Orthoceratium

{{short description|Genus of flies}}

{{Automatic taxobox

| image = Orthoceratium lacustre (10.3897-zookeys.782.26329) Figure 2.jpg

| image_caption = Orthoceratium lacustre

| taxon = Orthoceratium

| authority = Schrank, 1803{{cite book|last1=Schrank|first1=F. von P.|title=Fauna Boica. Durchgedachte Geschichte der in Baiern einheimischen und zahmen Thiere. Dritten und lezten Bandes, erst Abtheilung|url=https://www.biodiversitylibrary.org/page/31181684|date=1803|publisher=Philipp Krüll|place=Landshut|pages=i–viii + 1–272}}

| display_parents = 3

| type_species = Musca lacustris

| type_species_authority = Scopoli, 1763

| synonyms = *Alloeoneurus Mik, 1878{{cite journal|last1=Mik|first1=Josef|title=Dipterologische Untersuchungen|journal=Jahresber. K. K. Akad. Gymnasium|date=1878|pages=1–24, 1 pl}}

}}

Orthoceratium is a genus of flies in the family Dolichopodidae.{{cite book|last1=Yang|first1=D.|last2=Zhu|first2=Y.|last3=Wang|first3=M.|last4=Zhang|first4=L.|title=World Catalog of Dolichopodidae (Insecta: Diptera).|date=2006|publisher=China Agricultural University Press|location=Beijing|isbn=9787811171020|pages=1–704}} Only two species are included in the genus, Orthoceratium lacustre and Orthoceratium sabulosum. They are known from the West Palaearctic and Tanzania.

In 2018, researchers Marc Pollet and Andreas Stark found that the species O. sabulosum in northwestern Europe had been misidentified as O. lacustre for over 250 years. According to the researchers, these misidentifications can be explained by previous authors copying identification keys with misleading information, the omission by those authors to study the type specimens of O. sabulosum, and the loss of those of O. lacustre.{{cite journal|last1=Pollet|first1=M.|last2=Stark|first2=A.|year=2018|title=The quest for the identity of Orthoceratium lacustre (Scopoli, 1763) reveals centuries of misidentifications (Diptera, Dolichopodidae)|journal=ZooKeys|issue=782|pages=49–79|doi=10.3897/zookeys.782.26329|pmid=30275719|pmc=6160834|doi-access=free}}