Biogeographic Distribution Patterns Research Articles

Diversity and Distribution Patterns in High Southern Latitude Sponges

Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

Phylogeny and divergence time estimation of Coreoleuciscus splendidus populations (Teleostei: Cypriniformes) endemic to Korea based on complete mitogenome sequences

We determined the complete mitogenome sequences for four Coreoleuciscus splendidus strains (Teleostei: Cypriniformes) inhabiting the Han and Geum river drainages in the West Korea Subdistrict, and the Seomjin and Nakdong river drainages in the South Korea Subdistrict in the Korean peninsula. The gene contents and arrangement of C. splendidus were homogeneous to those of typical vertebrates. Phylogenetic analysis with the partitioned nucleotide matrix of concatenated mitochondrial genes revealed that C. splendidus formed a monophyletic group with gobionine species in the cyprinid lineage. The four river strains separated into two phylogenetically distinct groups, which were in accordance with the biogeographical distribution pattern in Korea according to subdistrict. The estimated divergence time among western and southern subdistrict populations was 37.9 ± 6.5 million years ago (Mya), whereas those between the two river strains in each subdistrict were estimated to be 3.2–3.4 Mya. The presence of such distinct historical lineages has great implications for biogeography of ichthyofauna in Korea and future management and conservation plans of C. splendidus populations.

The “Falcatae”, a new Gondwanan species group of Gieysztoria (Platyhelminthes: Dalyelliidae), with the description of five new species

GieysztoriaRuebush and Hayes, 1939, the most species-rich genus of limnic rhabdocoels (Platyhelminthes: Dalyelliidae), is subdivided into several groups based on stylet morphology. Most taxa are known from the Palearctic and the Neotropics. Very little is known about limnic, free-living flatworms in other tropical and subtropical regions. In this contribution five new species of Gieysztoria are described from India, Australia and South Africa, all former Gondwanan fragments. Gieysztoria garudaen.sp., G. ashokaen.sp. and G. ramayanan.sp. were collected in Goa (India), G. stokesin.sp. in the Northern Territory (Australia) and G. zuluensisn.sp. in KwaZulu-Natal (South Africa). All these new species share a typical, very complex stylet morphology, which deviates strongly from that of the groups into which the bulk of the other species within this genus are classified. Therefore a new subgroup, the “Falcatae”, is erected. In addition, four known species could also be included in this subgroup. Possible homologies, common ancestry and biogeographic distribution patterns are discussed.

Origin and diversification of major clades in parmelioid lichens (Parmeliaceae, Ascomycota) during the Paleogene inferred by Bayesian analysis.

There is a long-standing debate on the extent of vicariance and long-distance dispersal events to explain the current distribution of organisms, especially in those with small diaspores potentially prone to long-distance dispersal. Age estimates of clades play a crucial role in evaluating the impact of these processes. The aim of this study is to understand the evolutionary history of the largest clade of macrolichens, the parmelioid lichens (Parmeliaceae, Lecanoromycetes, Ascomycota) by dating the origin of the group and its major lineages. They have a worldwide distribution with centers of distribution in the Neo- and Paleotropics, and semi-arid subtropical regions of the Southern Hemisphere. Phylogenetic analyses were performed using DNA sequences of nuLSU and mtSSU rDNA, and the protein-coding RPB1 gene. The three DNA regions had different evolutionary rates: RPB1 gave a rate two to four times higher than nuLSU and mtSSU. Divergence times of the major clades were estimated with partitioned BEAST analyses allowing different rates for each DNA region and using a relaxed clock model. Three calibrations points were used to date the tree: an inferred age at the stem of Lecanoromycetes, and two dated fossils: Parmelia in the parmelioid group, and Alectoria. Palaeoclimatic conditions and the palaeogeological area cladogram were compared to the dated phylogeny of parmelioid. The parmelioid group diversified around the K/T boundary, and the major clades diverged during the Eocene and Oligocene. The radiation of the genera occurred through globally changing climatic condition of the early Oligocene, Miocene and early Pliocene. The estimated divergence times are consistent with long-distance dispersal events being the major factor to explain the biogeographical distribution patterns of Southern Hemisphere parmelioids, especially for Africa-Australia disjunctions, because the sequential break-up of Gondwana started much earlier than the origin of these clades. However, our data cannot reject vicariance to explain South America-Australia disjunctions.

Lower Cretaceous (upper Ryazanian–Hauterivian) chronostratigraphy of high latitudes (North-East Greenland)

Calcareous nannofossils of Lower Cretaceous sediments from four sections of the Wollaston Forland and Kuhn Ø, North-East Greenland, have been examined. Sediments of Ryazanian–Hauterivian age were deposited in North-East Greenland following a major Late Jurassic–earliest Cretaceous rifting event. The upper Ryazanian–Hauterivian marine post-rift sediments consist of fossiliferous calcareous mudstones 27–40 m thick, assigned to the Albrechts Bugt and Rødryggen members. These calcareous mudstones rest unconformably on dark Jurassic mudstones and are overlain by dark Barremian mudstones. The biodiversity of the calcareous nannofossil assemblages from North-East Greenland is lower than contemporaneous Tethyan assemblages of lower latitudes. Well-preserved assemblages consist of common Watznaueria spp., Crucibiscutum spp., Biscutum constans and other taxa. Integrated calcareous nannofossil and ammonite data form the basis of a biostratigraphic zonation scheme for the Boreal-Arctic Province of the Boreal Realm and this is correlated with existing Boreal zonation schemes. Important calcareous nannofossil marker species include Sollasites arcuatus, Crucibiscutum ryazanicum, Kokia borealis, Nannoconus oviformis, Triquetrorhabdulus shetlandensis, Micrantholithus speetonensis, Eiffellithus striatus, Tegumentum octiformis, Perissocyclus plethotretus, Tegulalithus septentrionalis, and Clepsilithus maculosus. This study shows that the existing calcareous nannofossil zonation schemes are applicable in the Boreal-Arctic Province. The occurrence of diverse and well-preserved calcareous nannofossil assemblages in North-East Greenland at a higher latitude than their typical known area of distribution marks a significant change in their biogeographic distribution pattern during the Early Cretaceous.

How dung beetles respond to a human‐modified variegated landscape in Mexican cloud forest: a study of biodiversity integrating ecological and biogeographical perspectives

AbstractAim To analyse how the dung beetles (Scarabaeinae) respond to a modified, variegated landscape, taking into account the biogeographical peculiarities of the Mexican Transition Zone.Location This study covers cloud forest (CF) of the Sierra Norte de Puebla mountain range and part of the Sierra Madre Oriental mountain range (Mexico).Methods We applied proportional sampling based on the landscape variegation model with Scarabaeinae as the indicator group, and using two approaches: structural units (vegetation type) and spatial units (windows). We used two measures – richness and Shannon diversity – and applied multiplicative diversity partitioning to obtain independent alpha and beta diversities for the landscape, windows and vegetation types. We grouped species by biogeographical distribution pattern for the biogeographical analysis and by whether they were originally from CF.Results The transformation of CF into secondary forest, pastures and other types of vegetation increases the Scarabaeinae diversity of the landscape, in vegetation types and windows. This increase is the result of species arriving from the tropical lowlands. However, the original dung beetle community of the CF dominates at different scales in the number of species, abundance and biomass. With increasing habitat modification, beta diversity increases in the windows, and species with the Tropical Palaeoamerican distribution pattern increase in abundance in vegetation types and windows.Main conclusions The variegated character of the landscape explains well the distribution and diversity of this dung beetle community. The peculiar characteristics of the Mexican Transition Zone have an effect owing to the overlap of fauna with different biogeographical origins. The conversion of fragmented landscapes to variegated landscapes could be a conservation goal in human‐modified mountain landscapes. Sampling proportional to the area of different types of vegetation and the use of windows offer an alternative experimental design in variegated landscapes.

Neogene reptiles of northeastern Thailand and their paleogeographical significance

In the last ten years, several fossil localities in Nakhon Ratchasima Province (northeastern Thailand) have yielded late Neogene turtle and crocodile taxa. Although not always well dated, the age of all these fossils is constrained between Middle Miocene and Pleistocene. Several crocodile taxa have been discovered: Crocodylidae, Alligatoridae and Gavialidae. In particular, the presence of Gavialis is attested in northeastern Thailand during the Pleistocene. Fossil turtles belong to several families: Geoemydidae, Testudinidae, and Trionychidae. In addition to the discovery of giant continental tortoises, some large aquatic trionychid and geoemydid turtles are present. The latter are only found in larger river systems and no longer encountered in the Mun or Chi Rivers of northeastern Thailand. Most fossil forms correspond to modern species and reveal interesting changes in biogeographical distribution patterns. These changes are likely related to changes in the size of the drainage and direction of the Mun River system. We suggest that the Mun River was probably not flowing from west to east to the Mekong River system as today but that it was flowing from east to west to the Chao Phraya River system.

Different competitive potential in two coexisting mouse lemur species in northwestern Madagascar

Interspecific competition has been suggested to influence the biogeographic distribution patterns of species. A high competitive potential could entail species-specific advantages during resource acquisition that could translate into a higher potential for range expansion. We investigated whether differences in the competitive potential of the morphologically similar and partially sympatric gray mouse lemur (Microcebus murinus) and golden-brown mouse lemur (Microcebus ravelobensis) may help to explain differences in their geographic range sizes. We carried out encounter experiments with 14 pairs of captured female mouse lemurs of both species. The experimental dyads were tested in a two-cage arrangement, with individuals being separated from each other outside the experiments. Two days of habituation and four subsequent days of 1-h encounter experiments were conducted, before releasing the animals again in the wild. In general, the M. murinus individuals won significantly more conflicts than their partners. In eight of 14 tested pairs, there was a significant species bias in winning conflicts, and in 87.5% of these dyads, M. murinus was the "dyad winner". A high competitive potential did not depend on body mass. Furthermore, "dyad winners" spent more time feeding (P < 0.05) and were less spatially restricted than "dyad losers". To conclude, our results suggest that the widely distributed M. murinus may indeed have a higher competitive potential than the regional endemic M. ravelobensis, which may, among other possible factors, have enabled this species to expand geographically, despite the presence of other competing congeners.

Biogeographic Distribution Patterns of South American Amphibians: A Regionalization Based on Cluster Analysis

We devise a regionalization system based on the geographical distribution of 2,265 amphibian species in South America. We used range maps of amphibians to obtain a presence/absence data grid resolved to 9310 km2. Biogeographical regions were generated by submitting the dataset to k-means clustering combined with v-fold cross-validation. The boundaries of the three clusters generated by multiple runs of the analysis are congruent with broadly defined biome structure in South America: 1) the Andes, the Atacama desert, Patagonia, and subtropics including grassland in southern Brazil, Argentina and Uruguay; 2) Amazon forest; 3) Atlantic forest and the Cerrado-Caatinga-Chaco complex. A few runs further distinguished Atlantic forest and Caatinga biome from other drier, more open biomes. The variable most strongly associated with the distribution of clusters was species richness, but climate also had moderately strong explanatory power. The regionalization scheme based on clustering is less finely resolved than previous schemes generated by expert opinion and rates of endemism but provides a general overview of the biogeographic signal contained in the current distribution patterns of amphibian species.

Extant morphotypes of Distephanus speculum (Silicoflagellata) from the Australian sector of the Southern Ocean: Morphology, morphometry and biogeography

Abstract Extant morphotypes of Distephanus speculum (Ehrenberg 1839) Heckel 1887, analysed from a latitudinal transect of surface water samples and one hydrological station in the Southern Ocean, display a distinct biogeographic distribution pattern. Morphometric analyses performed on a total of 250 specimens from 12 selected samples reveal that some morphotypes, separated through secondary morphological characters, can also be separated on a size basis. Small-sized specimens include D. speculum speculum, D. speculum var. monospicatus (var. nov.) and D. speculum bispicatus; medium-sized specimens are represented by D. speculum f. coronata and D. speculum minutus — coronatid and large-sized specimens correspond to D. speculum group B of Tsutsui et al. (2009). The ecological value of the morphological and morphometric characters is discussed here in relation with the latitudinal distribution of the morphotypes. A new taxon, D. speculum var. monospicatus (var. nov.), is described.

Broad-Scale Patterns of Late Jurassic Dinosaur Paleoecology

BackgroundThere have been numerous studies on dinosaur biogeographic distribution patterns. However, these distribution data have not yet been applied to ecological questions. Ecological studies of dinosaurs have tended to focus on reconstructing individual taxa, usually through comparisons to modern analogs. Fewer studies have sought to determine if the ecological structure of fossil assemblages is preserved and, if so, how dinosaur communities varied. Climate is a major component driving differences between communities. If the ecological structure of a fossil locality is preserved, we expect that dinosaur assemblages from similar environments will share a similar ecological structure.Methodology/Principal FindingsThis study applies Ecological Structure Analysis (ESA) to a dataset of 100+ dinosaur taxa arranged into twelve composite fossil assemblages from around the world. Each assemblage was assigned a climate zone (biome) based on its location. Dinosaur taxa were placed into ecomorphological categories. The proportion of each category creates an ecological profile for the assemblage, which were compared using cluster and principal components analyses. Assemblages grouped according to biome, with most coming from arid or semi-arid/seasonal climates. Differences between assemblages are tied to the proportion of large high-browsing vs. small ground-foraging herbivores, which separates arid from semi-arid and moister environments, respectively. However, the effects of historical, taphonomic, and other environmental factors are still evident.Conclusions/SignificanceThis study is the first to show that the general ecological structure of Late Jurassic dinosaur assemblages is preserved at large scales and can be assessed quantitatively. Despite a broad similarity of climatic conditions, a degree of ecological variation is observed between assemblages, from arid to moist. Taxonomic differences between Asia and the other regions demonstrate at least one case of ecosystem convergence. The proportion of different ecomorphs, which reflects the prevailing climatic and environmental conditions present during fossil deposition, may therefore be used to differentiate Late Jurassic dinosaur fossil assemblages. This method is broadly applicable to different taxa and times, allowing one to address questions of evolutionary, biogeographic, and climatic importance.

Does temperature regime govern the establishment of Heterobasidion annosum in Scandinavia?

We explored the reasons underlying the biogeographic distribution patterns of the economically important, wood-rotting basidiomycete Heterobasidion annosum in Sweden. Despite the commonness of suitable host trees, Heterobasidion annosum has not been recorded in the north of Sweden, whereas its relative, H. parviporum, is present throughout the country. To test the hypothesis that H. annosum has not spread to the north because of the effect of climate, mainly differences in the general temperature regime, we inoculated Norway spruce stumps and standing trees with H. annosum and H. parviporum at six field sites, three in the south and three in the north of Sweden. Three strains of both species were used in random combinations, so that each selected stump and tree was inoculated with both species at the same time. At 2 and 10 months after the inoculations, we compared the frequencies of detection of H. annosum and H. parviporum colonies at different distances from inoculation points in the stumps and in trees. The H. annosum colonies were detected only infrequently on disks cut from the inoculated stumps (0-4% of re-isolations) in both areas, whereas H. parviporum was detected much more frequently (26-47% of re-isolations). In standing trees, colonies belonging to H. annosum could be detected up to 210 cm (south) and 80 cm (north) and those belonging to H. parviporum up to 210 cm (south) and 140 cm (north) above the inoculation points. Our results suggest that difference in temperature regime does not provide an explanation for the distribution limit of H. annosum.

An assessment of the contribution of fossil cave deposits to the Quaternary paleontological record

Mammal-bearing cave deposits are an important part of the Quaternary fossil record, but the exact nature of the contribution that caves make to the fossil record is a research area that is largely unexplored. To explore this issue, late Pleistocene species representation in cave versuses non-cave deposits was examined. Additionally, this study examined how fossiliferous cave deposits influence perceptions of past biogeographic distributions, and evaluated factors that impact the distribution of cave deposits. Across the United States, cave deposits account for a high proportion of the individual species records known from the late Pleistocene and caves provide the only late Pleistocene records of 14 individual taxa. Calculated ratios of individual taxonomic records from caves relative to the total number of individual taxonomic records resulted in a value of 0.62. The impact of cave data on understanding of late Pleistocene biogeographic distribution patterns vary among individual species of sciurid rodents. Geographic analyses comparing the distribution of cave and non-cave sites in Texas suggest a strong relationship between site distribution and specific geologic and hydrologic features. Ultimately, understanding potential biases recorded in distinct depositional settings provides improved frameworks for interpreting the adequacy of the fossil record.

The genus Vachoniochactas González-Sponga (Scorpiones, Chactidae), a model of relictual distribution in past refugia of the Guayana region of South America

A new species, Vachoniochactas roraima sp. n. (Chactidae) is described from Mount Roraima, a site located on the borders of Brazil, Guyana and Venezuela. The description of the new species brings further evidence to the biogeographic pattern of distribution presented by the genus Vachoniochactas, as an endemic element to the Tepuys formations of South America. To cite this article: W.R. Lourenço, B. Duhem, C. R. Biologies 332 (2009).

From cells to coastlines: how can we use physiology to forecast the impacts of climate change?

The interdisciplinary fields of conservation physiology, macrophysiology, and mechanistic ecological forecasting have recently emerged as means of integrating detailed physiological responses to the broader questions of ecological and evolutionary responses to global climate change. Bridging the gap between large-scale records of weather and climate (as measured by remote sensing platforms, buoys and ground-based weather stations) and the physical world as experienced by organisms (niche-level measurements) requires a mechanistic understanding of how ;environmental signals' (parameters such as air, surface and water temperature, food availability, water flow) are translated into signals at the scale of the organism or cell (e.g. body temperature, food capture, hydrodynamic force, aerobic capacity). Predicting the impacts of how changing environments affect populations and ecosystems further mandates an understanding of how organisms ;filter' these signals via their physiological response (e.g. whether they respond to high or low frequencies, whether there is a time lag in response, etc.) and must be placed within the context of adult movement and the dispersal of larvae and gametes. Recent studies have shown that patterns of physiological stress in nature are far more complex in space and time than previously assumed and challenge the long-held paradigm that patterns of biogeographic distribution can be based on simple environmental gradients. An integrative, systems-based approach can provide an understanding of the roles of environmental and physiological variability in driving ecological responses and can offer considerable insight and predictive capacity to researchers, resource managers and policy makers involved in planning for the current and future effects of climate change.

Biogeography and biodiversity of gastropod molluscs from the eastern Brazilian continental shelf and slope

Biogeographic distributional patterns of gastropods are proposed based on the species’ geographic and bathymetric distribution. Samples were collected along the Brazilian continental margin between 18° S and 23° S, at 37 stations with depths from 20 m to 1,330 m. The analysis of the biogeographic distribution patterns confirmed the existence of a transitional zone from tropical to subtropical waters in the area of both the continental shelf and slope, suggesting a relationship with water mass circulation. We observed a high species turnover rate between the shelf and slope. The analysis of gastropod species distribution revealed a similar pattern on the shelf and slope and a large difference between shallow and deep-water faunas.

Slow molecular evolution in 18S rDNA, rbcL and nad5 genes of mosses compared with higher plants

The evolutionary potential of bryophytes (mosses, liverworts and hornworts) has been debated for decades. Fossil record and biogeographical distribution patterns suggest very slow morphological evolution and the retainment of several ancient traits since the split with vascular plants some 450 million years ago. Many have argued that bryophytes may evolve as rapidly as higher plants on the molecular level, but this hypothesis has not been tested so far. Here, it is shown that mosses have experienced significantly lower rates of molecular evolution than higher plants within 18S rDNA (nuclear), rbcL (chloroplast) and nad5 (mitochondrial) genes. Mosses are on an average evolving 2-3 times slower than ferns, gymnosperms and angiosperms; and also green algae seem to be evolving faster than nonvascular plants. These results support the observation of a general correlation between morphological and molecular evolutionary rates in plants and also show that mosses are 'evolutionary sphinxes' regarding both morphological and molecular evolutionary potential.

Relationship of Geographic Distance, Depth, Temperature, and Viruses with Prokaryotic Communities in the Eastern Tropical Atlantic Ocean

The richness and biogeographical distribution pattern of bacterial and archaeal communities was assessed by terminal restriction fragment length polymorphism analysis of polymerase chain reaction-amplified fragments of the 16S rRNA gene at the surface (15-25 m depth), in the deep chlorophyll maximum layer (DCM; 50 m depth), and deep waters (75-1000 m depth) of the eastern tropical Atlantic Ocean. Additionally, prokaryotic and viral abundance and the frequency of infected prokaryotic cells (FIC) were determined along with physico-chemical parameters to identify factors influencing prokaryotic richness and biogeography. Viral abundance was highest in the DCM layer averaging 45.5 x 10(6) ml(-1), whereas in the mixed surface layer and in the waters below the DCM, average viral abundance was 11.3 x 10(6) and 4.3 x 10(6) ml(-1), respectively. The average estimate of FIC was 8.3% in the mixed surface layer and the DCM and 2.4% in deeper waters. FIC was positively related to prokaryotic and viral abundance and negatively to archaeal richness. There was no detectable effect of geographic distance (maximum distance between stations approximately 4600 km) or differences between water masses on bacterial and archaeal community composition. Bacterial communities showed a clear depth zonation, whereas changes in archaeal community composition were related to temperature and FIC. The results indicate that planktonic archaeal virus host systems are a dynamic component of marine ecosystems under natural conditions.

Genetic diversity assessment of anoxygenic photosynthetic bacteria by distance-based grouping analysis of pufM sequences

To assess how completely the diversity of anoxygenic phototrophic bacteria (APB) was sampled in natural environments. All nucleotide sequences of the APB marker gene pufM from cultures and environmental clones were retrieved from the GenBank database. A set of cutoff values (sequence distances 0.06, 0.15 and 0.48 for species, genus, and (sub)phylum levels, respectively) was established using a distance-based grouping program. Analysis of the environmental clones revealed that current efforts on APB isolation and sampling in natural environments are largely inadequate. Analysis of the average distance between each identified genus and an uncultured environmental pufM sequence indicated that the majority of cultured APB genera lack environmental representatives. The distance-based grouping method is fast and efficient for bulk functional gene sequences analysis. The results clearly show that we are at a relatively early stage in sampling the global richness of APB species. Periodical assessment will undoubtedly facilitate in-depth analysis of potential biogeographical distribution pattern of APB. This is the first attempt to assess the present understanding of APB diversity in natural environments. The method used is also useful for assessing the diversity of other functional genes.

Pseudo- nitzschia pungens (Bacillariophyceae): A cosmopolitan diatom species?

Genetic, reproductive and morphological variation were studied in 193 global strains of the marine diatom species Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle to assess potential intraspecific variation and biogeographic distribution patterns. Genetic differentiation between allo- and sympatric strains was investigated using the ITS1–5.8S–ITS2 rDNA region. Three ITS clades were found. Clones of opposite mating type were sexually compatible within clades I or II, and viable F1 hybrid offspring were produced in crosses between them. The molecular differences between these clades were correlated with slight but consistent morphological differences. At present, nothing can be said about morphology and mating behavior for clade III clones because only ITS data were available. The three ITS clades showed different geographic distributions. Clade II was restricted to the NE Pacific, whereas clones belonging to clade III originated from geographically widely separated areas (Vietnam, China and Mexico). ITS clade I was recovered in all locations studied: the North Sea (Belgium, The Netherlands, France), the eastern and western N Atlantic (Spain, Canada), the NW and S Pacific (Japan, New Zealand) and the NE Pacific (Washington State). Clade I thus appears to be globally distributed in temperate coastal areas and provides the first strong evidence to date for the global distribution of a biologically, genetically and morphologically defined diatom species.