| Dicondylia | |
|---|---|
| |
| Clockwise from top left: dance fly ( Empis livida), long-nosed weevil ( Rhinotia hemistictus), mole cricket ( Gryllotalpa brachyptera), German wasp (Vespula germanica), emperor gum moth ( Opodiphthera eucalypti), assassin bug ( Harpactorinae) | |
| A chorus of several Magicicada species | |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Hexapoda |
| Class: | Insecta |
| (unranked): |
Dicondylia Hennig, 1953 |
| Subgroups | |
| Synonyms | |
| |
The Dicondylia are a taxonomic group ( taxon) that includes all insects except the jumping bristletails ( Archaeognatha). Dicondylia have a mandible attached with two hinges to the head capsule (dicondyl), in contrast to a hypothetical ancestral mandible with a single ball joint (monocondyl); the members of Archaeognatha do in fact have dicondylic mandibles, though they are not identical to the structure seen in "true" dicondylic insects. [2]
Dicondyle mandible and other features
The taxon is distinguished by the possession of a modified mandible with an additional joint canal, which also changes the muscle attachments of the mouth tools and allows a modified mandible movement compared to other mandibles (crustaceans, centipedes). This so-called dicondyle mandible has two joints with which it is attached to the head capsule, while non-insect taxa have only one single ball joint. [3] [4] The Archaeognatha were once thought to have only a single articulation, but it has since been shown that they do possess two articulations that are homologous to those in other insects, though slightly different. [2]
In addition to this feature, all members of the Dicondylia have a number of other group-specific features in their blueprint. They have a continuous occipital seam, and a further joint between the upper and lower limbs. [4] At the base of the oviposition tube ( ovipositor), there is an additional sclerite, the gonangulum, which allows for the improved coordination of the movement of the gonapophyses. In addition, all these insects ancestrally have a five-membered tarsus [4] and styli are present at their maximum at the two last abdominal segments. Another feature relates to embryonic development; all Dicondylia form a closed amniotic cavity around the embryos, producing two complete embryonic shells (the amnion and serosa).
Systematics
The Dicondylia includes all of the winged and secondarily wingless insects ( Pterygota), along with the Zygentoma (silverfish, etc.) that were formerly classified with the jumping bristletails in the now deprecated order Thysanura.
Notes and references
Notes
- ^ Engel, Michael S.; David A. Grimaldi (2004). "New light shed on the oldest insect". Nature. 427 (6975): 627–630. Bibcode: 2004Natur.427..627E. doi: 10.1038/nature02291. PMID 14961119.
- ^ a b Blanke, A., Machida, R., Szucsich, N.U., Wilde, F. and Misof, B. (2015) Mandibles with two joints evolved much earlier in the history of insects: dicondyly is a synapomorphy of bristletails, silverfish and winged insects. Syst. Entomol. 40: 357-364. https://doi.org/10.1111/syen.12107
- ^ Merkmale nach Klausnitzer 1997.
- ^ a b c Ward C. Wheeler, Michael Whiting, Quentin D. Wheeler, James M. Carpenter: The Phylogeny of the Extant Hexapod Orders. Cladistics 17, 2001; S. 113–169. ( PDF).
References
- Bernhard Klausnitzer: Insecta (Hexapoda), Insekten In Westheide, Rieger (Hrsg.): Spezielle Zoologie Teil 1: Einzeller und Wirbellose Tiere. Gustav Fischer Verlag, Stuttgart, Jena 1997; S. 626f.
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| Dicondylia | |
|---|---|
|
| |
| Clockwise from top left: dance fly ( Empis livida), long-nosed weevil ( Rhinotia hemistictus), mole cricket ( Gryllotalpa brachyptera), German wasp (Vespula germanica), emperor gum moth ( Opodiphthera eucalypti), assassin bug ( Harpactorinae) | |
| A chorus of several Magicicada species | |
|
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Hexapoda |
| Class: | Insecta |
| (unranked): |
Dicondylia Hennig, 1953 |
| Subgroups | |
| Synonyms | |
| |
The Dicondylia are a taxonomic group ( taxon) that includes all insects except the jumping bristletails ( Archaeognatha). Dicondylia have a mandible attached with two hinges to the head capsule (dicondyl), in contrast to a hypothetical ancestral mandible with a single ball joint (monocondyl); the members of Archaeognatha do in fact have dicondylic mandibles, though they are not identical to the structure seen in "true" dicondylic insects. [2]
Dicondyle mandible and other features
The taxon is distinguished by the possession of a modified mandible with an additional joint canal, which also changes the muscle attachments of the mouth tools and allows a modified mandible movement compared to other mandibles (crustaceans, centipedes). This so-called dicondyle mandible has two joints with which it is attached to the head capsule, while non-insect taxa have only one single ball joint. [3] [4] The Archaeognatha were once thought to have only a single articulation, but it has since been shown that they do possess two articulations that are homologous to those in other insects, though slightly different. [2]
In addition to this feature, all members of the Dicondylia have a number of other group-specific features in their blueprint. They have a continuous occipital seam, and a further joint between the upper and lower limbs. [4] At the base of the oviposition tube ( ovipositor), there is an additional sclerite, the gonangulum, which allows for the improved coordination of the movement of the gonapophyses. In addition, all these insects ancestrally have a five-membered tarsus [4] and styli are present at their maximum at the two last abdominal segments. Another feature relates to embryonic development; all Dicondylia form a closed amniotic cavity around the embryos, producing two complete embryonic shells (the amnion and serosa).
Systematics
The Dicondylia includes all of the winged and secondarily wingless insects ( Pterygota), along with the Zygentoma (silverfish, etc.) that were formerly classified with the jumping bristletails in the now deprecated order Thysanura.
Notes and references
Notes
- ^ Engel, Michael S.; David A. Grimaldi (2004). "New light shed on the oldest insect". Nature. 427 (6975): 627–630. Bibcode: 2004Natur.427..627E. doi: 10.1038/nature02291. PMID 14961119.
- ^ a b Blanke, A., Machida, R., Szucsich, N.U., Wilde, F. and Misof, B. (2015) Mandibles with two joints evolved much earlier in the history of insects: dicondyly is a synapomorphy of bristletails, silverfish and winged insects. Syst. Entomol. 40: 357-364. https://doi.org/10.1111/syen.12107
- ^ Merkmale nach Klausnitzer 1997.
- ^ a b c Ward C. Wheeler, Michael Whiting, Quentin D. Wheeler, James M. Carpenter: The Phylogeny of the Extant Hexapod Orders. Cladistics 17, 2001; S. 113–169. ( PDF).
References
- Bernhard Klausnitzer: Insecta (Hexapoda), Insekten In Westheide, Rieger (Hrsg.): Spezielle Zoologie Teil 1: Einzeller und Wirbellose Tiere. Gustav Fischer Verlag, Stuttgart, Jena 1997; S. 626f.
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