Characteristic features of biodiversity in European ixodid ticks (Acari, Ixodidae) as vectors of diseses with natural foci

The diapason of some biodiversity characteristics of ixodid ticks of the fauna of Europe and adjacent territories is analyzed. These characteristics include taxonomic and morphological diversity, the diversity of life cycles, host-parasite relations, species ranges, and biotopic associations. The significance of different aspects of biodiversity of ixodid ticks as a prerequisite of interrelations with pathogens with natural foci is estimated.     

Ticks Feeding on Humans: A Review of Records on Human-Biting Ixodoidea with Special Reference to Pathogen Transmission

In this article, literature records of argasid and ixodid ticks feeding on humans worldwide are provided in view of increased awareness of risks associated with tick bites. Ticks can cause paralyses, toxicoses, allergic reactions and are vectors of a broad range of viral, rickettsial, bacterial and protozoan pathogens. Approximately 12 argasid species (Argas and Ornithodos) are frequently found attached to humans who intrude into tick-infested caves and burrows. Over 20 ixodid tick species are often found on humans exposed to infested vegetation: four of these are Amblyomma species, 7 Dermacentor spp., 3 Haemaphysalis spp., 2 Hyalomma spp. and 6 Ixodes species. Personal protection methods, such as repellents and acaricide-impregnated clothing are advised to minimize contact with infected ticks. Acaricidal control of ixodid ticks is impractical because of their wide distribution in forested areas, but houses infested with soft ticks can be sprayed with acaricidal formulations. Attached ticks should be removed without delay. The best way is to grasp the tick as close to the skin as possible with fine tweezers and pull firmly and steadily without twisting. Finally, despite the fact that most people who are bitten destroy the offending tick in disgust, it is recommended that they preserve specimens in ethanol for taxonomic identification and detection of pathogens by molecular methods.     

Ixodid ticks of African buffalo (<Emphasis Type="Italic">Syncerus caffer</Emphasis>), impala (<Emphasis Type="Italic">Aepyceros melampus</Emphasis>) and elephant (<Emphasis Type="Italic">Loxodonta africana</Emphasis>) in five protected park estates in the Zambezi valley,Zimbabwe

Wildlife hosts many pathogens of economic importance and is considered as a reservoir of important tick-borne diseases of livestock in southern Africa. The species composition of ticks parasitizing buffalo (Syncerus caffer), impala (Aepyceros melampus) and elephant (Loxodonta africana) was investigated in five protected parks in the Zambezi valley, Zimbabwe. A total of 1104 adult ticks was collected from 75 adult animals comprising five buffaloes, five elephants and five impalas drawn from five protected wildlife parks. Five tick species belonging to two genera were recovered, with Rhipicephalus decoloratus being the most prevalent species in all the three animal groups. Amblyomma hebraeum was only recovered from buffaloes whereas Rhipicephalus zambeziensis was recovered from buffalos and elephants. Significant differences in mean tick species distribution and concentration were observed amongst the wildlife parks and these appeared to be influenced by the number of hosts in each park. The study revealed that buffaloes are the major host of R. decoloratus in the Zambezi valley. The presence of these ixodid ticks within the Zambezi valley may have significant ecological and economic impacts on wildlife conservation, domestic animals and human health.     

Morphological inversions during the ontogenesis of the ixodid ticks (Acari: Ixodidae) from the viewpoint of the hypermorphosis conception and their significance for systematics

Morphological inversions during the ontogenesis of the ixodid ticks consist in the deranges of species-specific tendencies in the development of some external structures by the female line. The inversions, which included a wide range of organs and their fine structures, have been described for the first time in 14 species of 4 from 7 Palearctic ixodid genera. Emphasis is placed on the study of the structures, which serve as differential characters for closely related species. It is shown, that the using of the structures subjected to inversions is unavoidable in systematics because of the great similarity of closely related species, especially in immature stages. It is established by the data on the variability of all active stages in the species distribution ranges, that the degree of the inversions manifestation may somewhat fluctuate in different subspecies or geographic morphotypes of the same species, but the peculiarity of the inversions always remains a species-specific character. The cause of inversions origin is the evolution of the Ixodidae by the way of morpho-ecological specialization, namely hypertrophic, giantism, the growth of teguments in the period of nutrition act by pasture ambushing, which led to the derange of the development coordination of the organs during ontogenesis. Biological implication of the inversions is a guarantee of the adaptive potential of species during the process of microevolution. Even though the inversions make identification of closely related species difficult, their substantial importance is that they form integral species-specific character for the whole active part of the species ontogenesis.     

The intraspecific taxonomic structure and identification of closely related species of ixodid ticks (Ixodidae)

Two variants of intraspecific morphological differentiation of 7 palearctic species of Ixodidae and respectively two variants of their intraspecific taxonomic pattern have been revealed on the basis of the study of geographic variation of each species. Three species--Ixodes pavlovskyi Pom., 1946, Haemaphysalis erinacei Pavesi, 1884, Hyalomma asiaticum Sch. et Schl., 1929, are subdivided into subspecies, and four ones--I. ricinus (L., 1758), I. persulcatus Sch., 1930, I. crenulatus Koch, 1844, Dermacentor marginatus (Sulzer, 1776),--into morphotypes by the degree of distinction of the whole complex of active stages in ontogenesis. Acknowledging the conventional character of the categories of subspecies and morphotype their criteria have been formulated for ixodid ticks. Paleogeographic and ecological grounds are given. Some data of geographic variation of immature stages favour the identification of closely related species in concrete localities.     

Birds as hosts of ixodid ticks (Acarina,Ixodidae)

rophic relations between ixodid ticks of the world fauna parasitizing as adults on birds are analyzed. These ticks include 60 out of 650 species of the family Ixodidae and belong to the genera Ixodes, Haemaphysalis, and Amblyomma. Relations between birds and ticks of the genus Ixodes are most ancient. Colonial marine birds seem to be the first hosts of ixodid ticks in the class of birds. Trophic specialization of ticks is not associated with bird taxa, because in most cases no tick specificity is caused by either phylogenetic features of hosts, or specific environmental conditions.     

Ixodid ticks (Acari: Ixodidae) infesting humans in Tokat Province of Turkey: species diversity and seasonal activity

Ixodid ticks (Acari: Ixodidae) are the major vectors of pathogens threatening animal and human health. Tokat Province, Turkey, is a suitable habitat for extended tick activity with its moderate climate and vegetation. In the present study, we surveyed humans visiting health centers to determine the species diversity, geographical distribution, and seasonal activity of ixodid ticks infesting them. Out of 5,999 adult ticks collected from humans from April to September, 2008, 800 ticks were identified to species, while the remaining were identified to genus according to their distinct morphological characteristics. Hyalomma marginatum, Hyalomma detritum, Rhipicephalus bursa, Rhipicephalus (Boophilus) annulatus, Haemaphysalis punctata, Dermacentor marginatus, and Ixodes laguri were the most prevalent tick species among 24 ixodid tick species infesting humans in the region. One of these tick species, Hyalomma isacii was identified as a new record for the ixodid tick fauna of Turkey. Hyalomma species were the most abundant in summer, while Dermacentor and Ixodes species displayed the lowest frequency. Hyalomma aegyptium infestation was very common on humans in the province. Results indicated that a variety of ixodid tick species infest humans depending on the season in the target area. It is possible that a variety of ixodid tick species may contribute to the spread of tick‐borne diseases such as Crimean‐Congo haemorrhagic fever virus (CCHFV), which is endemic in the region.     

Type specimens of Mitridae (Mollusca:Gastropoda) described by Linnaeus in the genera Voluta, Buccinum and Bulla between 1758 and 1771

From the 16 species of Mitridae described by Linnaeus between the years 1758-71 11 species are considered valid and available for taxonomic use; four specific names have been suppressed by the International Commission on Zoological Nomenclature for taxonomic usage (1968). One specific name, i.e. Voluta mitra episcopalis Linnaeus, has appeared in various combinations in malacological literature over the years. From the style of listing in the 10th edition of the Systerna Naturae , it is evident that 'episcopalis' has to be treated as of infraspecific rank; there is no evidence that 'episcopalis' is even a valid subspecies of Voluta mitra.
Three holotypes and five lectotypes designated in this paper are extant in the Linnaean collection; illustrations representing three Linnaean species have been selected as lectotypes.     

New data on the taxonomy and morphology of weevils of the genus <Emphasis Type="Italic">Plinthus</Emphasis> (Coleoptera,Curculionidae)

The taxonomic composition of the genus Plinthus Germar, 1817 is considered. The procedure of dissection of the weevil genitalia, variations in the endophallus armature, proventriculus, and crop in Plinthus species are described, and the terminology for these structures is explained. The taxonomic significance of the morphological characters of the endophallus, proventriculus, and crop, as well as the phylogenetic relationships of the genus Plinthus and its subgenera are discussed. New data on the taxonomy, morphology, and distribution of species from the subgenera Plinthomeleus Reitter, 1913 and Plinthus s. str. are presented. Keys to the subgenera of Plinthus and to species groups of the subgenus Plinthomeleus are given. Plinthus squalidus is recorded from the Caucasus and Russia for the first time.     

Food Webs and Disease: Is Pathogen Diversity Limited by Vector Diversity?

Classical predator–prey and host–parasite systems have been extensively studied in a food web context. Less attention has been paid to communities that include pathogens and their vectors. We present a coarse-grained, pan-African analysis of the relationships between the abiotic environment (location, precipitation, temperature), the species richness and community composition of ixodid ticks, and the species richness and community composition of pathogens that ticks transmit to humans. We found strong correlations between the abiotic environment and tick species richness, and a weak but significant correlation between the abiotic environment and pathogen species richness. A substantial amount of variation in community composition of parasites and pathogens was not explained by the variables that we considered. A structural equation model that compensated for the indirect effects of climate on the pathogen community via tick community composition suggested that while the environment strongly regulates tick community composition and tick community composition strongly regulates pathogen community composition, abiotic influences on pathogen species richness and community composition are weak. Our results support the view that changes in the broader environment will influence tick-borne pathogens primarily via the influence of the environment on ticks. The interactions that regulate host–vector–pathogen dynamics are of particular relevance in understanding the relationships between environmental change and health concerns, such as the impact of climate change on the occurrence of vector-borne diseases.     

Mammals as hosts of Ixodid ticks (Acarina,Ixodidae)

Trophic association between adult ticks of the world fauna with their mammal hosts (511 tick species out of 650 species of Ixodidae of the world fauna) are reviewed. Specific tick species parasitize on representatives of 22 (out of 27) mammal orders, but species of Paucituberculata, Notoryctemorphia, Peramelemorphia, Scandentia, and Dermoptera have no specific parasites. The highest number of tick species was recorded from Artiodactyla and rodents. Mammals, on which representatives of all the 14 genera of the family parasitize, provide the diversity of the ixodid tick fauna. The conclusion on the priority of ecological factors in comparison with phylogenetic status of hosts in the formation of specific characteristics of ticks confirms Balashov’s (1982) concept on the character of host-parasite association between ticks and mammals.     

Phylogeny of Geomydoecus and Thomomydoecus pocket gopher lice (Phthiraptera: Trichodectidae) inferred from cladistic analysis of adult and first instar morphology

The phylogeny for all 122 species and subspecies of chewing lice of the genera Geomydoecus and Thomomydoecus (Phthiraptera: Trichodectidae) hosted by pocket gophers (Rodentia: Geomyidae) is estimated by a cladistic analysis of fifty-eight morphological characters obtained from adults and first instars. The data set has considerable homoplasy, but still contains phylogenetic information. The phylogeny obtained is moderately resolved and, with some notable exceptions, supports the species complexes proposed by Hellenthal and Price over the the last two decades. The subgenera G. (Thaelerius) and T. (Thomomydoecus) are both shown to be monophyletic, but the monophly of subgenus T. (Jamespattonius) could not be confirmed, perhaps due to the lack of first-instar data for one of its component species. The nominate subgenus of Geomydoecus may be monophyletic, but our cladogram was insufficiently resolved to corroborate this. Mapping the pocket gopher hosts onto the phylogeny reveals a consistent pattern of louse clades being restricted to particular genera or subgenera of gophers, but the history of the host-parasite association appears complex and will require considerable effort to resolve.     

The effect of phylogeny on interspecific body shape variation in darters (Pisces: Percidae)

We conducted a geometric morphometric analysis of interspecific body shape variation among representatives of 31 species of darters (Pisces: Percidae) to determine whether there is evidence of a phylogenetic effect in body shape variation. Cartesian transformation grids representing relative shape differences of individual species and subspecies revealed qualitative similarities within most traditionally recognized taxonomic groups (genera and subgenera). Canonical variates analysis and a UPGMA cluster analysis were conducted to explore further the relationships among body shapes of species; both analyses revealed patterns of variation consistent with the interpretation that shape is associated with taxonomic affinities. Normalized Mantel statistics revealed a significant positive association between body shape differences and phylogenetic interrelatedness for each of four recent phylogenetic hypotheses, providing evidence of a phylogenetic effect. This result is somewhat surprising, however, given the largely incompatible nature of these four phylogenies. We provide evidence that this result may be due to (1) the inclusion of multiple sets of closely related species to represent the traditionally recognized genera and subgenera within each phylogeny and/or (2) the inclusion of several species with relatively divergent shapes and their particular positions within the phylogenies relative to one another or to the other species of darters.     

New and little-known crickets of the subfamily phalangopsinae (Orthoptera,Gryllidae): 4. Neotropical genus <Emphasis Type="Italic">Uvaroviella</Emphasis>

The former genera Acla Heb., Aclodes Heb., and Paraclodes Des.-Grand., are considered subgenera of the genus Uvaroviella Chop. Five new subgenera and nine new species of this genus from Ecuador and Guyana are described. Two new species names are proposed due to the secondary homonymy, and one old species name was resurrected from synonymy as a replacement name. Lectotype for U. cavicola Chop. is designated. New data on the geographical and bitopical distribution of some species are given. The paper is based on the material from the collections of the Zoological Institute, Russian Academy of Sciences, St. Petersburg (ZIN), and the Natural History Museum, London (NHM).     

The importance of type species and their correct identification: A key example from tintinnid ciliates (Alveolata,Ciliophora, Spirotricha)

Types and the corresponding rules in the International Code of Zoological Nomenclature are crucial for taxonomy and are meant to provide nomenclatural stability. In the case of neotypification, especially diligent taxonomic work is required to retain continuity. In the present communication, we first outline the main principles of typification and neotypification. We then discuss a critical case, using a current example from the marine planktonic tintinnid genus Tintinnopsis Stein, 1867 (Alveolata, Ciliophora). This diverse and ubiquitous genus is nonmonophyletic, but its revision and the erection of new related genera is currently prevented by the uncertain affiliation of its type species.     

Multivariate analyses of morphological characters of Leptolaena Thouars s.l. subgenera Mediusella and Xerochlamys (Sarcolaenaceae)

Leptolaena Thouars is one of the first described genera within Sarcolaenaceae, but represents the last great species-level taxonomic challenge in this endemic Malagasy plant family. As currently circumscribed, this genus comprises three subgenera, two of which, Mediusella Cavaco and Xerochlamys (Baker) Cavaco, exhibit patterns of morphological variation that have been understood differently and have led to an unstable taxonomy, such that a consensus on the delimitation of species has yet to be reached. Principal component analysis of morphological characters was performed on 211 herbarium specimens in order to evaluate the morphological variation within the two subgenera and to clarify historically problematical species boundaries. The results showed that ten entities could be distinguished on the basis of vegetative, floral, and fruit characters, and that they provide a robust basis for proposing a new species-level taxonomic framework.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 559–574.     

Molecular genetic relationships among east Palearctic ground squirrels of the genus Spermophilus (Sciuridae, Rodentia)

Genetic diversity in the four east Palearctic ground squirrel species of the genus Spermophilus--S. undulatus, S. parryi (subgenus Urocitellus), S. dauricus, and S. relictus (subgenus Citellus)--- was investigated using RAPD PCR with ten random primers. Siberian chipmunk, Tamias sibiricus, was used as an outgroup. Molecular markers for different taxonomic ranks were identified, including those for the genera Spermophilus and Tamias, subgenera Urocitellus and Citellus, as well as for each of the four species, S. undulatus, S. parryi, S. dauricus, and S. relictus. For the ground squirrel species and subgenera, genetic differentiation indices (H(t), H(s), D(st), G(st), Nm, and D) were calculated. In addition, for these groups the NJ phylogenetic reconstructions and UPGMA dendrograms of genetic similarity of the individuals and combined populations were constructed. Comparative molecular genetic analysis revealed a high genetic differentiation between S. undulates, S. dauricus, S. relicts, and S. parryi (G(st) = 0.58 to 0.82; D = 0.53 to 1.06), along with a low level of genetic differentiation of the subgenera Citellus and Urocitellus (G(st) = 0.33; D = 0.27), distinguished in accordance with the existing taxonomic systems of the genus Spermophilus.