Reproductive biology and isolation mechanisms in rupicolous species of the Acianthera prolifera complex (Orchidaceae) occurring in southeastern Brazil

We studied the floral biology and performed experimental intra- and interspecific pollinations in populations of a complex of four Acianthera (Orchidaceae) species occurring in Brazilian campo rupestre vegetation (A.?hamosa, A.?limae, A.?modestissima, and A.?prolifera). All four species flower synchronously, are partially intercompatible, and exhibited some degree of self-sterility. Floral morphology is similar in all the species, with their principal differences associated with size of the floral structures. The four species were visited only by Diptera species of the families Phoridae (Megaselia spp.) and Chloropidae, but visits are rare and fruit set is very low. Sympatric species were not pollinated by the same Diptera species. Acianthera hamosa and A.?modestissima have the smallest flowers, and no marked morphological differences between them were observed; they were both pollinated by very similar Megaselia species. Both prepollination barriers and postpollination events are important to maintaining the isolation of the species, functioning as overlapping filters that diminish the possibility of gene flow between them. However, putative hybrids between A.?prolifera and A.?limae have been found. Conversely, A.?hamosa and A.?modestissima, which are recognized only by vegetative characters that show high phenotypic plasticity, seem only to be isolated by geographical barriers, and they may actually constitute a single species or be sister species.     

Interactions Between Aphaenogaster carolinensis (Hymenoptera: Formicidae) and Four Sympatric Ant Species

Individual ants of Aphaenogaster carolinensis Wheeler were placed in two way combinations with four sympatric ant species (Aphaenogaster lamellidens Mayr, Crematogaster lineolata Say, Pachycondyla chinensis Emery and Prenolepis imparis Say) to determine whether their interspecific behavior was dependent upon the ant species they were confronted with. The tendency of A. carolinensis to initiate and terminate interactions, and the durations of those interactions, were measured for all combinations. There was no significant effect of species on initiation or termination. There was a significant effect of species on the duration of interactions that were both initiated and terminated by A. carolinensis. Durations of interactions with A. lamellidens were significantly longer than with other species. The conclusion is that the interspecific behavior of A. carolinensis is dependent in part on the species it is interacting with.     

History and current taxonomic status of genus Agrobacterium

The genus Agrobacterium was created a century ago by Conn who included it in the family Rhizobiaceae together with the genus Rhizobium. Initially, the genus Agrobacterium contained the non-pathogenic species Agrobacterium radiobacter and the plant pathogenic species Agrobacterium tumefaciens and Agrobacterium rhizogenes. At the end of the past century two new pathogenic species, Agrobacterium rubi and Agrobacterium vitis, were added to the genus. Already in the present century these species plus Agrobacterium larrymoorei were reclassified into genus Rhizobium. This reclassification was controversial and for a time both genus names were used when new species were described. Few years ago, after a taxonomic revision based on genomic data, the old species A. rhizogenes was maintained in the genus Rhizobium, the old species A. vitis was transferred to the genus Allorhizobium and several Rhizobium species were transferred to the genus Agrobacterium, which currently contains 14 species including the old species A. radiobacter, A. tumefaciens, A. rubi and A. larrymoorei. Most of these species are able to produce tumours in different plants, nevertheless the genus Agrobacterium also encompasses non-pathogenic species, one species able to nodulate legumes and one human pathogenic species. Taking into account that the species affiliations to five Agrobacterium genomospecies have not been determined yet, an increase in the number of species within this genus is expected in the near future.     

Hybridization and introgression in Carex aquatilis and C. paleacea

The diversification and distribution of Abies species throughout the Mediterranean region has led to a complex of species which are difficult to classify. An open question is whether these mainly allopatric taxa have exchanged genetic information via secondary contact. We studied the variation and geographic distribution of paternally inherited chloroplast DNA markers in nine Mediterranean Abies taxa. Markers with high and low mutation rates were applied in order to differentiate among a scenario of secondary genetic contact and a scenario of complete isolation after speciation. The observed molecular variation was analysed using statistical parsimony, geostatistics, and measures of population genetic differentiation. Ancient paternal lineages, represented by markers with low mutation rates, were shared among species. The central and widespread A. alba retained all ancient lineages whereas other species exhibited fewer, down to a single lineage. In contrast, modern lineages, depicted by markers with high mutation rates, were largely separated among species. The western Mediterranean A. pinsapo and A. numidica were clearly separated from each other and from the remaining Abies species. This indicates the absence of secondary contact. The same scenario applies to the eastern Mediterranean Abies species. An exception is the parapatric complex of A. alba, A. cephalonica, and their supposed hybrid A. borisii regis, which exhibited evidence of secondary contact.     

Floral traits and isolation of three sympatric Aquilegia species in the Qinling Mountains, China

Floral isolation has been considered to be an important reproductive mechanism governing the species diversification in many genera. In a classic example Aquilegia, sympatric species from North America with diverse floral traits are generally associated with specialized pollinators that prohibit interspecific hybridization. It remains unclear whether species diversification in the genus from Eurasia is also maintained by floral isolation. We investigated floral phenology, floral characteristics and pollinators in three sympatric Aquilegia species (A. ecalcarata, A. incurvata and A. yabeana) in the Qinling Mountains, Shanxi Province, China from 2001 to 2005. The spurless A. ecalcarata flowers earlier than the other two species with nectar spurs but their floral phenology overlaps. Major pollinators of A. ecalcarata are syrphid flies while bumblebees are major for A. incurvata and A. yabeana. Therefore our observations confirm that mechanical isolation through differential pollinators could contribute reproductive isolation between spurless and spurred species, as demonstrated by studies from North America. Whether floral isolation plays a major role in the reproductive isolation between two spurred species (A. incurvata and A. yabeana), however, remains to be seen. Further studies are required to quantify the potential role of geographical isolation because they occupy different habitats.     

A comparative study of sulphur content of someAllium L. Species

Garlic has been used worldwide as a folk medicine to cure a wide range of diseases. AlthoughAllium sativum is the species commonly used, several otherAllium species have been used as a substitute for common garlic, especially in the past. This work compares the extracts from bulbs of common garlic with those of otherAllium species. TLC analysis was used to compare the sulphur compounds inA. sativum, A. subhirsutum, A. pendulinum, A. roseum, andA. triquetrum. Results have showed that the use of the above mentioned wildAllium species is not without scientific support.     

Six new species of Pythiogeton in Taiwan,with an account of the molecular phylogeny of this genus

Pythiogeton is a little-studied genus of pythialean Oomycete. The genus is characterized by producing its zoospores outside of the sporangium within an apparently naked protoplasmic mass, which formed from a discharge tube-vesicle complex. A total of nine morphologically distinct Pythiogeton species were identified, of which six were new species (Pythiogeton abundans, Pythiogeton microzoosporum, Pythiogeton oblongilobum, Pythiogeton paucisporum, Pythiogeton proliferatum, and Pythiogeton puliensis). A phylogenetic analysis based on internal transcribed spacer sequences revealed that all isolates of Pythiogeton formed a highly supported clade, nested within the wider clade of Pythium species. Each newly recognized Pythiogeton species that was established on the basis of morphological characters was found to occur in a well-supported subgroup within the Pythiogeton clade, confirming their assignment to new species. Pythiogeton shares a common ancestor with the monophyletic group of Pythium species that have predominantly filamentous sporangia rather than with the separate clade of Pythium species that have predominantly globose or ovoid sporangia. This study confirms that Pythium is an extremely heterogenous and polyphyletic genus containing a number of distinct clades of species, including Pythiogeton, which possess morphologically distinguishable characters. A synoptic key to all the described Pythiogeton species is provided.     

Evaluating species nonmonophyly as a trait affecting genetic diversity: a case study of three endangered species of Antirrhinum L. (Scrophulariaceae)

Molecular markers are routinely used to assess levels of diversity within and among populations, particularly with regard to species of conservation concern. However, when interpreting the level and partitioning of diversity observed, an implicit assumption is often made that the populations of the species in question form a monophyletic group. We tested this assumption in three endemics of Antirrhinum (A. charidemi, A. subbaeticum, and A. valentinum) using 79 nuclear [internal transcribed spacer (ITS)] and 85 plastid (psbA-trnH, trnT-trnL, trnK-matK, trnS-trnG) sequences representing multiple accessions of each of 24 Antirrhinum species (single accession of A. cirrhigerum). These species share six life history traits implicated in levels of genetic diversity, and have been the subject of previous population genetic studies. Populations of all three species formed monophyletic groups on ITS analysis. In contrast, none of the three species formed monophyletic groups on plastid sequence analysis: populations of A. charidemi fall in a monophyletic group including one accession of A. mollissimum, populations of A. subbaeticum form a polyphyletic group with plastid sequences shared with A. pulverulentum, and populations of A. valentinum are unresolved within a clade containing six other species. Lack of monophyly using plastid sequences is interpreted as a combination of shared ancestral polymorphism and hybridization in a reticulate evolutionary history of these species. Monophyly in the ITS tree may reflect a more recent sequence homogenization. We draw attention to the evaluation of species monophyly alongside the contribution of other life history traits in the historical interpretation of the level and partitioning of genetic diversity, and its use in recommendations for species conservation programs.     

PHYLOGENETIC STUDIES OF THE GENUSARTHONIA

A phylogenetic analysis is presented, based on 57 morphological, anatomical, chemical and ecological characters, including 19 species from the generaArthonia,ArthotheliumandSyncesia. The aim of the study was to test the monophyly of some of the groups within the genusArthoniasuggested, for example, by Redinger (e.g. species with reddish ascomata, with grey–pruinose ascomata and with brown–black hypothecia). The results strongly support thatArthoniaandArthotheliumare paraphyletic genera. The best-supported node contains allArthoniaspecies together withA. crozalsianade Lesd.,A. ruanaA. Massal. (both hitherto placed inArthothelium) andSyncesia myrticola(Fée) Tehler. A well-supported clade is formed by a group of pioneer species, often non-lichenized or poorly lichenized, including the type species ofArthonia,A. radiata. The species with reddish and/or K+ reddish ascomata form one clade and the species with more or less brownish or blackish hypothecia form another clade withSyncesia myrticola, the sister group to theOpegraphaceaeandRoccellaceae. The results are discussed and compared with Redinger’s grouping. Relationships to other genera within Arthoniaceae are briefly discussed.Arthothelium scandinavicumTh. Fr.,Arthonia dispersa(Schrad.) Nyl.,A. punctiformisAch. andA. mediellaNyl. are lectotypified.     

Aspergillus takadae,a novel heterothallic species of Aspergillus section Fumigati isolated from soil in China

Aspergillus takadae is characterized by its heterothallic reproduction, pale yellow cleistothecia, broadly lenticular ascospores with two short equatorial crests and smooth convex surfaces, and broadly ellipsoidal to ovate conidia with a smooth wall. The validation of these novel species is supported further by the analyses of the β-tubulin, calmodulin, actin, and RPB2 sequences. In addition, the phylogenetic tree and DDBJ accession numbers of all the species of Aspergillus section Fumigati are presented. We report on the crossing of A. takadae species and the result of crossing A. takadae with a closely related species, A. spathulatus.     

The Success of Acinetobacter Species; Genetic,Metabolic and Virulence Attributes

An understanding of why certain Acinetobacter species are more successful in causing nosocomial infections, transmission and epidemic spread in healthcare institutions compared with other species is lacking. We used genomic, phenotypic and virulence studies to identify differences between Acinetobacter species. Fourteen strains representing nine species were examined. Genomic analysis of six strains showed that the A. baumannii core genome contains many genes important for diverse metabolism and survival in the host. Most of the A. baumannii core genes were also present in one or more of the less clinically successful species. In contrast, when the accessory genome of an individual A. baumannii strain was compared to a strain of a less successful species (A. calcoaceticus RUH2202), many operons with putative virulence function were found to be present only in the A. baumannii strain, including the csu operon, the acinetobactin chromosomal cluster, and bacterial defence mechanisms. Phenotype microarray analysis showed that compared to A. calcoaceticus (RUH2202), A. baumannii ATCC 19606^T was able to utilise nitrogen sources more effectively and was more tolerant to pH, osmotic and antimicrobial stress. Virulence differences were also observed, with A. baumannii ATCC 19606^T, A. pittii SH024, and A. nosocomialis RUH2624 persisting and forming larger biofilms on human skin than A. calcoaceticus. A. baumannii ATCC 19606^T and A. pittii SH024 were also able to survive in a murine thigh infection model, whereas the other two species were eradicated. The current study provides important insights into the elucidation of differences in clinical relevance among Acinetobacter species.     

Population genetic structures of three congeneric species of coastal pelagic fishes (Arripis: Arripidae) with extensive larval, post-settlement and adult movements

The population genetic structures of three congeneric coastal pelagic marine fishes (Arripis trutta, A. truttaceus and A. georgianus) were investigated to determine whether these structures were consistent with the apparently high gene flow life histories of these species. This investigation used fragment length polymorphisms at two to four nDNA intron loci (amplified by EPIC-PCR) in samples of each species collected from across their entire Australian distributions. The results revealed no evidence of genetic subdivision in any species based on an analysis of variation either across samples (with multilocus F _ST values ranging from effectively zero to 0.005), or between pairs of samples. These findings, when considered in combination with other available evidence, are consistent with the view that each of these species represents a rare example of a coastal fish species that is genetically homogeneous over a vast area, including the entire geographic range (A. truttaceus and A. georgianus) or Australian distribution (A. trutta).     

Systematics of the southern Patagonian-Fueguian endemic Abrothrix lanosus (Rodentia: Sigmodontinae): Phylogenetic position,karyotypic and morphological data

Abrothrix lanosus (Thomas, 1897) is morphologically redescribed on the basis of new specimens collected in Tierra del Fuego (Argentina). Cranial, mandibular, skeletal, penile, and chromosomal characteristics are described and compared with other species of Abrothrix, especially those of the Patagonian-Fueguian region. Its phylogenetic position within Abrotrichini is explored using DNA sequences of the mitochondrial cytochrome b (cyt b) and the nuclear Interphotoreceptor Retinoid Binding Protein (IRBP) genes. Phylogenetically, cyt b places A. lanosus as sister of A. jelskii, whereas IRBP groups A. lanosus and A. longipilis. The latter topology is most consistent with morphological data and taxonomic history. Several cranial and mandibular characters distinguish A. lanosus from the other species of the genus, including A. longipilis, which is its most similar species. A. lanosus shares with other congeners a 2n=52 karyotype and differs from other species of Abrothrix by at least 10% (p-distances) sequence divergence in cyt b. In conclusion, A. lanosus is a valid species, readily distinguishable from other Abrothrix in the southern Patagonian-Fueguian region. Although many data, including penile and skull morphology, suggest that A. longipilis is its closest living relative, A. jelskii is retained as a viable alternative until additional data are obtained.     

Development of DNA barcodes for selected Acacia species by using rbcL and matK DNA markers

Acacia species are very important tree species in tropical and subtropical countries of the World for their economic and medicinal benefits. Precise identification of Acacia is very important to distinguish the invasive species from rare species however, it is difficult to differentiate Acacia species based on morphological charcters. In addition, precise identification is also important for wood charcterization in the forest industry as these species are declining due to illegal logging and deforestation. To overcome thsese limitations of morphological identification, DNA barcoding is being used as an efficient and quick approach for precise identification of tree species. In this study, we selected two chloroplast and plastid base DNA markers (rbcL and matK) for the identification of five selected tree species of Acacia (A. albida, A. ampliceps, A. catechu, A. coriacea and A. tortilis). The genomic DNA of the selected Acacia species was extracted, amplified through PCR using specific primers and subsequently sequenced through Sanger sequencing. In matK DNA marker the average AT nucleotide contents were higher (59.46%) and GC contents were lower (40.44%) as compared to the AT (55.40%) and GC content (44.54%) in rbcL marker. The means genetic distance K2P between the Acacia species was higher in matK (0.704%) as compared to rbcL (0.230%). All Acacia species could be identified based on unique SNPs profile. Based on SNP data profiles, DNA sequence based scannable QR codes were developed for accurate identification of Acacia species. The phylogenetic analysis based on both markers (rbcL and matK) showed that both A. coriacea and A. tortilis were closely related with each other and clustered in the same group while other two species A. albida and A. catechu were grouped together. The specie A. ampliceps remained ungrouped distantly, compared with other four species. These finding highlights the potential of DNA barcoding for efficient and reproducible identification of Acacia species.     

Silurian (Ludlow) acastid trilobites from Gotland and Scania,Sweden

Acastid trilobites from Ludlow strata on Gotland include three stratigraphically non-overlapping species ofAcastella Reed:Acastella madidipes n. sp. (Hemse Marl and Eke Beds),A. breviceps (Angelin 1851) (Burgsvik Beds), andA. amatrix n. sp. (Hamra Beds, and probably Burgsvik Beds). Type and other material ofA. breviceps (Angelin) from the Klinta Formation, Scania, is revised. Meraspid and early holaspid material ofAcastella is described. Some characters supportAcaste and allied taxa of mostly Wenlock age as a monophyletic subfamily Acastinae.Acastella as widely recognized is a grade with Devonian species more closely related to Asteropyginae than to the Ludlow type species. Baltic Ludlow-P?00ED;dolí species previously placed inScotiella Delo form a distinct group,Ewacaste n. gen., that includes a species from the uppermost Eke Beds on Gotland.     

Ticks of the Central African Republic

A review is presented of the ticks of the Central African Republic (C.A.R.), based on unpublished data and a literature review. We consider as established in the C.A.R. two species of Argasidae (one species of each of the genera Carios and Ornithodoros) and 49 species of Ixodidae: 5 Ixodes, 11 Amblyomma, 2 Dermacentor, 9 Haemaphysalis, 4 Hyalomma, and 18 Rhipicephalus species, 3 of which belong to the subgenus Boophilus. Two of these species, one Amblyomma and one Dermacentor, may by now have disappeared from the country together with their hosts, the black and white rhinoceroses. Moreover, four other species of Ixodidae have been recorded, but are not necessarily established in the country, and 6 species of Ixodidae have apparently been reported incorrectly; the data for the occurrence of three other species of Ixodidae are uncertain. Rhipicephalus species in the C.A.R. present the greatest difficulties in identification, on the one hand because of uncertainties in taxonomy, particularly in the capensis group, on the other hand because of individual variability, which means that individual specimens cannot always be reliably identified to species. Examining the dissected and cleared gonopore structure of females helps, but is very time-consuming where large numbers are involved. Some of the species of the genus Haemaphysalis are also difficult to identify with certainty. There are only a few species of Hyalomma in the country. We revised also some old records of ticks in C.A.R., which we consider as unreliable and should be disregarded because of subsequent changes in taxonomy and nomenclature, unless the material is still available for examination.     

Biogeography and systematics of Aricia butterflies (Lepidoptera,Lycaenidae)

Butterflies of the Aricia species group represent a paradigm of unresolved taxonomy, both at the genus and species levels. We studied phylogenetic relationships, biogeography, and systematics based on genetic – nuclear and mitochondrial – and morphometric – external (wings) and internal (genitalia) – data. We show that Aricia is a monophyletic genus comprising the taxa Pseudoaricia, Ultraaricia and Umpria, which are here considered junior synonyms of Aricia. The taxa allous, inhonora, issekutzi, mandzhuriana, myrmecias and transalaica, which have often been raised to species rank, are shown to probably represent subspecies or synonyms. We show that montensis is likely a good species that is sister to all A. artaxerxes populations across the Palearctic region. The species A. anteros and A. morronensis are shown to display deep intraspecific divergences and they may harbor cryptic species. We also discovered that A. cramera and A. agestis exhibit a pattern of mutual exclusion on islands, and a parapatric distribution in mainland with a narrow contact zone where potential hybrids were detected. The lack of a prezygotic barrier that prevents their coexistence could explain this phenomenon. This study will hopefully contribute to the stability of the systematics of Aricia, a group with potential for the study of the link between speciation and biogeography.