''Choristotanyderus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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

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 Paleoz ...

period. The genus and species were first described by Edgar Frederick Riek 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 Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. 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 a ...

between

Mecoptera Mecoptera (from the Greek: ''mecos'' = "long", ''ptera'' = "wings") is an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their lar ...

and

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

. 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 their ...

''.

Morphology

''Choristotanyderus'', despite being closely related to

, 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

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