Two new myxozoan parasites, Myxobolus mayarum n. sp. and Kudoa mayarum n. sp., infecting the neotropical fish Mayan Cichlid, Mayaheros urophthalmus (Günther, 1862) in the Yucatán Peninsula, Mexico.

The biodiversity of freshwater fishes is extensive in Mexico; however, knowledge of their associated myxozoan parasites is limited. This study aimed to recognize myxozoan parasites in the endemic fish Mayaheros urophthalmus. Two new species, Myxobolus mayarum n. sp. and Kudoa mayarum n. sp. were described from M. urophthalmus collected in the Celestún Coastal Lagoon and Baldiosera Freshwater Spring from the Yucatán Peninsula. Myxobolus mayarum n. sp. was found in 100 % of the examined fish, infecting the gills, kidney, pectoral fins, and spleen. The spores were round, 11.34 ± 0.67 μm length, 10.03 ± 0.44 μm width, and 7.22 ± 0.45 μm thickness. The polar capsules were pyriform and equal in size, 3.85 ± 0.29 μm length and 2.27 ± 0.20 μm width. The polar tubule 30.71 ± 2.10 μm long and coiled 5-6 times. Kudoa mayarum n. sp. was found in 30 % of fish, infecting the heart, oesophagus, and stomach. The spores were subspherical, 5.40 ± 0.40 μm length and 5.76 ± 0.37 μm width. The polar capsules were ellipsoidal and equal in size, 1.90 ± 0.27 μm length and 1.46 ± 0.20 μm width. The phylogenetic analyses based on the small and large subunits ribosomal DNA (18S rDNA and 28S rDNA) sequences demonstrated that these two species are distinct from other published myxozoans, providing evidence to support the description of two new species. This study constitutes the first record of myxozoans from the Yucatán Peninsula, contributing to increase the knowledge about the biodiversity of myxozoans in neotropical regions.