60-461: Weevils are beetles belonging to the superfamily Curculionoidea , known for their elongated snouts. They are usually small – less than 6 mm ( 1 ⁄ 4 in) in length – and herbivorous . Approximately 97,000 species of weevils are known. They belong to several families, with most of them in the family Curculionidae (the true weevils ). It also includes bark beetles , which while morphologically dissimilar to other weevils in lacking
120-421: A "surprisingly narrow range" spanning all four estimates from a minimum of 0.9 to a maximum of 2.1 million beetle species. The four estimates made use of host-specificity relationships (1.5 to 1.9 million), ratios with other taxa (0.9 to 1.2 million), plant:beetle ratios (1.2 to 1.3), and extrapolations based on body size by year of description (1.7 to 2.1 million). This immense diversity led
180-448: A beetle is quite uniform, although specific organs and appendages vary greatly in appearance and function between the many families in the order. Like all insects, beetles' bodies are divided into three sections: the head, the thorax, and the abdomen. Because there are so many species, identification is quite difficult, and relies on attributes including the shape of the antennae, the tarsal formulae and shapes of these small segments on
240-481: A beetle's environment. Beetle families may use antennae in different ways. For example, when moving quickly, tiger beetles may not be able to see very well and instead hold their antennae rigidly in front of them in order to avoid obstacles. Certain Cerambycidae use antennae to balance, and blister beetles may use them for grasping. Some aquatic beetle species may use antennae for gathering air and passing it under
300-764: A few fossils from North America before the middle Permian , although both Asia and North America had been united to Euramerica . The first discoveries from North America made in the Wellington Formation of Oklahoma were published in 2005 and 2008. The earliest members of modern beetle lineages appeared during the Late Permian . In the Permian–Triassic extinction event at the end of the Permian, most "protocoleopteran" lineages became extinct. Beetle diversity did not recover to pre-extinction levels until
360-406: A mass of at least 115 g (4.1 oz) and a length of 11.5 cm (4.5 in). Adult male goliath beetles are the heaviest beetle in its adult stage, weighing 70–100 g (2.5–3.5 oz) and measuring up to 11 cm (4.3 in). Adult elephant beetles , Megasoma elephas and Megasoma actaeon often reach 50 g (1.8 oz) and 10 cm (3.9 in). The longest beetle
420-461: A mobile tooth on their left mandible. The consistency of beetle morphology , in particular their possession of elytra , has long suggested that Coleoptera is monophyletic , though there have been doubts about the arrangement of the suborders , namely the Adephaga , Archostemata , Myxophaga and Polyphaga within that clade . The twisted-wing parasites, Strepsiptera , are thought to be
480-490: A particularly hard exoskeleton and hard forewings ( elytra ) not usable for flying. Almost all beetles have mandibles that move in a horizontal plane. The mouthparts are rarely suctorial, though they are sometimes reduced; the maxillae always bear palps. The antennae usually have 11 or fewer segments, except in some groups like the Cerambycidae (longhorn beetles) and the Rhipiceridae (cicada parasite beetles). The coxae of
540-591: A series of conspicuous and relatively abrupt changes in body structure between hatching and becoming adult after a relatively immobile pupal stage. Some, such as stag beetles , have a marked sexual dimorphism , the males possessing enormously enlarged mandibles which they use to fight other males. Many beetles are aposematic , with bright colors and patterns warning of their toxicity, while others are harmless Batesian mimics of such insects. Many beetles, including those that live in sandy places, have effective camouflage . Beetles are prominent in human culture , from
600-708: A sister group to the beetles, having split from them in the Early Permian . Molecular phylogenetic analysis confirms that the Coleoptera are monophyletic. Duane McKenna et al. (2015) used eight nuclear genes for 367 species from 172 of 183 Coleopteran families. They split the Adephaga into 2 clades, Hydradephaga and Geadephaga, broke up the Cucujoidea into 3 clades, and placed the Lymexyloidea within
660-408: A string of beads , comb-like (either on one side or both, bipectinate), or toothed . The physical variation of antennae is important for the identification of many beetle groups. The Curculionidae have elbowed or geniculate antennae. Feather like flabellate antennae are a restricted form found in the Rhipiceridae and a few other families. The Silphidae have a capitate antennae with a spherical head at
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#1732794110014720-602: Is a Late Jurassic geologic formation in Mongolia . Dinosaur remains are among the fossils that have been recovered from the formation, although as of 2004 none have yet been referred to a specific genus . It is best known for the Shar Teeg locality which has lent its name to Shartegosuchidae , a family of mesoeucrocodylians (relatives of crocodilians), many of which have been found there; Shartegosuchus (the family's type genus ) means "Shar Teeg crocodile". It
780-526: Is a response to ecological demands of egg deposition. Another example of extreme dimorphism in weevils is that of the New Zealand giraffe weevil . Males measure up to 90 mm (3.5 in) and females 50 mm (2.0 in), although there is an extreme range of body sizes in both sexes. Beetle See subgroups of the order Coleoptera Beetles are insects that form the order Coleoptera ( / k oʊ l iː ˈ ɒ p t ər ə / ), in
840-489: Is as agricultural, forestry, and horticultural pests . Serious pest species include the boll weevil of cotton, the Colorado potato beetle , the coconut hispine beetle , the mountain pine beetle , and many others. Most beetles, however, do not cause economic damage and some, such as numerous species of lady beetles , are beneficial by helping to control insect pests. The name of the taxonomic order, Coleoptera, comes from
900-455: Is divided up into 2 subunits, the lower Shar Teg Beds and the upper Ulan Malgait Beds . The tritylodontids Shartegodon , Nuurtherium and Bienotheroides are known from the formation., As is docodontan Tegotherium . The turtles Annemys levensis and Annemys latiens and crocodylians Sunosuchus shartegensis and Adzhosuchus fuscus were also recovered from the formation. Numerous species of insects are also known from
960-438: Is found, from trees and their bark to flowers, leaves, and underground near roots - even inside plants in galls, in every plant tissue, including dead or decaying ones. Tropical forest canopies have a large and diverse fauna of beetles, including Carabidae , Chrysomelidae , and Scarabaeidae . The heaviest beetle, indeed the heaviest insect stage, is the larva of the goliath beetle , Goliathus goliatus , which can attain
1020-431: Is suggested below: Cimberididae Nemonychidae Anthribidae Belidae Attelabidae Caridae Brentidae Curculionidae Rhopalapion longirostre exhibits an extreme case of sexual dimorphism . The female rostrum is twice as long and its surface is smoother than in the male. The female bores egg channels into the buds of Alcea rosea . Thus, the dimorphism is not attributed to sexual selection. It
1080-548: Is the Hercules beetle Dynastes hercules , with a maximum overall length of at least 16.7 cm (6.6 in) including the very long pronotal horn. The smallest recorded beetle and the smallest free-living insect (as of 2015 ), is the featherwing beetle Scydosella musawasensis which may measure as little as 325 μm in length. The oldest known beetle is Coleopsis , from the earliest Permian ( Asselian ) of Germany, around 295 million years ago. Early beetles from
1140-437: Is the largest suborder, containing more than 300,000 described species in more than 170 families, including rove beetles (Staphylinidae), scarab beetles ( Scarabaeidae ), blister beetles (Meloidae), stag beetles (Lucanidae) and true weevils ( Curculionidae ). These polyphagan beetle groups can be identified by the presence of cervical sclerites (hardened parts of the head used as points of attachment for muscles) absent in
1200-425: The Colorado potato beetle , while others such as Coccinellidae (ladybirds or ladybugs) eat aphids , scale insects , thrips , and other plant-sucking insects that damage crops. Some others also have unusual characteristics, such as fireflies , which use a light-emitting organ for mating and communication purposes. Beetles typically have a particularly hard exoskeleton including the elytra , though some such as
1260-861: The Dytiscidae (diving beetles) , Haliplidae , and many species of Hydrophilidae , the legs, often the last pair, are modified for swimming, typically with rows of long hairs. Male diving beetles have suctorial cups on their forelegs that they use to grasp females. Other beetles have fossorial legs widened and often spined for digging. Species with such adaptations are found among the scarabs, ground beetles, and clown beetles ( Histeridae ). The hind legs of some beetles, such as flea beetles (within Chrysomelidae) and flea weevils (within Curculionidae), have enlarged femurs that help them leap. Ulan Malgait Formation The Ulan Malgait Formation
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#17327941100141320-531: The Greek koleopteros (κολεόπτερος), given to the group by Aristotle for their elytra , hardened shield-like forewings, from koleos , sheath, and pteron , wing. The English name beetle comes from the Old English word bitela , little biter, related to bītan (to bite), leading to Middle English betylle . Another Old English name for beetle is ċeafor , chafer, used in names such as cockchafer , from
1380-745: The Isoptera to do so. Because so many species exist in such diversity, the higher classification of weevils is in a state of flux. They are generally divided into two major divisions, the Orthoceri or primitive weevils, and the Gonatoceri or true weevils ( Curculionidae ). E. C. Zimmerman proposed a third division, the Heteromorphi, for several intermediate forms. Primitive weevils are distinguished by having straight antennae, while true weevils have elbowed (geniculate) antennae. The elbow occurs at
1440-664: The Middle Triassic . During the Jurassic ( 210 to 145 mya ), there was a dramatic increase in the diversity of beetle families, including the development and growth of carnivorous and herbivorous species. The Chrysomeloidea diversified around the same time, feeding on a wide array of plant hosts from cycads and conifers to angiosperms . Close to the Upper Jurassic, the Cupedidae decreased, but
1500-619: The Triassic through to tentatively the Oxfordian , have sometimes been considered weevils. Genera of the family have only been found in three formations in Kazakhstan , with most named in 1993. However, their phylogenetic position is contested, with others considering it part of Archostemata . The interfamilial relationships of Curculionoidea have been generally well resolved. The phylogeny by Li et al. (2023) based on phylogenomic data
1560-503: The maize weevil ( Sitophilus zeamais ), among others. The boll weevil ( Anthonomus grandis ) attacks cotton crops; it lays its eggs inside cotton bolls and the larvae eat their way out. Other weevils are used for biological control of invasive plants. A weevil's rostrum , or elongated snout, hosts chewing mouthparts instead of the piercing mouthparts that proboscis -possessing insects are known for. The mouthparts are often used to excavate tunnels into grains. In more derived weevils,
1620-400: The rove beetles have very short elytra while blister beetles have softer elytra. The general anatomy of a beetle is quite uniform and typical of insects, although there are several examples of novelty, such as adaptations in water beetles which trap air bubbles under the elytra for use while diving. Beetles are holometabolans , which means that they undergo complete metamorphosis , with
1680-431: The sacred scarabs of ancient Egypt to beetlewing art and use as pets or fighting insects for entertainment and gambling. Many beetle groups are brightly and attractively colored making them objects of collection and decorative displays. Over 300 species are used as food , mostly as larvae ; species widely consumed include mealworms and rhinoceros beetle larvae. However, the major impact of beetles on human life
1740-415: The telephone-pole beetle . The Archostemata have an exposed plate called the metatrochantin in front of the basal segment or coxa of the hind leg. Myxophaga contains about 65 described species in four families, mostly very small, including Hydroscaphidae and the genus Sphaerius . The myxophagan beetles are small and mostly alga-feeders. Their mouthparts are characteristic in lacking galeae and having
1800-707: The Cretaceous. The first scarab beetles were not coprophagous but presumably fed on rotting wood with the help of fungus; they are an early example of a mutualistic relationship. There are more than 150 important fossil sites from the Jurassic, the majority in Eastern Europe and North Asia. Outstanding sites include Solnhofen in Upper Bavaria , Germany, Karatau in South Kazakhstan ,
1860-572: The Permian, which are collectively grouped into the " Protocoleoptera " are thought to have been xylophagous (wood eating) and wood boring . Fossils from this time have been found in Siberia and Europe, for instance in the red slate fossil beds of Niedermoschel near Mainz, Germany. Further fossils have been found in Obora, Czech Republic and Tshekarda in the Ural mountains, Russia. However, there are only
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1920-483: The Proto-Germanic * kebrô ("beetle"; compare German Käfer , Dutch kever , Afrikaans kewer ). Beetles are by far the largest order of insects: the roughly 400,000 species make up about 40% of all insect species so far described, and about 25% of all animal species. A 2015 study provided four independent estimates of the total number of beetle species, giving a mean estimate of some 1.5 million with
1980-662: The Quaternary caused beetles to change their geographic distributions so much that current location gives little clue to the biogeographical history of a species. It is evident that geographic isolation of populations must often have been broken as insects moved under the influence of changing climate, causing mixing of gene pools, rapid evolution, and extinctions, especially in middle latitudes. The very large number of beetle species poses special problems for classification . Some families contain tens of thousands of species, and need to be divided into subfamilies and tribes. Polyphaga
2040-2009: The Tenebrionoidea. The Polyphaga appear to date from the Triassic. Most extant beetle families appear to have arisen in the Cretaceous. The cladogram is based on McKenna (2015). The number of species in each group (mainly superfamilies) is shown in parentheses, and boldface if over 10,000. English common names are given where possible. Dates of origin of major groups are shown in italics in millions of years ago (mya). Archostemata 160 mya (40) [REDACTED] Myxophaga 220 mya (94) [REDACTED] Hydradephaga (5,560) e.g. Dytiscidae (diving beetles) [REDACTED] Geadephaga ( 35,000 ) e.g. Carabidae (ground beetles) [REDACTED] Scirtoidea (800) + Derodontoidea (29) 200 mya [REDACTED] Staphylinidae 195 mya ( 48,000 , rove beetles) [REDACTED] Scarabaeoidea 145 mya ( 35,000 , scarabs, stag beetles, etc.) [REDACTED] Hydrophiloidea (2,800, water scavenger beetles) [REDACTED] Histeroidea (3,800, clown beetles) [REDACTED] Nosodendridae (70) Dascilloidea (180) [REDACTED] Buprestoidea ( 14,000 , jewel beetles) [REDACTED] Byrrhoidea (400, pill and turtle beetles, etc.) [REDACTED] Elateroidea ( 23,000 , click and soldier beetles, fireflies) [REDACTED] Bostrichoidea (3150, deathwatch, powderpost and skin beetles) [REDACTED] Coccinelloidea (6,000, ladybirds or lady beetles) [REDACTED] Tenebrionoidea 180 mya ( 35,000 , leaf/flower beetles, etc.) and Lymexyloidea [REDACTED] Cleroidea (9,900, checkered beetles and allies) [REDACTED] Cucujoidea (8,000) [REDACTED] Chrysomelidae ( 35,000 , leaf beetles) [REDACTED] Cerambycidae ( 25,000 , longhorn beetles) [REDACTED] Curculionoidea ( 97,000 , weevils) [REDACTED] Beetles are generally characterized by
2100-763: The Upper Cretaceous include Kzyl-Dzhar in South Kazakhstan and Arkagala in Russia. Beetle fossils are abundant in the Cenozoic; by the Quaternary (up to 1.6 mya), fossil species are identical to living ones, while from the Late Miocene (5.7 mya) the fossils are still so close to modern forms that they are most likely the ancestors of living species. The large oscillations in climate during
2160-742: The Yixian formation in Liaoning , North China, as well as the Jiulongshan formation and further fossil sites in Mongolia . In North America there are only a few sites with fossil records of insects from the Jurassic, namely the shell limestone deposits in the Hartford basin, the Deerfield basin and the Newark basin. The Cretaceous saw the fragmenting of the southern landmass, with the opening of
2220-456: The aquatic whirligig beetles ( Gyrinidae ), where they are split to allow a view both above and below the waterline. A few Longhorn beetles ( Cerambycidae ) and weevils as well as some fireflies ( Rhagophthalmidae ) have divided eyes, while many have eyes that are notched, and a few have ocelli , small, simple eyes usually farther back on the head (on the vertex ); these are more common in larvae than in adults. The anatomical organization of
2280-447: The back part of the thorax is concealed by the beetle's wings . This further segmentation is usually best seen on the abdomen. The multisegmented legs end in two to five small segments called tarsi. Like many other insect orders, beetles have claws, usually one pair, on the end of the last tarsal segment of each leg. While most beetles use their legs for walking, legs have been variously adapted for other uses. Aquatic beetles including
2340-631: The bark of trees together with the jewel beetles (Buprestidae). The diversity of jewel beetles increased rapidly, as they were the primary consumers of wood, while longhorn beetles ( Cerambycidae ) were rather rare: their diversity increased only towards the end of the Upper Cretaceous. The first coprophagous beetles are from the Upper Cretaceous and may have lived on the excrement of herbivorous dinosaurs. The first species where both larvae and adults are adapted to an aquatic lifestyle are found. Whirligig beetles (Gyrinidae) were moderately diverse, although other early beetles (e.g. Dytiscidae) were less, with
2400-433: The body whilst submerged. Equally, some families use antennae during mating, and a few species use them for defense. In the cerambycid Onychocerus albitarsis , the antennae have venom injecting structures used in defense, which is unique among arthropods . Antennae vary greatly in form, sometimes between the sexes, but are often similar within any given family. Antennae may be clubbed , threadlike , angled , shaped like
2460-555: The compound eyes may be modified and depends on whether a species is primarily crepuscular, or diurnally or nocturnally active. Ocelli are found in the adult carpet beetle (as a single central ocellus in Dermestidae ), some rove beetles ( Omaliinae ), and the Derodontidae . Beetle antennae are primarily organs of sensory perception and can detect motion, odor and chemical substances, but may also be used to physically feel
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2520-463: The distinctive snout, is a subfamily of Curculionidae. Some other beetles, although not closely related, bear the name "weevil", such as the leaf beetle subfamily Bruchinae , known as "bean weevils", or the biscuit weevil ( Stegobium paniceum ), which belongs to the family Ptinidae . Many weevils are considered pests because of their ability to damage and kill crops. The grain or wheat weevil ( Sitophilus granarius ) damages stored grain , as does
2580-651: The diversity of the early plant-eating species increased. Most recent plant-eating beetles feed on flowering plants or angiosperms, whose success contributed to a doubling of plant-eating species during the Middle Jurassic . However, the increase of the number of beetle families during the Cretaceous does not correlate with the increase of the number of angiosperm species. Around the same time, numerous primitive weevils (e.g. Curculionoidea ) and click beetles (e.g. Elateroidea ) appeared. The first jewel beetles (e.g. Buprestidae ) are present, but they remained rare until
2640-466: The end of the scape (first antennal segment) in true weevils, and the scape is usually much longer than the other antennal segments. Some exceptions occur, such as Nanophyini , primitive weevils with long scapes and geniculate antennae, while among the true weevils, Gonipterinae and Ramphus have short scapes and little or no "elbow". A 1995 classification system to family level was provided by Kuschel, with updates from Marvaldi et al. in 2002, and
2700-590: The evolutionary biologist J. B. S. Haldane to quip, when some theologians asked him what could be inferred about the mind of the Christian God from the works of His Creation, "An inordinate fondness for beetles". However, the ranking of beetles as most diverse has been challenged. Multiple studies posit that Diptera (flies) and/or Hymenoptera (sawflies, wasps, ants and bees) may have more species. Beetles are found in nearly all habitats, including freshwater and coastal habitats, wherever vegetative foliage
2760-440: The first part is called the scape and the second part is the pedicel. The other segments are jointly called the flagellum. Beetles have mouthparts like those of grasshoppers . The mandibles appear as large pincers on the front of some beetles. The mandibles are a pair of hard, often tooth-like structures that move horizontally to grasp, crush, or cut food or enemies (see defence , below). Two pairs of finger-like appendages,
2820-431: The legs are usually located recessed within a coxal cavity. The genitalic structures are telescoped into the last abdominal segment in all extant beetles. Beetle larvae can often be confused with those of other holometabolan groups. The beetle's exoskeleton is made up of numerous plates, called sclerites , separated by thin sutures. This design provides armored defenses while maintaining flexibility. The general anatomy of
2880-407: The legs, the mouthparts, and the ventral plates (sterna, pleura, coxae). In many species accurate identification can only be made by examination of the unique male genitalic structures. The head, having mouthparts projecting forward or sometimes downturned, is usually heavily sclerotized and is sometimes very large. The eyes are compound and may display remarkable adaptability, as in the case of
2940-489: The maxillary and labial palpi, are found around the mouth in most beetles, serving to move food into the mouth. In many species, the mandibles are sexually dimorphic, with those of the males enlarged enormously compared with those of females of the same species. The thorax is segmented into the two discernible parts, the pro- and pterothorax. The pterothorax is the fused meso- and metathorax, which are commonly separated in other insect species, although flexibly articulate from
3000-489: The most widespread being the species of Coptoclavidae , which preyed on aquatic fly larvae. A 2020 review of the palaeoecological interpretations of fossil beetles from Cretaceous ambers has suggested that saproxylicity was the most common feeding strategy, with fungivorous species in particular appearing to dominate. Many fossil sites worldwide contain beetles from the Cretaceous. Most are in Europe and Asia and belong to
3060-409: The number of beetle species is challenged by the number of species in dipterans (flies) and hymenopterans (wasps). Found in almost every habitat except the sea and the polar regions , they interact with their ecosystems in several ways: beetles often feed on plants and fungi , break down animal and plant debris, and eat other invertebrates . Some species are serious agricultural pests, such as
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#17327941100143120-490: The other suborders. Adephaga contains about 10 families of largely predatory beetles, includes ground beetles (Carabidae), water beetles ( Dytiscidae ) and whirligig beetles (Gyrinidae). In these insects, the testes are tubular and the first abdominal sternum (a plate of the exoskeleton ) is divided by the hind coxae (the basal joints of the beetle's legs). Archostemata contains four families of mainly wood-eating beetles, including reticulated beetles (Cupedidae) and
3180-410: The prothorax. When viewed from below, the thorax is that part from which all three pairs of legs and both pairs of wings arise. The abdomen is everything posterior to the thorax. When viewed from above, most beetles appear to have three clear sections, but this is deceptive: on the beetle's upper surface, the middle section is a hard plate called the pronotum , which is only the front part of the thorax;
3240-958: The recognition of the Cretaceous age family Mesophyletidae in 2018 from Burmese amber . The oldest weevils date to the Middle-Late Jurassic boundary, found in the Karabastau Formation of Kazakhstan, the Shar-Teg locality of Mongolia, the Daohugou locality in Inner Mongolia, China, and the Talbragar site in Australia. The extinct family Obrieniidae , with species dating from the Ladinian stage of
3300-473: The rostrum has a groove in which the weevil can fold the first segment of its antennae. Most weevils have the ability to fly (including pest species such as the rice weevil ), though a significant number are flightless, such as the genus Otiorhynchus , and others can jump. One species of weevil, Austroplatypus incompertus , exhibits eusociality , one of the few insects outside the Hymenoptera and
3360-664: The southern Atlantic Ocean and the isolation of New Zealand, while South America, Antarctica, and Australia grew more distant. The diversity of Cupedidae and Archostemata decreased considerably. Predatory ground beetles (Carabidae) and rove beetles (Staphylinidae) began to distribute into different patterns; the Carabidae predominantly occurred in the warm regions, while the Staphylinidae and click beetles (Elateridae) preferred temperate climates. Likewise, predatory species of Cleroidea and Cucujoidea hunted their prey under
3420-440: The superorder Holometabola . Their front pair of wings are hardened into wing-cases, elytra , distinguishing them from most other insects. The Coleoptera, with about 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. However,
3480-702: The temperate climate zone during the Cretaceous. Lower Cretaceous sites include the Crato fossil beds in the Araripe basin in the Ceará , North Brazil, as well as overlying Santana formation; the latter was near the equator at that time. In Spain, important sites are near Montsec and Las Hoyas . In Australia, the Koonwarra fossil beds of the Korumburra group, South Gippsland , Victoria, are noteworthy. Major sites from
3540-485: The tip. The Scarabaeidae typically have lamellate antennae with the terminal segments extended into long flat structures stacked together. The Carabidae typically have thread-like antennae. The antennae arises between the eye and the mandibles and in the Tenebrionidae, the antennae rise in front of a notch that breaks the usually circular outline of the compound eye. They are segmented and usually consist of 11 parts,
3600-407: Was achieved using phylogenetic analyses. The accepted families were the primitive weevils, Anthribidae , Attelabidae , Belidae , Brentidae , Caridae , and Nemonychidae , and the true weevils Curculionidae . Most other weevil families were demoted to subfamilies or tribes. Further work resulted in the elevation of Cimberididae to family from placement as a subfamily of Nemonychidae in 2017 and
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