Aptorchis aequalis Nicoll, 1914 (Digenea: Plagiorchiidae) is a senior synonym of Dingularis anfracticirrus Jue Sue & Platt, 1999 (Digenea: Plagiorchiidae).

Examination of the type-specimen of Aptorchis aequalis Nicoll, 1914 (Digenea: Plagiorchiidae) revealed anatomical features not included in the original description; most notably the intestinal caeca extend to near the posterior end of the worm instead of terminating just posterior to the ventral sucker. A comparison of the type of A. aequalis with specimens identified as Dingularis anfracticirrus Jue Sue & Platt, 1999, from the author's collection yielded no differences that would justify the recognition of two genera. Therefore, Dingularis Jue Sue & Platt, 1999, is considered a junior subjective synonym of Aptorchis Nicoll, 1914. Principal components analysis of specimens of Aptorchis collected from three species of freshwater turtles at various localities in Queensland and New South Wales, Australia revealed no differences between these specimens and the type-specimen of Dingularis anfracticirrus. Therefore, D. anfracticirrus is considered a junior subjective synonym of A. aequalis. Aptorchis Nicoll, 1914, includes the following species: A. aequalis (= Dingularis anfracticirrus new synonymy); A. pearsoni (Jue Sue & Platt, 1999) n. comb.; and A. megapharynx (Jue Sue & Platt, 1999) n. comb.