Two new species of heligmosomoid Trichostrongylina nematodes belonging to the genera Neoheligmonella Durette-Desset, 1970 and Heligmonina Baylis, 1928 are described. They are parasitic in the small intestine of three species of Mastomys from Senegal living in sympatry: M. natalensis (Smith, 1834), M. erythroleucus (Temminck, 1853) and M. huberti (Wroughton, 1909). Neoheligmonella granjoni n. sp. is closely related to three species from Senegal. They concern: N. bai Diouf & Durette-Desset, 2002 and N. dielmensis Diouf, Bâ & Durette-Desset, 1998, both parasitic in Arvicanthis niloticus Geoffroy, 1903 and N. mastomysi Diouf et al., 1998, a parasite of M. erythroleucus. N. granjoni n. sp. differs from these species by having 15 cuticular ridges at mid-body versus 13, a large carene and spicules taking up 10-15% of body length versus 5.3-7.1%. Heligmonina kanei n. sp. differs from the most related species H. kotoensis Diouf, Daouda & Durette-Desset 2005, a parasite of M. natalensis from Benin in the following features: spicules taking up 11.6% of body length on average versus 16.8%; a female tail three times longer than the distance anus-vulva versus a tail of equivalent size to this distance. In N. granjoni n. sp., where the material is abundant in all three hosts, the infra-specific variations observed (morphological or morphometrical) were not related to the host species. This is the first report of the genera Neoheligmonella and Heligmonina in M. huberti. The relevance of the phenomenon of host capture concerning the evolution of these two genera is confirmed.