Morphological and molecular data on helminths of Didelphis virginiana and Philander vossi (Mammalia: Didelphidae) from the Yucatán Peninsula, southeast Mexico Author Panti-May, Jesús Alonso Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. Author Chan-Casanova, Anyela Jackelin 0009-0001-2396-0050 Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. anyii91099@hotmail.com Author Canche-Pool, Elsy 0000-0002-0080-9737 Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. elsy.canche@correo.uady.mx Author Tello-Martín, Raúl 0000-0001-8882-8221 Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. raul.tello@correo.uady.mx Author Ruiz-Piña, Hugo 0000-0002-3080-1752 Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. rpina@correo.uady.mx Author Concha-Guillermo, Henry 0009-0003-8783-279X Pet-Ro, clínica veterinaria privada, Mérida, Yucatán, México. concha.guillermo@hotmail.com Author Guiascón, Oscar Retana- 0000-0001-5765-8506 Centro de Estudios de Desarrollo Sustentable y Aprovechamiento de la Vida Silvestre, Universidad Autónoma de Campeche, Campeche, Campeche, México. ogretana@uacam.mx Author Vega, Pedro Pablo Martínez 0000-0002-2738-2278 Centro de Investigaciones Regionales “ Dr. Hideyo Noguchi ”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. pedro.martinez@correo.uady.mx Author Chablé-Santos, Juan 0000-0002-4267-3049 Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. jcsantos@correo.uady.mx Author Martínez, Erendira Estrella- Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. mirna.estrella@correo.uady.mx Author Moguel-Chin, Wilson Isaias Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México. wilson-im@hotmail.com Author Hernández-Orts, Jesús S. Natural History Museum, London, United Kingdom. & Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic. Author Hernández-Mena, David I. Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México. Author Mendoza-Garfias, Berenit Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México. Author García-Prieto, Luis Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México. text Zootaxa 2024 2024-06-04 5463 1 1 24 http://dx.doi.org/10.11646/zootaxa.5463.1.1 journal article 298432 10.11646/zootaxa.5463.1.1 93218dbc-0e0e-4b1f-81cd-38cc6b58ecbd 1175-5326 11609981 A2EC1CDC-939A-42E0-802D-E672B4C31870 Mathevotaenia sp. Site of infection: Small intestine. Host species: Didelphis virginiana . Locality: Mérida ( Yucatán ). Prevalence: 16.7% (1/6). Intensity: 6. Specimen deposited: CNHE 12896. GenBank accession number: PP662454. Comments: The specimens of Mathevotaenia possess an unarmed scolex, 270 long by 310‒330 wide ( Figure 2A ). Suckers 135‒148 long by 127‒132 wide. Proglottids craspedote. Genital pores alternate irregularly. Testes from 45 to 48 in number, arranged in two lateral fields between both ovary and vitelline gland, 40‒45 long by 34‒40 wide. Elongated cirrus pouch, reaching lateral osmoregulatory canals. Ovary 200 long by 460 wide, medial, in anterior half of proglottid ( Figure 2B ). Eggs spherical, 38‒40 in diameter. Seven species of Mathevotaenia have been reported from numerous species of opossums in the Americas: Mathevotaenia bivittata (Janicki) , Mathevotaenia didelphidis (Rudolphi) , Mathevotaenia marmosae (Beddard) , Mathevotaenia pennsylvanica (Chandler & Melvin) , Mathevotaenia surinamensis (Cohn) , Mathevotaenia argentinensis Campbell,Gardner&Navone ,and Mathevotaenia sanmartini Jiménez, Braun, Campbell & Gardner. The number of testes (45‒48) allowed the differentiation of the Yucatán specimens from M . argentinensis (vs 19‒29) ( Campbell et al. 2003 ), M . bivittata (vs 5‒13) ( Hughes, 1940 ; Campbell et al . 2003 ), M . sanmartini (26‒41) ( Jiménez et al. 2008 ), M . surinamensis (vs 90‒100) ( Buchanan 1956 ), M . didelphidis (vs 20) ( Hughes 1940 ), M . pennsylvanica (30‒40) ( Campbell et al. 2003 ), and M . marmosae (vs>100) ( Beddard 1914 ). Moreover, the studied specimens had a narrower scolex (310‒330) than that of M . argentinensis (vs 392‒536), M . bivittata (vs 460‒600), M . sanmartinensis (vs 843‒1246), M . surinamensis (vs 580‒800), and M . pennsylvanica (vs 946). These differences suggest that the specimens from Yucatán may represent a species not described yet. In Mexico , unidentified species of Mathevotaenia have been reported from D . virginiana in Chiapas ( Monet-Mendoza et al. 2005 ) and Colima ( García-Prieto et al. 2012 ; García-Valle et al. 2023 ). This is the first report of Mathevotaenia in the Yucatán Peninsula.