The enigmatic genus Ctenostylum Macquart with the description of a new species from the Brazilian Amazon Basin and a checklist of world Ctenostylidae species (Diptera) Author Rafael, José Albertino Author Pimentel, Therezinha De Jesus Author Godoi, Fabio Siqueira P. Author Machado, Renato Jose Pires text Zootaxa 2009 2026 63 68 journal article 10.5281/zenodo.186177 9d108029-093e-4e4b-88d6-a60b73186328 1175-5326 186177 Ctenostylum Macquart, 1851 : 140 . Type-species: C. rufum Macquart, 1851 (orig. des.). This genus was originally comprised of C. rufum Macquart, 1851 , described from one male specimen. Soon after the original description the type-specimen was studied by Bigot (1882) who rectified the original description. McAlpine (1989) reported that the type of Ctenostylum rufum was lost and he described a male from Costa Rica but did not give a name to it. He did not evaluate variation between the two male specimens because Macquart’s description was not very detailed, the illustrations were innacurate and a series of specimens was not available. Looking for ctenostylid specimens in the Amazon Basin we found one Ctenostylum specimen housed at MPEG. It was collected in Serra Norte, Carajás, Southeastern Pará state, and it appeard to be different from C. rufum according to Macquart’s original description and Bigot’s (1882) rectification, and different from the undescribed male from Costa Rica ( McAlpine 1989 ). The two previously-known specimens are males and here we describe the first female of this genus. The arista of the female is very complex, with dendritic branching ( Fig. 4 ), identical to females of other ctenostylid genera. but female tergite and sternite 7 ( Fig. 8 ) are not fused, as is found in the remainder of the family( McAlpine 1989 ).