Taxonomic diversity of the terrestrial bird and mammal fauna in temperate and boreal biomes of the northern hemisphere

Abstract. Using comprehensive range information of northern Hemisphere birds and mammals, we assessed the taxonomic diversity of these two groups in four different regions: Europe, east Asia, and western and eastern North America. East Asia is the richest region in the number of bird and mammal species, genera, families and orders, except that mammal species richness is highest in western North America. Eastern North America is taxonomically the poorest region, but when only forest-associated taxa were considered in mammals taxonomic diversity is equally low in Europe and in eastern North America, and in birds, Europe is the least diverse region. Patterns in endemic taxa follow overall taxonomic diversity. The proportion of shared taxa between regions is higher among boreal species and genera than among all taxa. A comparison with tree species diversity underpins the role of east Asia as the most diverse of all northern biota. Largely congruent patterns at different taxonomic levels emphasizes the role of historical processes, such as differential extinction rate in response to paleoenvironmental fluctuations, in producing these patterns, but we stress the need for more research on the coevolution of species diversity and habitat diversity.     

Intercontinental disjunctions between eastern Asia and western North America in vascular plants highlight the biogeographic importance of the Bering land bridge from late Cretaceous to Neogene

This review shows a close biogeographic connection between eastern Asia and western North America from the late Cretaceous to the late Neogene in major lineages of vascular plants (flowering plants, gymnosperms, ferns and lycophytes). Of the eastern Asian–North American disjuncts, conifers exhibit a high proportion of disjuncts between eastern Asia and western North America. Several lineages of ferns also show a recent disjunct pattern in the two areas. In flowering plants, the pattern is commonly shown in temperate elements between northeastern Asia and northwestern North America, as well as elements of the relict boreotropical and Neogene mesophytic and coniferous floras. The many cases of intercontinental biogeographic disjunctions between eastern Asia and western North America in plants supported by recent phylogenetic analyses highlight the importance of the Bering land bridge and/or the plant migrations across the Beringian region from the late Cretaceous to the late Neogene, especially during the Miocene. The Beringian region has permitted the filtering and migration of certain plant taxa since the Pliocene after the opening of the Bering Strait, as many conspecific taxa or closely related species occur on both sides of Beringia.     

The genus Artemisia (Asteraceae: Anthemideae) at a continental crossroads: molecular insights into migrations, disjunctions, and reticulations among Old and New World species from a Beringian perspective

Artemisia is the largest genus (ca. 350-500+ spp.) in the tribe Anthemideae and is composed of ecologically, morphologically, and chemically diverse species that are found primarily throughout the Northern Hemisphere. Two major centers of diversity for the genus are located in Eurasia and western North America, but phytogeographic links connecting these two regions are observed all across the North Pacific Rim and adjacent areas in the Arctic, including many islands and archipelagos. Previous phylogenetic studies have helped to clarify major lineages and identify likely sister relationships, but many questions remain unanswered regarding the relationships and migration history of New and Old World species. Here we investigate the phylogenetics of Artemisia within a biogeographic context centered in the Beringian Region and offer new hypotheses concerning species relationships, migration history, and the likely role of reticulate evolution in the genus. Our sampling included many new taxa and emphasized multiple accessions of widespread species, species from proposed refugia, and species with disjunct/vicariant distributions. The ITS phylogeny contained 173 accessions (94 new and 79 from GenBank) and indicated that Artemisia is paraphyletic by the exclusion of several small Asian genera and the North American genus Sphaeromeria. Following a survey of thirteen chloroplast loci, phylogenies based on two plastid markers (psbA-trnH and rpl32-trnL spacers) were constructed with a reduced data set, and though largely consistent with the ITS topology, revealed several cases of possible introgression among New World and Beringian species. Our analysis reveals that North American Artemisia species have multiple origins, and that western North America has served as a source for some colonizing elements in eastern Asia and South America.     

Rediscovery of the lost little dogwood Cornus wardiana (Cornaceae)—Its phylogenetic and morphological distinction and implication in the origin of the Arctic‐Sino‐Himalayan disjunction

The dwarf dogwoods (subgenus Arctocrania) have been widely known to consist of three circumboreal species Cornus suecica, Cornus canadensis, and Cornus unalaschkensis. A fourth putative species was discovered from the northern Myanmar in 1937, but it had never been formally reported on. Here, we formally report the species on the basis of phylogenetic and morphological evidence and name it Cornus wardiana Rushforth & Wahlsteen (sp. nov.). We conducted phylogenetic and morphometric analyses to determine its evolutionary relationship and differentiation from the existing relatives. We dated the phylogeny using molecular data and conducted a biogeographic analysis to gain insights into the evolution and biogeography of the Arctic‐Sino‐Himalayan disjunction. The phylogenetic analysis used sequences of the nrITS and plastid matK and rbcL genes and included all four dwarf dogwoods and 20 other species representing the three other major lineages of Cornus and the outgroup. The morphometric analyses included 60 populations and 102 specimens of dwarf dogwood, representing the entire range of the subgenus. The results showed that C. wardiana diverged first within subgenus Arctocrania in the Miocene, from a wide‐spread ancestor. Results from principal component analysis and discriminant analysis also showed that the Myanmar samples are well separated from the others. Taken together, these results suggest that the dwarf dogwood lineage split from the big‐bracted dogwoods in Asia or Asia‐western North America during the late Paleocene and spread widely to form a Eurasia‐North America distribution; the Arctic‐Sino‐Himalayan disjunction was the result of southward migration in the Miocene followed by extinction in the intervening highland areas.     

中国鹅膏菌属(担子菌)的物种多样性

鹅膏菌属（Ａｍａｎｉｔａ）是一个近世界性广布的大属,全球已被描述而又被承认的有近５００种。在文献中,我国此属已记载约２００种。然而,许多种都是原初描述于欧洲或北美的种类。近来的研究表明,东亚的鹅膏菌独特且有其自身的分布范围。东亚的有些种虽与产于欧洲或北美的某些种相似,但仔细的野外观察,详尽的形态解剖学和分子进化生物学研究结果表明,东亚的鹅膏菌是独立的分类群。在欧洲,人们有采集著名食菌恺撒鹅膏菌的习     

The phytogeographical studies of Thermopsis (Fabaceae)

The present article is the first comprehensive treatment of phytogeography of Thermopsis (Fabaceae) in the world. Thermopsis is one of the few genera within Fabaceae with the distribution pattern of the East Asia-North American disjunction. The distribution patterns of 5 recognized sections (including a new one) covering 21 species in Thermopsis are analyzed, and the results show four centres of frequency of the genus: the Eastern Asiatic Region (9 spp. / 3 sects., including 4 endemic species), the Irano-Turanian Region (7 spp./3 sects., including 3 endemic species), the Rocky Mountain Region (7 spp./2 sects., all endemic), and the Atlantic North American Region (3 spp. / 1 sect., all endemic). In the light of the fact that most species and sections, a number of phylogenetic series of the genus, and the most primitive sections and most advanced sections in Thermopsis occur in the East Asia, the Eastern Asiatic Region might be the centre of diversity of the genus. As the Irano-Turanian Region and the Rocky Mountain Region were just second to that of Eastern Asiatic Region in number of sections and species, and many polyploids appeared in these regions, they were considered as the secondary centres of distribution and speciation of the genus. The speciation looks to be frequent and complex in these regions, and many new taxa have been described from there while many new reduced or incorporated taxa have happened over there. However, recent molecular data has shown that two reduced taxa of Thermopsis are distinct in these regions. Based on the modern distribution patterns and evolutionary trends in morphological characters of the genus, and available fossil record of the genus and the historical geology, we speculate that Thermopsis had already existed on Eurasia and North America before the Late Miocene, and probably originated from an ancestral form of Sophora-like taxa with lupine alkaloids somewhere in the Laurasia in the Early Tertiary or Late Cretaceous. After the separation of the two continents, species on different continents developed distinctly under influences of different evolutionary factors. In Asia, the late Tertiary orogeny, disappearing of the Tethys and aridity and freezing caused by the Quaternary glaciation were the main forces to promote the speciation and evolutionary processes, whereas in North America it was the Quaternary glaciation and the orogeny of partial area to promote evolution of the genus. According to the evolutionary trends in Thermopsis and the distribution pattern of the primitive taxa, Sino-Japanese Subregion of Eastern Asiatic Region may be considered asthe centre of primitive forms of Thermopsis.     

Molecular insights into the taxonomy of Glyceria (Poaceae: Meliceae) in North America

Eighteen Glyceria species grow in the United States and Canada, with 16 being native to the region. We used data from morphology and three chloroplast DNA intergenic regions to address taxonomic questions concerning Glyceria in North America, particularly the status of G. declinata, G. occidentalis, G. fluitans, G. striata, and G. elata in western North America. The chloroplast data confirmed the presence of two European species, G. declinata and G. fluitans, in western North America. Glyceria occidentalis was exceptional among the taxa studied in having chloroplast genotypes that fell into two different clades, one of which contained G. fluitans and the other the North American species G. leptostachya. The morphological data showed G. occidentalis to be intermediate between G. fluitans and G. leptostachya with respect to their distinguishing characters. Based on these results, we hypothesize that G. occidentalis consists of hybrids between G. fluitans and G. leptostachya. Glyceria elata and G. striata, which have sometimes been treated as a single species, had different chloroplast genotypes, supporting their recognition as distinct taxa. DNA data from all three intergenic regions would be needed for unequivocal identification of the non-hybrid species examined.     

Phylogenetic relationships and biogeographic history of the unique Saxifraga sect. Irregulares (Saxifragaceae) from eastern Asia

Saxifraga L. is the largest genus in Saxifragaceae and a characteristic component of the herbaceous flora of the temperate and alpine mountains in the Northern Hemisphere. Section Irregulares is a small group of 15–20 species, representing one of the early‐diverged lineages in the genus characterized with unique zygomorphic flowers. We used both nuclear internal transcribed spacer and chloroplast DNA regions (psbA‐trnH, trnL‐F, and matK) to reconstruct its species relationships, estimate divergence times, and infer its historical biogeography. Our phylogenetic results corroborate the monophyly of sect. Irregulares and its sister relationship to sect. Heterisia from North America. The section was well resolved into two lineages corresponding to their morphological features and biogeographic distributions. One represents ser. Stoloniferae including S. stolonifera Curtis and S. nipponica Makino with long‐creeping stolons/rhizomes and small petals with spots and the other comprises the remaining taxa (ser. Rufescentes) which lack long‐creeping rhizomes. Spots on leaves (abaxially spotted vs. abaxially without spots) and spots on petals (without spots vs. with spots) are inferred to be phylogenetically informative within ser. Rufescentes. Divergence time estimates and ancestral area analysis suggested a western North American origin of sect. Irregulares with migration into East Asia by way of the Bering land bridge in the Middle Oligocene. The development of drying and desertification belt in the late Miocene could have played an important role in the subsequent restriction and separation of the north and south lineages within eastern Asia.     

Fossil fruits of Illigera (Hernandiaceae) from the Eocene of central Tibetan Plateau

Illigera (Hernandiaceae) is a liana genus distributed mainly in the tropical Asia and Africa. Previous fossil records suggested that Illigera was restricted in western North America during the Eocene. Recent paleobotanical investigation has unveiled a Paleogene flora that is totally different from today's vegetation in central Tibet. This provides novel insights into the paleoenvironmental change during the evolution of the Tibetan Plateau (TP). Here, we investigated 10 fruit impressions of Illigera from the early middle Eocene Niubao Formation in the Bangor Basin, central TP. The fossil winged fruits are characterized by their eroded fruit wings, well preserved fusiform locular areas with a median ridge bisecting the fruit, and short veins fanning radially outward. These features allow us to assign these fossils to Illigera eocenica, a species originally discovered in the Eocene of western North America. This is the second fossil occurrence of Illigera worldwide, and the first in Asia. Our finding suggests a warm and humid climate in the central TP during the early middle Eocene, and a close floristic link between Asia and North America during the Paleogene. We also propose a Northern Hemisphere origin and a Paleogene dispersal event from Northern Hemisphere to Africa for Illigera.     

Inferences on the phylogeography of the fungal pathogen Heterobasidion annosum, including evidence of interspecific horizontal genetic transfer and of human-mediated, long-range dispersal

Fungi in the basidiomycete species complex Heterobasidion annosum are significant root-rot pathogens of conifers throughout the northern hemisphere. We utilize a multilocus phylogenetic approach to examine hypotheses regarding the evolution and divergence of two Heterobasidion taxa associated with pines: the Eurasian H. annosum sensu stricto and the North American H. annosum P intersterility group (ISG). Using DNA sequence information from portions of two nuclear and two mitochondrial loci, we infer phylogenetic relationships via parsimony, Bayesian and median-joining network analysis. Analysis of isolates representative of the entire known geographic range of the two taxa results in monophyletic sister Eurasian and North American lineages, with North America further subdivided into eastern and western clades. Genetically anomalous isolates from the Italian presidential estate of Castelporziano are always part of a North American clade and group with eastern North America, upholding the hypothesis of recent, anthropogenically mediated dispersal. P ISG isolates from Mexico have phylogenetic affinity with both eastern and western North America. Results for an insertion in the mitochondrial rDNA suggest this molecule was obtained from the Heterobasidion S ISG, a taxon sympatric with the P ISG in western North America. These data are compatible with an eastern Eurasian origin of the species, followed by dispersal of two sister taxa into western Eurasia and into eastern North America over a Beringean land bridge, a pattern echoed in the phylogeography of other conifer-associated basidiomycetes.     

Annotated key to the trematode species infecting Batillaria attramentaria (Prosobranchia: Batillariidae) as first intermediate host

In eastern Asia and western North America at least nine morphologically distinguishable species of digenean trematode infect the mud snail, Batillaria attramentaria (Sowerby 1855) (=B. cumingi (Crosse 1862)), as first intermediate host. Further, molecular and morphological evidence indicates that several of these trematode species comprise complexes of cryptic species. I present an identification key to these nine trematode morphospecies (including four newly reported species). Additionally, I provide an annotated list, which includes further diagnostic information on the larval stages (cercariae, parthenitae, and metacercariae), information on second intermediate host use, links to the previous relevant reports of trematodes infecting B. attramentaria and notes on other aspects of the species' biology.     

Paleobiogeographic relationships of angiosperms from the Cretaceous and early Tertiary of the North American area

The biogeographic affinities of the Cretaceous and early Tertiary angiosperm floras of the North American area (which includes Meso-America, and the Greater Antilles) have been the subject of considerable interest. Although recent treatments of isolated taxa have shown affinities between North American, European, east Asian and Neotropic floras, the relationships have not been quantified. This study compiles the records of fossils whose familial relationships seem secure. This provides a carefully culled, and uniformly presented review of the Cretaceous and Paleogene record from 1950 to 1989 and supplements LaMotte (1950). A subset of these records, which showed compelling evidence of subfamilial relationships, was analyzed to quantify the relationships of the Cretaceous, Paleocene, Eocene and Oligocene floras to other regions. The analysis suggests that for the entire period 24% of the fossil species had affinities with extant taxa from the Northern Hemisphere; 10% with taxa from the Northern Hemisphere that have a few species in South America; 17% with taxa from Eurasia; 3% with taxa with a disjunct Eurasian-South American pattern; 19% with taxa from South America and/or Africa; 8% with taxa from South America and/or Africa that have an important sister group in southeast Asia; 5% with taxa from the Old World; and 13% with taxa having other distribution patterns. Those fossils with affinities to Laurasian taxa are mostly found in the northern and western portions of the North American area. The fossils with affinities to South American and/or African taxa are found in the southern portions of North America, Meso-America, and the Greater Antilles. The taxa with disjunct distributions show both patterns. These patterns suggest that during this time there were wide-spread temperate elements, found throughout Laurasia; Boreotropical flora elements, distributed in North America, Europe and along the Tethys seaway to southeast Asia; and West Gondwana elements which show dispersion from South America across the proto-Caribbean. The paleobotanical data are compatible with current geological, paleontological and biogeographical studies.     

Nuclear ribosomal DNA and karyotypes indicate a NW African origin of South American Hypochaeris (Asteraceae, Cichorieae)

Hypochaeris has a disjunct distribution, with more than 15 species in the Mediterranean region, the Canary Islands, Europe, and Asia, and more than 40 species in South America. Previous studies have suggested that the New World taxa have evolved from ancestors similar to the central European H. maculata. Based on internal transcribed spacer (ITS) sequences and fluorescence in situ hybridization (FISH) with 5S and 18S-25S rDNA of the previously overlooked Hypochaeris angustifolia from Moyen Atlas, Morocco, we show that it is sister to the entire South American group. A biogeographic analysis supports the hypothesis of long-distance dispersal from NW Africa across the Atlantic Ocean for the origin of the South American taxa rather than migration from North America, through the Panamian land bridge, followed by subsequent extinction in North America. With the assumption of a molecular clock, the trans-Atlantic dispersal from NW Africa to South America is roughly estimated to have taken place during Pliocene or Pleistocene.     

Phylogenetic relationships and evolution in Chrysosplenium (Saxifragaceae) based on matK sequence data

Chrysosplenium (Saxifragaceae) consists of 57 species widely distributed in temperate and arctic regions of the Northern Hemisphere, with two species restricted to the southern part of South America. Species relationships within the genus are highly problematic. The genus has traditionally been divided into two groups, sometimes recognized as sections (Oppositifolia and Alternifolia), based on leaf arrangement, or, alternatively, into 17 series. Based on morphological features, Hara suggested that the genus originated in South America and then subsequently migrated to the Northern Hemisphere. We conducted phylogenetic analyses of DNA sequences of the chloroplast gene matK for species of Chrysosplenium to elucidate relationships, test Hara's biogeographic hypothesis for the genus, and examine chromosomal and gynoecial diversification. These analyses revealed that both sections Oppositifolia and Alternifolia are monophyletic and form two large sister clades. Hence, leaf arrangement is a good indicator of relationships within this genus. Hara's series Pilosa and Macrostemon are each also monophyletic; however, series Oppositifolia, Alternifolia, and Nepalensia are clearly not monophyletic. MacClade reconstructions suggest that the genus arose in Eastern Asia, rather than in South America, with several independent migration events from Asia to the New World. In one well-defined subclade, species from eastern and western North America form a discrete clade, with Old World species as their sister group, suggesting that the eastern and western North American taxa diverged following migration to that continent. The South American species forms a clade with species from eastern Asia; this disjunction may be the result of ancient long-distance dispersal. Character mapping demonstrated that gynoecial diversification is dynamic, with reversals from inferior to half-inferior ovaries, as well as to ovaries that appear superior. Chromosomal evolution also appears to be labile with several independent origins of n = 12 (from an original number of n = 11) and multiple episodes of aneuploidy.     

Phylogeny and biogeography of Fagus (Fagaceae) based on 28 nuclear single/low-copy loci

Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably time-calibrated phylogeny. In this study, we sequenced 28 nuclear single/low-copy loci (18 555 bp in total) of 11 Fagus species/segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation-based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent-based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid-Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time-calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere.     

Vuilleminia erastii sp. nov. (Corticiales), an amphi-Beringian species and revision of the occurrence of Vuilleminia comedens in North America

Vuilleminia is a basidiomycete genus the species of which have resupinate, corticioid fruiting bodies. It is apparently a North Hemisphere genus, and the majority of its species are distributed in Europe and western Asia. In North America, there are two reports of Vuilleminia comedens. Detailed study of North American specimens and comparisons with additional collections led to the conclusion that they belong to a new lineage named Vuilleminia erastii sp. nov., whose distribution extends from western North America to East Asia, Siberia, and Finland. The species is recognized by the decorticating fruiting bodies with preference for species of Betulaceae in the boreal zone, relatively small allantoid basidiospores, and little-developed cystidia with apical appendix.     

New Eocene fossil fruits and leaves of Menispermaceae from the central Tibetan Plateau and their biogeographic implications

Menispermaceae are a pantropical and temperate family with an extensive fossil record during the Paleogene period, especially in North America and Europe, but with much less evidence from Asia. The latest fossil evidence indicates a succession of tropical to subtropical flora on the central Tibetan Plateau during the Paleogene. However, the biogeographic histories of these floras are still unresolved. Here, we report on endocarps and leaves of Menispermaceae from the Middle Eocene of Jianglang village, Bangor County, central Tibetan Plateau. The endocarps belong to two genera: Stephania, which is characterized by a horseshoe-shaped endocarp and with one lateral crest ornamented by spiny to rectangular ribs, and a condyle area; and Cissampelos (s.l.), which has two characteristic lateral ridges and a conspicuous external condyle. Associated leaves belong to the genus Menispermites, and are characterized by actinodromous primary venation, brochidodromous secondary veins, entire margins, and the presence of marginal secondary veins. The biogeographic history of Menispermaceae is complex, but evidence from these new fossils indicates an early diversification of the group in Asia, probably in response to the warming climate during the Eocene. The Jianglang flora appears to be part of a boreotropical flora, connecting Asia with North American and European floras during the Middle Eocene. The modern distribution of menispermaceous taxa found in Jianglang, as well as other families represented in the Jianglang flora, show that a tropical to subtropical climate occurred during the Eocene in central Tibet.