''Choristotanyderus'' is an extinct,

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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 n ...

protodiptera Protodiptera is an extinct suborder of mecoptera Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Endopterygota with about six hundred species in nin ...

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 pairs ...

containing a single species, ''Choristotanyderus nanus'' which lived during the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Pale ...

period. The genus and species were first described by

Edgar Frederick Riek Edgar Frederick Riek (1920–2016) was an Australian entomologist and invertebrate zoologist known for his research on fossil insects and the taxonomy of freshwater crayfish. He later became known as prominent viticulturist and winemaker. Affil ...

in 1953 from a specimen found in

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, Australia. It is considered a

transitional form A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross ...

between

Mecoptera Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Endopterygota with about six hundred species in nine Family (biology), families worldwide. Mecopterans ...

and Diptera. The genus is placed in the

n family

Permotanyderidae The Permotanyderidaea are an extinct family of insects within the order Protodiptera. Along with Permotipulidae (''Permotipula'' and ''Permila'', Willmann, 1989) and the Robinjohniidae (Robinjohnia, Scherbakov ET to., 1995), the somewhat more ...

with the related genus ''

Permotanyderus ''Permotanyderus'' is an extinct genus of protodipteran insect of the Permotanyderidae family, first described by Edgar F. Riek in Australia in 1953 and which contains a single species ''P. ableptus''. Evidence of the presence of Diptera or thei ...

''.

Morphology

''Choristotanyderus'', despite being closely related to Diptera, retained four wings, with the hind wings being about one third as long as the forewings. These wings show the characteristic kink at the base of the R vein which is diagnostic of Diptera, but other venation patterns were more characteristic of

. The third thorax segment was also reduced, which has been considered another intermediate feature between the Mecoptera and the Diptera .

References

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species). It is one of the modern descendan ...

Prehistoric insect genera Permian insects Fossil taxa described in 1953 Prehistoric arthropods of Oceania Protodiptera {{permian-insect-stub