''Rhyniognatha'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of arthropod of disputed placement. It has been considered in some analyses as the oldest

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

known, as well as possibly being a

flying insect The Pterygota ( grc, πτερυγωτός, pterugōtós, winged) are a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings b ...

. ''Rhyniognatha'' is known from a partial head with preserved mouthparts from the

Early Devonian The Early Devonian is the first of three epochs comprising the Devonian period, corresponding to the Lower Devonian series. It lasted from and began with the Lochkovian Stage , which was followed by the Pragian from and then by the Emsian, ...

aged

Rhynie chert The Rhynie chert is a Lower Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness (a Lagerstätte). It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is locate ...

around 400 million years old, when Earth’s first terrestrial

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s were being formed. The type, and only species is ''R. hirsti'', which was named and described in 1928.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 Other analyses have interpreted the specimen as a

myriapod Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. The fossil record of myriapods reaches back into the late Silurian, ...

Evidence

Partial restorations of Rhyniognatha as myriapod

The head part of a specimen, preserved in a fragment of

Rhynie Chert The Rhynie chert is a Lower Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness (a Lagerstätte). It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is locate ...

, was collected in 1919 by the Reverend W. Cran, who provided it to S. Hirst,

Samarendra Maulik Samarendra Nath Maulik (25 December 1881 in Tamluk – 9 July 1950 in Chelsea) was an Indian entomologist who worked at the Natural History Museum, London and specialized in the systematics of the leaf beetles. He worked briefly at the Univ ...

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 Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...

. Several other pieces, including the ''Rhyniognatha'' head, were also described as ''R. praecursor'', stating the specimen to be a "supposed

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

l insect". The specimen was correctly identified as a different species and renamed ''Rhyniognatha hirsti'' in 1928 by entomologist Robin J. Tillyard. It was later donated by D.J. Scourfield to the

Natural History Museum A natural history museum or museum of natural history is a scientific institution with natural history collections that include current and historical records of animals, plants, fungi, ecosystems, geology, paleontology, climatology, and more. ...

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

where it is currently displayed on a microscope slide. 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. Nevertheless, a detailed reanalysis by Carolin Haug & Joachim T. Haug in 2017 came to a different interpretation, concluding that the identity of ''Rhyniognatha hirsti'' as a

, specifically a scutigeromorph centipede, was better supported by the available evidence, without being able to exclude an insect identity completely.

References

{{Taxonbar, from=Q1946495 Prehistoric insects of Europe Devonian insects Fossil taxa described in 1928 Fossils of Great Britain Transitional fossils Prehistoric insect genera Taxa named by Robert John Tillyard Controversial taxa