Christelenkidae, a new extinct family based on a new taxon from Eocene Baltic amber (Diptera: Acalyptratae), with X-ray synchrotron microtomography imaging of its structures

A new family of Diptera Acalyptratae, Christelenkidae Rohacek fam. nov., is established for Christelenka multiplex Rohacek gen. et sp. nov., an unusual extinct taxon described from a unique male specimen preserved in Baltic amber (Mid-late Eocene, ca 48-34 Ma). Apart from detailed examination by light microscopy and photography, the holotype of the new species has also been studied by means of X-ray synchrotron microtomography with the aim of obtaining additional morphological data for consideration of its relationships. Because of a very peculiar combination of morphological characters, the new family is tentatively considered a sepa-rate lineage of Acalyptratae having no apparent sister-group relationship with any of the known families. Its probable relationships to some families of Opomyzoidea and Ephydroidea are discussed.