C. nahuelhuapensis was found in the intestine of the rufous-legged owl (Strix rufipes) in Patagonia, Argentina. The proboscis is armed with 31–33 rows of hooks 16 or 17 hooks per row. The hooks in each row are distributed into 5 true hooks, 4 transitional hooks, and 7–8 spiniform hooks. It has three cement glands. The worm has a filiform body. Phylogenetic analysis was conducted using the small and large ribosomal subunits confirming the placement of this species in the genus Centrorhynchus.
