Spinitectus mixtecoensis sp. Nov. (Nematoda: Cystidicolidae), from the Oaxaca killifish Profundulus punctatus (Osteichthyes: Profundulidae) from Mexico, with comments on the distribution of Spinitectus humbertoi in the genera Profundulus and Tlaloc

Spinitectus mixtecoensis sp. nov. was isolated from the intestine of Profundulus punctatus from the rivers Apoala and Los Sabinos, Oaxaca, Mexico. The new species is described based on morphological and metric analyses, scanning electron microscopy, and partial sequences of the mitochondrial cytochrome c oxidase 1 (cox 1) gene. Spinitectus mixtecoensis sp. nov. is characterized by possessing 7 rings and few spines per ring, between 22-28 in both sexes and 5-8 spines per sector. The new species most closely resembles Spinitectus humbertoi, a parasite of Profundulus and Tlaloc from Central America. Specimens of Spinitectus mixtecoensis sp. nov. (n = 3) and S. humbertoi (n = 2) were sequenced for the cox 1 gene, and the sequences were aligned with other nematode sequences available in GenBank. Maximum likelihood and Bayesian inference analyses indicated that this new species forms an independent, well-supported clade with high posterior probability (pp). Spinitectus mixtecoensis sp. nov. is the third species of Spinitectus recorded in profundulid fish from Central America.