Reconstructed wings of Lycocercus goldenbergi, from Kukalová (1969).

Belongs within: Pterygota.
Contains: Panephemeroptera, Odonatoptera, Diaphanopterodea, Megasecoptera, Eugereonoidea, Spilapteroidea.

The Palaeoptera are a group of insects in which the wings are ancestrally held extending laterally from the body at rest and cannot be folded back flat over the abdomen. They include the modern mayflies and dragonflies, together with the Palaeodictyoptera, a group of usually large (sometimes extremely large) plant-sucking insects known from the latest Early Carboniferous to the Late Permian (Sinitshenkova 2002).

Big suckers
Published 17 April 2009
Reconstruction by Werner Kraus of the palaeodictyopteran Scepasma mediomatricorum. “Flügelspannweite” means “wingspan”—the model is life size.

Palaeodictyopteroids were Palaeozoic pterygotes (okay, I’ll stop now) that include what was until recently the very earliest known winged insect, the Early Carboniferous Delitzschala bitterfeldensis (a slightly older wing fragment described by Prokop et al., 2005, has since managed to nudge it from the record-holder’s spot). It was, without a doubt, the beginning of a glorious show. All palaeodictyopteroids were large in comparison to modern insects (those with wingspans of one centimetre were among the smallest), while the largest were spectacular by anybody’s standards, up to around 55 centimetres for the aptly-named Mazothairos enormis. Patterning preserved on wings in the form of light and dark bands indicates that at least some palaeodictyopteroids were strikingly coloured. The palaeodictyopteroids were also the first plant-feeding insects, with a long piercing beak superficially similar to that of modern hemipterans.

Drawing by Woodward (1876) of a fossil of Lithomantis carbonaria. Many palaeodictyopteroids (and a number of other Palaeozoic insects) possessed a pair of broad paranotal lobes on the first segment of the thorax, which has lead to their being described as “six-winged”. However, the paranotal lobes differ from true wings in not being articulated. Image via Tree of Life.

Ancestral palaeodictyopteroids possessed what are called palaeopterous wings. The majority of modern insects (all except dragonflies and mayflies) belong to a clade called Neoptera, characterised by the ability to fold the wings neatly back over the abdomen when not in use. Non-neopteran (i.e. palaeopterous) insects are unable to fold their wings back flat against the body, only move them up and down, so their wings are permanently open*. One group of palaeodictyopteroids, the Diaphanopterodea, did evolve the ability to fold the wings back, but they did so independently of neopterans. Their palaeopterous wings and early appearance have led to a general agreement that palaeodictyopteroids were one of the earliest lineages of winged insect to diverge**. This is also consistent with their development—palaeodictyopteroids had the closest thing to ametabolous development possible for a winged insect, with the wings extended (but curved backwards) in the terrestrial nymphs and growing and straightening incrementally until they reached adulthood (Kukalová-Peck 1991). As such, palaeodictyopteroids were quite possibly able to fly before they reached full maturity. Among modern insects, mayflies are the only ones to continue growth (undergoing a single moult) after extending their wings.

*Damselflies get around this limitation by having a steeply-angled thorax, so that moving the wings “up” effectively moves them back. They still can’t close them flat like a neopteran.

**A notable exception can be found in the Russian school of palaeoentomologists (Sinitshenkova 2002). The Russian school, who differ from other entomologists in regarding the neopteran ability to fold the wings as primitive and the palaeopterous orders as derive, regard the palaeodictyopteroids as related to modern hemipterans and psocopterans on the basis of the sucking beak.

Fossils of two megasecopterans, Mischoptera nigra above and Sphecoptera brongniarti below, showing the extremely narrowly attached wings on the elongate body. From Carpenter (1951).

Palaeodictyopteroids would have certainly been among the most spectacular features of the Carboniferous coal forests. Broad-winged forms such as the Palaeodictyoptera would have been reasonably fast fliers, but perhaps not particularly graceful ones, and probably resembled nothing so much as a miniature World War II bomber plane. Other palaeodictyopteroids, the Megasecoptera, developed elongate wings with very narrow bases. Megasecopterans probably did not fly as quickly as the palaeodictyopterans, but would have been very agile, possibly even able to hover in some forms. One subgroup of the Megasecoptera, the Dicliptera or Permothemistida, were also among those insects to lose the hind pair of wings.

While palaeodictyopteroids did not become extinct until the end of the Permian, they were in decline long before then (Shcherbakov 2008). Correlations have been pointed out between the decline of the palaeodictyopteroids and increasing abundance of dragonflies—the speedy dragonflies seemingly finding the relatively slow palaeodictyopteroids to be a flying smorgasbord. Other factors may have been competition from the also-diversifying Hemiptera, and the replacement of early plants such as progymnosperms with more advanced forms with better protection against herbivores. Like the Silurian giant fungus Prototaxites, palaeodictyopteroids had initially diversified when they were pretty much the only game in town, and perhaps they were simply unable to handle the increasing heat. Whatever the reason for their disappearance, they were the most fabulous animals of their time, and the world is all the poorer for their loss.

Systematics of Palaeoptera
    |--Hydropalaeoptera [Syntonopterida, Syntonopterodea]SBG11
    |    |  i. s.: Aedoeophasma anglicaR02
    |    |--Triplosoba [Protephemerida, Protephemeroptera, Triplosobida, Triplosobidae]SBG11
    |    |    `--*T. pulchellaR02
    |    |--PanephemeropteraSBG11
    |    |--OdonatopteraSBG11
    |    `--Bojophlebia [Bojophlebiidae]SBG11
    |         `--B. prokopiSBG11
    `--Palaeodictyopteroidea [Dictyoneuridea, Palaeodictyopterida]GC12
         |  i. s.: Namuroningxiidae [Namuronigxiidae]SBG11
         |  `--MegasecopteraGE05
         `--Palaeodictyoptera [Dictyoneurida, Paleodictyoptera]GE05
              |  i. s.: Rochdalia parkeriK-P91
              |         Idoptilus onisciformisK-P83
              |         Stenodictya lobataGE05
              |         Mazothairos enormisGE05, K-P91
              |         Moravia grandisGE05
              |         PermoneuridaeRJ93
              |         Straeleniella [Straeleniellidae]RJ93
              |           `--S. namurensis Laurentiaux-Vieira & Laurentiaux 1986RJ93
              |    |--FrankenholzioideaS02
              |    |    |--PsychroptilusZ02 [PsychroptilidaeS02]
              |    |    `--+--DictyoneurellidaeS02
              |    |       `--FrankenholziaRJ93 [FrankenholziidaeS02]
              |    |            `--F. culmanniRJ93
              |    `--ArcioneuroideaS02
              |         |--ArcioneuridaeS02
              |         |--ElmoboriidaeS02
              |         `--+--Eubrodia Carpenter 1967 [Eubrodiidae]S02
              |            `--Eukuloja [Eukulojidae]S02
              |                 `--E. cubitalisS02
                   |  i. s.: ArchaeoptilidaeS02
                   |         LithoptilidaeS02
                   |         Mecynoptera tuberculataS02
                   |  `--DictyoneuroideaS02
                   |       |--PeromapteridaeS02
                   |       |--SaarlandiidaeS02
                   |       `--DictyoneuridaeS02
                   |            |--Palaeoneura qiligouensis Hon 1985S02, RJ93
                   |            `--Schmidtopteron adictyonRJ93
                      |  |    |--MongolodictyidaeS02
                      |  |    `--Sharovia [Calvertiellidae]S02
                      |  |         `--S. sojanicaS02
                      |  `--BreyerioideaS02
                      |       |--StobsiidaeS02
                      |       |--CryptoveniidaeS02
                      |       `--BreyeriidaeS02
                      |            |--Jugobreyeria sippelorum Brauckmann et al. 1985RJ93
                      |            `--Breyeria bouleiRJ93
                                   |--Parathesoneura carpenteri Sharov & Sinichenkova 1977K-P83
                                   |--Mazonopterum wolfforum Kukalová-Peck & Richardson 1983K-P83
                                   |--Ostrava nigra (Kukalová 1960)K-P83
                                   |--Adolarryia bairdi Kukalová-Peck & Richardson 1983K-P83
                                   |--Monsteropterum moravicum Kukalová-Peck 1972K-P83
                                   |    |--H. giganteaRJ93
                                   |    `--H. vorhallensisS02 [=Homaloneura vorhallensisZ02]
                                   |--Thesoneura [Thesoneuridae]SBG11
                                   `--Lycocercus [Lycocercidae]SBG11
                                        |--L. goldenbergiRJ93
                                        `--L. pictusSBG11

*Type species of generic name indicated


Carpenter, F. M. 1951. Studies on Carboniferous insects from Commentry, France: part II. The Megasecoptera. Journal of Paleontology 25 (3): 336–355.

[GC12] Garrouste, R., G. Clément, P. Nel, M. S. Engel, P. Grandcolas, C. D’Haese, L. Lagebro, J. Denayer, P. Gueriau, P. Lafaite, S. Olive, C. Prestianni & A. Nel. 2012. A complete insect from the Late Devonian period. Nature 488: 82–85.

[GE05] Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press: New York.

[K-P83] Kukalová-Peck, J. 1983. Origin of the insect wing and wing articulation from the arthropodan leg. Canadian Journal of Zoology 61: 1618–1669.

[K-P91] Kukalová-Peck, J. 1991. Fossil history and the evolution of hexapod structures. In: CSIRO. The Insects of Australia: A textbook for students and research workers vol. 1 pp. 141–179. Melbourne University Press: Carlton (Victoria).

Prokop, J., A. Nel & I. Hoch. 2005. Discovery of the oldest known Pterygota in the Lower Carboniferous of the Upper Silesian Basin in the Czech Republic (Insecta: Archaeorthoptera). Geobios 38 (3): 383–387.

[R02] Rasnitsyn, A. P. 2002. Cohors Libelluliformes Laicharting, 1781 (=Subulicornes Latreille, 1807, =Hydropalaeoptera Rohdendorf, 1968). In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 85–89. Kluwer Academic Publishers: Dordrecht.

[RJ93] Ross, A. J., & E. A. Jarzembowski. 1993. Arthropoda (Hexapoda; Insecta). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 363–426. Chapman & Hall: London.

[S02] Sinitshenkova, N. D. 2002. Superorder Dictyoneuridea Handlirsch, 1906 (=Palaeodictyopteroidea). In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 115–124. Kluwer Academic Publishers: Dordrecht.

[SBG11] Staniczek, A. H., G. Bechly & R. J. Godunko. 2011. Coxoplectoptera, a new fossil order of Palaeoptera (Arthropoda: Insecta), with comments on the phylogeny of the stem group of mayflies (Ephemeroptera). Insect Systematics and Evolution 42: 101–138.

[Z02] Zherikhin, V. V. 2002. Ecological history of the terrestrial insects. In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 331–388. Kluwer Academic Publishers: Dordrecht.

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