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Ticks exotic for the Neotropical region were found on Python regius imported into Argentina and Chile. All ticks (7 males and 3 females) were classified as Amblyomma latum Koch, 1844 ( = Aponomma latum). Additionally, four lots comprising 18 males of the Argentinean tortoise tick, Amblyomma argentinae Neumann, 1904, were found on a terrestrial tortoise, Chelonoidis chilensis, and on three terrestrial tortoises (probably C. chilensis) imported to Uruguay presumably from Argentina). These findings alert us to the risk of expanding the distribution of reptile parasites and their diseases into regions previously free of these parasites.

The world's argasid tick fauna comprises 183 species in four genera, namely Argas, Carios, Ornithodoros and Otobius in the family Argasidae. The ixodid tick fauna consists of 241 species in the genus Ixodes and 442 species in the genera Amblyomma, Anomalohimalaya, Bothriocroton, Cosmiomma, Dermacentor, Haemaphysalis, Hyalomma, Margaropus, Nosomma, Rhipicentor and Rhipicephalus in the family Ixodidae, with the genus Boophilus becoming a subgenus of the genus Rhipicephalus. The family Nuttalliellidae is represented by the monospecific genus Nuttalliella. The species names of these ticks, based on seven previous complete or partial listings, as well as those of recently described new species, are presented in tabular format.

Phylogenetic studies of ticks have been increasing in recent years, particularly in the use of molecular data. However, all of the studies to date are either limited to the mitochondrial genome or to a few nuclear ribosomal genes. There is a need to explore the use of nuclear protein-encoding genes because these genes direct most aspects of the phenotypic traits in the development of an organism. We report here the test of a nuclear protein-encoding gene, RNA polymerase II, for the phylogenetic study of ticks. Thirty-eight ticks representing 26 species of hard and soft ticks were chosen for the study. The pairwise divergences among sampled species are ranged from 0.3 to 15.2% and most of the substitutions are transitions. In addition, the nucleotide composition is not obviously biased in POL II gene. The trees inferred from the POL II sequences using maximum parsimony (MP), neighbor joining (NJ), and maximum likelihood (ML) by PAUP* and MrBayes are largely concordant with the existing phylogenies. Our study demonstrated that POL II gene sequences contain strong phylogenetic signals in ticks at the generic and higher levels. POL II has proven to be a useful gene for resolving tick phylogeny.

A portion of mitochondrial 12S rDNA sequences (337-355 base pairs) and 63 morphological characters of 36 hard-tick species belonging to 7 genera were analyzed to determine the phylogenetic relationships among groups and species of Rhipicephalus and between the genera Rhipicephalus and Boophilus. Molecular and morphological data sets were first examined separately. The molecular data were analyzed by maximum parsimony (MP), maximum likelihood, and neighbor-joining distance methods; the morphological data were analyzed by MP After their level of congruence was evaluated by a partition homogeneity test, all characters were combined and analyzed by MP. The branches of the tree obtained by combining the data sets were better resolved than those of the trees inferred from the separate analyses. Boophilus is monophyletic and arose within Rhipicephalus. Boophilus species clustered with species of the Rhipicephalus evertsi group. Most of the clustering within Rhipicephalus was, however, consistent with previous classifications based on morphological data. Morphological characters were traced on the molecular reconstruction in order to identify characters diagnostic for monophyletic clades. Within the Rhipicephalus sanguineus complex, the sequences of specimens morphologically identified as Rhipicephalus turanicus were characterized by a high level of variability, indicating that R. turanicus-like morphology may cover a spectrum of distinct species.

A study of ticks associated with wild animals was carried out from September 1996 to April 1998 at the Fazenda Alegria (21,000 ha), in the Nhecolândia Pantanal, State of Mato Grosso do Sul, Brazil, a sunken plain bordering the upper Paraguay river, located 19 x 08'S; 56 x 46'W. A total of 81 wild animals (13 species, 6 orders) were captured with the aid of nets, and ticks were found on 63 (78%). Tick species identified included Boophilus microplus (Canestrini), Amblyomma cajennense (F.), A. parvum (Aragão), A pseudoconcolor (Aragão), A. scalpturatum (Neumann), A. nodosum (Neumann), A. ovale (Koch), and A. tigrinum (Koch). Dragging from grasslands (campos) yielded negative results compared to the high concentration of ticks, mainly nymphs, that were collected from leaves in the forests (capão). Predominance of immature instars (Amblyomma genera) was observed in the end of winter (August-September). Ticks were associated mainly with coatis, deer (Mazama gouazoubira) and anteater, and these animals may play a role in the epidemiology of tick-transmitted pathogens in the Pantanal if one considers their co-existence with local domestic animals.

Researchers on ticks and tickborne diseases have been extremely fortunate in having at their fingertips the tick bibliographies produced by Harry Hoogstraal and his coworkers at the U.S. Naval facility at Cairo, Egypt, and by Mildred Doss and her colleagues at the U.S. Department of Agriculture laboratory at Beltsville, Maryland, USA. The Doss checklist of tick families, genera, species, and subspecies is now 25 years out of date, and the following checklist of one new genus, nine new subgenera, and 110 new species of Ixodida brings together the nomenclature on ticks produced during the last quarter century.

A dichotomous identification key, with important characters illustrated by scanning electron micrographs, is provided for nymphs of the 9 species of the genus Amblyomma occurring in the United States. Species included are A. americanum (L.), A. cajennense (F.), A. dissimile Koch, A. imitator Kohls, A. inornatum (Banks), A. longirostre (Koch), A maculatum Koch, A. rotundatum Koch, and A. tuberculatum Marx. Notes on the geographical distributions, medical and veterinary importance, and nymphal stage hosts are included for each species.

The first records of 3 ixodid tick species collected in the state of Maine are reported. A total of 23 records of the lone star tick, Amblyomma americanum (L., 1758), in 11 counties from hosts with no history of travel outside the state demonstrates that this tick is now a resident of Maine. Ixodes dentatus Marx, 1899 is recorded from Waldo and Lincoln counties, and Ixodes uriae White, 1852 is recorded from Matinicus Rock in Knox County. This is the first report of I. uriae from the eastern United States. Disease agents such as those causing human monocytic ehrlichiosis, Lyme disease, Rocky Mountain spotted fever, and several arboviruses have been recorded from 1 or more of these tick species.

Phylogenetic relationships among tick subfamilies have been estimated using morphological and molecular characters. However, the phylogeny based on a portion of the 16S mitochondrial rDNA gene differed from the morphologically based phylogeny in a number of important respects. The entire 18S rDNA gene was examined in 18 taxa from all tick subfamilies to test the 16S rDNA based phylogeny. The 18S phylogeny supports the earlier 16S based phylogeny in placing members of Hyalomminae on a common branch with members of the Rhipicephalinae and in indicating long branch lengths among soft tick taxa. However, unlike the 16S phylogeny, Amblyomminae was monophyletic and members of Haemaphysalinae did not arise within Amblyomminae. Argasinae formed a monophyletic group within Argasidae and was not a sister taxon of the hard ticks. In most respects, the phylogeny based on the 18S rDNA gene resembles the morphologically based phylogeny.

Evolutionary patterns in ticks have traditionally been cast in terms of host associations. Largely untested assumptions of cospeciation and observations of current host associations are used to estimate the age of different taxa. Several recent phylogenetic studies of supraspecific relationships in ticks, based on both morphological and DNA-sequence data, allow the first rigorous testing of these assumptions. Reanalysis of patterns of tick-host associations suggests that the perception of host specificity in ticks may be an artifact of incomplete sampling. An analysis of tick-host and -habitat associations and biogeographical patterns, in the context of the newly derived phylogenies, suggests that much of the existing host-association patterns may be explained as artifacts of biogeography and ecological specificity.

The larva, nymph, and female of Ixodes (Ixodes) venezuelensis are diagnosed using scanning electron microscopy, and the larva is described for the first time. This ixodid tick is recorded from the northern neotropics as a parasite of five species of didelphid marsupials and eighteen species of rodents (one sciurid, two heteromyids, eleven murids, two dasyproctids, and two echimyids). Collection records of I. venezuelensis are presented for Costa Rica, Colombia, Panama and Venezuela, with the Costa Rican records being new and extending the known range of this tick by at least 300 km. Altitudinally, I. venezuelensis has been collected between elevations of 24 and 2410 m with most collections between 100 and 800 m. The possibility that I. venezuelensis may be parthenogenetic is discussed.

Aponomma (Bothriocroton) glebopalma, n. subgen., n. sp., and Amblyomma glauerti, n. sp. (Acari: Ixodidae), are described from the monitor lizards Varanus glebopalma Mitchell and Varanus glauerti Mertens in Western Australia and the Northern Territory, Australia. The new subgenus is erected to accomodate A. (Bothriocroton) glebopalma, a new species with a deeply pitted and pilose scutum in both the adult and immature stages, unlike all other described species of Aponomma. This new species is found in an area where Aponomma fimbriatum Koch, a parasite of varanid lizards and various species of snakes, was the only known member of the genus found in both Western Australia and the Northern Territory. Amblyomma glauerti n. sp., an ornate Australian reptile tick found on the same two hosts in Western Australia and the Northern Territory, is also described. These two new species were recovered from formalin-preserved lizard specimens; therefore, nothing is known of their life cycles, except that all stages parasitize varanid lizards.

The male of Amblyomma rotundatum is described for the first time, and the nymph and larva are redescribed. This tick is a parthenogenetically reproducing species parasitic on amphibians and reptiles in the warmer areas of the New World. Attempts to mate male and female A. rotundatum under laboratory conditions were unsuccessful.

Haemaphysalis juxtakochi Cooley, 1946, an ectoparasite of deer and other large mammals from Mexico southward through Central and South America, was recovered from the ear of a white-tailed deer, Odocoileus virginanus Zimmermann, in Ohio. This represents the first record of H. juxtakochi from the United States.

The parthenogenetic tick Amblyomma rotundatum, a Central and South American species, has become established in southern Florida. The date of introduction is unknown, but it is suspected to be either during the 1930s, when 1 of its natural hosts, the giant or marine toad, Bufo marinus, was introduced to southern Florida as a potential biological control of pest beetles in sugar cane fields, or between 1955 and 1964 when specimens of B. marinus were accidentally or deliberately released in the greater Miami area. Several museum specimens of this toad collected in the Miami area 25 April 1979 had nymphal and adult A. rotundatum attached. Subsequent examination of living giant toads collected at another Miami area site from 1983 through 1985 revealed larval, nymphal, and adult A. rotundatum and confirmed colonization of this tick. Under laboratory conditions, another neotropical amphibian and reptile tick, Amblyomma dissimile, is capable of transmitting Cowdria ruminantium, the causative agent of heartwater, a disease present in the Caribbean area. Therefore, we suggest that A. rotundatum should also be tested for vectorial competence.

Rhipicephalus exophthalmos sp. nov., a species which has in the past been confused with Rhipicephalus oculatus Neumann, 1901, is described and illustrated from laboratory-reared specimens. Preferred hosts for the adults of this tick are various domestic and wild ungulates and hares. It is widely distributed in Namibia and in the southeastern Cape Province, South Africa, with only scattered records from elsewhere. The adults of R. oculatus are redescribed and illustrated, and the immature stages are described and illustrated for the first time. All stages feed virtually exclusively on leporids. It is common in parts of the eastern and southern Cape Province, with few records as yet from other parts of South Africa and Namibia.

This tick, originally referred to as Rhipicephalus species III by Yeoman & Walker (1967), was first collected from a sitatunga, Tragelaphus spekei, and then occasionally from cattle, in Tanzania. Further collections, mostly from sitatunga, have since been seen from Uganda and Zambia. Descriptions of the adults of this species are given, together with information on their hosts and their distribution.

The larva and nymph of Ixodes (Pholeoixodes) baergi Cooley & Kohls are described for the first time. This tick has been collected only in the United States on cliff swallows, Hirundo pyrrhonota, in their nests, or in adjacent habitats. To date, it has been reported from Arkansas, Colorado, Illinois, Oklahoma, and Texas. Brief notes on the synchronization of the life cycle of I. baergi with that of its host are included.

Ornithodoros (Alectorobius) capensis Neumann, an ectoparasite of seabirds found circumglobally in the tropics and subtropics, has become established along the southeastern seacoast of the United States. The tick has been found feeding primarily on brown pelicans, Pelecanus occidentalis, but also has been found on the laughing gull, Larus atricilla, and the American oystercatcher, Haematopus palliatus. We report here the presence of O. (A.) capensis from New Hanover and Brunswick counties (near the mouth of the Cape Fear River) in North Carolina, to the Charleston Harbor area of South Carolina and thence south to Cumberland Island (a barrier island) in Camden County, Georgia, just north of the Florida state line.

Previous reports from the literature have indicated the northernmost range of extension of Ixodes minor Neumann to be southern Georgia with the greatest number of collections having been made in the coastal regions of that state. An unpublished record in the U.S. National Tick Collection indicated that I. minor had been collected as far north as South Island, Georgetown County, S.C., as early as 1933. I. minor was collected on three separate occasions in Charleston County, S.C., between October 1990 and February 1991, thus verifying the northern extension of this tick's range and the probable existence of a stable population on the coast of South Carolina. The roof rat (Rattus rattus) is reported for the first time serving as a host for I. minor.

A literature review and compilation of the tick specimens found in Peru and now held in the National Tick Collection was carried out to develop a working list of the tick species likely to be found in Peru. Evidence of 44 species (29 Ixodidae, 15 Argasidae), was found; representatives of 40 species are held as reference specimens. This report adds 14 species to the previously published list.

Adults of 18 of the 22 species constituting the subgenus Argas, which parasitize birds nesting and resting in rocky habitats in each faunal region of the world (15 species) or in trees (e species) (2 Neotropical, 1 Nearctic), were studies by SEM. In each except three Neotropical species, the nine setae of the anterior pit of tarsus I are arranged in an anterior group (1 serrate, 1 setiform, 1 conical) and a posterior group (2 fine, e porose, 2 grooved), or the two groups are more or less confluent. Abnormally, additional setae may occur on one or both tarsi of a single specimen. In one Neotropical species, only the three anterior group setae are present. In three Neotropical species, only these three setae and a fourth seta are present (whether 6 or 5 additional setae are concealed within the tarsal structure should be investigated). The Haller's organ capsule is entirely open (unroofed) (3 species), roofed posteriorly and open anteriorly (7 species), or mostly roofed by a plate which is pierced by one large aperture and by more or less numerous, small, or medium-sized perforations (8 species plus one other not studied by use). This study suggests that the structure of Haller's organ has evolved in different lines in response to a multiplicity of biologic al factors related to the behavior and habitat of individual species.

Ornithodoros (Alectorobius) spheniscus n. sp., described from wild-caught and laboratory-reared females, males, nymphs, and larvae parasitizing the Humboldt Penguin, Spheniscus humboldti Meyen, is the fifth species of the Ornithodoros (Alectorobius) capensis group to be recognized in the Neotropical Region. A related Peruvian species, Ornithodoros (Alectorobius) amblus Chamberlin, also parasitizes S. humboldti but is recorded from a wider range of marine birds breeding on the Pacific coast and offshore islands, where the birds congregate to feed on the rich fish fauna usually produced by the Humboldt current. Differential criteria are provided for the new species, O. (A.) amblus, and Ornithodoros (Alectorobius) yunkeri Keirans, Clifford, and Hoogstraal of the Galapagos. These 3 members of the O. (A.) capensis group parasitize marine birds associated with the Humboldt current in western South America and the Galapagos. Persons visiting Humboldt Penguin breeding sites in caves and on barren coastal ledges are eagerly attacked by nymphal and adult O. (A.) spheniscus and suffer afterward from pruritus and slowly-healing blisters. The O. (A.) spheniscus life cycle required 128 to 193 days in the laboratory and, as typical of bird-parasitizing members of the subgenus Alectorobius, the first nymphal instar did not feed.

The male, nymph and larva of Ixodes (A), bakeri are described and illustrated with line drawings and scanning electron microscope photographs. This species was originally described from 1 female from Otomys sp., Nyika Plateau, Malawi. The present material consists of 28 collections from insectivores and 19 collections from rodents, Van Riebeeck Nature Reserve, Transvaal, plus 1 collection from a rodent in the Jonkershoek Valley, Cape Province, Republic of South Africa. Its biology in South Africa is also discussed.

The female, male, nymphal instars, and larva of Ornithodoros puertoricensis Fox are redescribed from specimens collected in Haiti. Data on host species and geographic distribution are also presented.

Adults of 4 of the 6 species constituting the subgenus Carios and of 3 of the 4 species constituting the subgenus Chiropterargas were studied by scanning electron microscopy. All species parasitize Old World cave-dwelling insectivorous bats (Microchiroptera). The anterior pit setae number 10 in Carios and 10 or 11 in Chiropterargas. In most Carios, the setiform seta is replaced by a second serrate seta. In 2 of the 3 studied Chiropterargas species, 1 of the 2 grooved setae is exceptionally long. Porose setae number 3 in Carios and 3 or 4 in Chiropterargas. The Haller's organ roof in both subgenera is solid, lacking perforations; the aperture is narrowly transverse in Carios, irregularly wide or wide and transverse in Chiropterargas; uniquely, 1 or 2 sensilla protrude from the aperture of Chiropterargas species. The protruding sensilla and long grooved seta of Chiropterargas suggest a probably distinctive sensory-behavior pattern common to these ticks. Other morphological characters are discussed and compared to show relationships between these 2 subgenera and the subgenera Argas and Persicargas and distinctive characters present only in adult and/or larval Carios and Chiropterargas.

In 1967, Vermeil and Marguet described Ornithodoros coniceps maritimus from larvae reared from larvae taken from marine birds on Dumet Island (Atlantic Ocean), Basse Bretagne, France. We collected O. (A.) coniceps Canestrini, 1890, from the type locality (Venice, Italy) and determined that the taxons coniceps and maritimus each require full species status. We selected a lectotype and paralectotypes for the taxon maritimus from the original Dumet Island material. The larva of maritimus is redescribed and the nymph, male, and female are described for the first time. Collection data are recorded from Dumet and other islands off France, Aegimures Islands off Tunisia, Puffin Island off northern Wales, and Great Saltee Island off Ireland. This tick infests nesting colonies of the common tern, roseate tern, sandwich tern, herring gull (northern and Mediterranean races), common cormorant, shag, razorbill, common murre, black-legged kittiwake, and probably other marine birds nesting nearby. Adults and nymphs (tentatively identified as maritimus but lacking associated larvae for full confirmation) were taken near nests of the little egret in Lake Tunis, Tunisia. Soldado virus was isolated from Puffin Island tick samples and a Soldado-like virus from Great Saltee Island tick samples. An experimental study of West Nile virus in the Tunisian tick population is reviewed. The birds species associated with maritimus in each collecting locality, and their nesting and resting habits and migration patterns in relation to tick and arbovirus survival and distribution, will be reported in the following paper in this series.

A new arbovirus was isolated from Texas, U.S.A., populations of the Cliff Swallow parasits Argas (Argas) cooleyi Kohls and Hoogstraal, 1960. The virus, named Sunday Canyon, is serological urelated to any of 185 arbovirus strains or 20 other viral agents with which it was compared. Morphologically it resembles Bunyamwera viruses and, in common with them, is sensitive to lipid solvents and acid pH, and apparently possesses RNA. Although considerably resistant to a temperature of 41.5 degrees C, it rapidly loses infectivity when incubated at 56 degrees C. It is lethal for newborn white mice and infective for the Vero and Antheraea eucalypti cell lines. Sundays Canyon virus is the second tick-associated, Bunyamwera virus-like agent known from North America and the third virus to be reported from A. cooleyi in Texas.

Six genera and 27 species of hard ticks (Ixodidae) currently are recognized in the United States east of the Mississippi River as follows: Amblyomma (4 species), Boophilus (1), Dermacentor (3), Haemaphysalis (2), Ixodes (16), and Rhipicephalus (1). We present a diagrammatic couplet key to the adults of the six genera and 27 species of Ixodidae found in the eastern portion of the United States.

Figures of the types of Rhipicephalus kochi, and of its synonym Rhipicephalus neavei Warburton, 1912, are presented. These are accompanied by complete descriptions of all stages of R. kochi, illustrated with scanning electron microscope photographs. The basic differences between this species, Rhipicephalus pravus Dönitz, 1910 and Rhipicephalus punctatus Warburton, 1912 are outlined. R. kochi occurs south of the Equator in parts of eastern, central and southern Africa. Its adults feed most commonly on cattle, various antelopes and wild pigs, and on hares. Little is known about the hosts of the immature stages; nymphae have been recorded in a field collection once only, from Petrodromus tetradactylus, the 4-toed elephant shrew.

Ornithodoros (Alectorobius) amblus Chamberlin 1920, adults previously were described inadequately. Practically nothing was known regarding the identity, hosts, distribution, and biology of this species. We redescribe both sexes, describe the nymph and larva, and present criteria for differentiating these stages from those of other members of the O. (A.) capensis group in the Western Hemisphere. Samples were collected from 13 localities on the Pacific coast and on offshore islands of Peru. Hosts recorded are the Peruvian Brown Pelican, Peruvian Booby, Blue-footed Booby, Red-legged Cormorant, Guanay Cormorant, and Inca Tern. These birds are not long-distance migrants and more widely distributed species of the O. (A.) capensis group have not been found parasitizing them. The life cycle is characteristic of the O. (A.) capensis group; the first nymphal instar does or does not feed. Humans are attacked eagerly by O. (A.) amblus and suffer afterward from severe inflammation and "incredible" pruritus, and possibly from more severe illness. Viruses infecting this tick are Punta Salinas (Hughes serogroup, family unclassified) and Huacho (Reoviridae, genus Orbivirus, Kemerovo serogroup). Dense tick populations cause breeding birds to desert numerous nests; thus, O. (A.) amblus is economically important to the Peruvian guano industry. Certain spiders and lizards may prey on this tick.

Ornithodoros (Alectorobius) coniceps (Canestrini 1890), which was briefly described from adult specimens from St. Mark's Cathedral, Venice, Italy, has been a confusing taxon. We redescribe and illustrate the adult and immature stages from St. Mark's Cathedral (topotypes) and elsewhere, list criteria to distinguish this species from others in the O. (A.) capensis complex, and provide data for 36 collections, chiefly from nest sites of wild and domestic pigeons in humid, rocky situations, and from a nest of the pallid swift, in Italy, France, Egypt, Kenya, Israel, Jordan, Afghanistan, Ukrainia, and Turkmenia. Other collections of small-sized adults and nymphs, lacking larvae, from pigeon, swallow, and swift nest in Nepal, India, and Sri Lanka, are tentatively assigned to this taxon. This is the only member of the O. (A.) capensis group not associated with marine or wading birds. Humans bitten by O. (A.) coniceps in buildings or caves may suffer from pain, edema, chills, and fever. BAku virus (Reoviridae) has been isolated from this tick in Uzbekistan, but most reports of other viruses and infectious agents are clouded by probable misidentification of O. (A.) maritimus as O. (A. coniceps. Published data on the life cycle and dynamics are reviewed briefly. Previously, this tick has not been reported from the Ethiopian Faunal Region (Kenya).

A rickettsia of the spotted fever group was isolated on three occasions from Ixodes pacificus in western Oregon. These isolations, and additional evidence furnished by complement fixation tests on guinea pigs inoculated with other Oregon ticks of this species, indicate that the association of this rickettsia with the Pacific Coast tick may be widespread. This is the first isolation of a spotted fever group rickettsia from I. pacificus. Because the Oregon isolates are mildly virulent for guinea pigs they resemble the Western U and Rickettsia montana strains of rickettsiae. However, preliminary evidence from cross-immunofluorescence tests of mouse antisera suggests the Tillamook and Grants Pass strains are antigenically different from all known spotted fever group agents.

Ixodes (Afrixodes) neitzi n. sp. is described from females and males collected from the mountain reedbuck (Redunca fulvorufula) at Loskop Dam Nature Reserve, Transvaal, Republic of South Africa. Information is provided to distinguish this new species from other closely related Ixodes species that occur in the Ethiopian region. Its predilection sites are noted and the area in which it occurs is described briefly.