Systematic & Applied Acarology (2003) 8, 85-88.
ISSN 1362-1971
The genus Amblyomma Koch, 1844 (Acari: Ixodidae) in Chile, with new records of A. argentinae Neumann, 1904 and A. tigrinum Koch, 1844 DANIEL GONZÁLEZ ACUÑA1, JOSÉ M. VENZAL2, JAMES E. KEIRANS3, ALBERTO A. GUGLIELMONE4 1
Facultad de Medicina Veterinaria, Universidad de Concepción, Casilla 537, Chillán, Chile. E-mail:
[email protected]
2
Departamento de Parasitología Veterinaria, Facultad de Veterinaria, Universidad de la República, Av. Alberto Lasplaces 1550, Montevideo, Uruguay.
3
United States National Tick Collection, Institute of Arthropodology and Parasitology, Georgia Southern University, Statesboro, GA 30460, USA
4
Instituto Nacional de Tecnología Agropecuaria, CC 22, CP 2300 Rafaela, Santa Fe, Argentina.
Abstract Two species of Amblyomma Koch, 1844 occur in Chile: A. parvitarsum Neumann, 1901 and A. tigrinum Koch, 1844. Despite published reports of A. americanum (L., 1758), A. maculatum Koch, 1844 and A. varium var. albida Neumann, 1899 from Chile, these three taxa do not occur there. Amblyomma inflatum was described from Chile, but this species is a nomen dubium. There are Chilean records for the terrestrial tortoise tick A. argentinae Neumann, 1904, but this species is thought to be exotic because no natural populations of terrestrial tortoises exist in Chile. Herein we present new records of A. argentinae from the terrestrial tortoise Chelonoides chilensis (Gray, 1870), illegally introduced from Argentina, and of A. tigrinum Koch, 1844 from the fox Pseudalopex griseus (Gray, 1837) in Chile’s Region V. Key words: Ixodidae, Amblyomma, Amblyomma argentinae, Amblyomma tigrinum, Chile
Introduction The genus Amblyomma Koch, 1844 contains slightly more than 100 species worldwide (Keirans 1992). Several members of this genus are known to infest humans and transmit human pathogens (Estrada Peña & Jongejan, 1999). Although many species of Amblyomma are common in the Neotropical Zoogeographic Region, only three have been recorded from Chile: A. argentinae Neumann, 1904 [= A. testudinis (Conil, 1877)], A. parvitarsum Neumann, 1901, and A. tigrinum Koch, 1844 (Tagle, 1971). Chilean records of Amblyomma maculatum Koch, 1844 resulted from confusion with A. tigrinum before the resurrection of A. tigrinum by Kohls (1956) (Tagle & Alvarez, 1959). Neumann (1899) described A. varium var. albida Neumann, 1899, presumably from Chile, but this country lies outside the range of the principal hosts of A. varium, sloths of the family Bradypodidae Gray, 1821, and the tick specimen itself may have been erroneously labeled. Amblyomma americanum (L., 1758) has also been cited as present in Chile (Casanueva, 2001), but there are no confirmed Chilean records of this Nearctic tick species. As well, a nymph of A. inflatum Neumann, 1901 was collected from an undetermined host in Chile, but Neumann (1901) was unsure of the genus to which this specimen
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belonged, leading Robinson (1926) to declare A. inflatum a nomen dubium, a decision with which we concur. In this paper we present new records of A. argentinae and A. tigrinum from Chile and discuss the status of A. argentinae in this country.
Materials and methods Tick specimens were obtained from the Museo de San Antonio, Region V, Chile. One collection was from a pet terrestrial tortoise, Chelonoides chilensis (Gray, 1870), illegally introduced from Argentina to San Antonio ( 33º 35´S 71º 37´W) on October 28, 1995 (collector J. Brito). The Museo de San Antonio also possessed ticks from a male fox, Pseudalopex griseus (Gray, 1837), captured in April 1995 in Santo Domingo (33º 37´S 71º 37´W), Region V (collector J. Brito). All tick specimens were preserved in 70% ethanol and are currently housed in the collection of the Departamento de Ciencias Pecuarias, Laboratorio de Zoología, Universidad de Concepción, Chillán, Chile. Our tick determinations were based on the descriptions and keys of Boero (1957), Jones et al. (1972) and Estrada Peña et al. (1993).
Results and discussion The tick collection from C. chilensis comprised two males of A. argentinae. Previous Chilean records of A. argentinae have been reported as A. testudinis. Olalquiaga Fauré (1951) found A. argentinae on a terrestrial tortoise in Región Metropolitana. However, since there are no natural populations of terrestrial tortoises in Chile, Olalquiaga Fauré’s tick specimens were probably introduced on an infested tortoise from Argentina. Tagle (1971) reported A. argentinae from an unusual host, a bird (thrush), found in Chiloé; these tick specimens (two males) were deposited in the United States National Tick Collection (RML 50413) with label data indicating that they were removed from an austral thrush (Turdus falklandii magellanicus King, 1831), a bird that ranges from northern Chile to southern Argentina and Chile, including the islands close to the South American mainland (Meyer de Schauensee, 1970). One of us (JEK) has subsequently checked both tick specimens and confirmed their identity. Amblyomma argentinae appears to be restricted to Argentina, although there are uncorroborated records for other Neotropical countries (Guglielmone et al., 2001). This tick is a common parasite of C. chilensis in the Argentinean Chaco phytogeographic domain, where its ecogeographical distribution closely matches that of its host (Guglielmone et al., 2001). It is difficult to explain the avian record above, but since the infestation itself may have originated outside Chile (Argentina?), we are regarding it as an accidental importation. Two females of A. tigrinum were collected from P. griseus. Amblyomma tigrinum has been reported as A. maculatum (Donoso, 1953; Tagle & Alvarez, 1957; Tagle, 1966, 1971) and under its correct name (Tagle & Alvarez 1959; González Acuña et al., 2002) in the central area of Chile from Pirque (33º 37´S 70º 33´W) to Arauco (37º 50´S 72º 58´W). Our new record of A. tigrinum is close to the northern limit of previous collections. Amblyomma tigrinum adults have been found on domestic dogs and the foxes Pseudalopex culpaeus (Molina, 1782) and P. griseus. Larvae and nymphs of A. tigrinum have recently been found on the birds Callipepla californica brunnescens (Ridgway, 1884), Nothoprocta perdicaria (Kittlitz, 1830), and Zenaida auriculata (Des Murs, 1847) (González Acuña et al., 2002) in Ñuble.
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Amblyomma tigrinum is known from several South American countries (Argentina, Bolivia, Brazil, French Guiana, Paraguay, Peru, Uruguay) in addition to Chile (Jones et al., 1972). This tick is usually a parasite of Canidae (Guglielmone et al., 2000), and Hoogstraal and Aeschlimann (1982) classified the adults of A. tigrinum as strict to moderately specific for Carnivora. The avian hosts of A. tigrinum in Chile indicate that birds may be an important source of blood for the immature stages of this tick species. Amblyomma tigrinum has been found in contrasting phytogeographical regions within Argentina, showing a plasticity unusual for Amblyomma ticks (Guglielmone et al., 2000). The distribution of A. tigrinum in Chile probably exceeds that indicated by collection records, and additional research is need to clarify this species’ actual range.
Acknowledgments We thank Mr. José Luis Brito, Curator of the Museo de San Antonio, for permitting us to examine the tick specimens in his care. This study was supported in part by National Institutes of Allergy and Infectious Diseases grant AI 40729 to JEK. We also gratefully acknowledge the support of INTA and the Fundación ArgenINTA to AAG.
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