Rhyniognatha

Rhyniognatha is an extinct genus of arthropod of disputed placement. It has been considered in some analyses as the oldest insect known, as well as possibly being a flying insect[1] Rhynignatha is known from a partial head with preserved mouthparts from the Early Devonian aged Rhynie chert around 400 million years old, when Earth’s first terrestrial ecosystems were being formed. The type, and only species is R. hirsti, which was named and described in 1928.[2] Other analyses have interpreted the specimen as a myriapod.

Rhyniognatha
Temporal range: Early Devonian, 400 Ma
↓
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Genus: †Rhyniognatha
Tillyard, 1928
Species:
†R. hirsti
Binomial name
†Rhyniognatha hirsti
Tillyard, 1928
Synonyms

Evidence

The head part of a specimen, preserved in a fragment of Rhynie Chert, was collected in 1919 by the Reverend W. Cran, who provided it to S. Hirst, Samarendra Maulik and D.J. Scourfield. Hirst and Maulik published a report in 1926; in it they described Rhyniella praecursor, which is now known to be a springtail. Several other pieces, including the Rhyniognatha head, were also described as R. praecursor, stating the specimen to be a "supposed larval insect". The specimen was correctly identified as a different species and renamed Rhyniognatha hirsti in 1928 by entomologist Robin J. Tillyard.[2] It was later donated by D.J. Scourfield to the Natural History Museum in London where it is currently displayed on a microscope slide.[3] In 2004 Michael S. Engel and David A. Grimaldi (2004) analyzed Rhyniognatha hirsti's mouthparts, and came to the conclusion that Rhyniognatha likely had wings, as they determined the mouthparts resembled those of a mayfly, a flying insect.[4] Nevertheless, a detailed reanalysis by Carolin Haug & Joachim T. Haug came to a different interpretation, concluding that the identity of Rhyniognatha hirsti as a myriapod was better supported by the available evidence, without being able to exclude an insect identity completely.[5]

Food

Like other insects of its time, Rhyniognatha presumably fed on plant sporophylls—which occur at the tips of branches and bear sporangia, the spore-producing organs. The insect’s anatomy might also give clues as to what it ate. The creature had large mandibles which may or may not have been used for hunting.[6]

References
  1. The University of Aberdeen Image of type specimen (University of Aberdeen)
  2. R. J. Tillyard. 1928. Some remarks on the Devonian fossil insects from the Rhynie chert beds, Old Red Sandstone. Transactions of the Entomological Society of London 76:65-71
  3. Andrew Ross. "The oldest fossil insect in the world". Natural History Museum.
  4. Engel, Michael; Grimaldi, David (12 February 2004). "New Light Shed on the Oldest Insect". Nature. 427 (6975): 627–630. Bibcode:2004Natur.427..627E. doi:10.1038/nature02291. PMID 14961119.
  5. Carolin Haug & Joachim Haug (2017). "The presumed oldest flying insect: more likely a myriapod?". PeerJ. 5: e3402. doi:10.7717/peerj.3402. PMC 5452959. PMID 28584727.
  6. Paul Rincon (2004-02-11). "Oldest insect delights experts". BBC News.


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