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 Travassostrongylus sp. Site of infection: Small intestine. Host species: Didelphis virginiana . Localities: Umán , Mérida (Yucatán) and Chencoh (Campeche). Prevalence: 50% (3/6). Mean intensity: 7.3 (range 2‒17). Specimens deposited: CNHE 12880‒12882. FIGURE 4. A. Male caudal bursa of Viannaia arriguensis from Philander vossi , ventral view. B. Male caudal bursa of Viannaia sp. from Didelphis virginiana , ventral view. C. Cross section at midbody showing features of the synlophe of male Travassostrongylus sp. from Didelphis virginiana . D. Male caudal bursa of Travassostrongylus sp. from Didelphis virginiana , ventral view. E. Anterior end of female Strongyloides sp. from Philander vossi , ventral view. F. Female tail of Strongyloides sp. from Philander vossi showing the anus, lateral v iew. G. Vulva of Strongyloides sp. from Philander vossi , lateral view. Abbreviations: anus (a), egg (e), intestine (i), spicule (s), vulva (v), dorsal ray (dr), esophagus (es). GenBank accession number: PP662462. Comments: The characteristics of the studied nematodes agree with those established for the genus Travassostrongylus ( Durette-Desset 2009 ) . Coiled nematodes with 10 continuous ridges at midbody in both sexes. Five dorsal and five ventral ridges, orientated from right to left and symmetrically arranged with respect to frontal axis; ridges absent from lateral fields ( Figure 4C ). Male 4,190 ‒5,040 in body length. Male with caudal bursa subsymmetrical and a pattern type of 2-1-2. Dorsal ray short. Rays 10 shorter than rays 9 ( Figure 4D ). Spicules subequal, short, bi-radiate at end point, 110‒135 long. Gubernaculum 35‒40 long. Female body length 5,050‒6825. Didelphic female with prominent anterior lip. Eggs ovoid, 60‒65 long by 32‒40 wide. The genus Travassostrongylus comprises 11 species ( Hodda 2022 ): Travassostrongylus callis (Travassos) , Travassostrongylus orloffi Travassos , Travassostrongylus tertiuos Travassos , Travassostrongylus quatour Texeira de Freitas , Travassostrongylus quintus Texeira de Freitas , Travassostrongylus sextus Texeira de Freitas , Travassostrongylus travassosi Durette-Desset , Travassostrongylus paranquintus Durette-Desset , Travassostrongylus tourei Diaw , Travassostrongylus yungaensis Navone, Suriano & Pujol , and Travassostrongylus scheibelorum Scheibel, Catzeflis & Jiménez. The studied specimens closely resemble T. callis . However, T . callis has a larger gubernaculum (94 vs 35‒40). Also, the distal end of the spicules of our specimens is simple whereas that of T . callis end with exposed lamina ( Diaw 1976 ). Based on these differences, the specimens from the Yucatán Peninsula could represent a species not described yet. Only one species of Travassostrongylus has been reported from opossums in Mexico : T . orloffi from D . marsupialis in Veracruz ( Scheibel et al. 2014 ).Also, an unidentified species of Travassostrongylus has been recorded in Didelphis sp. in Chiapas ( Acosta-Virgen et al. 2015 ). The present study adds the first record of Travassostrongylus in the Yucatán Peninsula.