Ixodes (Ixodes) pararicinus Keirans & Clifford, 1985 (Acari: Ixodidae) description of the immature stages, distribution, hosts and medical veterinary importance

The immature stages of the Neotropical tick Ixodes (Ixodes) pararicinus Keirans & Clifford, 1985 are describedfrom specimens in a laboratory colony initiated from engorged females collected on cattle and larvaefed on mice and chickens. The larva and nymph of I. pararicinus are described using SEM micrographs as wellas drawings for some features of the larva. Additionally, immature stages of I. pararicinus collected on wildmice and birds in Uruguay and Argentina were compared with specimens from the laboratory colony. Ataxonomic key to the nymphs of the species of the ricinus complex established in the Western Hemisphere ispresented. The distribution of I. pararicinus comprises Argentina, Colombia and Uruguay, but it is alsoprobably established in Bolivia, Brazil, Chile and Peru. Most adult ticks of this species have been found onintroduced domestic artiodactyles, although Neotropical deer species must have been the ancestral host.Larvae and nymphs of I. pararicinus have also been found on sigmodontine rodents and passeriformbirds. Although I. pararicinus is a member of the ricinus complex, which contains the main vectors ofBorrelia burgdorferi (sensu lato), there are few studies concerning its potential for pathogen transmission.

Three new species of Antricola (Acari Argasidae) from Brazil, with a key to the known species in the genus

Three new species of Antricola (Acari: Argasidae) are described from adult specimens collected on bat guano in different caves in Brazil. The female of Antricola guglielmonei n. sp. is easily determined by the presence of 2 smooth, depressed areas lacking setae in the posterolateral portions of the dorsum of the idiosoma, together with the partial fusion of the tubercles in the anteromedian portion of the idiosoma. The male of this species has a small spiracular plate surrounded by a pattern of tubercles disposed concentrically in its dorsal portion. Both sexes have cervical grooves very slightly marked. Antricola delacruzi n. sp. represents the only Antricola species with the dorsum of the idiosoma devoid of tubercles in both sexes and with scarce and minute setae placed over the smooth cuticle. The female of A. inexpectata n. sp. is known only from a few specimens. In this species, lines of smooth cuticle lacking setae separate the tubercles of the dorsum. In addition, there are 3 clumps of plumose setae close to the spiracular plate, in the ventrolateral portions of the idiosoma, in 3 well-delimited regions over cuticular thickenings. These 3 species share the peculiarity of a Haller's organ with the anterior pit bearing only 7 + 2 setae. The collection of these new species in Brazilian caves greatly expands the known range of the genus. A key to the adults of all known species of the genus is provided.