Myxophaga

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Subclassis: Pterygota
Cladus: Metapterygota
Infraclassis: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Coleopterida
Ordo: Coleoptera
Subordo: Myxophaga
Superfamiliae (2): Lepiceroidea – Sphaeriusoidea

Familiae overview (4 + 1†): Hydroscaphidae – Lepiceridae – Sphaeriusidae – Torridincolidae – †Triamyxidae

Unplaced genera: †Leehermania
Name

Myxophaga Crowson, 1955
References
Additional references

Anton, E.; Beutel, R.G. 2006: On the head morphology of Lepiceridae (Coleoptera: Myxophaga) and the systematic position of the family and suborder. European journal of entomology, 103: 85–95. PDF
Arce Pérez, R. 1997: Sinopsis del suborden Myxophaga (Coleoptera) de México. Dugesiana, 4(2): 41–50. [in Spanish, with English abstract] Reference page. 
Beutel, R.G. 1999: Phylogenetic analysis of Myxophaga (Coleoptera) with a redescription of Lepicerus horni (Lepiceridae). Zoologischer Anzeiger, 237: 291–308.
Beutel, R.G. 2005: 6. Myxophaga Crowson, 1955. Introduction, phylogeny. Pp. 43-44 in: Beutel, R.G. & Leschen, R.A.B. (volume eds.) Coleoptera, Beetles. Volume 1: Morphology and systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim). In: Kristensen, N.P. & Beutel, R.G. (eds.) Handbook of zoology. A natural history of the phyla of the animal kingdom. Volume IV. Arthropoda: Insecta. Part 38. Berlin, New York: Walter de Gruyter. DOI: 10.1515/9783110904550.43
Beutel, R.G.; Maddison, D.R.; Haas, A. 1999: Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters. Systematic entomology, 24: 171–192.
Bouchard, P. & Bousquet, Y. 2020. Additions and corrections to “Family-group names in Coleoptera (Insecta)”. ZooKeys 922: 65–139. DOI: 10.3897/zookeys.922.46367 Open access. Reference page. 
Bouchard, P., Bousquet, Y., Davies, A.E., Alonso-Zarazaga, M.A., Lawrence, J.F., Lyal, C.H.C., Newton, A.F., Reid, C.A.M., Schmitt, M., Ślipiński, S.A. & Smith, A.B.T. 2011. Family-group names in Coleoptera (Insecta). ZooKeys 88: 1–972. DOI: 10.3897/zookeys.88.807 Open access. PMC: 3088472 Open access. Reference page. 
Hinton, H.E. 1967: On the spiracles of the larvae of the suborder Myxophaga (Coleoptera). Australian journal of zoology 15(5): 955–959. DOI: 10.1071/ZO9670955 Reference page. 
Kirejtshuk, A.G.; Poinar, G., jr. 2006: Haplochelidae, a new family of Cretaceous beetles (Coleoptera: Myxophaga) from Burmese amber. Proceedings of the Entomological Society of Washington, 108: 155–164. Internet Archive BHL
Catalogue of Palearctic Coleoptera. Vol. 1 ed. I. Löbl, & A. Smetana, Apollo Books, Stenstrup, Denmark, 2003 and 2004, p.25 ISBN 87-88757-73-0
Qvarnström, M., Fikáček, M., Wernström, J.V., Huld, S., Beutel, R.G., Arriaga-Varela, E., Ahlberg, P.E. & Niedźwiedzki, G. 2021. Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin. Current Biology 31(15): 3374–3381.e5. DOI: 10.1016/j.cub.2021.05.015 Open access. Reference page. 
Reichardt, H. 1973: A critical study of the suborder Myxophaga, with a taxonomic revision of the Brazilian Torridincolidae and Hydroscaphidae (Coleoptera). Arquivos de zoologia, 24(2): 73–162. full text and pdf
van Vondel, B.J., Ostovan, H. & Ghahari, H. 2017. An annotated checklist of Iranian Myxophaga (Hydroscaphidae, Sphaeriusidae) and Adephaga (Gyrinidae, Haliplidae, Noteridae, Rhysodidae) (Insecta: Coleoptera). Zootaxa 4216(3): 225–246. DOI: 10.11646/zootaxa.4216.3.2 Reference page. 

Links

Australian Faunal Directory
Tree of Life Web Project. 2007. Myxophaga. Version 07 August 2007 (temporary) in The Tree of Life Web Project
Atlas of beetles of Russia (a project dedicated to the 100th anniversary of G.G. Jacobson's book "Beetles of Russia")

Vernacular names
беларуская: Міксафага
čeština: řasožraví
English: myxophagans
suomi: Rihmansyöjät
日本語: ツブミズムシ亜目 (粘食亜目)
русский: Миксофага
svenska: Svampätarbaggar
中文: 藻食亚目

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.

Description

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]
Taxonomy

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.[a]

Superfamily Lepiceroidea Hinton, 1936

Family Lepiceridae Hinton, 1936
Lepicerus Hinton, 1936
†Lepiceratus Jałoszyński et al. 2020

Superfamily Sphaeriusoidea Erichson, 1845

Family Hydroscaphidae LeConte, 1874
Hydroscapha LeConte, 1874
Scaphydra Reichardt, 1973
Yara Reichardt & Hinton, 1976
Confossa Short, Joly, García & Maddison, 2015
Family Sphaeriusidae Erichson, 1845
Sphaerius Waltl, 1838
†Burmasporum Kirejtshuk 2009
Family Torridincolidae Steffan, 1964
Claudiella Reichardt & Vanin, 1976
Delevea Reichardt, 1976
Iapir Py-Daniel, da Fonseca & Barbosa, 1993
Incoltorrida Steffan, 1973
Satonius Endrödy-Younga, 1997
Torridincola Steffan, 1964
Ytu Reichardt, 1973

Family †Triamyxidae Qvarnström et al. 2021

†Triamyxa Qvarnström et al. 2021

Unplaced in family

†Leehermania Chatzimanolis et al. 2012

Distribution

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.[5]
Fossil record

Little about the fossil record of Myxophaga is known. 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,[6][7][8] as well as Burmasporum, which belongs to Sphaerusidae.[9] No impression fossils of myxophagan beetle were described until 2012, probably because of their small body size and specialized habitat.[10] A fossil specimen, assigned to the living genus Hydroscapha in Hydroscaphidae, was described in 2012 from the Yixian Formation in the Jehol Biota, dating from the Early Cretaceous (Aptian).[10] In 2019, Leehermania from the Late Triassic (Norian) Cow Branch Formation of North Carolina, which had previously been interpreted as the oldest known rove beetle was reinterpreted as an early diverging relative of the family Hydroscaphidae, making it the then oldest known Myxophagan.[11] In 2021, numerous specimens of a new myxophagan were described from a coprolite found in Late Triassic (Carnian) aged sediments in Poland. The new taxon Triamyxa, was placed in its own monotypic family Triamyxidae, and was resolved as either the most basal myxophagan or sister to Hydroscaphidae.[12]
Gallery

Specimen of Sphaerius minutus (Sphaeriusidae) in various views

Specimen of Sphaerius minutus (Sphaeriusidae) in various views
Specimens of Hydroscapha natans (Hydroscaphidae)

Specimens of Hydroscapha natans (Hydroscaphidae)
Specimen of Lepicerus inaequalis (Lepiceridae)

Specimen of Lepicerus inaequalis (Lepiceridae)

See also

List of subgroups of the order Coleoptera

Notes

† Denotes that the group is extinct

References

Beutel, R.; Leschen, R. (2005). "Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim)". Band 4 Part 38: Arthropoda, Hälfte: Insecta, Coleoptera, Beetles. Handbuch der Zoologie/Handbook of Zoology. Vol. 1. Walter de Gruyter. ISBN 3-11-017130-9.
Beutel & Leschen 2005, p. 43
"Myxophaga". Tree of Life Web Project. 2007. Retrieved 2017-05-26.
Mesaros, Gabor (2013). "Sphaeriusidae (Coleoptera, Myxophaga): A new beetle family to the fauna of Serbia". Bulletin of the Natural History Museum (6): 71–74. doi:10.5937/bnhmb1306071m.
Sampaio, Brunno H.L.; Short, Andrew E.Z. (2018), "Families Hydroscaphidae and Torridincolidae", Thorp and Covich's Freshwater Invertebrates, Elsevier, pp. 519–525, doi:10.1016/b978-0-12-804223-6.00022-6, ISBN 978-0-12-804223-6, retrieved 2021-07-26
Kirejtshuk, A. G.; Poinar, G. (2006). "Haplochelidae, a new family of cretaceous beetles (Coleoptera: Myxophaga) from Burmese amber". Proceedings of the Entomological Society of Washington. 108: 155–164.
Ge, S. Q.; Friedrich, F.; Beutel, R. G. (2010). "On the systematic position and taxonomic rank of the extinct myxophagan dagger Haplochelus (Coleoptera)". Insect Systematics and Evolution. 41 (4): 329–338. doi:10.1163/187631210X537385.
Jałoszyński, Paweł; Luo, Xiao-Zhu; Hammel, Jörg U.; Yamamoto, Shûhei & Beutel, Rolf G. (2020). "The mid-Cretaceous †Lepiceratus gen. nov. and the evolution of the relict beetle family Lepiceridae (Insecta: Coleoptera: Myxophaga)". Journal of Systematic Palaeontology. 18 (13). doi:10.1080/14772019.2020.1747561
Kirejtshuk, A. G. (2009). "A new genus and species of Sphaeriusidae (Coleoptera, Myxophaga) from Lower Cretaceous Burmese amber" (PDF). Denisia. 26: 99–102.
Cai, C.; Short, A. E. Z.; Huang, D. (2012). "The First Skiff Beetle (Coleoptera: Myxophaga: Hydroscaphidae) from Early Cretaceous Jehol Biota". Journal of Paleontology. 86 (1): 116–9. doi:10.1666/11-050.1. S2CID 140170420.
Fikáček, Martin; Beutel, Rolf G.; Cai, Chenyang; Lawrence, John F.; Newton, Alfred F.; Solodovnikov, Alexey; Ślipiński, Adam; Thayer, Margaret K.; Yamamoto, Shûhei (January 2020). "Reliable placement of beetle fossils via phylogenetic analyses – Triassic Leehermania as a case study (Staphylinidae or Myxophaga?)". Systematic Entomology. 45 (1): 175–187. doi:10.1111/syen.12386. ISSN 0307-6970.
Qvarnström, Martin; Fikáček, Martin; Vikberg Wernström, Joel; Huld, Sigrid; Beutel, Rolf G.; Arriaga-Varela, Emmanuel; Ahlberg, Per E.; Niedźwiedzki, Grzegorz (June 2021). "Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin". Current Biology: S0960982221006746. doi:10.1016/j.cub.2021.05.015.