Skrjabinodon castillensis (Nematode: Pharyngodonidae) parasitizing Liolaemus gracielae lizard (Squamata: Iguania: Liolaemidae) from Argentina.

Skrjabinodon castillensis is mentioned and illustrated here, based on specimens found in the large intestines of Liolaemus gracielae (Squamata: Liolaemidae) collected in San Juan province, Argentina. The species found is assigned to Skrjabinodon based lateral alae present in males. Lateral alae beginning midway between lips and nerve ring and ending just posterior to first pair of caudal papillae. In males, caudal alae absent, paired caudal papillae present. The species recorded in this study differs from all other species assigned to Skrjabinodon by morphology and number of tail filament spines. Skrjabinodon castillensis is the ninth species from the Neotropical realm and the only species of this genus known from Argentina.

Skrjabinodon castillensis n. sp. (Nematoda:Pharyngodonidae) from the Homonota horrida and H.darwinii (Squamata: Phyllodactylidae) from Argentina and key for the Neotropical species of the genus Skrjabinodon.

Skrjabinodon castillensis n. sp. is described and illustrated here, based on specimens found in the large intestines of Homonota horrida (province San Juan) and Homonota darwinii (province Neuquén) (Squamata: Phyllodactylidae) from Argentina. The new species is assigned to Skrjabinodon based lateral alae present in males, absent in females. Lateral alae beginning midway between lips and nerve ring and ending just posterior to first pair of caudal papillae. Females with vulva near esophageal bulb. In males, caudal alae absent, paired caudal papillae present. Skrjabinodon castillensis n. sp. represents the 9th species from the Neotropical realm. The new species differs from all other species assigned to Skrjabinodon by morphology of tail filament and number of tail filament spines. Skrjabinodon castillensis n. sp. is the only species of this genus known from Argentina. A key to the species of Skrjabinodon in the Neotropical realm is provided.

First record of Amblyomma tigrinum (Acari: Ixodidae) on puma (Puma concolor) in Argentina and new associations for carnivores in San Juan province.

Amblyomma tigrinum is a tick species widely distributed in South America. In Argentina, it has been recorded to occur in nearly all phytogeographic regions, exhibiting its plasticity to different types of environments. This tick is of medical and veterinary importance because its adult stages have been recorded primarily in mammals, including humans. Specifically in San Juan province, records of A. tigrinum are almost non-existent, with only two mentions, but which have no indication of host or specific place of collection. For this reason, the goal of this study is to report the first case of A. tigrinum in Argentina, as well as two new parasite-host associations of the adult tick in other carnivores in San Juan. We analyzed two individuals, one puma and one fox, which arrived at the Wildlife Rehabilitation, Environmental Education and Responsible Recreation Center (Parque Faunistico). Moreover, we analyzed one canid specimen obtained during a field sampling event. Our results indicated new records for San Juan province of A. tigrinum parasitizing Canis familiaris and Lycalopex gymnocercus, in addition to the first record for Argentina of this tick parasitizing a Puma concolor individual. The present study affords novel information about natural associations for carnivore hosts in San Juan province, and the first record of this tick on a puma for Argentina. Thus, we are contributing to the knowledge of parasite-host relationships on the group of carnivores in Argentina.

Description of Ornithodoros montensis n. sp. (Acari, Ixodida: Argasidae), a parasite of the toad Rhinella arenarum (Amphibia, Anura: Bufonidae) in the Monte Desert of Argentina.

A new tick species of the genus Ornithodoros (Acari: Argasidae) was described from larvae collected on the toad Rhinella arenarum in a locality from Argentina belonging to the Monte Biogeographic Province. Ornithodoros montensis n. sp. was described based on morphological traits and sequences of the mitochondrial 16S rRNA gene. The diagnostic characters for this species are a combination of idiosoma oval, dorsal plate pyriform with posterior margin slightly concave, dorsal surface with 17 pairs of setae (7 anterolateral, 4 to 5 central and 5 to 6 posterolateral), ventral surface with 6 pairs of setae and 1 pair on anal valves, three pairs of sternal setae, postcoxal setae absent, and hypostome pointed apically with dental formula 3/3 in the anterior half and 2/2 posteriorly almost to base. Phylogenetic analysis of 16S rDNA sequences and a principal component analysis based on morphometric characters provided additional support to the description of O. montensis as an independent lineage within the genus Ornithodoros. Larvae of O. montensis are phylogenetically closely related to O. puertoricensis, O. rioplatensis, O. talaje s.s., O. guaporensis, O. hasei and O. atacamensis, all of them belonging to the "O. talaje group".

New association between Amblyomma parvitarsum (Acari: Ixodidae) and the endemic lizard Liolaemus eleodori (Iguania: Liolaemidae) in Argentina

Records of lizard parasitizing ticks in Argentina are scarce and incomplete. We recorded a new population of Liolaemus eleodori, a lizard endemic to Argentina, parasitized by the hard tick Amblyomma parvitarsum. Hence, the objective of this study is to report this new association and enhance knowledge about its parasitism on reptiles of Argentina. To do this, we researched ectoparasitic loads. We determined different ecological predictors: intensity, mean intensity and prevalence. Our results provide the first data on the parasitism of nymphal stages on this lizard. We found a tick prevalence of 91.6% and a mean intensity of 2.45. Considering sexes, mean intensity was higher in females than in males. The gular region and lower ventral abdomen were the highest parasitized anatomical regions. This new record of the host-parasite association suggests that this relationship is not accidental, with this lizard species being central to the tick's life cycle. Probably, the microhabitat of this lizard species is essential for the tick to reach high prevalence. Our study represents an important contribution and provides additional information on parasitism in lizards of Argentina.