Beringian Region Research Articles

Comparative phylogeography uncovers evolutionary past of Holarctic dragonflies

Here, we investigate the evolutionary history of five northern dragonfly species to evaluate what role the last glaciation period may have played in their current distributions. We look at the population structure and estimate divergence times for populations of the following species: Aeshna juncea (Linnaeus), Aeshna subarctica Walker, Sympetrum danae (Sulzer), Libellula quadrimaculata Linnaeus and Somatochlora sahlbergi Trybom across their Holarctic range. Our results suggest a common phylogeographic pattern across all species except for S. sahlbergi. First, we find that North American and European populations are genetically distinct and have perhaps been separated for more than 400,000 years. Second, our data suggests that, based on genetics, populations from the Greater Beringian region (Beringia, Japan and China) have haplotypes that cluster with North America or Europe depending on the species rather than having a shared geographic affinity. This is perhaps a result of fluctuating sea levels and ice sheet coverage during the Quaternary period that influenced dispersal routes and refugia. Indeed, glacial Beringia may have been as much a transit zone as a refugia for dragonflies. Somatochlora sahlbergi shows no genetic variation across its range and therefore does not share the geographic patterns found in the other circumboreal dragonflies studied here. Lastly, we discuss the taxonomic status of Sympetrum danae, which our results indicate is a species complex comprising two species, one found in Eurasia through Beringia, and the other in North America east and south of Beringia. Through this study we present a shared history among different species from different families of dragonflies, which are influenced by the climatic fluctuations of the past.

A Review of Recently Discovered Remains of the Pleistocene Branchiopods (Anostraca, Notostraca) from NE Siberia and Arctic Canada

In this study, we examine, identify, and discuss fossil remains of large branchiopod crustaceans collected from six sites across the Beringian region (north-eastern Asia and north-western North America). Eggs and mandibles from Anostraca and Notostraca, as well as a notostracan telson fragment and a possible notostracan second maxilla, were collected from both paleosediment samples and also from large mammal hair. The remains of large branchiopods and other species that are limited to seasonally astatic aquatic habitats (temporary wetlands) could be useful indicator organisms of paleoecological conditions. Different recent large branchiopod species have very different ecological preferences, with each species limited to specific geochemical component tolerance ranges regarding various salinity, cation, and gypsum concentrations. Our purpose is to bring the potential usefulness of these common fossil organisms to the attention of paleoecologists.

Crustacean remains from the Yuka mammoth raise questions about non-analogue freshwater communities in the Beringian region during the Pleistocene

Frozen permafrost Pleistocene mammal carcasses with soft tissue remains are subject to intensive study and help elucidate the palaeoenvironment where these animals lived. Here we present an inventory of the freshwater fauna and flora found in a sediment sample from the mummified Woolly Mammoth carcass found in August 2010, from the Oyogos Yar coast near the Kondratievo River in the Laptev Sea region, Sakha (Yakutia) Republic, NE Russia. Our study demonstrates that the waterbody where the carcass was buried could be characterized as a shallow pond or lake inhabited mainly by taxa which are present in this area today, but additionally by some branchiopod crustacean taxa currently absent or unusual in the region although they exist in the arid zone of Eurasia (steppes and semi-deserts). These findings suggest that some “non-analogue” crustacean communities co-existed with the “Mammoth fauna”. Our findings raise questions about the nature of the waterbodies that existed in Beringia during the MIS3 climatic optimum when the mammoth was alive.

The Beringian Coevolution Project: holistic collections of mammals and associated parasites reveal novel perspectives on evolutionary and environmental change in the North

The Beringian Coevolution Project (BCP), a field program underway in the high northern latitudes since 1999, has focused on building key scientific infrastructure for integrated specimen-based studies on mammals and their associated parasites. BCP has contributed new insights across temporal and spatial scales into how ancient climate and environmental change have shaped faunas, emphasizing processes of assembly, persistence, and diversification across the vast Beringian region. BCP collections also represent baseline records of biotic diversity from across the northern high latitudes at a time of accelerated environmental change. These specimens and associated data form an unmatched resource for identifying hidden diversity, interpreting past responses to climate oscillations, documenting contemporary conditions, and anticipating outcomes for complex biological systems in a regime of ecological perturbation. Because of its dual focus on hosts and parasites, the BCP record also provides a foundation for comparative analyses that can document the effects of dynamic change on the geographic distribution, transmission dynamics, and emergence of pathogens. By using specific examples from carnivores, eulipotyphlans, lagomorphs, rodents, ungulates, and their associated parasites, we demonstrate how broad, integrated field collections provide permanent infrastructure that informs policy decisions regarding human impact and the effect of climate change on natural populations.

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

AbstractThis 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.

New Records ofTipula(Vestiplex) Crane Flies from the Palaearctic [Diptera: Tipulidae] with a New Synonym

Abstract Tipula (Vestiplex) tchukchi obtusidens Savchenko, 1964 is designated as a synonym of the nominotypical species Tipula (Vestiplex) tchukchi Alexander, 1934 syn. nov. Tipula (Vestiplex) aldrichiana Alexander, 1929 and Tipula (Vestiplex) balioptera Loew, 1863 are reported as new to the Russian fauna and the Palaearctic – East Beringian region.

Evolution of the eastern Asian–North American biogeographic disjunctions in ferns and lycophytes

AbstractThis paper reviews 31 groups in ferns and lycophytes hypothesized to show eastern Asian–North American disjunctions. Fourteen lineages have been supported by recent phylogenetic evidence: Lycopodium nikoense and Lycopodium sitchense; Isoëtes asiatica and the clade of the North American species complex closely allied to I. maritima; Osmundastrum cinnamomeum; Osmunda claytoniana; the Adiantum pedatum complex; the Cryptogramma acrostichoides complex; Diplaziopsidaceae; Cystopteris chinensis and the Cystopteris bulbifera clade; Asplenium rhizophyllum and Asplenium ruprechtii; diploid Phegopteris; Onoclea sensibilis; the Polypodium appalachianum clade; and the Polypodium glycyrrhiza clade. Phylogenetic and/or cytological evidence did not support the biogeographic disjunctions in six cases: (1) Isoëtes asiatica and I. truncata; (2) Botrychium ternatum; (3) Thelypteris beddomei and T. nipponica—Thelypteris noveboracensis and T. nevadensis; (4) Thelypteris glanduligera and Thelypteris. japonica—T. simulata; (5) Woodwardia japonica and W. virginica; and (6) Woodwardia orientalis and Woodwardia fimbriata. Both vicariance and dispersal have been suggested to be the mechanisms for the formation of the disjunct pattern; and the Beringian region has been an active pathway for the migration of ferns and lycophytes between Asia and North America. Disjunctions of ferns and lycophytes reviewed here have been dated in the Tertiary, and are similar to the ages of eastern Asian–North American disjunctions in seed plants, supporting the close biogeographic co‐diversification of ferns and seed plants. Future studies are needed to estimate divergence times and reconstruct biogeographic events in a broad phylogenetic framework, and to test the morphological stasis hypothesis in disjunct ferns and lycophytes.

Parasite diversity at the Holarctic nexus: species of Arostrilepis (Eucestoda: Hymenolepididae) in voles and lemmings (Cricetidae: Arvicolinae) from greater Beringia

Previously unrecognized species of hymenolepidid cestodes attributable to Arostrilepis Mas-Coma & Tenora, 1997 in arvicoline rodents from the greater Beringian region and western North America are described. Discovery and characterization of these tapeworms contributes to the recognition of a complex of cryptic species distributed across the Holarctic region. Three species are proposed: Arostrilepis gulyaevi sp. n. is named for cestodes in Myodes rufocanus from the Republic of Buryatia, southeastern Siberia and from the Khabarovskiy Kray, Chukotka Autonomous Okrug, and Magadanskaya Oblast', Russian Far East (western Beringia); A. cooki sp. n. is named for cestodes in Myodes gapperi from British Columbia, Canada and Montana, USA; and A. rauschorum sp. n. is named for cestodes in Microtus oeconomus, M. longicaudus, M. pennsylvanicus and M. xanthognathus from the Brooks Range, Seward Peninsula, north-central interior, and Arctic coastal plains of Alaska (eastern Beringia) and Montana, USA. Consistent with recent studies defining diversity in the genus, the form, size, and spination (pattern, shape and size) of the cirrus are diagnostic; species are further distinguished by the relative position and length of the cirrus sac, and arrangement of the testes. Assessment of genetic data from the cytochrome b gene of mitochondrial DNA complements differentiation of this complex based on morphological attributes and confirms known species diversity within the genus. New data for geographical distribution and host specificity of known Arostrilepis spp. indicate that 3 of 12 recognized species have Holarctic distributions extending across Beringia. These include Arostrilepis beringiensis (Kontrimavichus & Smirnova, 1991) in lemmings (species of Lemmus and Synaptomys), A. cf. janickii Makarikov & Kontrimavichus, 2011 in root voles (M. oeconomus) MAKARIKOV ET AL. 402 · Zootaxa 3608 (6) © 2013 Magnolia Press and A. macrocirrosa Makarikov, Gulyaev & Kontrimavichus, 2011 in red backed voles (species of Myodes) and less often other rodent host species.

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.

A revision of the genera Pseudosmittia Edwards, 1932, Allocladius Kieffer, 1913, and Hydrosmittia gen. n. (Diptera: Chironomidae, Orthocladiinae)

The genera Pseudosmittia Edwards, 1932, and Allocladius Kieffer, 1913, supported by parsimony analysis, can be divided into three groups, Pseudosmittia, Allocladius and Hydrosmittia gen. n. Generic diagnoses to all stages and both sexes of all three genera are given. The mostly Neotropical and Afrotropical Allocladius together with the mostly Holarctic and Afrotropical Hydrosmittia form the sister group of the more widespread Pseudosmittia. Allocladius in addition to some basal species is divided into a paraphyletic nearly Cosmopolitan fortispinatus group, a monotypic Afrotropical soemmei group, an Afrotropical and Palaearctic niger group, a Holarctic nanseni group, and a Neotropical, Afrotropical and Holarctic longicrus group; Hydrosmittia into an Afrotropical and Palaearctic brevicornis group and a mostly Holarctic ruttneri group. Pseudosmittia is divided into 13 species groups in phyletic sequence: gracilis [simplex + rotunda (topei (digitata (xanthostola + brachydicrana + insulsa)], [conjuncta (tokaraneoa + albipennis (brevifurcata (angusta group, divided into angusta, trilobata, lamasi, danconai, uncata and forcipata subgroups)]. The xanthostola and brachydicrana groups are with few exceptions known only from South Asia and the Indo-Pacific region, while most other groups are present in most regions. Keys to male and female imagines, pupae and larvae of all three genera are given. Type material of 180 species assigned to Pseudosmittia, Camptocladius v. d. Wulp, Spaniotoma Philippi, Smittia Holmgren, Mesosmittia Brundin, Orthosmittia Goetghebuer, Ancylocladius Sublette et Wirth, Allocladius Kieffer, and Lindebergia Tuiskunen, belonging to 15 museums have been re-examined, lectotypes designated, and new combinations and synonyms given. An additional 21 species are lost or could not be located, of these 5 are declared nomina dubia. Another 4 species were not available for study or not examined. Most of these could be placed in other genera or as synonyms of species in Pseudosmittia. One hundred and thirty species are treated, 37 of which are new, 93 species are completely redescribed in all available stages. The following new species are described: Allocladius bubatus, A. caspersi, A. deborae, A. hirticaudatus, A. luciniolus, A. soemmei, A. wangorum, Hydrosmittia aagaardi, H. annulata, H. falsicostata, H. soelii, H. tenuistylata, Pseudosmittia aculeathrix, P. acutilobata, P. carita, P. christmasensis, P. cristagata, P. cunealata, P. dolabrata, P. digitrienta, P. fusata, P. laticauda, P. legonensis, P. licina, P. longicornia, P. malickyi, P. navama, P. parifusata, P. parinavama, P. pedata, P. propetropis, P. pugnata, P. siamensis, P. spinispinata, P. tericristata, P. tokunagai, and P. unniae. Ten species of Allocladius (including 2 parthenogenetic), 4 species of Hydrosmittia (including 2 parthenogenetic), and 31 species of Pseudosmittia (including 3 parthenogenetic and 3 species known only from females) are known as female imagines; 5 species of Allocladius, 6 species of Hydrosmittia and 12 species of Pseudosmittia are known as pupae; and 4 species of Allocladius, 5 species of Hydrosmittia and 10 species of Pseudosmittia are known as larvae. Errors in previous publications are corrected and remarks on variation given. The genera treated contain at least 7 apparently obligate parthenogenetic species, while facultative parthenogenesis is found in at least one species and may be widespread. The species of Hydrosmittia probably all are truly aquatic, while Allocladius has species found in both fully aquatic environments and in moist earth. In Pseudosmittia there are no certain fully aquatic species. Most species appear to be semiaquatic to semiterrestrial or live in the marine intertidal zone. The insulsa, brachydicrana, and xanthostola groups contain mostly marine seashore species, and several groups have species, which larvae live both in semiaquatic freshwater localities and on the seashore. In the angusta group, however, only P. bifurcata appears to be intertidal.Only in Allocladius a cool southern transantarctic Gondwanian vicariance may have taken place, but combined with dispersal to West Asia, further to the Euro-Mediterranean and East Asian Regions, and across a Beringian Region to North America. A more northern warm Gondwanian connection between West Africa and East South America could be present but not common in Pseudosmittia. The dominating distribution pattern in Pseudosmittia appear to be caused by direct dispersal, in America across the Caribbean and the Central American lowland, in the Indian Ocean and the Pacific across oceans by floating debris and vegetation.

Molecular phylogeny of long-tailed shrews (genus Sorex) from México and Guatemala

We present a molecular phylogeny of North American species of long-tailed shrews of the genus Sorex. Our focus is on Mexican and Guatemalan species to begin understanding their evolutionary relationships and to test the validity of nominal species. Seventy-seven sequences of the mitochondrial cytochrome b gene were analyzed, including 19 specimens representing nine Mexican and one Guatemalan species. Phylogenetic analyses using parsimony, maximum likelihood and Bayesian approaches revealed two major clades of North American species, all within the subgenus Otisorex. The first major clade includes S. trowbridgii and southern species (S. macrodon from Oaxaca; S. veraecrucis from Nuevo León, Michoacán, Chiapas, S. saussurei from Jalisco and Guatemala; S. veraepacis from Guerrero and Guatemala). Relatively deep branches among taxa characterize this clade and suggest that their early divergence from other North American shrews was soon after arrival of the ancestral stock from the Beringian region. The other major clade includes all other North American species of Sorex we examined, with two Mexican species, S. milleri and S. emarginatus, grouped in a subclade with the S. cinereus complex. Sorex veraecrucis is not, however, a monophyletic taxon because specimens of this nominal species were included in both the major clades. The Isthmus of Tehuantepec has likely played a role as a biogeographic barrier in the evolutionary history of Mexican shrews. This study of mitochondrial variation in southern North American shrews of the genus Sorex indicates there is substantial, previously undetected diversity that necessitates a revision of the taxonomy of S. veraecrucis and S. veraepacis.

Composition, Phytogeography, and Relict Status of the Vascular Flora of Alvars and Cliff Tops Southwest of Great Slave Lake, Northwest Territories, Canada

Alvars in the vicinity of Enterprise, Northwest Territories, had 87 species of vascular plants. Of these, 14 were frequent or at least locally abundant, including: Juniperus horizontalis, J. communis var. depressa, Geum triflorum var. triflorum, Carex richardsonii, Populus tremuloides, Elymus trachycaulus subsp. trachycaulus, Koeleria macrantha, Saxifraga tricuspidata, Artemesia campestris subsp. borealis, Senecio lugens, Arctostaphylos uva-ursi, and Galium boreale. Of the trees comprising the surrounding forest, only Populus tremuloides and Pinus banksiana were common in the open areas. The cliff tops had fewer species but they also had some species of arctic and high boreal affinity that were absent from the alvars. Associations characterized by Deschampsia caespitosa occurred in lower areas of alvar that collect run-off, whereas higher areas were characterized by a variety of plants including Carex richardsonii, Elymus trachycaulus, and Geum triflorum. Cracks in the limestone pavement in elevated areas were occupied by Pinus banksiana and Juniperus communis. Approximately 12% of the species present were rare and/or restricted, including Avenula hookeri, Carex filifolia, and Dodecatheon pulchellum. Compared to the alvars of the Great Lakes region, the alvars and cliff tops of Northwest Territories had a much higher percentage of species that were also found in the Beringian region of northwestern North America. Higher numbers of boreal, arctic, and cordilleran species also contributed to the distinctive nature of Northwest Territories alvars, based on clustering of similarity coefficients from species presence or absence data. The alvar flora of Northwest Territories is believed to have been established in the region of Great Slave Lake between 10,000 and 8000 years ago, prior to invasion of the boreal forest. At this time, the northwestern Beringian and Cordilleran floras met the retreating tundra and prairie floras from the south in an expanding ice-free corridor. The relict flora of Northwest Territories alvars and cliff tops includes species of the Beringian steppes and tundras such as Plantago canescens, species of the central North American plains such as Geum triflorum, and many species that could have originated from the prairie-like habitats of either region. This unusual relict flora, originating in early postglacial times, is now isolated within the present boreal forest that spread through the region approximately 8000 years ago.

Phylogeny, origin, and biogeographic history of Aesculus L. (Sapindales) – an update from combined analysis of DNA sequences, morphology, and fossils

AbstractConflicting phylogenies and biogeographic hypotheses for Aesculus L. were reevaluated using data integrating morphology, fossils, and DNA sequences. A more robust phylogeny of Aesculus was constructed by increasing taxon and character sampling to include 42 morphological characters and five DNA regions including rps16, trnHK, matK, ITS, and part of the LEAFY gene. Our analyses revealed three well‐supported major lineages in Aesculus. These are sect. Calothyrsus excluding A. californica, sect. Macrothyrsus + A. californica, and sect. Aesculus + sect. Pavia + sect. Parryana. The relationship of sect. Aesculus to sect. Parryana + sect. Pavia is strongly supported and previously unreported. Relationships among the three major clades remained incompletely resolved. Biogeographic and divergence time analyses using DIVA and Multidivtime support a Paleocene origin of Aesculus in eastern Asia and western North America, and showed that the genus subsequently dispersed into eastern North America, Central America, and Europe. Our results support that Aesculus originated as an element of the Paleogene mesophilic flora in the Beringian region with multiple eastward migrations characterizing the early spatial history of this genus. This biogeographic history supports Trans‐Beringian migration of plants in the very early Paleogene.

Pacific walruses, indigenous hunters, and climate change: Bridging scientific and indigenous knowledge

Abstract This paper presents and evaluates two perspectives on changing climate–walrus–human relationships in the Beringian region, from the viewpoints of marine biology and ecology, and from that of indigenous hunters. Bridging these types of knowledge is vital in order to grasp the complexity of the processes involved and for advancing understanding of subarctic marine ecosystems that are currently experiencing rapid ecological and social change. We argue that despite substantial gaps and distinctions, information generated by scientists and indigenous hunters have many similarities. Differences in interpretation are primarily due to scaling and temporal rates of change of knowledge, which could be rectified through more active sharing of expertise and records, enhanced documentation of indigenous observations, more collaborative research, and increased insight from the social sciences.

Discovery of a Possibly Relict Outbreeding Morphotype of Sparrow's-egg Lady's-slipper Orchid, <em>Cypripedium passerinum</em>, in Southwestern Yukon

An outbreeding morphotype of Cypripedium passerinum with separate anthers and stigma was discovered in the Beringian region of southwestern Yukon. The occurrence of this breeding system in Beringia is attributed to the persistent advantage of outbreeding over hundreds of thousands of years in this unglaciated area, whereas the widespread occurrence of exclusively self-pollinating races elsewhere in Canada is attributed to advantages in colonization of recently deglaciated territory which first became available less than 10,000 years ago, and/or to a changing and more forested habitat.

Discovery of the First Early Cenozoic Euprimate (Mammalia) from Inner Mongolia

Although it is widely thought that euprimates originated in Asia, the fossil record of early euprimates remains sparse there. We describe herein a new omomyid euprimate, Baataromomys ulaanus, n. gen. et sp., based on an isolated right lower m2 from Bumbanian strata at Wulanboerhe in the Erlian Basin of Inner Mongolia, China. In terms of the size and proportions of m2, Baataromomys ulaanus is intermediate between Eurasian and North American species that are usually assigned to Teilhardina. Morphologically, m2 of Baataromomys differs from that of Teilhardina and North American small-bodied omomyids (including Anemorhysis, Tetonoides, Trogolemur, and Sphacorhysis) in having a smaller paraconid that is less fully connate with the metaconid, a lower entoconid, a weaker crest connecting the metaconid with the entoconid, and a weaker buccal cingulid. The new taxon is much smaller and lower crowned than Steinius, a genus commonly regarded as a basal omomyid. Despite the substantial difference in size, the m2s of Baataromomys and Steinius share some important features, including a very broad talonid basin and a relatively low hypoconid and cristid obliqua. Given its early occurrence and primitive anatomy, Baataromomys may eventually help to clarify the phylogenetic relationships among basal omomyids, but more complete specimens will be required to test this possibility. Baataromomys brandti from the basal Wasatchian zone Wa-0 in the northern Bighorn Basin, Wyoming, was previously allocated to Teilhardina. However, several dental features shared by B. brandti and B. ulaanus suggest that they are closely related. The co-occurrence of Baataromomys in Asia and North America indicates that small-bodied euprimates were able to dispersal across the Beringian region near the Paleocene–Eocene boundary.

On Some Saxicolous Lecideoid Lichens of the Beringian Region and Adjacent Areas of Eastern Siberia and the Russian Far East

1) Miriquidica leucophaeoides (syn. Lecidea leucophaeoides Nyl.) is proposed as a new combination. 2) The following taxa are synonyms (correct names in parenthesis): Lecidea aglaeida Nyl. (= Calvitimela aglaea), Lecidea cheiloplaca Vain. (= Miriquidica deusta), Lecidea chlorophanoides H.Magn. in Malme (= Candelariella vitellina), Lecidea confluens f. refluens Vain. (= Lecidea confluens), Lecidea declinans f. subsculptella Nyl. (= Lecidea lapicida var. lapicida), Lecidea konyamensis Nyl. (= Miriquidica leucophaeoides), Lecidea lenensis Oxner (= Calvitimela aglaea), Lecidea lugubrior Nyl. (= Clauzadeana macula), Lecidea melapsepha Nyl. (= Cecidonia xenophana), Lecidea reducens Vain. (= Lecidea lapicida var. lapicida), Lecidea subfumosa (Arnold) Zwackh f. melanocarpa Vain. (= Rhizocarpon polycarpum), Lecidea subfumosa f. poliocarpa Vain. (= Lecidea atrobrunnea: chemorace 0), Lecidea subtristiuscula Nyl. (= Miriquidica leucophaeoides). 3) Lectotypes were chosen for Lecidea konyamensis Nyl., Lecidea lygotropa Nyl., Lecidea reducens Vain., Lecidea subfumosa f. melanocarpa Vain., Lecidea subfumosa f. poliocarpa Vain., Lecidea subtristiuscula Nyl. 4) New records are documented for: Cecidonia umbonella (new to Beringian Alaska), Cecidonia xenophana (new to Asia), Lecidea confluentula (new to Asia), Lecidea ecrustacea (new to Beringian Alaska), Lecidea lapicida (new to Kamchatka), Lecidea paupercula (new to Kamchatka and to Beringian Alaska), Lecidea plana (new to Alaska and Kamchatka), Lecidea swartzioidea (new to Kamchatka), Lecidea umbonata (new to Chukotka), Miriquidica deusta (new to Alaska), Miriquidica leucophaeoides (new to Alaska and Taimyr), Rimularia impavida (new to Alaska), and Schaereria fuscocinerea (new to mainland Alaska).

Freshwater midges of the Yukon and adjacent Northwest Territories: a new tool for reconstructing Beringian paleoenvironments?

AbstractDistributions of freshwater midges, including Chironomidae, Chaoboridae, and Ceratopogonidae, were analyzed along a transect of lakes extending north from Whitehorse (Yukon Territory) to the Arctic Ocean (Northwest Territories). Abiskomyia, Mesocricotopus, Monodiamesa, and Paracladius were restricted to arctic tundra lakes, whereas Chaoborus, Pseudochironomus, Polypedilum, and Glyptotendipes were clearly associated with forest and forest–tundra environments. Many other taxa were broadly distributed with little apparent regard to latitude or ecoclimatic region. Canonical correspondence analyses revealed that midge distributions were most strongly correlated with total Kjeldahl N, maximum lake depth, pH, and summer surface water temperature. The distribution patterns suggest that subfossil midges may provide valuable proxy evidence for paleoenvironmental conditions in the Beringian region of northwestern Canada and Alaska.

Sturgeons (Chondrostei: Acipenseridae) and their metazoan parasites: patterns and processes in historical biogeography

Abstract Aim The historical biogeography of host‐parasite associations is examined in a geologically old group of fishes, the sturgeons (Osteichthyes: Acipenseridae), and their parasite assemblage. Evidence from phylogenetics and biogeographical studies of several parasite groups is used to formulate and evaluate hypotheses about the coevolutionary history of this host‐parasite association and, ultimately, the origin of sturgeons. Location The geographical areas discussed in this study are the temperate regions of North America and Eurasia, including the North Atlantic, North Pacific, Mediterranean and Ponto‐Caspian basins and their drainages. Methods Relationships of parasites in several clades (Truttaedacnitis, Diclybothriidae, Deropristiidae, Spinitectus and Acrobothriidae) are analysed or re‐analysed using cladistics. These results are combined with hypotheses of relationships of sturgeons and their biogeography. We largely follow an ‘empirical synthetic pattern approach' (Grande & Bemis, 1998) where the search is primarily for broadly congruent patterns, keeping interpretations close to the data and to known or postulated Earth history (palaeogeography). The evidence from the cladistic analyses is first interpreted within the context of vicariance events, but dispersalist scenarios are also discussed where warranted. We also use the concept of Croizat's ‘biogeographical tracks' to characterize broadly congruent distributional patterns. Results Phylogenetic hypotheses and biogeography of parasites indicate three major biogeographical tracks, of which a Holarctic track involving northern and north‐eastern Asian regions and North America is predominant (in Crepidostomum auriculatum, Polypodium hydriforme, Truttaedacnitis, Capillospirura, Diclybothriidae, Amphilina), with evidence for a recurring basal trans‐Pacific track (in Truttaedacnitis, Diclybothriidae). Trans‐Atlantic tracks appear to be either independent of (in Deropristidae) or secondarily derived from (in Bothrimonus and Truttaedacnitis sphaerocephala) a Holarctic track. Evidence from parasites supports the hypothesis of sister relationships between Acipenser medirostris and A. mikadoi, and between A. fulvescens and A. brevirostrum. Main conclusions This host–parasite association was historically structured by colonization and subsequent coevolution. Dispersal and vicariance of acipenserids resulted in small but widespread, highly distinct, monophyletic parasite lineages. Species of such parasite clades remain associated with major and often discrete continental and oceanic formations, and occasionally with related sturgeon species. Biogeographical tracks implicate the Cretaceous and early Tertiary Asian–American peninsula (Beringian region) as a historically important region in the origin and early geodispersion of the parasite fauna. This is consistent with hypotheses of the northern north‐eastern Asian region, or the more inclusive Asian–American peninsula, as a key area in the early diversification of sturgeons and the acquisition of their parasite fauna. The parasite fauna supports the hypothesis of a former continuous distribution of Nearctic and eastern Palaearctic (Siberian) sturgeons that was subsequently fragmented by geological and climatic events, resulting in major displacement of ancestral sturgeon populations in North America. The parasites also reflect a historical connection with marine and brackish water environments that pre‐dates the diversification of sturgeons, indicating that ancestral acipenserids were diadromous.

Constraints for the latest glacial advance on Wrangel Island, Arctic Ocean, from rock surface exposure dating

During an expedition to Wrangel Island in 1997, three samples of quartz veins were collected for surface exposure dating. Two were bedrock surface samples from different parts of the island, one was from a local boulder. The samples were collected where former coverage by valley glaciers can be excluded. Especially, the bedrock surface samples were expected to provide new constraints for the chronology of glaciations on the island and on the arctic continental shelf in the Beringian region. Minimum exposure age estimates for these bedrock samples, calculated on the basis of 10Be concentrations, are 64,600±6400 and 26,400±2100 years. These estimates suggest that no major glaciations have affected Wrangel Island or the adjacent shelf area after 64,600±6400 years. Specifically, these dates seem to rule out any major glaciation during the Last Glacial Maximum (LGM). The estimates should however be regarded as preliminary, as only two bedrock surface samples were analysed, but are compatible with the absence of glacial morphology and sediments, and with radiocarbon dates from mammoth remains.