Mitochondrial rDNA Sequences Research Articles

Plastome variation and phylogeny of Taxillus (Loranthaceae).

Several molecular phylogenetic studies of the mistletoe family Loranthaceae have been published such that now the general pattern of relationships among the genera and their biogeographic histories are understood. Less is known about species relationships in the larger (> 10 species) genera. This study examines the taxonomically difficult genus Taxillus composed of 35–40 Asian species. The goal was to explore the genetic diversity present in Taxillus plastomes, locate genetically variable hotspots, and test these for their utility as potential DNA barcodes. Using genome skimming, complete plastomes, as well as nuclear and mitochondrial rDNA sequences, were newly generated for eight species. The plastome sequences were used in conjunction with seven publicly available Taxillus sequences and three sequences of Scurrula, a close generic relative. The Taxillus plastomes ranged from 121 to 123 kbp and encoded 90–93 plastid genes. In addition to all of the NADH dehydrogenase complex genes, four ribosomal genes, infA and four intron-containing tRNA genes were lost or pseudogenized in all of the Taxillus and Scurrula plastomes. The topologies of the plastome, mitochondrial rDNA and nuclear rDNA trees were generally congruent, though with discordance at the position of T. chinensis. Several variable regions in the plastomes were identified that have sufficient numbers of parsimony informative sites as to recover the major clades seen in the complete plastome tree. Instead of generating complete plastome sequences, our study showed that accD alone or the concatenation of accD and rbcL can be used in future studies to facilitate identification of Taxillus samples and to generate a molecular phylogeny with robust sampling within the genus.

Full Mitochondrial Genome and Nuclear 18S rDNA Sequences Refine the Taxonomic Placement of Choleoeimeria taggarti n. comb. from the Prostate of Antechinus flavipes (Yellow-Footed Antechinus)

An unusual coccidian parasite was described previously from the prostate of a male Antechinus flavipes (family: Dasyuridae; common name: yellow-footed antechinus). Morphometrics and a partial nuclear 18S small subunit rDNA (18S rDNA) sequence were used to assign this parasite to the genus Eimeria; it was named Eimeria taggarti. We generated full nuclear 18S rDNA and mitochondrial genome sequences from this parasite and used the newly completed 18S rDNA and mitochondrial cytochrome c oxidase subunit I (COI) sequences to perform a more in-depth phylogenetic analysis. The parasite clustered closely with Choleoeimeria spp. and Acroeimeria spp. infecting herptiles in a well-supported clade that was the sister lineage to the Eimeriidae sensu stricto. The mitochondrial genome of this parasite contained 2 inverted segments compared to mitochondrial genomes from parasites in the Eimeriidae sensu stricto (i.e., Stieda body-possessing coccidia with 4 dizoic sporocysts); this mitochondrial genome arrangement was shared with the only Choleoeimeria species for which sequence data were available publicly. Examination of histological preparations and TEM images uncovered bivalvate sporocysts and otherwise confirmed previously described morphological features of the parasite. Based on our phylogenetic analyses and histological observations, we propose the generic reclassification of E. taggarti to Choleoeimeria taggarti n. comb.

The complete mitochondrial DNA of three monozoic tapeworms in the Caryophyllidea: a mitogenomic perspective on the phylogeny of eucestodes

BackgroundExternal segmentation and internal proglottization are important evolutionary characters of the Eucestoda. The monozoic caryophyllideans are considered the earliest diverging eucestodes based on partial mitochondrial genes and nuclear rDNA sequences, yet, there are currently no complete mitogenomes available. We have therefore sequenced the complete mitogenomes of three caryophyllideans, as well as the polyzoic Schyzocotyle acheilognathi, explored the phylogenetic relationships of eucestodes and compared the gene arrangements between unsegmented and segmented cestodes.ResultsThe circular mitogenome of Atractolytocestus huronensis was 15,130 bp, the longest sequence of all the available cestodes, 14,620 bp for Khawia sinensis, 14,011 bp for Breviscolex orientalis and 14,046 bp for Schyzocotyle acheilognathi. The A-T content of the three caryophyllideans was found to be lower than any other published mitogenome. Highly repetitive regions were detected among the non-coding regions (NCRs) of the four cestode species. The evolutionary relationship determined between the five orders (Caryophyllidea, Diphyllobothriidea, Bothriocephalidea, Proteocephalidea and Cyclophyllidea) is consistent with that expected from morphology and the large fragments of mtDNA when reconstructed using all 36 genes. Examination of the 54 mitogenomes from these five orders, revealed a unique arrangement for each order except for the Cyclophyllidea which had two types that were identical to that of the Diphyllobothriidea and the Proteocephalidea. When comparing gene order between the unsegmented and segmented cestodes, the segmented cestodes were found to have the lower similarities due to a long distance transposition event. All rearrangement events between the four arrangement categories took place at the junction of rrnS-tRNAArg (P1) where NCRs are common.ConclusionsHighly repetitive regions are detected among NCRs of the four cestode species. A long distance transposition event is inferred between the unsegmented and segmented cestodes. Gene arrangements of Taeniidae and the rest of the families in the Cyclophyllidea are found be identical to those of the sister order Proteocephalidea and the relatively basal order Diphyllobothriidea, respectively.

The full-length mitochondrial rDNA sequence of Tyrophagus longior (Astigmata: Acaridae) and phylogeny of astigmatid mites based on mitochondrial rDNA sequences

Mites of the genus Tyrophagus are economically important as they are polyphagous stored product pests and cause medically allergic reactions to human. Considering that examining the phylogenetic relationship among Astigmata species might help to understand their evolutionary process, we sequenced and analyzed the mitochondrial (mt) rDNA of the Tyrophagus longior and compared with those of six other astigmatid mites, as well as assessed the phylogenetic relationship among astigmatid species based on the complete mt rDNA sequences. Sequence analysis showed that the mt rDNA sequences of seven Astigmata species have high A + T contents (average value: 72.0% for 12S rRNA and 72.4% for 16S rRNA, respectively). The genetic distance and transition/transversion (TS/TV) of the seven Astigmata species reached interspecies level. In addition, the predicted stem-loop secondary structure of T. longior mt rDNA closely resembled those of other reported acariform mites. Finally, phylogenetic analyses based on complete sequences of 12S rRNA and 16S rRNA genes revealed that a close relationship between the families Acaridae and Pyroglyphidae, and supported the monophyly of the Acaridae as well as the Astigmata. These results are consistent with traditional classifications. Therefore, the mt rRNA genes are suitable for inferring phylogenetic relationship among astigmatid mites in this study, although the differentiation among the seven astigmata species has approached interspecies level.

Development of a Mitochondrial 12S rDNA Analysis for Distinguishing Sciuridae Species With Potential to TransmitEhrlichiaandBorreliaSpecies to FeedingAmblyomma americanum(Acari: Ixodidae)

Unique oligonucleotide probes were synthesized to distinguish among closely related vertebrate mitochondrial rDNA sequences present in residual bloodmeals in emergent Amblyomma americanum (L.) (Acari: Ixodidae) nymph life-stage ticks. Use of these probes enabled the identification of the Eastern gray squirrel as an important bloodmeal source in nymphs harboring Ehrlichia and Borrelia species. These results were confirmed by identifying these same bacterial genera in Eastern gray squirrel tissues.

Phylogenetic placement of lichenicolous Phoma species in the Phaeosphaeriaceae (Pleosporales, Dothideomycetes)

More than twenty species of lichenicolous fungi have been described in Phoma, a large anamorphic genus of primarily plant-associated pathogens with broad geographic distributions. We obtained nuclear and mitochondrial rDNA sequences from 19 fungal cultures isolated from specimens representing four described and two undescribed lichenicolous species in the genus. Our multilocus phylogeny indicates that lichenicolous Phoma species represent at least two phylogenetically distinct clades in the Phaeosphaeriaceae, one including a new species, Phoma puncteliae, isolated from a specimen of Punctelia rudecta collected in Maryland, USA, and another group of primarily lichenicolous species. This latter group includes four described lichenicolous Phoma species, an unidentified melanized rock fungus, and a new lichenicolous Phoma species isolated from Xanthomendoza species collected in Canada that we are naming P. xanthomendozae. Some specimens in this clade collected from different lichen genera and species were found to be very similar genetically, which calls into question the recent practice of recognizing lichenicolous Phoma species mainly by differences in host preference.

Phylogenetic relationships of the Rhacophorus everetti‐group and implications for the evolution of reproductive modes in Philautus (Amphibia: Anura: Rhacophoridae)

Hertwig, S., Das, I., Schweizer, M., Brown, R., & Haas, A. (2011). Phylogenetic relationships of the Rhacophorus everetti‐group and implications for the evolution of reproductive modes in Philautus (Amphibia: Anura: Rhacophoridae). —Zoologica Scripta, 41, 29–46.This study presents the first phylogenetic analysis of the enigmatic Rhacophorus everetti species group and the first description of its unique tadpole. A total sample of 95 12S and 16S mitochondrial rDNA sequences were compiled including new sequence data from 28 rhacophorid species. Based on 1332 and 1407 bp, respectively, and on the gap coding method applied, a new hypothesis about the phylogeny of rhacophorid tree frogs from Sundaland was obtained. While Rhacophorus was uncovered as a polyphyletic assemblage, the monophyly of the Bush Frogs of the genus Philautus, including the Rhacophorus everetti‐group, is robustly supported. We, therefore, transfer the everetti‐group to the genus Philautus. As a second step, we recognise Philautus macroscelis (comb. nov.) from Borneo and P. everetti (comb. nov.) from Palawan as distinct allopatric species. Molecular and morphological evidence clearly indicates that each is a distinct lineage with a unique ancestry and discrete evolutionary fate. Moreover, close phylogenetic relationships of several Philautus species from Borneo to taxa from outside Borneo were recovered; P. everetti and P. macroscelis being the only one example. These findings indicate a complex biogeographical history of Sundaland Bush Frogs, which can only be explained by repeated dispersal and vicariance events between the Asian mainland and the Sunda islands. Finally, a single tadpole discovered on Gunung Kinabalu was matched genetically to P. macroscelis. Features of its peculiar external morphology suggest that this larva is endotrophic and possibly nidicolous. A comparable reproductive biology was formerly unknown in rhacophorid tree frogs. The presence of a free‐swimming tadpole in Philautus challenges the notion that terrestrial direct development represents an apomorphic character unambiguously shared by all members of this genus. The implications for the evolution of reproductive modes in Bush Frogs are discussed in a phylogenetic context.

A new lichenicolous teleomorph is related to plant pathogens in Laetisaria and Limonomyces (Basidiomycota, Corticiales)

Molecular and morphological data were used to assess the taxonomic placement of an undescribed lichenicolous basidiomycete teleomorph collected in Luxembourg, Belgium and Germany. The new species is ecologically and morphologically similar to Marchandiobasidium aurantiacum, teleomorph of the common bulbilliferous lichen pathogen Marchandiomyces aurantiacus. However phylogenetic analysis of nuclear and mitochondrial rDNA sequences indicated a close relationship of the new species—not to M. aurantiacum but to turf grass pathogens in genera Laetisaria and Limonomyces, including the generic type of Laetisaria. We are including the new species in Laetisaria based on strong statistical support for the clade containing these teleomorphs and several Marchandiomyces anamorphs. The morphological and ecological diversity of this clade indicates a potentially significant evolutionary role played by lichen-associated species in the Corticiales.

Genetic and cytological evidence of hybridization between native Ruditapes decussatus and introduced Ruditapes philippinarum (Mollusca, Bivalvia, Veneridae) in NW Spain

The introduction of foreign species in marine ecosystems is an established method to increase productivity and generate income in aquaculture. A good example is the introduction of the Japanese carpet shell, Ruditapes philippinarum, now the major contributor to clam landings in Europe. The similarity of R. philippinarum and the native grooved carpet shell, R. decussatus, the plasticity of their shell morphology and the presence of both species on the same beds make it very difficult sometimes for the morphological identification of specimens that show intermediate shell characteristics. A species identification method using length differences in the internal transcribed spacer (ITS) region of the major ribosomal RNA genes and the whole repeat sequence of the minor ribosomal RNA genes (5S rDNA) was developed for Ruditapes. Following morphological recognition, this method enabled the identification of both species of Ruditapes. However, nine of the 222 individuals morphologically identified as R. decussatus had sequences specific to both R. decussatus and R. philippinarum in both the ITS region and the 5S rDNA and were putative hybrids. Species-specific ITS and 5S rDNAs were used as probes in fluorescent in situ hybridization (FISH) experiments to map these sequences on surface spread synaptonemal complexes (SCs) of R. decussatus and R. philippinarum. Differences on the chromosomal location of those sequences between species were also detected. FISH on the SCs of two of the nine hybrid individuals also showed signal patterns corresponding to those detected in both R. decussatus and R. philippinarum thus confirming their hybrid nature. The hybrids showed 16S mitochondrial rDNA sequences of R. decussatus. In conclusion, genetic and cytological evidence of the occurrence of hybridization between female R. decussatus and male R. philippinarum was obtained.

The obligately lichenicolous genus Lichenoconium represents a novel lineage in the Dothideomycetes

Lichenicolous fungi are obligately lichen-associated organisms that have evolved many times throughout the Ascomycota and Basidiomycota. Approximately 20 % of lichenicolous ascomycetes are recognized only from asexual (anamorphic) characteristics, so the phylogenetic position of many groups has never been resolved. Here we present the first molecular phylogeny of Lichenoconium, a genus of strictly asexual, obligately lichenicolous species with broad geographic distributions and diverse host ecologies. We obtained nuclear and mitochondrial rDNA sequences from fungal cultures isolated from four species in the genus, including a new species, Lichenoconium aeruginosum sp. nov., collected in France, Luxembourg and Netherlands. Our multilocus phylogeny supports the monophyly of fungi in the genus Lichenoconium, and places the genus in the Dothideomycetes, an ascomycete class made up mainly of saprobes and plant-associated endophytes and pathogens. There are only a few recognized groups of lichen-formers in the Dothideomycetes, but Lichenoconium is not supported as being closely related to any of these, nor to any other recognized order within the Dothideomycetes. Given that Lichenoconium is but one of over 100 genera of anamorphic lichenicolous fungi, most of which have never been studied phylogenetically, we suggest that asexual lichenicolous fungi may represent novel and evolutionarily significant phylogenetic groups in the Kingdom Fungi.

Mycorrhizal specificity, preference, and plasticity of six slipper orchids from South Western China

Mycorrhizal fungi of six endangered species, Paphiopedilum micranthum, Paphiopedilum armeniacum, Paphiopedilum dianthum, Cypripedium flavum, Cypripedium guttatum, and Cypripedium tibeticum, from two closely related genera in the Orchidaceae from Southwestern China, were characterized using the nuclear internal transcribed spacer (ITS) and part of the large subunit gene of mitochondrial rDNA (mtLSU) sequences. The most frequently detected fungi belonged to the Tulasnellaceae. These fungi were represented by 25 ITS sequence types and clustered into seven major clades in the phylogenetic analysis of 5.8S sequences. Species of Paphiopedilum and Cypripedium shared no fungal ITS sequence types in common, but their fungal taxa sometimes occurred in the same major clade of the 5.8S phylogenetic tree. Although it had several associated fungal ITS sequence types in a studied plot, each orchid species had in general only a single dominant type. The fungal sequence type spectra of different species of Paphiopedilum from similar habitats sometimes overlapped; however, the dominant sequence types differed among the species and so did the sequence-type spectra within Cypripedium. Orchids of P. micranthum and P. armeniacum transplanted from the field and grown in two greenhouses had a greater number of mycorrhizal associations than those sampled directly from the field. Root specimens from P. micranthum taken from the greenhouses were preferably associated with mycobionts of the Tulasnella calospora complex, while those from the field had mycorrhizal associations of other tulasnelloid taxa. Such plasticity in mycorrhizal associations makes ex situ conservation or even propagation by means of mycorrhization of axenically grown seedlings possible.

Ixodes downsi Kohls, 1957 in Venezuela

Abstract Three females and three nymphs of Ixodes downsi Kohls, 1957 were collected in guano deposited in Guacharos Cave, State of Monagas, Venezuela. The cave is inhabited by bats and oilbirds (Steatornis caripensis Humboldt) and is frequented by carnivores. Previous records of this tick are from Trinidad & Tobago and Peru, and it is unclear whether the principal hosts are Chiroptera or Aves. The present record of I. downsi in Venezuela does not provide new host data but expands this tick's known range, which is probably greater than collections indicate. Phylogenetic analyses based on 16S mitochondrial rDNA sequences of Ixodes species from the Neotropical Zoogeographic Region, plus two Australian Ixodes and three argasids, were conducted to clarify the systematic position of I. downsi. The analyses showed an unexpected relationship with I. (Multidentatus) auritulus Neumann, 1904. However, as with other Neotropical Ixodes, the subgeneric status of I. downsi remains undetermined.

Phylogenetic diversity of lichen-associated homobasidiomycetes

The vast majority of lichenicolous fungi are relatively host-specific, nonvirulent ascomycetes and heterobasidiomycetes. A few known lichenicolous homobasidiomycetes (mushroom-forming fungi) generally exhibit broad host ecologies and in some cases, high virulence. Many produce conspicuous sclerotia or bulbils, thought to be adaptive in dispersal and survival. To more clearly understand the evolution of these atypical behaviors in lichenicolous basidiomycetes, we isolated or acquired specimens or cultures of 23 lichenicolous homobasidiomycetes and their relatives, from which we obtained mainly nuclear and some mitochondrial rDNA sequences. Phylogenetic analyses in this study indicate that a lichenicolous habit arose in four major clades. In two of these clades the habit represents a major evolutionary theme linked to the origin of well-known basidiolichens. The phylogenetic diversity of these fungi indicates that the lichenicolous habit arose recently and independently in the mushroom-forming fungi.

Systematics and biogeography of Rhodniini (Heteroptera: Reduviidae: Triatominae) based on 16S mitochondrial rDNA sequences

AbstractAim The tribe Rhodniini is one of six comprising the subfamily Triatominae (Heteroptera: Reduviidae), notorious as blood‐sucking household pests and vectors ofTrypanosoma cruzithroughout Latin America. The human and economic cost of this disease in the American tropics is considerable, and these bugs are unquestionably of great importance to man. Studies of the evolution, phylogeny, biogeography, ecology, physiology and behaviour of the Rhodniini are needed to help improve existing Chagas’ disease control programmes. The objective of the study reported here was to propose biogeographical hypotheses to explain the modern geographical distribution of the species of Rhodniini.Location Neotropical region.Methods We employed mitochondrial rDNA sequences (16S) currently available in GenBank to align sequences of Rhodniini species using ClustalX. The analyses included 16S sequences from predatory reduviid subfamilies (Stenopodainae, Ectrichodiinae, Harpactorinae, Reduviinae and Salyavatinae) present in GenBank as an outgroup. Cladistic analysis used the program PAUP to derive trees based on maximum parsimony (MP) and maximum likelihood (ML). Known distribution data for Rhodniini species were obtained from reviews and plotted on maps of South and Central America using the program iMap. An area cladogram was derived from the cladistic result to show the historical connections among the studied taxa and the endemic areas. The program TreeMap (Jungle Edition) was used to deduce taxon–area associations where the optimal solutions to explain the biogeographical hypothesis of the Rhodniini in the Neotropics were those with lowest total cost.Results Parsimony and maximum‐likelihood analysis of 16S rDNA sequences included 14 species of Rhodniini, as well as five species of predatory Reduviidae representing five of the predatory subfamilies. Tanglegrams were used to show the relationship between the Neotropical areas of endemism and Rhodniini species. When TreeMap with codivergence (vicariance) events were weighted as 0 and duplication (sympatry), lineage losses (extinction) and host switching (dispersal) were all weighted as 1, 20 scenarios were found to explain the biogeographical history of Rhodniini in the Neotropical region. Twelve of the optimal solutions with the lowest total cost were used to explain the biogeography of the Rhodniini in the Neotropics. These optimal reconstructions require six vicariance events, 20 duplications (sympatry), at least three dispersals, and at least one extinction event.Main conclusions The Rhodniini have a complex biogeographical history that has involved vicariance, duplications (sympatry), dispersal and extinction events. The main geological events affecting the origin and diversification of the Rhodniini in the Neotropics were (1) uplift of the Central Andes in the Miocene or later, (2) break‐up of the Andes into three separate cordilleras (Eastern, Central and Western) in the Plio‐Pleistocene, (3) formation of a land corridor connecting South and North America in the Pliocene, and (4) uplift of the Serra do Mar and Serra da Mantiqueira mountain systems between the Oligocene and Pleistocene. The relationships and biogeographical history of the species of Rhodniini in the Neotropical region probably arose from the areas of endemism shown in our work.

The phylogenetic position of Ixodes stilesi Neumann, 1911 (Acari: Ixodidae): morphological and preliminary molecular evidences from 16S rDNA sequences

The female of Ixodes stilesi Neumann, 1911 (Acari Ixodidae) is redescribed and the male and nymph are described from specimens collected from Pudu puda (Molina) (Artiodactyla: Cervidae) in Chile. Both sexes of I. stilesi have characteristics of the subgenera Ixodes Latreille, 1795 and Ixodiopsis Filippova, 1957. The females of I. stilesi are peculiar in having the combination of the sinuous scutum outline, rounded porose areas with distinct borders separated by the width of one area, slender and long palpi, and two subequal spurs on coxa I. The male is unique in having a combination of a posteriorly wrinkled marginal folder, a basis capituli longer than wide, a non-crenulate hypostome toothed portion, two spurs on coxa II to IV and the presence of a pseudoscutum. The nymph of I. stilesi has blunt anterior and posterior processes on palpal article I (characteristics of the subgenus Ixodiopsis and some Pholeoixodes Schulze, 1942) and a wing-shaped basis capituli with a prominent triangular cornua. Phylogenetic analyses based on 16S mitochondrial rDNA sequences of 12 Neotropical and two Australian Ixodes species, plus three argasids, were carried out to clarify the position of I. stilesi. The results of phylogenetic analyses and morphological characters indicate a close relationships between I. stilesi and two other Neotropical species of uncertain subgeneric status, I. neuquenensis Ringuelet, 1947 and I. sigelos Keirans, Clifford & Corwin, 1976.

Analysis of Andes frogs (Phrynopus, Leptodactylidae, Anura) phylogeny based on 12S and 16S mitochondrial rDNA sequences

South American leptodactylid frogs of the genus Phrynopus occur in cloud‐forest, páramo, subpáramo and puna habitats (1000–4400 m elevation) from Colombia to Bolivia. Currently, there are 34 described species; however, many additional species new to science have been reported from Colombia, Peru, and Bolivia. The phylogeny of the species‐diverse Phrynopus is unknown and the position of the genus within Leptodactylidae is poorly understood. We present the results of a phylogenetic study based on 12S and 16S mitochondrial rDNA. Fifteen species of Phrynopus from Bolivia to Ecuador are included, along with several other genera of Leptodactylidae and representatives of other frog families. Our results indicate that Phrynopus is phylogenetically nested within Eleutherodactylus, whereas Phyllonastes is phylogenetically nested within Phrynopus. Based on the recovered phylogeny, we transfer Phrynopus simonsii to Eleutherodactylus, and show that Phrynopus carpish needs to be removed from Phrynopus. Eleven of the 13 Phrynopus species occurring in Central Peru share the absence of an external and internal ear.

A Collection of Ticks (Ixodidae) from Wild Birds in Uruguay

Thirty nine wild birds from seven families (Alcedinidae, Emberizidae, Furnariidae, Parulidae, Trochilidae, Turdidae and Tyrannidae) were caught from 4 to 7 of February, 2004 at Rincón da Vassoura (31 degrees 15' S 56 degrees 03' W) Department of Tacuarembó, Uruguay. Ninety one nymphs and forty one larvae of Ixodidae were recovered from them. The majority of ticks were conventionally identified but 16S mitochondrial rDNA sequences were obtained for larvae and nymphs of Amblyomma with uncertain specific status to be compared with sequences of species from this genus. The 16S rDNA of Haemaphysalis juxtakochi Cooley was also obtained. Most ticks, 1 nymph of Amblyomma longirostre (Koch), 5 larvae of Amblyomma aureolatum (Pallas) and 3 nymphs of Amblyomma spp., 10 nymphs and 71 larvae of H. juxtakochi, 23 nymphs and 12 larvae of Ixodes pararicinus Keirans and Clifford, were found on the 5 Turdus albicollis Vieillot and 6 Turdus rufiventris Vieillot (Turdidae) caught. One nymph of A. longirostre and 2 nymphs of I. pararicinus were collected from the only Syndactyla rufosuperciliata (Lafresnaye) (Furnariidae) captured; 1 larva of I. pararicinus was collected on one of two Basileuterus leucoblepharus (Vieillot) (Parulidae) trapped and 1 nymph of A. longirostre was found on one of nine Elaenia parvirostris Pelzeln (Tyrannidae) captured. All these findings constitute new host records with the exception of I. pararicinus on S. rufosuperciliata, and stress the importance of Turdus as hosts for I. pararicinus, H. juxtakochi and A. aureolatum. Nymphs of H. juxtakochi and Amblyomma spp. were also found on man and vegetation.

Sigmodontinae rodents as hosts for larvae and nymphs ofIxodes loricatusNeumann, 1899 (Acari: Ixodidae)

Larvae and nymphs of Ixodes loricatus Neumann, 1899 ticks (confirmed by morphological characters and by comparison of 16S mitochondrial rDNA sequences) were collected from Sigmodontinae Wagner, rodents in central and northern Argentina and Uruguay. A total of 100 larvae and 38 nymphs of I. loricatus were collected on the genera Akodon Meyen (n = 36 individuals), Calomys Waterhouse (n = 2), Oligoryzomys Bang in = 12), Oxymycterus Waterhouse (n = 9), and Scapteromys Waterhouse (n = 13). 72 larvae and 18 nymphs were collected on Akodon. Adults of I. loricatus were found in central Argentina and Uruguay on Didelphimorphia of the genera Didelphis Linnaeus and Lutreolina Thomas. Ixodes loricatus has been considered a species with strict total specificity to Didelphimorphia. Our results show that this statement may not be justified. Sigmodontinae rodents are sympatric and share habitats with the phylogenetically distant Didelphimorphia; infestation with I. loricatus seems to be its consequence. We tentatively consider I. loricatus moderately specific to Didelphimorphia.

Description of the nymph and larva and redescription of the female of Ixodes neuquenensis Ringuelet, 1947 (Acari: Ixodidae), a parasite of the endangered Neotropical marsupial Dromiciops gliroides Thomas (Microbiotheria: Microbiotheriidae).

The female of Ixodes neuquenensis Ringuelet, 1947 (Acari: Ixodidae) is redescribed and the nymph and larva are described from specimens collected from the endangered marsupial Dromiciops gliroides Thomas (Microbiotheria: Microbiotheriidae) in Argentina. At first sight the female of I. neuquenensis resembles a member of the subgenus Ixodes Latreille, 1795. However, the female of I. neuquenensis is peculiar in having the combination of two spurs on coxae II-IV and a pair of chitinous plaques internal to coxa I. Both the nymph and larva have an anterior and posterior process on palpal article I, characteristics of the subgenus Ixodiopsis Filippova, 1957 and some representatives of the subgenus Pholeoixodes Schulze, 1942. Analysis of 16S mitochondrial rDNA sequences showed no strong relationship with any known Ixodes subgenus.

Mitochondrial 12S rDNA Sequence Relationships Suggest That the Enigmatic Bovid “Linh Duong” Pseudonovibos spiralis Is Closely Related to Buffalo

The phylogenetic position and taxonomic status of the recently described Southeast Asian endemic bovid Pseudonovibos spiralis were deduced from nearly complete 12S mitochondrial rDNA sequences of this species and Bubalus bubalis alongside 26 sequences of Bovidae from GenBank using Cervus elaphus (Cervidae) as outgroup. Maximum-likelihood analyses performed by PUZZLE and fastDNAml nested P. spiralis at the base of the subtribe buffalo Bovini, suggesting the close relationship of this enigmatic species with buffalo and enabling its distinction into the separate subtribe Pseudonovibovina.