A new species of Trichuris Roederer, 1761 (Nematoda: Trichuridae) from Heteromys gaumeri Allen & Chapman (Rodentia: Heteromyidae) in Yucatan, Mexico

Helminths of small rodents (Heteromyidae and Cricetidae) in the Yucatan Peninsula, Mexico: an integrative taxonomic approach to their inventory

In this survey, we inventoried the helminths of heteromyid and cricetid rodents captured in the Yucatan Peninsula from 2017 to 2019. Helminths were identified using morphological techniques (clearing, staining, and scanning electron microscopy). Also, the 28S rRNA gene of individuals from several helminth taxa was successfully amplified and sequenced. To confirm the identification at the generic level, and in some cases at the specific level, and the genealogical relationships of the parasites, phylogenetic analyses were performed with the new 28S sequences. We identified 22 species of helminths including three trematodes (Brachylaimidae, Dicrocoeliidae, and Microphallidae), five cestodes (Davaineidae, Hymenolepididae, and Taeniidae), and 14 nematodes (Trichuridae, Ancylostomatidae, Ornithostrongylidae, Heligmonellidae, and Oxyuridae) from Heteromys gaumeri (Heteromyidae), Ototylomys phyllotis, Oligoryzomys fulvescens, Peromyscus yucatanicus, Sigmodon toltecus, and Reithrodontomys gracilis (Cricetidae). The overall frequency of infection in small rodents was 84.1% (143/170); all specimens of H. gaumeri, S. toltecus and Ol. fulvescens were infected with helminths. In total, we provided 46 new sequences of the 28S gene from 17 species of helminths. Seven species are likely undescribed species, six are reported for the first time in rodents from Mexico, and 12 are new host records in the Americas. Before this study, 87 taxa of helminths had been reported from 35 cricetid and 12 heteromyid species in 21 Mexican states. Our findings increase to 93 the helminth taxa in these rodents, and to 36 the cricetid species parasitized by helminths. This large scale-survey is the first to use an integrative approach to inventory the helminths of wild small rodents in Mexico.

New species of Trichuris (Nematoda: Trichuridae) parasitizing Heteromys salvini (Rodentia: Heteromyidae) from Costa Rica, with a key to Trichuris species described from Heteromyidae

Trichuris guanacastei n sp., a parasite isolated from the Salvin' spiny mouse Heteromys salvini, collected from the Guanacaste Conservation Area, Costa Rica, during February 1996 is described. The new species was compared morphologically with the 29 known species that parasitize rodents distributed in 12 families in North and South America; T. guanacastei n. sp. it is characterized by the following set of traits: presence of a spicular tube (measuring 0.72-0.99); thick proximal cloacal tube and a short distal cloacal tube with a total length of 0.72-1.36; eggs 0.03-0.05 long and a semi-protrusible vulva. The new species represents the first one described in the genus in Costa Rica and the fifth one described in the Americas that parasite Heteromyidae.

A new Trichuris species (Nematoda: Trichuridae) from capybaras: Morphological-molecular characterization and phylogenetic relationships

A new species of Trichuris (Nematoda: Trichuridae) is described from the capybara, Hydrochoeris hydrochaeris (Rodentia: Caviidae), from two localities of Corrientes Province, based on morphological characteristics and ITS1 and ITS2 of nuclear rDNA region sequences. This species present morphological differences with 28 species of the genus described from North and South American rodents. Also, the new species is molecularly characterized and differentiated from those species from Muridae, Cricetidae and Myocastoridae rodents recorded from North and South America, Europe and Africa. Trichuris cutillasae n. sp. constitutes the ninth record from rodents of Argentina, and the second record for Caviidae. The phylogenetic analysis showed that the specimens of new species are in the same clade, and separated from specimens of T. myocastoris (ITS1and ITS2), T. navonae, T. bainae, Trichuris sp. and T. pardinasi (ITS2). Similarly, analysis of concatenated sequences ITS1 and ITS2 added further evidence that T. cutillasae n. sp. is a different species from those previously analyzed.

Morphological-molecular characterization and phylogenetic relationships of a new Trichuris species (Nematoda: Trichuridae) parasitic on Holochilus chacarius (Cricetidae: Sigmodontinae) from the Chaco ecoregion (Argentina)

A new Trichuris species isolated from Holochilus chacarius (Cricetidae: Sigmodontinae) from the Chaco ecoregion in Argentina is described based on morphological characteristics and mitochondrial (cox1, cob) and nuclear (ITS2) markers. The new species is distinguished from 27 species of Trichuris from North and South American rodents based on morphological and biometrical features, such as the absence of a spicular tube, presence of a cylindrical spicular sheath, non-protrusive vulva, length of spicule, and proximal and distal cloacal tube. In addition, the results based on three molecular markers of the new species and three Trichuris species previously analysed from sigmodontine rodents: Trichuris pardinasi, Trichuris navonae and Trichuris bainae confirmed that the specimens here studied belong to a different species. Molecular data are further used to discuss the phylogenetic relationships among the Trichuris species of rodents from Argentina. The combined analysis of mitochondrial genes (cox1 and cob) revealed four clades corresponding with four different species of Trichuris. T. navonae (Akodontini rodents) and T. massoiai n. sp. as a sister group related to T. bainae (Oryzomyini rodents) and separated of T. pardinasi (Phyllotini rodents).