Helminths of small rodents (Heteromyidae and Cricetidae) in the Yucatan Peninsula, Mexico: an integrative taxonomic approach to their inventory Author Panti-May, Jesús Alonso Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. Author Moguel-Chin, Wilson Isaias 0000-0002-2564-4086 wilson-im @ hotmail. com; https: // orcid. org / 0000 - 0002 - 2564 - 4086 wilson-im@hotmail.com Author Hernández-Mena, David Iván 0000-0003-0822-3498 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mérida, Yucatán, México & dahernandez. 243 @ gmail. com; https: // orcid. org / 0000 - 0003 - 0822 - 3498 dahernandez.243@gmail.com Author Cárdenas-Vargas, Miguel Humberto 0009-0003-3622-6351 miguel. carvar 23 @ gmail. com; https: // orcid. org / 0009 - 0003 - 3622 - 6351 miguel.carvar23@gmail.com Author Torres-Castro, Marco 0000-0002-8295-0100 Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. & antonio. torres @ correo. uady. mx; https: // orcid. org / 0000 - 0002 - 8295 - 0100 antonio.torres@correo.uady.mx Author García-Prieto, Luis 0000-0002-7529-1514 Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México. & luis. garcia @ ib. unam. mx; https: // orcid. org / 0000 - 0002 - 7529 - 1514 luis.garcia@ib.unam.mx Author Digiani, Maria Celina 0000-0002-1626-9309 CONICET. División Zoología Invertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina & mdigiani @ fcnym. unlp. edu. ar; https: // orcid. org / 0000 - 0002 - 1626 - 9309 mdigiani@fcnym.unlp.edu.ar Author Hernández-Betancourt, Silvia F. 0000-0001-7302-9582 hbetanc @ correo. uady. mx; https: // orcid. org / 0000 - 0001 - 7302 - 9582 hbetanc@correo.uady.mx Author Vidal-Martínez, Víctor Manuel 0000-0002-6829-6317 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mérida, Yucatán, México & vvidal @ cinvestav. mx; https: // orcid. org / 0000 - 0002 - 6829 - 6317 vvidal@cinvestav.mx text Zootaxa 2023 2023-10-18 5357 2 205 240 http://dx.doi.org/10.11646/zootaxa.5357.2.3 journal article 10.11646/zootaxa.5357.2.3 1175-5326 10017978 A8932459-5A17-4812-8557-B9613DE69CEB Taenia rileyi Loewen (= Taenia lyncis Skinker ) Site of infection: Liver Host species: Sigmodon toltecus Locality: Kuncheil ranch ( Yucatan ) Specimens deposited: CNHE 11977 Comments: Each cyst contained one small, poorly developed metacestode 1.5‒2.8 mm long (without bladder). The metacestodes examined in this study showed characters which agreed with descriptions given by Mollhagen (1979) from S . hispidus , Rausch (1981) from Myodes rutilus (Pallas) and Tamiasciurus hudsonicus (Erxleben) , and the updated revision of the genus Taenia ( Loos-Frank 2000 ) , i.e., invaginated scolex with four suckers 140 long by 160 wide and rostellum with 2 crowns of 19‒20 hooks each ( Figure 3E ), longer hooks 240 in length and smaller hooks 190‒205 in length ( Figure 3F ). While some studies have reported strobilocercus larvae for T . rileyi ( Grundmann 1958 ; Mollhagen 1979 ), other studies refer to it as cysticercus ( Mahrt & Soo-Jeet 1972 ; Mollhagen 1978 ). There is considerable confusion on the form of larval T . rileyi due to the different levels of development of the strobilization. Since strobilization might easily interpret an evaginated cysticercus of T . rileyi , Mollhagen (1979) suggested not considering it as the sole diagnostic criterion. In Mexico , metacestodes of Hyd . taeniaeformis have also been reported in the liver of cricetid and murid rodents ( Preisser & Falcón-Ordaz 2019 ; Panti-May et al . 2021 ). However, the length of large hooks of Hyd . taeniaeformis is larger than those of T . rileyi . The only record of T . rileyi in Mexico was reported by Flores-Barroeta (1966) in Canis familiaris Linnaeus from Mexico City . Our study reports T. rileyi for the first time in rodents from Mexico .