Rediscovery of Nebela ansata (Amoebozoa: Arcellinida) in eastern North America: biogeographical implications

Aim The question whether free‐living protists are generally cosmopolitan is currently a matter of debate. In this study we investigate the geographical distribution of a distinctive testate amoeba species, Nebela ansata, and use our data to assess the potential for highly restricted distribution patterns in some protist species. Location Global. Methods We analysed (1) 3400 testate amoeba publications from North America and other continents, (2) unpublished slides of the Penard Collection of the Natural History Museum, London, UK, and (3) 104 Sphagnum samples from eastern North America. Non‐metric multidimensional scaling (NMDS) was used to visualize the similarities in testate amoeba community composition among 1012 North American samples, including two communities that contained N. ansata. Results We rediscovered N. ansata at a site in New Jersey located close to its type locality, and in Nova Scotia. We also report the existence of an apparently unpublished museum specimen originally collected from New Jersey. Our extensive literature survey confirmed the presence of this species only in the temperate part of eastern North America. The NMDS revealed that communities with N. ansata were less similar to each other than to communities from other parts of North America, suggesting that favourable habitats for N. ansata occur in other Sphagnum‐dominated peatlands, a habitat type that has been extensively sampled in North America and elsewhere. Main conclusions These data provide an unusually convincing case of a free‐living microorganism with a very limited distribution range in the temperate part of eastern North America. The remarkably restricted distribution of N. ansata highlights the extent of our ignorance about the natural history of free‐living microorganisms, and raises questions about the lack of attention to microbial diversity in conservation biology.     

DSP toxin production de novo in cultures of Dinophysis acuminata (Dinophyceae) from North America

For decades, many aspects of Dinophysis biology have remained intractable due to our inability to maintain these organisms in laboratory cultures. Recent breakthroughs in culture methods have opened the door for detailed investigations of these important algae. Here, for the first time, we demonstrate toxin production in cultures of North American Dinophysis acuminata, isolated from Woods Hole, MA. These findings show that, despite the rarity of Dinophysis-related DSP events in North America, D. acuminata from this area has the ability to produce DSP toxins just as it does in other parts of the world where this species is a major cause of DSP toxicity. In our cultures, D. acuminata cells were observed feeding on Myrionecta rubra using a peduncle. Culture extracts were analyzed using LC–MS/MS, providing unequivocal evidence for the toxin DTX1 in the Dinophysis cultures. In addition, a significant amount of an okadaic acid diol ester, OA-D8, was detected. These results suggest that this Dinophysis isolate stores much of its OA as a diol ester. Also, toxin PTX-2 and a hydroxylated PTX-2 with identical fragmentation mass spectrum to that of PTX-11, but with a different retention time, were detected in this D. acuminata culture. This demonstration of toxin production in cultured North American Dinophysis sets the stage for more detailed studies investigating the causes of geographic differences in toxicity. It is now clear that North American Dinophysis have the ability to produce DSP toxins even though they only rarely cause toxic DSP events in nature. This may reflect environmental conditions that might induce or repress toxin production, genetic differences that cause modifications in toxin gene expression, or physiological and biochemical differences in prey species.     

Molecular phylogeny of the Sphaerophorus globosus species complex

The Sphaerophorus globosus complex (Lecanorales, lichenized Ascomycota) shows a large morphological variation, and three relatively distinct morphotypes can be distinguished in parts of the distribution area. Here, we utilize a multigene‐based maximum‐parsimony approach (nITS+ LSU rDNA, mtSSU rDNA, β‐tubulin, and actin) to investigate whether these morphotypes constitute distinct species. The results show that there are at least two well‐supported monophyletic groups that we interpret as phylogenetic species within the S. globosus complex. These species do not completely correspond to the predefined morphotypes. One group, an apparently undescribed species, contains noncoralloid specimens from the North American Pacific Northwest. The other group, S. globosus, consists of two well‐supported monophyletic groups: one contains coralloid epiphytic specimens from the North American Pacific Northwest that are morphologically indistinguishable from epiphytic specimens from Europe and are presently interpreted as belonging to the same species and the other is morphologically variable and contains terrestrial specimens from Europe, North America, and southernmost South America and coralloid epiphytic and epilithic specimens from Europe. The results suggest that the population in southernmost South America originated by long‐distance dispersal from arctic populations in the Northern Hemisphere.     

GIS analysis of the biogeography of beetles of the subgenus Anisodactylus (Insecta: Coleoptera: Carabidae: genus Anisodactylus)

The advent of GIS technology and the World Wide Web, respectively, facilitate analysing geographical relationships and electronically storing and exchanging biogeographic data. This paper illustrates GIS technology with a study of the subgenus Anisodactylus Dejean (Insecta: Coleoptera: Carabidae: genus Anisodactylus). Species are concentrated in three centres of biodiversity in North America and in four in lands near the western Mediterranean. These centres largely correspond to current areas of wetlands. Eurasia has fewer species than expected based on its area, probably because large portions have habitats unfavourable for the subgenus and/or are poorly collected for Carabidae. Members of the subgenus are primarily adapted to areas with January temperatures between ?10 and 10 °C, July temperatures from 10 to 30 °C and mean annual precipitation from 20 to 200 mm. Cold is apparently a major limiting factor because it typically occurs during several consecutive months of winter and is difficult to escape except by hibernation. Heat is less of a stress when moisture is sufficient. The size of geographical ranges is often larger in the North than in the South and correlates with the latitude of the centre of ranges at r =0.42 (level of significance=0.05). Geographic ranges are often smaller in western North America and in the western Mediterranean than elsewhere in the Northern Hemisphere. Explanations for the smaller sizes include portions of western North America having unfavourable desert or montane habitats, the Rocky Mountains and deserts barring eastward dispersal of species, and the smaller size and more patchy distribution of climatic zones and habitats. In North America geographical ranges west of the Rocky Mountains are north–south elongated because they track primarily north–south orientated climatic zones and because mountains and deserts bar eastward extension. Ranges in north-eastern and north-central North America tend to extend east–west along temperature isotherms. In Eurasia many ranges are stretched east–west because of the shape of the continent and because many northern and southern areas lack suitable habitats. Species with relatively high numbers of apomorphic character states cluster in western Eurasia and to a lesser extent in western North America. The North American centres of biodiversity are post-Wisconsin phenomena while those near the western Mediterranean probably date from the Oligocene or Miocene.     

CHROMOSOME NUMBERS AND EVOLUTION IN NORTH AMERICAN SPECIES OF LINUM

Among the North American species of Linum there are three basic chromosome numbers representing invasions from the Old World of three distinct evolutionary lines. N = 9 is found only in the blue-flowered group represented in North America by two species, L. lewisii and L. pratense which are closely related to and may be conspecific with the Old World L. perenne. The basic number for the yellow-flowered species is n = 18 which is characteristic of the Scabrella and Virginiana subgroups. The loss of chromosomes in the Neo-mexicana (n = 13) and Sulcata-Rigida (n = 15) subgroups suggests that the basic haploid number of 18 might be a polyploid derivative of an Old World ancestor with n = 9. The incidence of n = 9 among Old World species of Linum may indicate that this represents an ancestral condition. Linum catharticum has n = 8; this number and features of morphology and distribution suggest that it is not directly related to either the blue-flowered or yellow-flowered groups in North America but represents a separate introduction on this continent.     

Precise direct tracking and remote sensing reveal the use of forest islands as roost sites by Purple Martins during migration

Direct tracking methods in combination with remote sensing data allow examination of habitat use by birds during migration. Species that roost communally during migration, such as some swallows, form large aggregations that can attract both avian and terrestrial predators. However, the extent to which they might use patchy habitats that could reduce predation risk during migration is unknown. We tested the hypothesis that Purple Martins (Progne subis) use forest islands (patches of suitable forest habitat surrounded by unsuitable habitat) as roost sites during migration between breeding sites in North America and overwintering sites in South America. We used high‐precision (< 10 m), archival GPS units deployed and retrieved during the 2015 and 2016 breeding seasons, respectively, at 12 colonies located across eastern North America. We found that Purple Martins roosted in forest islands more often than expected based on availability during both spring and fall migration. Despite an apparent association with urban habitats by Purple Martins based on observational and radar data in North America during the fall, the roost locations we identified during spring and fall migration were not more closely associated with urban areas than random locations. The use of forest islands during both spring and fall migration suggest that Purple Martins may use these habitats to reduce predation risk during migration. Our results suggest that some species of birds may use similar habitats as stopover sites during migration and that patches of forest habitat may be important conservation targets for Purple Martins and other species. Identifying habitat use during migration represents an important advance in support of full annual‐cycle conservation of Purple Martins and other migratory species with declining populations.     

Distribution of halophilous species of horse flies in Croatia (Diptera: Tabanidae)

In the past 20 years, fauna and ecology of horse flies (Tabanidae) were intensively studied in Croatia, especially in the Ramsar sites as wetlands of international importance. Different habitat requirements of larvae were recognised and adults of 78 species in 10 genera were recorded. The true aquatic and semiaquatic larvae are represented by several species of the genera Chrysops Meigen, 1803 Hybomitra Enderlein, 1922. Some species from this ecological group are typical inhabitants of saline biotopes. In the Croatian fauna three halophilous species were recorded: Chrysops italicus Meigen, 1804, Hybomitra acuminata (Loew, 1858) and H. expollicata (Pandellé, 1883). The distribution of these species in Croatia covers 7, 17 and 3 UTM (Universal Transverse Mercator) grids, respectively. Specimens were primarily collected in habitats with brackish water along the Adriatic coast, such as Vransko Lake, the mouth of the River Cetina, the delta of the River Neretva and Mljet Island. Only specimens of H. acuminata were recorded in the continental part of Croatia. They were sporadically collected on localities along the Danube floodplain and on four localities near the river Drava. The distribution of H. acuminata in the continental part indicates otherwise rare saline habitats along the Drava and Danube rivers (1.38% of the total catch of the Hybomitra – species from the floodplain).     

HISTORICAL BIOGEOGRAPHY IN NORTH AMERICAN ARID REGIONS: AN APPROACH USING MITOCHONDRIAL-DNA PHYLOGENY IN GRASSHOPPER MICE (GENUS ONYCHOMYS)

Restriction-endonuclease-site variation of mitochondrial DNA (mtDNA) was used to investigate patterns of geographic and phylogenetic divergence within the rodent genus Onychomys. Onychomys has occupied arid habitats in the western North American deserts, shrub-steppes, and grasslands since the late Tertiary. A phylogenetic analysis of the total mtDNA restriction-site variation throughout the range of Onychomys suggests that the distribution of this genus has been affected by the same Quaternary pluvial-interpluvial climatic fluctuations that have resulted in the periodic fragmentation of arid habitats in western North America. Onychomys mtDNA haplotypes define at least five discrete geographical subsets, suggesting that there are five areas of endemism for biota restricted to arid and semiarid habitats in North America. The mtDNA-haplotype phylogeny can be used to infer an hypothesis of historical relationships among the five areas of endemism as follows: ([{(Wyoming Basin + Interior Plains + Colorado Plateaus) + (Columbia Basin + Great Basin)} + Gulf Coastal Plain] + Chihuahuan) + Western Deserts. The results of this study point to the potential use of mtDNA-haplotype phylogenies to reconstruct historical biogeographic events in Quaternary time. The utility of mtDNA variation depends in part on the ecology and distribution of the species being examined. Therefore, our hypothesized area cladogram can be tested by investigating regional relationships in other western North American taxa with distributions similar to Onychomys.     

Effect of Radiation Spectral Composition on Nicotiana spp. Seedlings Grown in vitro

The aim of this work was to assess the responses of seedlings of five species of Nicotiana genus to red and far red radiation. N. acuminata exhibits positive photoblastic behaviour and germination was completely inhibited under far red and darkness. In N. glauca germination was reduced under far red and darkness, but the other species showed neutral behaviour. The hypocotyl elongation was inhibited in N. glauca and N. tabacum under white and far red radiation. In N. langsdorffii and N. debneyi hypocotyl was elongated under far red radiation. Only in N. acuminata red radiation promote greater hypocotyl elongation than dark condition. On the phylogenetic tree obtained from restriction analysis N. glauca and N. acuminata are grouped in one branch, while the other species, N. langsdorffii, N. debneyi and N. tabacum, are grouped in the other branch cluster. Moreover, the N. debneyi behaviours under different radiation treatments were similar to those of N. tabacum. These two species are allopolyploid members of the genus Nicotiana, as also was confirmed by this study. This revised version was published online in July 2006 with corrections to the Cover Date.     

The long‐term history of dispersal among lizards in the early Eocene: new evidence from a microvertebrate assemblage in the Bighorn Basin of Wyoming,USA

Abstract: Early Eocene mammal faunas of North America were transformed by intercontinental dispersal at the Paleocene–Eocene boundary, but lizard faunas from the earliest Eocene of the same area were dominated by immigrants from within the continent. A new lizard assemblage from the middle early Eocene of Wyoming sheds light on the longer‐term history of dispersal in relation to climate change. The assemblage consists of three iguanid species (including two new species possibly closely related to living Anolis), Scincoideus, ‘Palaeoxantusia’, four anguids, two species of an undescribed new anguimorph clade, Provaranosaurus and a varanoid (cf. Saniwa). Most North American glyptosaurin glyptosaurines are now referred to Glyptosaurus, and Glyptosaurus hillsi is given a new diagnosis. Scincoideus is otherwise known only from the mid‐Paleocene of Belgium, and the specimens described here are the first to document intercontinental dispersal to North America among lizards in the early Eocene. Like in mammals, some immigrant lizard lineages first appearing in the Bighorn Basin in the earliest Eocene persisted in the area long after the Paleocene–Eocene thermal maximum, but other immigrants appear to have been restricted to the Paleocene–Eocene thermal maximum.     

SYSTEMATICS OF SOUTH AMERICAN TRIPSACUM (GRAMINEAE)

The genus Tripsacum is widely distributed between 42°N and 24°S latitude. In South America, the genus extends around the Amazon and Orinoco basin, and from the Caribbean coast south to Brazil and Paraguay. The most common South American taxon is T. dactyloides (L.) L. var. meridonale de Wet and Timothy (2n = 36), which differs from North American representatives of the species in having subdigitate recemes usually appressed with the apical male sections typically curved. Closely related to T. dactyloides, but usually occupying more seasonally moist and dry habitats, is T. australe Cutler and Anderson. This species is typically robust with the basal leaf sheaths tomentose, and the much elongated culms becoming decumbent in older plants. Smaller plants, with essentially erect culms and leaf sheaths on the culms hirsute rather than tomentose, are recognized as T. australe var. hirsutum de Wet and Timothy. The two varieties of T. australe are both diploid (2n = 36) and they cross to produce fertile hybrids. They also cross with T. dactyloides var. meridonale (2n = 36), but these hybrids are partially sterile. Tripsacum cundinamarce de Wet and Timothy (2n = 36) is a robust species with glaucus leaves. It resembles robust specimens of T. dactyloides in having glabrous leaf sheaths, but can always be recognized by inflorescences that are composed of racemes arranged along a several-noded primary axis. This species is confined to moist habitats, while T. dactyloides occupies a range of habitats in South America. Tripsacum peruvianum de Wet and Timothy is a gametophytic apomict with 2n = 72, 90 or 108 chromosomes. It is characterized by an erect growth habit and strongly hirsute leaf sheaths. The cultivated Guatemala grass, T. andersonii Gray, occurs spontaneously in the mountains of Venezuela, Colombia, and Peru. This sexually sterile species is characterized by 2n = 64, and may combine 54 Tripsacum and 10 Zea chromosomes in its genome. Electrophoretic patterns of seed storage proteins confirm the validity of recognizing T. cundinamarce as distinct from T. dactyloides, and T. peruvianum as distinct from T. australe.     

Preadult competition between Drosophila subobscura and Drosophila pseudoobscura

The Palaearctic species Drosophila subobscura has recently colonized a large area of North America where it coexists with Drosophila pseudoobscura. The viability and developmental rate of these species were studied at 13 d?C, 18d?C and 23 d?C and at densities of 10, 50, 100 and 200 eggs per vial. The two species were differently affected by density and temperature in the ranges studied. Both intra- and interspecific cultures showed that D. pseudoobscura was best adapted to 23 d?C, where it was clearly the dominant species. On the other hand, at 18 d?C and especially at 13 d?C, although D. subobscura was less viable than D. pseudoobscura, its developmental time was shorter, which may give advantage to this species. Results reported here agree with the observed distribution of these species in North America.     

Observations on the morphology of some North American nemertines with consequent taxonomic changes and a reassessment of the architectonics of the phylum

A majority of the nemertine species from the western North Atlantic were originally described from life in the nineteenth century. Many of these were established by A. E. Verrill who had ‘an eye for species’ no matter which phylum he was working with, and thus when living nemertines which he described are encountered, they can usually be recognized. The morphology of most of these species has never been reported; some may prove to be species described earlier from the eastern North Atlantic. Morphological observations on the nemertine species from the North East coast of the Pacific are inadequate and have prevented satisfactory comparison with species from Japan and eastern Russia. The morphology of some species collected in the Gulf of Maine and from Cape Cod, as well as a re-examination of some of the slides of type specimens of species from the west coast of North America, indicates that their generic placement must be re-examined. The architectonic plan of the heteronemertines postulated over 100 years ago can not be substantiated and is redescribed. Three new heteronemertean genera are described: Tenuilineus gen.n. Parvicirrus gen.n., Tarrhomyos gen.n.     

Habitat use and seed removal by invasive rats (Rattus rattus) in disturbed and undisturbed rain forest,Puerto Rico

Despite frequent occurrences of invasive rats (Rattus spp.) on islands, their known effects on forests are limited. Where invasive rats have been studied, they generally have significant negative impacts on native plants, birds, and other animals. This study aimed to determine invasive rat distribution and effects on native plant populations via short‐term seed removal trials in tropical rain forest habitats in the Luquillo Experimental Forest, Puerto Rico. To address the first objective, we used tracking tunnels (inked and baited cards inside tunnels enabling animal visitors’ footprints to be identified) placed on the ground and in the lower canopy within disturbed (treefall gaps, hurricane plots, stream edges) and undisturbed (continuous forest) habitats. We found that rats are present in all habitats tested. Secondly, we compared seed removal of four native tree species (Guarea guidonia, Buchenavia capitata, Tetragastris balsamifera, and Prestoea acuminata) between vertebrate‐excluded and free‐access treatments in the same disturbed and undisturbed habitats. Trail cameras were used to identify animals responsible for seed contact and removal. Black rats (Rattus rattus) were responsible for 65.1% of the interactions with seeds, of which 28.6% were confirmed seed removals. Two plant species had significantly more seeds removed in disturbed (gaps) than undisturbed forest. Prestoea acuminata had the lowest seed removal (9% in 10 days), whereas all other species had >30% removal. Black rats are likely influencing fates of seeds on the forest floor, and possibly forest community composition, through dispersal or predation. Further understanding of rat–plant interactions may be useful for formulating conservation strategies.     

COSII genetic maps of two diploid Nicotiana species provide a detailed picture of synteny with tomato and insights into chromosome evolution in tetraploid N. tabacum

Using single-copy conserved ortholog set (COSII) and simple sequence repeat (SSR) markers, we have constructed two genetic maps for diploid Nicotiana species, N. tomentosiformis and N. acuminata, respectively. N. acuminata is phylogenetically closer to N. sylvestris than to N. tomentosiformis, the latter two of which are thought to contribute the S-genome and T-genome, respectively, to the allotetraploid tobacco (N. tabacum L., 2n = 48). A comparison of the two maps revealed a minimum of seven inversions and one translocation subsequent to the divergence of these two diploid species. Further, comparing the diploid maps with a dense tobacco map revealed that the tobacco genome experienced chromosomal rearrangements more frequently than its diploid relatives, supporting the notion of accelerated genome evolution in allotetraploids. Mapped COSII markers permitted the investigation of Nicotiana–tomato syntenic relationships. A minimum of 3 (and up to 10) inversions and 11 reciprocal translocations differentiate the tomato genome from that of the last common ancestor of N. tomentosiformis and N. acuminata. Nevertheless, the marker/gene order is well preserved in 25 conserved syntenic segments. Molecular dating based on COSII sequences suggested that tobacco was formed 1.0MYA or later. In conclusion, these COSII and SSR markers link the cultivated tobacco map to those of wild diploid Nicotiana species and tomato, thus providing a platform for cross-reference of genetic and genomic information among them as well as other solanaceous species including potato, eggplant, pepper and the closely allied coffee (Rubiaceae). Therefore they will facilitate genetic research in the genus Nicotiana.     

Two New Species of Paramoeba from Maine*

SYNOPSIS Four clonal strains of amoebae isolated from salt-water habitats of the Maine coast show the characteristic Nebenkörper or paranucleus of the genus Paramoeba Schaudinn, 1896, this being the first report of free-living members of that genus from North America. The isolates are identified as 2 species, P. pemaquidensis n. sp. and P. aestuarina n. sp. In form and mitotic pattern, these 2 species resemble members of the family Mayorellidae.     

Taxonomy and phylogeny of the Hister servus group (Coleoptera: Histeridae): a Neotropical radiation

The Hister servus group contains ten species and two species complexes. Although the group’s diversity is centred in Mexico and Central America, one lineage, comprising H. indistinctus Say, H. defectus LeConte and H. fungicola Schaeffer, has probably diversified entirely in the south-eastern U.S. The servus group also contains the following species: H. servus Erichson , H. nodatus lewis , H. doyeni sp.n., H. lagoi sp.n., H. bullatus lewis , H. coronatus Marseul and H. diadema Marseul and two diverse species complexes, dubbed the comes complex and the montivagus complex. These two complexes require additional sampling and study before species within them can be recognized. They are, however, closely related to each other and appear to be paraphyletic with respect to a clade comprising H. bullatus, H. coronatus and H. diadema. A prior hypothesis that the servus group includes H. sallei, H. matador sp.n. and the species of Hister (Spilodiscus) is not well supported. Several sister groups within the servus group show geographical disjunction between seasonal tropical habitats of western North America and wetter montane habitats of the eastern parts of the continent along the Gulf and Caribbean coasts.     

Cryptic invasion in Southern Europe: The case of <Emphasis Type="Italic">Ferrissia fragilis</Emphasis> (Pulmonata: Ancylidae) Mediterranean populations

Four populations of the North American ancylid gastropod Ferrissia fragilis have been found in Southern Italy, thus expanding the known Eurasian distribution range of this invasive gastropod to the Mediterranean area. Both mitochondrial markers used for the molecular identification of the sampled specimens (16S and COI) showed a modest to absent haplotypic diversity in the studied Ferrissia populations from Europe and Asia, and their perfect identity with some of the haplotypes observed in North American F. fragilis populations. In the light of the scarce molecular diversity observed in the whole Palaearctic area and of the growing evidences for the ongoing spreading of the species in Europe, the occurrence of a single invasion event from North America possibly linked with aquarium plant trade followed by a rapid spreading of the species in Eurasia is suggested. The record of F. fragilis in Southern Italy caused some doubts on the presence of autochthonous Ferrissia populations in Europe and on the actual existence of Ferrissia wautieri. A molecular analysis of Ferrissia specimens from the loci typici of F. wautieri (Northern Italy) and F. clessiniana (Egypt) is definitely opportune.