Enterobius gregorii

The pinworm Enterobius gregorii is a parasitic roundworm of the phylum Nematoda.

In 1983 Jean-Pierre Hugot declared his isolation of a new human parasite. While examining Oxyuridae of Malagasy Lemurs and in Old World Monkeys, he concluded that what had been previously assumed to be a single species of parasite was in fact couples of sister-species. Says Hugot, "In the Human parasites, which are very closely related to those of the Old World Monkeys, two types of spicules were described and we consider that each type belongs to a different species: Enterobius vermicularis (L., 1758) for the larger spicule (100 to 122 micrometers), and Enterobius gregorii n. sp. for the shorter spicule (70 to 80 micrometers)." 

This fine distinction is only of minor importance to all but the most statistically-minded researcher, however. For all practical purposes, the morphology, life cycle, clinical presentation, and treatment of Enterobius gregorii is identical to Enterobius vermicularis.