Metanephrocerus collini

Metanephrocerus Temporal range: Ypresian–Priabonian PreЄ Є O S D C P T J K Pg N
Metanephrocerus belgardeae holotype
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Pipunculidae
Subfamily:	†Protonephrocerinae
Genus:	†Metanephrocerus Carpenter & Hull, 1939
species
M. belgardeae M. collini M. groehni M. hoffeinsorum

Metanephrocerus is an extinct genus of big-headed flies in the dipteran subfamily Protonephrocerinae, for which it is one of only two genera. The genus contains four described species, Metanephrocerus belgardeae, M. collini, M. groehni, and M. hoffeinsorum. Metanephrocerus is known from a group of Middle Eocene fossils which were found in Europe and a single early Eocene fossil from North America.

When first described, Metanephrocerus was known only from two separate fossils, the holotype female, and the female paratype were fossilized as inclusions in transparent chunks of Baltic amber. Baltic amber is approximately forty-six million years old, having been deposited during the Lutetian stage of the Middle Eocene. There is debate on what plant family produced the amber, with evidence supporting relatives of either an Agathis or a Pseudolarix relative.

Fossils of the type species, M. collini, were first studied by American entomologist Frank M. Carpenter and F. M. Hull who placed the new species in the fossil genus Protonephrocerus. Carpenter and Hull's 1939 type description of the new species was published in the monograph series Bernstein-Forschungens. The species was moved to the new genus Metanephrocerus in a 1948 paper by Martin L Aczél, and since that time both the type specimens have been lost and are considered possibly destroyed. After the M. collini description, 75 years passed before an additional three related species were described. Two of those, M. groehni and M. hoffeinsorum. were described from solitary fossil inclusions in Baltic amber. The 2014 descriptions were made by Christian Kehlmaier, Manuel Dierick and Jeffrey H. Skevington, based on detailed CT scans of the specimens. They chose the species name "groehni" is a patronym honoring Carsten Gröhn, who supported the research of the authors, and who was the owner of the specimen before description. The fossil was to be deposited into the collections of the Geologisch-Paläontologisches Institut und Museum der Universität Hamburg Similarly, the epithet of the second species "hoffeinsorum" is a patronym for Christel and Hans-Werner Hoffeins for the donation of the type fossil to the Senckenberg Deutsches Entomologisches Institut and for their support of the authors research. The third related species, M. belgardeae, bringing the total to four, was described from a compression fossil found in the early Eocene, Ypresian Klondike Mountain Formation lagerstätten, its discovery expanding both the temporal range and geographic range.M. belgardeae was described by S. Bruce Archibald, Christian Kehlmaier, and Rolf Mathewes from a single partial female. The specific epithet is a matronym of Azure Rain Belgarde, who collected the type specimen, SR 08-06-02, and donated it to the Stonerose Interpretive Center.