Rhyniognatha hirsti is the world’s oldest known insect. It emerged very early during the Early Devonian Period, around 400 million years ago, when earth’s first terrestrial ecosystems were being formed. While Rhyniognatha remains an arthropod of uncertain affinities, several facts are apparent.
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, S. 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. It was later donated by D.J. Scourfield to the Natural History Museum
where it is currently displayed on a microscope slide. Scientists have not found much information, but due to the shape of the jaws they think it was probably winged.
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.
Engel & Grimaldi (2004) show that R. hirsti was relatively derived within early insects, sharing many characteristics with winged insects. This could mean that R. hirsti itself was already winged.