Gongylonema neoplasticum (Fibiger & Ditlevsen)

(= Spirometra neoplastica Fibiger & Ditlevsen; = Gongylonema problematicum Schulz; = Gongylonema orientale Yokogawa)

Site of infection: Stomach

Hosts: Mus musculus and R. rattus

Locality: Xkalakdzonot

Prevalence and mean intensity (range): Mus musculus 6.7% (5/75) and 3.2 (1–7), R. rattus 11.9% (14/118) and 9.4 (1–20)

Specimens deposited: MLP-He 7438, 7441 and CNHE 10710

Comments: The characteristics presented by our material agreed with descriptions given by Hall (1916) and Kruidenier & Peebles (1958), i.e. anterior portion of the body with longitudinal cuticular bosses; two prominent lateral alae beginning at level of base of pharynx (95–136 from the anterior tip); the tail of males curved ventrally with two subsymmetrical caudal alae; left spicule longer (519–671) than right (97–110); and 8–9 pairs of caudal papillae (4–5 precloacal and 4 postcloacal).

In México, G. neoplasticum has been reported previously for R. norvegicus in Michoacán (Hierro-Huerta 1992). Also, unidentified species of Gongylonema were reported for M. musculus in Hidalgo (Pulido-Flores et al. 2005) and Dipodomys merriami atronasus Merriam in Zacatecas (Martínez-Salazar et al. 2016). This is the first record of G. neoplasticum for R. rattus and M. musculus in México.