Australia, New Zealand, New Caledonia, and South America, which all were formerly part of the supercontinent Gondwana.
Yuri Alexandrovich Popov was a Soviet and Russian paleoentomologist, an authority on the taxonomy and evolution of fossil true bugs (Heteroptera) and Coleorrhyncha. He described more than 20 new families and subfamilies and 300 new genera and species from the Mesozoic and Cenozoic. He also was one of the founders of the modern higher classification of true bugs: three of seven heteropteran infraorders have been established by him. He was the author of more than 170 publications, including a classic monograph on the evolution of water bugs.
