Wang Q.,Sichuan University |
Liu J.,Sichuan University |
Allen G.A.,University of Victoria |
Ma Y.,Lanzhou University |
And 3 more authors.
New Phytologist | Year: 2016
Many plant species comprising the present-day Arctic flora are thought to have originated in the high mountains of North America and Eurasia, migrated northwards as global temperatures fell during the late Tertiary period, and thereafter attained a circumarctic distribution. However, supporting evidence for this hypothesis that provides a temporal framework for the origin, spread and initial attainment of a circumarctic distribution by an arctic plant is currently lacking. Here we examined the origin and initial formation of a circumarctic distribution of the arctic mountain sorrel (Oxyria digyna) by conducting a phylogeographic analysis of plastid and nuclear gene DNA variation. We provide evidence for an origin of this species in the Qinghai-Tibet Plateau of southwestern China, followed by migration into Russia c. 11 million yr ago (Ma), eastwards into North America by c. 4 Ma, and westwards into Western Europe by c. 1.96 Ma. Thereafter, the species attained a circumarctic distribution by colonizing Greenland from both sides of the Atlantic Ocean. Following the arrival of the species in North America and Europe, population sizes appear to have increased and then stabilized there over the last 1 million yr. However, in Greenland a marked reduction followed by an expansion in population size is indicated to have occurred during the Pleistocene. © 2015 New Phytologist Trust.
Allen G.A.,University of Victoria |
Marr K.L.,Royal British Columbia Museum |
McCormick L.J.,University of Victoria |
Hebda R.J.,University of Victoria
Ecology and Evolution | Year: 2012
The ranges of arctic-alpine species have shifted extensively with Pleistocene climate changes and glaciations. Using sequence data from the trnH-psbA and trnTtrnL chloroplast DNA spacer regions, we investigated the phylogeography of the widespread, ancient (>3 million years) arctic-alpine plant Oxyria digyna (Polygonaceae). We identified 45 haplotypes and six highly divergent major lineages; estimated ages of these lineages (time to most recent common ancestor, TMRCA) ranged from ̃0.5 to 2.5 million years. One lineage is widespread in the arctic, a second is restricted to the southern Rocky Mountains of the western United States, and a third was found only in the Himalayan and Altai regions of Asia. Three other lineages are widespread in western North America, where they overlap extensively. The high genetic diversity and the presence of divergent major cpDNA lineages within Oxyria digyna reflect its age and suggest that it was widespread duringmuch of its history. The distributions of individual lineages indicate repeated spread of Oxyria digyna through North America over multiple glacial cycles. During the Last Glacial Maximum it persisted in multiple refugia in western North America, including Beringia, south of the continental ice, and within the northern limits of the Cordilleran ice sheet. Our data contribute to a growing body of evidence that arctic-alpine species have migrated from different source regions over multiple glacial cycles and that cryptic refugia contributed to persistence through the Last Glacial Maximum. © 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.
Marr K.L.,Royal British Columbia Museum |
Allen G.A.,University of Victoria |
Hebda R.J.,Royal British Columbia Museum |
Hebda R.J.,University of Victoria |
Mccormick L.J.,University of Victoria
Journal of Biogeography | Year: 2013
Aim: We investigated genetic variation in Bistorta vivipara, a widespread Northern Hemisphere tundra species, to infer patterns of migration and where it may have survived during the Last Glacial Maximum (LGM). Location: Samples came primarily from western North America, with a few from the Arctic and Eurasia. Methods: We sequenced two chloroplast DNA spacer regions, trnH-psbA and trnS-G, in individuals from 199 populations and mapped haplotype distributions and their relationships using a haplotype network. We calculated genetic and molecular diversity statistics for the seven geographical regions from which we obtained samples. Results: Fifteen haplotypes were detected, with very little divergence among them. The haplotypes are separated into two main groups by the presence or absence of a 22 bp tandem duplication. Four haplotypes are common, widespread and with substantial range overlap; 11 are rare and mostly unique to one region. Two rare haplotypes were found only in British Columbia (BC). Western North America and Asia have the highest levels of genetic and molecular diversity. Northern and southern BC have different haplotype complements. Main conclusions: Bistorta vivipara has relatively low genetic diversity, with much less genetic structure than we expected for such a widespread species. We expected significant geographical structure due to the combined effects of genetic drift and geographical isolation. The asexual reproductive mode of B. vivipara may facilitate relatively rapid population establishment and spread compared with sexual reproduction by seed. Bistorta vivipara probably originated in Asia and spread to North America and Europe prior to the LGM. In western North America it spread to its modern distribution from Beringia and the western USA following the LGM. Populations in northern and southern BC may have different histories, possibly related to the timing and extent of glaciation. The occurrence of two unique haplotypes within BC suggests that some individuals may have survived in full glacial refugia within BC. © 2012 Blackwell Publishing Ltd.
Cannings R.A.,Royal British Columbia Museum |
Kahanpaa J.,University of Helsinki
Entomologica Fennica | Year: 2013
Lasiopogon septentrionalis Lehr, 1984 is recorded for the first time from Finland, and Europe as a whole. The species was previously known only from the Russian Far East. A key to the three north European Lasiopogon species is provided. © Entomologica Fennica. 24 June 2013.
Sendall K.,Royal British Columbia Museum |
Salazar-Vallejo S.I.,Colegio de Mexico
ZooKeys | Year: 2013
Sternaspid polychaetes are common and often abundant in soft bottoms in the world oceans. Some authors suggest that only one species should be recognized, whereas others regard a few species as widely distributed in many seas and variable depths from the low intertidal to about 4400 m. There are some problems with species delineation and the distinctive ventro-caudal shield has been disregarded or barely used for identifying species. In order to clarify these issues, the ventral shield is evaluated in specimens from the same locality and its diagnostic potential is confirmed. On this basis, a revision of Sternaspis Otto, 1821 (Polychaeta: Sternaspidae) is presented based upon type materials, or material collected from type localities. The sternaspid body, introvert hooks and shield show three distinct patterns, two genera have seven abdominal segments and tapered introvert hooks, and one genus has eight abdominal segments and spatulate introvert hooks. The ventro-caudal shield has three different patterns: stiff with ribs, and sometimes concentric lines, stiff with feebly-defined ribs but no concentric lines, and soft with firmly adhered sediment particles. Sternaspis is restricted to include species with seven abdominal segments, falcate introvert hooks, and stiff shields, often exhibiting radial ribs, concentric lines or both. Sternaspis includes, besides the type species, S. thalassemoides Otto, 1821 from the Mediterranean Sea, S. affinis Stimpson, 1864 from the Northeastern Pacific, S. africana Augener, 1918, stat. n. from Western Africa, S. andamanensis sp. n. from the Andaman Sea, S. costata von Marenzeller, 1879 from Japan, S. fossor Stimpson, 1853 from the Northwestern Atlantic, S. islandica Malmgren, 1867 from Iceland, S. maior Chamberlin, 1919 from the Gulf of California, S. princeps Selenka, 1885 from New Zealand, S. rietschi Caullery, 1944 from abyssal depths around Indonesia, S. scutata (Ranzani, 1817) from the Mediterranean Sea, S. spinosa Sluiter, 1882 from Indonesia, and S. thorsoni sp. n. from the Iranian Gulf. Two genera are newly proposed to incorporate the remaining species: Caulleryaspis and Petersenaspis. Caulleryaspis gen. n. is defined by the presence of falcate introvert hooks, seven abdominal segments, and soft shields with sediment particles firmly adhered on them; it includes two species: C. gudmundssoni sp. n. from Iceland and C. laevis (Caullery, 1944) comb. n. from Indonesia. Petersenaspis gen. n. is defined by the presence of spatulate introvert hooks, eight abdominal segments, and stiff shields with poorly defined ribs but no concentric line; it includes P. capillata (Nonato, 1966) from Brazil and P. palpallatoci sp. n. from the Philippines. Neotypes are proposed for eight species: S. thalassemoides, S. affinis, S. africana, S. costata, S. fossor, S. maior, S. scutata and S. spinosa, to stabilize these species-group names, and a lectotype is designated for S. laevis which is transferred to Caulleryaspis gen. n. The geographic range of most species appears to be much smaller than previously indicated, and for some species additional material in good condition is needed to clarify their distributions. Keys to genera and to all species are also included. © K. Sendall, S.I. Salazar-Vallejo.
Dyke G.,University of Southampton |
Vremir M.,Transylvanian Museum Society EME |
Kaiser G.,Royal British Columbia Museum |
Naish D.,University of Southampton
Naturwissenschaften | Year: 2012
Despite a rapidly improving fossil record, the reproductive biology of Mesozoic birds remains poorly known: only a handful of undisputed, isolated Cretaceous eggs (some containing embryonic remains) are known. We report here the first fossil evidence for a breeding colony of Mesozoic birds, preserved at the Late Cretaceous (Maastrichtian) Oarda de Jos (Od) site in the Sebeş area of Transylvania, Romania. A lens of calcareous mudstone with minimum dimensions of 80 cm length, 50 cm width and 20 cm depth contains thousands of tightly packed, morphologically homogenous eggshell fragments, seven near-complete eggs and neonatal and adult avialan skeletal elements. Eggshell forms 70-80% of the matrix, and other fossils are entirely absent. The bones exhibit clear characters of the Cretaceous avialan clade Enantiornithes, and the eggshell morphology is also consistent with this identification. Both taphonomy and lithology show that the components of this lens were deposited in a single flood event, and we conclude that it represents the drowned remains of a larger enantiornithine breeding colony, swamped by rising water, washed a short distance and deposited in a shallow, low-energy pond. The same fate often befalls modern bird colonies. Such a large concentration of breeding birds suggests aquatic feeding in this species, augments our understanding of enantiornithine biology and shows that colonial nesting was not unique to crown birds. © Springer-Verlag 2012.
Hanke G.F.,Royal British Columbia Museum |
Davis S.P.,505 King Court
Geodiversitas | Year: 2012
New anatomical details are described for the acanthodian Lupopsyrus pygmaeus Bernacsek & Dineley, 1977, based on newly prepared, nearly complete body fossils from the MOTH locality, Northwest Territories, Canada. New interpretations of previously known structures are provided, while the head, tail, and sensory lines of L. pygmaeus are described for the first time. The pectoral girdle of L. pygmaeus shows no evidence of pinnal and lorical plates as mentioned in the original species description. Instead, the dermal elements of the pectoral region appear to comprise a single pair of prepectoral spines which rest on transversely oriented procoracoids, and large, shallowly inserted, ornamented pectoral fin spines which contact both the procoracoids and scapulocoracoids. The scales of L. pygmaeus lack growth zones and mineralized basal tissue, and superficially resemble scales of thelodonts or monodontode placoid scales of early chondrichthyans, and not the typical scales of acanthodians. However, L. pygmaeus possesses perichondrally-ossified pork-chop shaped scapulocoracoids, a series of hyoidean gill plates, and scale growth that originates near the caudal peduncle; these features suggest a relationship to acanthodians. Prior to this study, both authors conducted separate cladistic analyses which resulted in differing tree positions for L. pygmaeus and its relationships within the Acanthodii. However, both analyses did agree that there is no evidence allying L. pygmaeus to the traditional "climatiid" acanthodians contrary to previous historical classifications. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
Cannings R.A.,Royal British Columbia Museum
Canadian Entomologist | Year: 2011
Efferia okanagana sp. nov. is described from specimens collected in the grasslands of the southern Interior of British Columbia, Canada, mainly the Okanagan Valley. The male and female genitalia are described and illustrated. The existing key to species of Efferia Coquillett is modified to enable identification of male and female E. okanagana. The species belongs to the E. arida species group and perhaps is most closely related to E. arida (Williston) and E. pinali Wilcox. Efferia coulei Wilcox is the closest sympatric relative. Sequences of the cytochrome oxidase I gene (DNA barcode) for E. okanagana and E. coulei show distinct clusters for each species that are approximately 7.0% divergent (uncorrected p distance). Efferia okanagana has an early flight period (May and June) and lives in low-elevation grasslands dominated by bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) . Lve) (Poaceae), especially where the soil is gravelly. It is considered a potential species at risk by the Committee on the Status of Endangered Wildlife in Canada. © 2011 Entomological Society of Canada.
News Article | September 2, 2016
A rare small-bodied pterosaur, a flying reptile from the Late Cretaceous period approximately 77 million years ago, is the first of its kind to have been discovered on the west coast of North America. Pterosaurs are the earliest vertebrates known to have evolved powered flight. The specimen is unusual as most pterosaurs from the Late Cretaceous were much larger with wingspans between 4 and 11 meters (the biggest being as large as a giraffe, with a wingspan of a small plane), whereas this new specimen had a wingspan of only 1.5 meters. The fossils of this animal are the first associated remains of a small pterosaur from this time, comprising a humerus, dorsal vertebrae (including three fused notarial vertebrae) and other fragments. They are the first to be positively identified from British Columbia, Canada and have been identified as belonging to an azhdarchoid pterosaur, a group of short-winged and toothless flying reptiles which dominated the final phase of pterosaur evolution. Previous studies suggest that the Late Cretaceous skies were only occupied by much larger pterosaur species and birds, but this new finding, which is reported in the Royal Society Open Science journal, provides crucial information about the diversity and success of Late Cretaceous pterosaurs. "This new pterosaur is exciting because it suggests that small pterosaurs were present all the way until the end of the Cretaceous, and weren't outcompeted by birds. The hollow bones of pterosaurs are notoriously poorly preserved, and larger animals seem to be preferentially preserved in similarly aged Late Cretaceous ecosystems of North America. This suggests that a small pterosaur would very rarely be preserved, but not necessarily that they didn't exist," said lead author Elizabeth Martin-Silverstone, a palaeobiology PhD Student at the University of Southampton. The fossil fragments were found on Hornby Island in British Columbia in 2009 by a collector and volunteer from the Royal British Columbia Museum, who then donated them to the Museum. At the time, it was given to Victoria Arbour, a then PhD student and dinosaur expert at the University of Alberta. Victoria, as a postdoctoral researcher at North Carolina State University and the North Carolina Museum of Natural Sciences, then contacted Martin-Silverstone and the Royal BC Museum sent the specimen for analysis in collaboration with Mark Witton, a pterosaur expert at the University of Portsmouth. "The specimen is far from the prettiest or most complete pterosaur fossil you'll ever see, but it's still an exciting and significant find. It's rare to find pterosaur fossils at all because their skeletons were lightweight and easily damaged once they died, and the small ones are the rarest of all. But luck was on our side and several bones of this animal survived the preservation process. Happily, enough of the specimen was recovered to determine the approximate age of the pterosaur at the time of its death. By examining its internal bone structure and the fusion of its vertebrae we could see that, despite its small size, the animal was almost fully grown. The specimen thus seems to be a genuinely small species, and not just a baby or juvenile of a larger pterosaur type" said Witton. "The absence of small juveniles of large species—which must have existed—in the fossil record is evidence of a preservational bias against small pterosaurs in the Late Cretaceous. It adds to a growing set of evidence that the Late Cretaceous period was not dominated by large or giant species, and that smaller pterosaurs may have been well represented in this time. As with other evidence of smaller pterosaurs, the fossil specimen is fragmentary and poorly preserved: researchers should check collections more carefully for misidentified or ignored pterosaur material, which may enhance our picture of pterosaur diversity and disparity at this time," added Martin-Silverstone.
News Article | February 21, 2017
This ice cream cone sporting woolly mammoth tusks inhabited by the Flying Spaghetti Monster is a creature called Haplophrentis. It actually existed. It made a small splash in Nature last month when scientists studying over 1,500 fossils of this creature made some new discoveries about its anatomy and, consequently, family tree. Haplophrentis is a type of hyolith, a group of shell-bearing creatures that was abundant during the 280 million years of the Paleozoic but went extinct during the Great Dying before dinosaurs even appeared. For a long time people have wondered exactly what they were and how they fit into Earth's evolutionary tree, because their odd combination of anatomy – a conical shell fitted with a shield-shaped lid and sometimes sporting a pair of spines – doesn’t resemble much else. But scientists didn't have much to go on. Most fossils contained only the hard parts of the creature, and the few traces of soft tissue that did occur commonly were unrevealing. So a trio of Canadian and British scientists rustled up the 1,500 fossils -- including several new soft-tissue containing specimens from the exciting new Marble Canyon and Stanley Glacier localities of Canada's Burgess Shale -- and, one would imagine, spent a great deal of time peering. Among the new fossils were 254 that preserved traces of the animal’s soft tissue. They saw that the animal had a retractable organ covered in 12-16 tentacles. The organ strongly resembles the feeding apparatus (a lophophore) of a modern group called the lophophorates. Here is what the modern lophophore of a moss animal, or bryozoan, looks like: The tentacles allowed them to conclude that the animal was not closely related to mollusks as has generally been thought, but instead related to a group of lophophorates called brachiopods. Brachiopods are still with us today in deep water and the polar ocean, but 500 million years ago they were even bigger business. The arrangement of the tentacles in adult Haplophrentis is very similar to that found in the larvae of modern brachiopods, but unlike the complex lophophore stylings of brachiopod adults. The fossils also indicated that the lophophore was retractable, and that the animal had a U-shaped digestive tract. Putting it all together, they came up with a hypothesis for how the creature looked and operated, as you can see in the artist's reconstruction at the top of this page and below. In the images below, a-d show the "Hatch Open" configuration, while e-f show "Business Hours are Over". Those tusks -- technically called helens -- are really something else. For the record, here are mammoth tusks, as depicted in a diorama at the Royal British Columbia Museum: Previously, scientists had speculated that Haplophrentis burrowed in the sediment. But in four separate fossils in the new study, smaller brachiopods had glued themselves to the hyolith's helens, as depicted in the reconstruction at the top of this post (go have a look). These same Haplophrentis fossils contained soft tissue traces and the shell parts still seemed firmly attached to one another, making it likely the brachiopods clung to the creature while it was still alive (the creature must have been buried quickly after death for it to be preserved so well). Today, brachiopods filter food from seawater, so their presence on the helens of a living hyolith indicates that Haplophrentis must have lived on top of the sediment and not within it. The authors speculate that the animal rotated its spiral-shaped tusks to prop itself up off the seabed, perhaps to elevate its feeding tentacles to a place where currents were stronger and food more abundant. Encrusting creatures (something like barnacles) were also found on Haplophrentis shells’ tops and bottoms, supporting the idea they could be lifted off the seabed like a lowrider.