Paucituberculata Ameghino

Paucituberculata Ameghino: Caenolestidae Trouessar (only family in the order) 1) Ixodes jonesae Kohls, Sonenshine and Clifford, 1969 is a South American species known from several specimens collected from Sigmodontinae and several larvae from Caenolastidae (Guglielmone et al. 2003 b). Venezuela, Táchira, South-West of San Cristóbal (07º 28´N 72 º 27´W), L on Caenolestes obscurus (= Caenolestes fuliginosus (Tomes)) (Jones et al. 1972). A total of 37 tick species were allegedly found on Didelphimorphia. Most tick species were occasionally found on these types of hosts, apart from some doubtful diagnoses such as those of A. dissimile on Monodelphis and Didelphis by Botelho et al. (2002), vague reports on marsupial infestation like that for A. tigrinum in Paraguay by Massi Pallarés and Benítez Usher (1982) or South American records of A. pseudoconcolor on Philander sp. in Guglielmone et al. (2003 a). Ticks found on Didelphimorphia are mostly Ixodes and to a lesser extent Amblyomma. Records from the Neotropical region with known tick stages found on South American marsupials total 239 for Ixodes versus 46 for Amblyomma. The difference in usage of Didelphimorphia as hosts for these genera is further enhanced because the total records for all species of Amblyomma for the whole Neotropical Region is 6947, while the corresponding number for all Ixodes is 1127. In other words, 21.2 % and 0.7 % of all records of Ixodes and Amblyomma, respectively, established in South America (exclusively or non-exclusively) are for infestation on Didelphimorphia and this difference is statistically significant (P