Systematic & Applied Acarology
ISSN 1362-1971
An international journal of the Systematic and Applied Acarology Society, published since 1996

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Systematic & Applied Acarology (2005) 10, 37-40

Ixodes sigelos Keirans, Clifford & Corwin, 1976 (Acari: Ixodidae) in Argentina and southern Chile

1 Instituto Nacional de Tecnología Agropecuaria, CC 22, CP 2300 Rafaela, Santa Fe, Argentina; e-mail:
2 Facultad de Medicina Veterinaria, Universidad de Concepción, Casilla 537, Chillán, Chile; e-mail:
3 Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán (4000), Argentina. PIDBA (Programa de Investigaciones de Biodiversidad Argentina); e-mail:
4 Departamento de Parasitología Veterinaria, Facultad de Veterinaria, Universidad de la República, Av. Alberto Lasplaces 1550, CP 11600 Montevideo, Uruguay; e-mail:


Single nymphs of Ixodes sigelos Keirans, Clifford & Corwin, 1976 were collected in Region XI, Chile, on Akodon olivaceus (Waterhouse 1837) in Puerto Aysen (45º23´S 72º41´W), Oligoryzomys longicaudatus (Bennett 1832) in the vicinity of Lago General Carrera (46º26´S 72º00´W) and Akodon xanthorhinus (Waterhouse 1837) in Puerto Ibañez (46º17´S 71º56´W), as well as in Tucumán Province, Argentina, on Akodon spegazzinii Thomas, 1897, 3 km SW of Hualinchay (26º20´S 65º39´W). Akodon xanthorhinus and A. spegazzinii are new hosts for I. sigelos, and these are the first records of this tick from Argentina and southern Chile. The nymph of I. sigelos and nymphs of three other Neotropical Ixodes (I. neuquenensis Ringuelet, 1947, I. nuttalli Lahille, 1913, I. stilesi Neumann, 1911) bear anterior and posterior processes on palpal article I. However, I. sigelos is unique in possessing both a basis capituli that appears winged in dorsal aspect and a bifurcate posterior process on palpal article I. These collections greatly expand the known range of I. sigelos and underscore the importance of sigmodontine rodents as hosts of Neotropical ticks, especially immature stages.

Key words: Ixodidae, Ixodes sigelos, Sigmodontinae, Argentina, southern Chile


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