However, C.
extraneus n. sp. can be easily differentiated from them by the following
differences: C. arii has distinctly longer oesophagus (1.2–1.3 mm) and
male tail (0.37–0.39 mm), and slightly shorter gubernaculum (0.09–
0.11 mm); C. robustus and C. filiformis have a pseudobuccal capsule almost
as wide as or slightly wider than posterior part of oesophagus;
moreover, C. robustus has distinctly longer oesophagus (1.43–
1.51 mm, representing 9.1–10.3% of body length); C. filiformis has
much shorter spicules (0.75–1.15 mm); C. spirocaudus has distinctly
longer oesophagus (1.21–1.34 mm in the males) and different number
and arrangement of caudal papillae.