A Galleria mellonella (L.) baiting method was used to collect the entomopathogenic nematode, Steinernema ralatorei, from sugarcane (Saccharum officinarum L.) areas in the municipality of Paso del Macho, Veracruz, Mexico. Based on morphological, morphometric and molecular analyses, we found that three isolates of the nematode were similar and belonged to the bicornutum-ceratophorum-riobrave group. The nematode was characterized by an elongated, bottle-shaped anterior region in some first- and second-generation males and females, which occurs in a ratio of 1:3 (one individual with the characteristic to three normal individuals); this feature has not been reported for other Steinernema species. However, the body length of infective juveniles (591.7 ± 37.2 µm; range of 532.6–692.4 µm) and the formula of lateral fields (2, 4, 5, 6, 8, 6, 5, 4, 2) were similar to S. riobrave, followed by S. papillatum. The body length of males was 1753.4 ± 143.3 µm (range of 1585.9–2078.6 µm). Males had long, golden yellow spicules, 68.6 ± 8.1 µm (56.9–76.9 µm) in length, with variability in the shape of the manubrium. Analysis of ITS-rDNA, targeting the 5.8S, 12S, and 28S rDNA regions, and morphometric analyses confirmed the nematode should be placed in group IV, close to S. riobrave, as a new species in the family Steinernematidae.