A new species of the genus Paractinolaimus, P. magistris sp. n., is described and illustrated. It is characterized by having body 1.9-2.3 mm long; low, truncate lip region; four massive, acute onchia; stoma walls covered with sparse tiny denticles; odontostyle 29-35 μm long; well developed, didelphic-amphidelphic female reproductive apparatus; vulva a longitudinal oval pore; absence of advulval papillae; female tail about as long as anal body diameter (c’=1.0- 1.1), conoid, curved ventrad, and with acute terminus; mail tail convex conoid with blunt terminus; and 14-15 nearly contiguous ventromedian supplements. The new species, among the numerous species of Paractinolaimus described so far, has a unique female tail shape: instead of the usual convex conoid initial part followed by a more or less elongated slender part, it shows a quite short, Eudorylaimus-like conoid tail. A compendium of morphometrics of the nominal species of the genus is also provided.