First Evidence for Wollemi Pine-type Pollen (Dilwynites: Araucariaceae) in South America

We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.     

Antarctic moss carpets facilitate growth of Deschampsia antarctica but not its survival

The vegetation of the Antarctic tundra is dominated by mosses and lichens. Deschampsia antarctica, the Antarctic hairgrass, is one of two vascular plant species which grow along the west coast of the Antarctic Peninsula. However, little is known about its recruitment and interaction with non-vascular tundra plants. Although several authors propose that tolerance and/or competition should be the main forms of interaction between moss carpets and D. antarctica, no relevant studies exist so far. We investigated whether positive interactions are predominant at the Shetland Islands and the west coast of the Antarctic Peninsula and focussed on the role that moss carpets play in the recruitment of D. antarctica. Across the studied zone, D. antarctica showed a significant association with moss carpets, with higher frequencies as well as more and larger individuals than on bare ground. At one site, we conducted moss removal and seedlings transplant experiments to assess the relevance of the moss carpets for different life stages of hairgrass. All experimental individuals survived until the following summer whether the moss carpet was removed or not, but growth rate was significantly lower in tussocks with moss carpets removed. Likewise, tiller size was higher in plants growing in moss carpets than on bare ground. The detected positive interactions with mosses seem to be important for the expansion of D. antarctica, raising the question about their importance under future climate change scenarios.     

Eukaryotic phylotypes in aquatic moss pillars inhabiting a freshwater lake in East Antarctica, based on 18S rRNA gene analysis

Aquatic mosses of Leptobryum species form unique tower-like pillars of vegetation termed “moss pillars” in Antarctic lakes. Moss pillars have distinct redox-affected sections: oxidative exteriors and reductive interiors. We have proposed that a “pillar” is a community and habitat of functionally interdependent organisms and may represent a mini-biosphere. Batteries of 16S rRNA genotypes, or phylotypes, of eubacteria and cyanobacteria, but no archaea, have been identified in moss pillars. However, detailed identification or phylogenetic analyses of the moss and their associated eukaryotic microbiota have not been performed. This study analyzed near-full-length 18S rRNA gene sequences obtained from two whole moss pillars. In total, 28 PCR clone libraries from two whole moss pillars were constructed, and 96 clones from each library (total 2,688 clones) were randomly selected and sequenced. Molecular phylogenetic analysis revealed that the phylotype belonging to Bryophyta, considered to be derived from moss, was closely related (99.9?%) to the 18S rRNA gene sequence from Leptobryum pyriforme. Unexpectedly, phylotypes belonging to a novel clade of fungi dominated (approximately 27–75?%) the moss pillar libraries. This suggests that fungi may contribute to carbon cycling in the moss pillar as parasites or decomposers. In addition, phylotypes related to ciliates and tardigrades were subdominant in the exterior, while the phylotype of the ameba-like, single-celled eukaryote, Cercomonas (Cercozoa), was detected only in the interior. These features were shared by both moss pillars. The 18S rRNA gene-based profiles demonstrated that redox-related factors may control distribution of some eukaryotic microbes in a whole moss pillar.     

Modelling reproductive effort in sub-and maritime Antarctic mosses

A comparison is made of the reproductive effort (RE), considered as the investment in sporophyte relative to gametophyte biomass, of eight species of moss occurring at sub-and maritime Antarctic sites. Six of the species showed smaller sporophytes and game-tophytes at the climatically more extreme maritime Antaretic sites and one species showed no size difference between regions. The remaining species, although showing no regional difference, showed some evidence of a reverse pattern, with higher altitude samples having greater biomass than lower altitude samples. Spore counts indicated a measure of compensation in maritime Antarctic samples, with no significant decrease in spore output in several species despite smaller sporophyte biomass. The relationship between sporophyte (S) and gametophyte (G) biomass within samples was described by an allometric curve (S=aG ^b ) which gave a better fit than a straight line for six species. This form of model allows comparisons of patterns of RE to be made between samples with non-or partially overlapping size distributions, even when the relationship involves size-dependence. An allometric curve was not appropriate for describing samples of one species (Andreaea regularis), and insufficient data were available to identify any relationship in Polytrichum alpinum. The exponent (b) differed between species, but there were no statistically significant differences between exponents from samples of the same species. Samples of two species could further be described by the same coefficient (a), indicating that they lie on the same curve. However, samples of three species from sub-Antarctic South Georgia gave significantly higher coefficients, indicating increased RE relative to maritime Antarctic populations.     

Entrapment of long-distance transported pollen grains by various moss species in coastal Victoria Land,Antarctica

Summary In northern Victoria Land (continental Antarctica, between 72° and 76°S, 162° and 169°E), 18 moss samples have been collected and analysed for the presence of pollen. In turfs and cushions of 8 different moss species, at least 27 pollen taxa could be identified. The pinus-type pollen and those of grasses were very common. More than 60% of the total grains were damaged or could not be identified. There is evidence that the Antarctic continent could act as a sink for wind-transported pollen from sub-Antarctic islands or from plants (native or cultivated) in South America, Australia, New Zealand and South Africa. However, the pollen concentration in air ( 1 pollen grain/100 m³) and its entrapment rate on moss (about 0.12 grain/cm²/year) result in a very low pollen density in these plants.     

The polar lichens Caloplaca darbishirei and C. soropelta highlight the direction of bipolar migration

A proper phytogeographic affiliation of Antarctic lichen species has become feasible using molecular phylogeographic methods. Caloplaca citrina is a heterogeneous taxon including several species which occurs in polar regions and is common in Antarctica. Collections of C. citrina from the Antarctic were revised using morphological, anatomical and molecular characters (ITS). They were found to belong to two species: Caloplaca darbishirei (C.W. Dodge & G.E. Baker) Cretz. and C. soropelta (E.S. Hansen, Poelt & S?chting) S?chting. The molecular phylogeny showed them to be sister species, but well separated. Morphological and chemical characters, ecology and distribution of the species are discussed. C. darbishirei is the most common species in the Antarctic, and it is so far known only from Antarctica and Southern South America. C. soropelta, reported here as new to South America, is a bipolar species with all close relatives in the Southern Hemisphere; it is therefore most likely that the species colonized the Arctic from the south. C. citrina s. str. is not confirmed to occur in Antarctica. The study emphasizes the suitability of genotyping for understanding the taxonomy and phylogeography of bipolar lichens.     

Distribution,habitat and trophic ecology of Antarctic squid Kondakovia longimana and Moroteuthis knipovitchi: inferences from predators and stable isotopes

Cephalopods have a key role in the marine environment though knowledge of their distribution and trophic ecology is limited by a lack of observations. This is particularly true for Antarctic species. Toothfish species are key predators of cephalopods and may be viewed as ideal biological samplers of these species. A total of 256 cephalopod lower beaks were identified from the stomachs of Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni), captured in fisheries of South Georgia and the South Sandwich Islands in the South Atlantic between March and April 2009. Long-armed octopus squid (Kondakovia longimana) and smooth-hooked squid (Moroteuthis knipovitchi) were the main cephalopod prey and both were predated upon wherever toothfish were captured, though this cephalopod species appear to inhabit deeper waters at the South Sandwich Islands than at South Georgia. Measurements of δ¹³C from beak material indicated a clear segregation of habitat use comparing adult and sub-adult sized K. longimana. Variation in δ¹⁵N with size indicated an ontogenetic shift in the diet of cephalopods and also suggested some trophic plasticity among years. This study provides new insights into the private life of some elusive Antarctic cephalopods in an underexplored region of the South Atlantic.     

Vegetation of Barton Peninsula in the neighbourhood of King Sejong Station (King George Island,maritime Antarctic)

Plant communities were studied on Barton Peninsula around King Sejong Station on King George Island, maritime Antarctic. The objective of this study was to document the occurrence and distribution of plant assemblages to provide the bases for monitoring the effects of environmental changes and human impact on the vegetation of this area. Approximately 47% of the investigated area was covered by vegetation. Crustose lichens showed the highest mean cover (21%) among vegetation components. The total mean cover of the four dominant taxa, together with the other three major subdominant components, i.e., Usnea spp., Andreaea spp. and Sanionia georgico-uncinata, was 78.2% of the total cover of all the species. Lichen cover and species diversity increased with altitude and the time of exposure from snow. Lichens contributed substantially more to the increased species density and diversity than did bryophytes. Ten plant communities were recognized within the study area. All of them belong to the Antarctic cryptogam tundra formation; they were grouped into four subformations: fruticose lichen and moss cushion subformation, crustose lichen subformation, moss carpet subformation and moss hummock subformation. The moss turf subformation was not found on this region. The Antarctic herb tundra formation was also not found; however, the populations of both Antarctic vascular plants have rapidly expanded around Barton Peninsula in recent years, which may allow development of the Antarctic herb tundra formation in the future.     

Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont,and Associated Sex-Ratio Differences

The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.     

Pollen and spores transport into the Antarctic

Summary Pollen deposition in a 7 cm thick moss turf (Polytrichum juniperinum) from a site in Admiralty Bay (King George Island, maritime Antarctic zone) and in three cushions of Schistidium antarcticum (1–3 cm thick) from Bailey and Clark Peninsula (Wilkes Land, Greater Antarctica) were investigated. Twenty-four pollen and spore taxa were identified from a total of 1094 grains in the sample from Admiralty Bay. By contrast, the 3 samples from Wilkes Land contained only 10 grains (5 taxa). While the former sample was poor in lichen-mycobiont spores the latter revealed very many. Pollen deposition appears to be a good indicator of direction and frequency of immigration of cryptogamic propagules. It seems that the presence of cryptogamic species in the maritime Antarctic zone is predominantly the result of long-distance transport from neighbouring South America and a selection by climatic factors. The low frequency of pollen in Wilkes Land indicates a separation of this part of Antarctica from propagule exchange with other continents and the cryptogams of most of the Antarctic continent may represent a largely relictual flora which survived in ice-free refugia.Dedicated to Professor Dr. W. Halbsguth on the occasion of his 75th birthday     

Abundance and diversity of soil invertebrates in the Windmill Islands region,East Antarctica

The harsh climate and patchy distribution of habitable terrestrial ecosystems constrain soil invertebrate communities in continental Antarctica. The Windmill Islands in East Antarctica have a relatively gentle climate by Antarctic standards, and the region supports some of the most well-developed moss beds on the continent. These moss beds and soils are known to sustain invertebrate communities dominated by nematodes, rotifers and tardigrades, but our knowledge of the diversity and composition of these communities remains limited. We extracted soil fauna from 74 soil samples representing a wide range of microhabitats, and 24 moss samples, collected at Clark Peninsula, Bailey Peninsula and Robinson Ridge in the Windmill Islands during the 2012–2013 austral summer. Invertebrates were present in all samples, but densities varied considerably both within and between sites with limited correlation with edaphic variables or cover type. Taxa found included two species of nematodes (Plectus murrayi; Plectus frigophilus), one mite (Nanorchestes antarcticus) as well as tardigrades and rotifers (enumerated only). No springtails were found in this study, but individuals of the genus Cryptopygus were later recovered from moss collected near Casey Station. The Windmill Islands soils and moss beds support dense populations of soil fauna. However, despite the relatively mild climate conditions and favorable soil properties, species diversity is low. The diversity is possibly limited by recent deglaciation and limited dispersal opportunities to the region. Given favorable local conditions, it is likely that colonizing species will perform well, whether these arrive by natural means or are accidentally introduced by humans.     

Accidental transfer of non-native soil organisms into Antarctica on construction vehicles

Antarctic terrestrial ecosystems currently include very few non-native species, due to the continent’s extreme isolation from other landmasses. However, the indigenous biota is vulnerable to human-mediated introductions of non-native species. In December 2005, four construction vehicles were imported by contractors to the British Antarctic Survey’s (BAS) Rothera Research Station (Antarctic Peninsula) from the Falkland Islands and South Georgia (South Atlantic) on board RRS James Clark Ross. The vehicles were contaminated with >132 kg of non-Antarctic soil that contained viable non-native angiosperms, bryophytes, micro-invertebrates, nematodes, fungi, bacteria, and c. 40,000 seeds and numerous moss propagules. The incident was a significant contravention of BAS operating procedures, the UK Antarctic Act (1994) and the Protocol on Environmental Protection to the Antarctic Treaty (1998), which all prohibit the introduction of non-native species to Antarctica without an appropriate permit. The introduction of this diverse range of species poses a significant threat to local biodiversity should any of the species become established, particularly as the biota of sub-Antarctic South Georgia is likely to include many species with appropriate pre-adaptations facilitating the colonisation of more extreme Antarctic environments. Once the incident was discovered, the imported soil was removed immediately from Antarctica and destroyed. Vehicle cleaning and transportation guidelines have been revised to enhance the biosecurity of BAS operations, and to minimise the risk of similar incidents occurring.     

Areas of endemism in the Antarctic – a case study of the benthic hydrozoan genus Oswaldella (Cnidaria,Kirchenpaueriidae)

Aim The aim of this study is to investigate areas of endemism within the distribution of Oswaldella species in the Southern Ocean, thereby testing previous hypotheses and proposing alternative scenarios for Antarctic evolution. Location Southern Ocean, Antarctic and sub-Antarctic waters of southern South America. Methods We prepared a database for the 31 currently known species of the Antarctic genus Oswaldella, which includes geographical locations gathered from published taxonomic studies as well as materials from museums and expeditions. A parsimony analysis of endemicity (PAE) was used to test hypotheses of distribution patterns. Results Four areas of endemism are hypothesized: southern South America, two high Antarctic areas (eastern and western) and a larger area, mainly in western Antarctica at lower latitudes and including insular areas (but not the Balleny Islands). Main conclusions The results support, in part, previous hypotheses for the Southern Ocean region, while providing more detailed resolution. The areas of endemism may reflect both historical and ecological processes that influenced the Antarctic biota. The Magellanic area reflects the well-known affinities of the Antarctic biota with that of South America and may be a consequence of dispersal through deeper (and colder) waters, followed by speciation. The second area, the largest one, encompasses most of the insular faunas and may also be associated with deeper waters formed since 43 Ma. The third area may be explained by the development of seaways in the circum-Antarctic region beginning 50 Ma. Finally, the fourth zone, with a very poor fauna, coincides with the opening of the Tasman Strait and the formation of the Australo-Antarctic Gulf, associated with a minor wind-driven current.     

Genetic Diversity in Lens Species Revealed by EST and Genomic Simple Sequence Repeat Analysis

Low productivity of pilosae type lentils grown in South Asia is attributed to narrow genetic base of the released cultivars which results in susceptibility to biotic and abiotic stresses. For enhancement of productivity and production, broadening of genetic base is essentially required. The genetic base of released cultivars can be broadened by using diverse types including bold seeded and early maturing lentils from Mediterranean region and related wild species. Genetic diversity in eighty six accessions of three species of genus Lens was assessed based on twelve genomic and thirty one EST-SSR markers. The evaluated set of genotypes included diverse lentil varieties and advanced breeding lines from Indian programme, two early maturing ICARDA lines and five related wild subspecies/species endemic to the Mediterranean region. Genomic SSRs exhibited higher polymorphism in comparison to EST SSRs. GLLC 598 produced 5 alleles with highest gene diversity value of 0.80. Among the studied subspecies/species 43 SSRs detected maximum number of alleles in L. orientalis. Based on Nei’s genetic distance cultivated lentil L. culinaris subsp. culinaris was found to be close to its wild progenitor L. culinaris subsp. orientalis. The Prichard’s structure of 86 genotypes distinguished different subspecies/species. Higher variability was recorded among individuals within population than among populations.     

The Biting Midge Culicoides sonorensis (Diptera: Ceratopogonidae) Is Capable of Developing Late Stage Infections of Leishmania enriettii

BackgroundDespite their importance in animal and human health, the epidemiology of species of the Leishmania enriettii complex remains poorly understood, including the identity of their biological vectors. Biting midges of the genus Forcipomyia (Lasiohelea) have been implicated in the transmission of a member of the L. enriettii complex in Australia, but the far larger and more widespread genus Culicoides has not been investigated for the potential to include vectors to date.Conclusions/SignificanceWe demonstrate that L. enriettii can develop late stage infections in the biting midge Culicoides sonorensis. This midge was found to be susceptible to L. enriettii to a similar degree as Lutzomyia longipalpis, the vector of Leishmania infantum in South America. Our results support the hypothesis that some biting midges could be natural vectors of the L. enriettii complex because of their vector competence, although not Culicoides sonorensis itself, which is not sympatric, and midges should be assessed in the field while searching for vectors of related Leishmania species including L. martiniquensis and "L. siamensis".     

Diversity, ecology and biogeography of the freshwater diatom communities from Ulu Peninsula (James Ross Island, NE Antarctic Peninsula)

The diversity, ecology and biogeography of diatoms in lakes, seepage areas and streams on the Ulu Peninsula, a large ice-free area in the northern part of James Ross Island (Weddell Sea), were studied. A diverse diatom flora of 123 taxa was observed, dominated by several Nitzschia taxa, Psammothidium papilio, Eolimna jamesrossensis, Fragilaria capucina and Fistulifera saprophila. The results from the similarity and diversity analysis suggest James Ross Island to be biogeographically positioned within the Maritime Antarctic region, yet with some affinities with the flora of Continental Antarctica, as shown by the presence of Luticola gaussii and Achnanthes taylorensis. Based on our data, James Ross Island can thus be located close to the boundary of the two main Antarctic biogeographical regions. Diatom communities present in streams and seepage areas could be clearly distinguished from those in lakes, the latter being much more species rich. Based on the multivariate analysis, conductivity and nutrients were selected as the two main environmental factors determining the diatom composition in the Ulu Peninsula lakes. The revised taxonomy of the Antarctic diatom flora induced the construction of a transfer function for water conductivity in the studied lakes that can be applied in further palaeoecological studies.     

Nodulation in Dimorphandra wilsonii Rizz. (Caesalpinioideae), a Threatened Species Native to the Brazilian Cerrado

The threatened caesalpinioid legume Dimorphandra wilsonii, which is native to the Cerrado biome in Brazil, was examined for its nodulation and N₂-fixing ability, and was compared with another, less-threatened species, D. jorgei. Nodulation and potential N₂ fixation was shown on seedlings that had been inoculated singly with five bradyrhizobial isolates from mature D. wilsonii nodules. The infection of D. wilsonii by two of these strains (Dw10.1, Dw12.5) was followed in detail using light and transmission electron microscopy, and was compared with that of D. jorgei by Bradyrhizobium strain SEMIA6099. The roots of D. wilsonii were infected via small transient root hairs at 42 d after inoculation (dai), and nodules were sufficiently mature at 63 dai to express nitrogenase protein. Similar infection and nodule developmental processes were observed in D. jorgei. The bacteroids in mature Dimorphandra nodules were enclosed in plant cell wall material containing a homogalacturonan (pectic) epitope that was recognized by the monoclonal antibody JIM5. Analysis of sequences of their rrs (16S rRNA) genes and their ITS regions showed that the five D. wilsonii strains, although related to SEMIA6099, may constitute five undescribed species of genus Bradyrhizobium, whilst their nodD and nifH gene sequences showed that they formed clearly separated branches from other rhizobial strains. This is the first study to describe in full the N₂-fixing symbiotic interaction between defined rhizobial strains and legumes in the sub-family Caesalpinioideae. This information will hopefully assist in the conservation of the threatened species D. wilsonii.