The small genusCoelophthiniaEdwards, 1941 of the subfamily Gnoristinae (Diptera, Mycetophilidae) is so far known to harbour four species from the Palaearctic, Nearctic and Neotropical Regions. Extensive DNA barcoding of fungus gnats of the family Mycetophilidae through the International Barcode of Life project (iBOL) have initiated integrative studies resulting in taxonomic upgrades and a better understanding of many species and their delimitation. The opportunity was also taken to describe the mitogenome of a member ofCoelophthiniafor the first time.The integrative studies give evidence for splitting the European speciesC. thoracicaEdwards, 1941 into three different species. Four new species are described from the USA, Japan and the Nordic Region in Europe,Coelophthinia cirraKerrsp. n.,Coelophthinia itoaeKurinasp. n.,Coelophthinia lataKjaerandsensp. n.andCoelophthinia loraasiKjaerandsensp. n., raising the number of Holarctic species from two to six. The mitogenome ofCoelophthinia loraasisp. n. is described and analysed.