Archostemata Explained

The Archostemata are the smallest suborder of beetles, consisting of 50 living species in five families and over 200 described fossil species.^[1] They are an ancient lineage with a number of primitive characteristics. Antennae may be thread-shaped (filiform) or like a string of beads (moniliform). This suborder also contains the only beetles where both sexes are paedogenic, Micromalthus debilis. Modern archostematan beetles are considered rare, but were more diverse during the Mesozoic.

The term "Archostemata" is used more broadly by some authors to include both modern archostematans as well as stem-group beetles like "protocoleopterans", which some modern archostematans closely resemble to due to their plesiomorphic morphology.^[2] Genetic research suggests that modern archostematans are a monophyletic group. Some genetic studies have recovered archostematans as the sister group of Myxophaga.^[3]

A 2009 paper argued that the poor diversity of modern Archostemata, compared with the staggering evolutionary success of most other Coleoptera lineages, could be due to the lower efficiency of the thoracic locomotor apparatus, the absence ofcryptonephric Malpighian tubules, and competition with other beetles more adapted to angiosperms.^[4]

Taxonomy

There are five extant families.^{[5] [6]}

• Family Crowsoniellidae Iablokoff-Khnzorian, 1983
• Family Cupedidae Laporte, 1838
• Family Micromalthidae Barber, 1913
• Family Ommatidae Sharp and Muir, 1912
• Family Jurodidae Ponomarenko, 1985

Phylogeny

A partial phylogeny of Archostemata and early coleopterans, based on palaeontological data, from Boudinot et al. 2022.^[2]

According to Li et al. 2023;^[1] archostematan families are in bold.

See also

• List of subgroups of the order Coleoptera

External links

• Tree of Life - Archostemata

Notes and References

1. Li . Yan-Da . Tihelka . Erik . Yamamoto . Shûhei . Newton . Alfred F. . Xia . Fang-Yuan . Liu . Ye . Huang . Di-Ying . Cai . Chen-Yang . 2023-08-22 . Mesozoic Notocupes revealed as the sister group of Cupedidae (Coleoptera: Archostemata) . Frontiers in Ecology and Evolution . 11 . 10.3389/fevo.2023.1015627 . 2296-701X. free .
2. Boudinot . Brendon Elias . Yan . Evgeny Viktorovich . Prokop . Jakub . Luo . Xiao-Zhu . Beutel . Rolf Georg . 28 July 2022 . Permian parallelisms: Reanalysis of †Tshekardocoleidae sheds light on the earliest evolution of the Coleoptera . Systematic Entomology . 48 . 1 . en . 69–96 . 10.1111/syen.12562 . 251171914 . 0307-6970. free .
3. Hörnschemeyer . Thomas . July 2009 . The species-level phylogeny of archostematan beetles—where do Micromalthus debilis and Crowsoniella relicta belong? . Systematic Entomology . en . 34 . 3 . 533–558 . 10.1111/j.1365-3113.2009.00476.x . 2009SysEn..34..533H . 84795808.
4. Friedrich . Frank . Farrell . Brian D. . Beutel . Rolf G. . The thoracic morphology of Archostemata and the relationships of the extant suborders of Coleoptera (Hexapoda) . Cladistics . 2009 . 25 . 25 . 1–37 . 10.1111/j.1096-0031.2008.00233.x . 34879618 . 31 July 2024.
5. Patrice Bouchard . Yves Bousquet . Anthony E. Davies . Miguel A. Alonso-Zarazaga . John F. Lawrence . Chris H. C. Lyal . Alfred F. Newton . Chris A. M. Reid . Michael Schmitt . S. Adam Ślipiński . Andrew B. T. Smith . Family-group names in Coleoptera (Insecta) . 2011 . ZooKeys . 88 . 1–972 . 10.3897/zookeys.88.807. 21594053 . 3088472 . free . 2011ZooK...88....1B .
6. Bouchard. P.. Bousquet. Y.. 2020. Additions and corrections to "Family-group names in Coleoptera (Insecta)". ZooKeys. 922. 65–139. 32256157. 10.3897/zookeys.922.46367. 7113323. free. 2020ZooK..922...65B .