The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings.
In hymenopterans of the suborder Apocrita (wasps, bees and ants), the mesosoma consists of the three thoracic segments and the first abdominal segment (the propodeum). For historical reasons, in ants it is commonly referred to by the alternative name alitrunk. [1] [2] [3]
In scorpions, the mesosoma is composed of six segments and forms the first part of the abdomen, containing all of the major organs. The first segment contains the sexual organs as well as a pair of vestigial and modified appendages forming a structure called the genital operculum. The second segment bears a pair of featherlike sensory organs known as the pectines; the final four segments each contain a pair of book lungs. The mesosoma is armoured with chitinous plates, on the upper surface by the tergites and on the lower surface by the sternites.
In other arachnids such as spiders, the mesosoma is fused with the metasoma to form the opisthosoma.
Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host or in a nest cell provisioned by their mothers.
Gall wasps, also traditionally calledgallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generally very small creature are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America.
The abdomen is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal cavity. In arthropods, it is the posterior tagma of the body; it follows the thorax or cephalothorax.
This glossary of entomology describes terms used in the formal study of insect species by entomologists.
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum (dorsal), the metasternum (ventral), and the metapleuron (lateral) on each side. The metathorax is the segment that bears the hindwings in most winged insects, though sometimes these may be reduced or modified, as in the flies (Diptera), in which they are reduced to form halteres, or flightless, as in beetles (Coleoptera), in which they may be completely absent even though forewings are still present. All adult insects possess legs on the metathorax. In most groups of insects, the metanotum is reduced relative to the mesonotum. In the suborder Apocrita of the Hymenoptera, the first abdominal segment is fused to the metathorax, and is then called the propodeum.
The propodeum, propodeon or propodium is the first abdominal segment in Apocrita Hymenoptera. It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is strongly constricted posteriorly to form the articulation of the petiole, and gives apocritans their distinctive shape. There may be a suture between the propodeum and the thorax, like in Symphyta or not, and the presence or absence of such suture can aid in identifying specimens.
The metasoma is the posterior part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory system, and circulatory system, and the apical segments are typically modified to form genitalia. In a few of the most primitive insects, the metasomal segments bear small, articulated appendages called "styli", which are often considered to be vestigial. There are also pre-apical appendages in most insect orders, called cerci, which may be multi-segmented and almost resembling a posterior pair of antennae; these may be variously modified, or lost entirely. Otherwise, most adult insects lack appendages on the metasoma, though many larval insects have some form of appendages, such as prolegs or, in aquatic insects, gills.
In entomology, petiole is the technical term for the narrow waist of some hymenopteran insects, especially ants, bees, and wasps in the suborder Apocrita.
Evaniidae is a family of parasitoid wasps also known as ensign wasps, nightshade wasps, hatchet wasps, or cockroach egg parasitoid wasps. They number around 20 extant genera containing over 400 described species, and are found all over the world except in the polar regions. The larvae of these solitary wasps are parasitoids that feed on cockroaches and develop inside the egg-cases, or oothecae, of their hosts.
Sphecomyrma is an extinct genus of ants which existed in the Cretaceous approximately 79 to 92 million years ago. The first specimens were collected in 1966, found embedded in amber which had been exposed in the cliffs of Cliffwood, New Jersey, by Edmund Frey and his wife. In 1967, zoologists E. O. Wilson, Frank Carpenter and William L. Brown, Jr. published a paper describing and naming Sphecomyrma freyi. They described an ant with a mosaic of features—a mix of characteristics from modern ants and aculeate wasps. It possessed a metapleural gland, a feature unique to ants. Furthermore, it was wingless and had a petiole which was ant-like in form. The mandibles were short and wasp-like with only two teeth, the gaster was constricted, and the middle and hind legs had double tibial spurs. The antennae were, in form, midway between the wasps and ants, having a short first segment but a long flexible funiculus. Three additional species, S. canadensis, S. mesaki and S. nexa, were described in 1985, 2005, and 2024, respectively.
The thorax is the midsection (tagma) of the hexapod body. It holds the head, legs, wings and abdomen. It is also called mesosoma or cephalothorax in other arthropods.
Kollasmosoma sentum is a parasitoid wasp in the family Braconidae, which lays its eggs inside adult ants. It was featured as one of "the top 10 new species of 2012" in a list compiled by Conservationists at the Arizona State University International Institute for Species Exploration.
Megaphragma is a genus of wasp in the family Trichogrammatidae. It contains some of the smallest known insects, Megaphragma caribea and Megaphragma mymaripenne, which are roughly the same size as some unicellular protozoans.
Zigrasimecia is an extinct genus of ants which existed in the Cretaceous period approximately 98 million years ago. The first specimens were collected from Burmese amber in Kachin State, 100 kilometres (62 mi) west of Myitkyina town in Myanmar. In 2013, palaeoentomologists Phillip Barden and David Grimaldi published a paper describing and naming Zigrasimecia tonsora. They described a dealate female with unusual features, notably the highly specialized mandibles. Other features include large ocelli, short scapes, 12 antennomeres, small eyes, and a clypeal margin that has a row of peg-like denticles. The genus Zigrasimecia was originally incertae sedis within Formicidae until a second species, Zigrasimecia ferox, was described in 2014, leading to its placement in the subfamily Sphecomyrminae. Later, it was considered to belong to the distinct subfamily Zigrasimeciinae.
Pristomyrmex tsujii is a species of ant in the genus Pristomyrmex. Known from Fiji, where they are widely distributed but rarely encountered. The species has a discrete ergatoid queen caste that is intermediate between a worker and an alate queen.
Archimyrmex is an extinct genus of ant in the formicid subfamily Myrmeciinae, described by palaeoentomologist Theodore Cockerell in 1923. The genus contains four described species, Archimyrmex rostratus, Archimyrmex piatnitzkyi, Archimyrmex smekali and Archimyrmex wedmannae. Archimyrmex is known from a group of Middle Eocene fossils which were found in North America, South America, and Europe. The genus was initially placed in the subfamily Ponerinae, but it was later placed in Myrmeciinae; it is now believed to be the ancestor of the extant primitive genus Myrmecia from Australia. Despite this, Archimyrmex is not a member to any tribe and is regarded as incertae sedis within Myrmeciinae. However, some authors believe Archimyrmex should be assigned as incertae sedis within Formicidae. These ants can be characterised by their large mandibles and body length, ranging from 13.2 to 30 mm. They also have long, thin legs and an elongated mesosoma (thorax) and petiole.
Emplastus is an extinct morphogenus of ants in the subfamily Dolichoderinae, known from fossils found in Asia and Europe. The genus contains twelve species described from sites in England, Eastern Europe and Far Eastern Russia.
Yantaromyrmex is an extinct genus of ants first described in 2013. Members of this genus are in the subfamily Dolichoderinae of the family Formicidae, known from Middle Eocene to Early Oligocene fossils found in Europe. The genus currently contains five described species, Y. constrictus, Y. geinitzi, Y. intermedius, Y. mayrianum and Y. samlandicus. The first specimens were collected in 1868 and studied by Austrian entomologist Gustav Mayr, who originally placed the fossils in other ant genera until the fossils were reviewed and subsequently placed into their own genus. These ants are small, measuring from 4 to 6 mm in length and can be characterized by their trapezoidal shaped head-capsules and oval compound eyes that are located slightly to the rear of the capsules midpoint, with no known ocelli present.
Gerontoformica is an extinct genus of stem-group ants. The genus contains thirteen described species known from Late Cretaceous fossils found in Asia and Europe. The species were described between 2004 and 2016, with a number of the species formerly being placed into the junior synonym genus Sphecomyrmodes.
The superfamily Chalcidoidea is a megadiverse group of parasitic wasps that share these features:
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