- Specimen of Sphaerius minutus (Sphaeriusidae) in various views
- Specimens of Hydroscapha natans (Hydroscaphidae)
- Specimen of Lepicerus inaequalis (Lepiceridae)
Myxophaga Temporal range: | |
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Satonius kurosawai (Torridincolidae) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Suborder: | Myxophaga Crowson, 1955 |
Families | |
Hydroscaphidae Contents |
Myxophaga is the second-smallest suborder of the Coleoptera after Archostemata, consisting of roughly 65 species of small to minute beetles in four families. The members of this suborder are aquatic and semiaquatic, and feed on algae.
Myxophaga have several diagnostic features: the antennae are more or less distinctly clubbed with usually fewer than nine segments, mesocoxal cavities are open laterally and bordered by a mesepimeron and metanepisternum, the hind wings are rolled apically in the resting positions. Internally, they are characterised by the presence of six malpighian tubules and the testes are tube-like and coiled. [1]
Beetles of this suborder are adapted to feed on algae. Their mouthparts are characteristic in lacking galeae and having a mobile tooth on their left mandible. [2]
There are four extant families in the suborder Myxophaga divided between two superfamilies, [3] containing about 65 described species, [4] and at least one extinct family. [lower-alpha 1]
Superfamily Lepiceroidea Hinton, 1936
Superfamily Sphaeriusoidea Erichson, 1845
Family †Triamyxidae Qvarnström et al. 2021
Unplaced in family
Living members of Lepiceridae are confined to northern South America and Central America. Members of Sphaeriusidae occur on all continents except Antarctica, while Hydroscaphidae occurs on all continents except Australia and Antarctica. Torridincolidae occurs in Africa, Asia, and South America. [10]
The fossil record of myxophagan beetles is sparse, likely due to their small size limiting preservation potential. [5] The currently oldest myxophagan is Triamyxa, described in 2021 from numerous specimens of found in a coprolite found in Late Triassic (Carnian) aged sediments in Poland. It was placed in its own monotypic family Triamyxidae, and was resolved as either the most basal myxophagan or sister to Hydroscaphidae. [9] The next oldest is Leehermania from the Late Triassic (Norian) Cow Branch Formation of North Carolina, which had previously been interpreted as the oldest known rove beetle but in 2019 was reinterpreted as an early diverging relative of the family Hydroscaphidae. [5] A fossil impression assigned to the living genus Hydroscapha in Hydroscaphidae is known from the Yixian Formation in the Jehol Biota, dating from the Early Cretaceous (Aptian). [11] Fossils from the early Late Cretaceous (Cenomanian) aged Burmese amber from Myanmar, have been assigned to the extant genus Lepicerus and extinct genus Lepiceratus within Lepiceridae, [12] [13] [14] as well as the extant Sphaerius and Bezesporum and the extinct Burmasporum and Crowsonaerius , belonging to Sphaerusidae. [7] [8] [6]
Sphaerius is a genus of beetles in the family Sphaeriusidae, comprising 18 species. It is one of the two extant genera in the family, the other being Bezesporum. They are typically found along the edges of streams and rivers, where they feed on algae; they occur on all continents except Antarctica. Three species occur in the United States.
The Hydroscaphidae are a small family of water beetles known commonly as skiff beetles. As of 2010, there are 23 species in the family. Several are recently described.
Scirtoidea is a superfamily of beetles. It is traditionally considered to consist of four families: Clambidae, Decliniidae, Eucinetidae and Scirtidae. However, genetic studies have suggested that Clambidae and Eucinetidae belong to a separate superfamily Clamboidea, which also includes Derodontidae. Scirtoidea and Clamboidea are the two earliest diverging lineages of living polyphagans.
Lepicerus is a genus of myxophagan beetles containing three described species in the family Lepiceridae; it is the only extant genus in the family, with another genus, Lepiceratus only known from fossils. Extant species occur in the Neotropics, from Mexico south to Venezuela and Ecuador. Fossils referrable to the genus are known from the early Late Cretaceous of Southeast Asia.
Nosodendridae is a family of beetles, with less than a hundred species in three extant genera, which are found worldwide. Nosodendron, the largest genus, is found in forests and attracted to yeast generated slime on the wounds of trees, and likely consumes fermented substances as well as fungi and microorganisms. Several additional genera and species are known from the fossil record. Nosodendridae is considered to be an isolated lineage within Polyphaga, being the sister group to the clade containing Staphyliniformia, Bostrichoidea and Cucujiformia.
The Ommatidae are a family of beetles in the suborder Archostemata. The Ommatidae are considered the extant beetle family that has most ancestral characteristics. There are only seven extant species, confined to Australia and South America. However, the geographical distribution was much wider during the Mesozoic spanning across Eurasia and Australia, suggesting that they were widespread on Pangea. So far, over 26 extinct genera containing over 170 species of these beetles have been described. Three extant genera have been assigned to this family: Omma,Tetraphalerus and Beutelius. The family is considered to be a subfamily of Cupedidae by some authors, but have been found to be more closely related to Micromalthidae in molecular phylogenies. A close relationship with Micromalthidae is supported by several morphological characters, including those of the mandibles and male genitalia. Due to their rarity, their ecology is obscure, it is likely that their larvae feed on deadwood.
Kateretidae also known as short-winged flower beetles are a family of beetles in the superfamily Cucujoidea. There are 10 extant and 4 extinct genera, and at least 40 described species. They are found worldwide except in New Zealand. Adults are anthophagous, feeding on flowers, while the larvae are spermatophagous inside the flower corolla.
Sphindidae is a family of beetles, in the suborder Polyphaga. They are called slime mold beetles due to their exclusive feeding on slime molds during adult and larval stages, other aspects of their life history are obscure. Palaeontological discoveries since 2015 have added to the geologic history of Sphindidae, including the discovery of Libanopsis, placed in the extinct subfamily Libanopsinae.
Helotidae is a family of beetles, in the suborder Polyphaga. The family includes about five extant genera, Helota MacLeay, Neohelota Ohta, Afrohelotina Kirejtshuk, Metahelotella Kirejtshuk, and Strophohelota Kirejtshuk. Helotidae are found mainly in the Old World tropics and are absent from Australia and Madagascar. The antennae are clubbed on the final three segments and is retractable within grooves under the head. The wings have reduced venation with just 4 anal veins. Helotids are known to be associated with sap, fruit and flowers, and the larvae of some species are known to bore into wood in order to pupate.
Phloeostichidae is a family of beetles in the superfamily Cucujoidea. They are typically found under the bark of dead trees. Larvae have been found to consume plant tissue and some fungi, while the adults appear to be exclusively fungivores. The family contains four extant genera, Phloeostichus is native to the Palearctic, Rhopalobrachium is native to central-southern South America and eastern Australia, Hymaea is native to southeastern Australia, and Bunyastichus is found in Tasmania.
Monotomidae is a family of beetles in the superfamily Cucujoidea. The family is found worldwide, with approximately 240 species in 33 genera. The ecological habits of the family are diverse, with different members of the group being found under tree bark, in decaying vegetation, on flowers and in ant nests. Their ecology is obscure, while at least some species are mycophagous, feeding on the fruiting bodies of ascomycete fungi, Rhyzophagus are predators on bark beetles and possibly Phoridae larvae, with the larvae of some species also being mycophagous.
The Protocoleoptera are a paraphyletic group of extinct beetles, containing the earliest and most primitive lineages of beetles. They represented the dominant group of beetles during the Permian, but were largely replaced by modern beetle groups during the following Triassic. Protocoleopterans typically possess prognathous (horizontal) heads, distinctive elytra with regular window punctures, culticles with tubercles or scales, as well as a primitive pattern of ventral sclerites, similar to the modern archostematan families Ommatidae and Cupedidae. They are thought to have been xylophagous and wood boring.
Throscidae is a family of elateroid beetles found worldwide with around 150 species in 5 extant genera. The larvae are soil-dwelling, siphoning fluid from mycorrhizae attached to trees. The adults are short-lived, with the adult males being noted for a complex mating dance. Like some other elateroids, they are capable of clicking.
2019 in paleoentomology is a list of new fossil insect taxa that were described during the year 2019, as well as other significant discoveries and events related to paleoentomology that were scheduled to occur during the year.
2015 in paleoentomology is a list of new fossil insect taxa that were described during the year 2016, as well as other significant discoveries and events related to paleoentomology that were scheduled to occur during the year.
Bukhkalius is an extinct genus of beetle belonging to the family Ommatidae, it contains the single species, Bukhkalius lindae. It was described in 2017 initially as a species of the extant genus Tetraphalerus and was placed into a separate monotypic genus in 2020, which was reaffirmed in a 2021 study. It is known from a single specimen from Burmese amber, dating to the Cenomanian stage of the Late Cretaceous. The specimen is around 4.7 mm long and around 1.3 mm wide.
Burmese amber is fossil resin dating to the early Late Cretaceous Cenomanian age recovered from deposits in the Hukawng Valley of northern Myanmar. It is known for being one of the most diverse Cretaceous age amber paleobiotas, containing rich arthropod fossils, along with uncommon vertebrate fossils and even rare marine inclusions. A mostly complete list of all taxa described up until 2018 can be found in Ross 2018; its supplement Ross 2019b covers most of 2019.
Triamyxa is an extinct genus of myxophagan beetle in the monotypic family Triamyxidae from the Carnian stage of Late Triassic, approximately 230 million years ago. It was found in the Keuper Claystone of Poland. The type species is Triamyxa coprolithica and it was identified from specimens found in the coprolite ZPAL AbIII/3520, likely belonging to the dinosauriform Silesaurus opolensis. Because Triamyxa specimens were found inside coprolites, this may offer a new method of finding insect fossils aside from amber. It is currently the oldest known member of Myxophaga. It was interpreted as either the most basal member of Myxophaga, or a sister group to Hydroscaphidae.
Kirejtomma is an extinct genus of ommatid beetle, known from the early Late Cretaceous (Cenomanian) aged Burmese amber of Myanmar. The type and only known species K. zhengi was described in 2020 as a species of Clessidromma, and placed into the new genus in 2021.
Lepidomma is an extinct genus of ommatid beetle. The genus was first described in 2019 for the species L. tianae. Lepidomma was synonymised with Clessidromma by Kirejtshuk, 2020. This synonymy was disputed by Li et al. (2021), who maintained Lepidomma as a separate genus from Clessidromma. Three additional species of Lepidomma were described in 2020 and 2022. All four species are known from the Cenomanian aged Burmese amber of Myanmar.