Zhang Z.,Northwest University, China |
Holmer L.E.,Uppsala University |
Robson S.P.,The Manitoba Museum |
Hu S.,Yunnan Geological Survey and Yunnan Institute of Geological Science |
And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2011
Durophagy, the macro-predatory consumption of hard-shelled organisms, has been proposed as an important driving and selective force ("arms race") responsible for the explosive advent of Cambrian skeleton-bearing animals. Nevertheless, the direct evidence of durophagous predation is mostly restricted to borings or drillholes in skeletons at around the Ediacaran-Cambrian transition. In contrast, pre-ingestive breakage or crushing of shell, another important type of durophagous predation evidence, is very rarely fossilized. Here we present the first evidence of durophagous shell-breaking in an exceptionally preserved pedunculate lingulate brachiopod from the Lower Cambrian Wulongqing Formation (Series 2, early Stage 4), Yunnan, southern China. The repaired shells of Diandongia pista all have elongate (up to 36. mm) pedicles that demonstrate that they survived the failed predation and remained in situ. The bite embayment shows three sets of distinctive drape-like convex arcs of shell repairs, suggesting that the specific drape-like ornamentation usually seen in lingulate shells could be taken as reparative responses to shell damage and malformation. Discovery of sublethal shell damage demonstrates that durophagous predators may have caused an increasing predation pressure on brachiopods since the Canglangpuian Stage (Series 2, Stage 4). In contrast there are no records of durophagous shell-breaking recognized from thousands of Chengjiang (Series 2, Stage 3) specimens of D. pista with fully developed organization of tissues and organ system. It is therefore assumed that that predation was of little importance to the earliest evolution of Cambrian lingulates. © 2011.
Young G.A.,The Manitoba Museum |
Young G.A.,University of Manitoba |
Hagadorn J.W.,Denver Museum of Nature and Science
Palaeoworld | Year: 2010
Fossils of cnidarian medusae are extremely rare, although reports of fossil " medusoids," most of which do not represent medusae, are rather common. Our previous inability to distinguish these fossils has hampered attempts to investigate patterns and processes within the medusozoan fossil record. Here we describe criteria for the recognition of bona fide fossil medusae and use them to assess the evolutionary, paleoenvironmental, and taphonomic history of the Medusozoa. Criteria include distinctive sedimentologic and taphonomic features that result from transport, stranding, and burial of hydrous clasts, as well as unequivocal body structures comparable to those of extant animals. Because the latter are uncommon, most fossil medusae remain in open nomenclature; many are assigned to stem-group scyphozoans.The majority of described medusae are associated with coastal depositional environments (such as tidal flats or lagoons). They rarely occur in oxygen-poor deeper-water facies. All medusan groups have long geologic histories. Scyphozoa are known from the Cambrian, but more derived scyphomedusae were not demonstrably present until the Carboniferous; Mesozoic scyphozoans are rather diverse. Hydromedusae are known from the Ordovician but may extend back to the Cambrian. The record of cubozoans is shorter and sparser; the oldest definite cubozoan is Carboniferous in age. © 2010 Elsevier Ltd and Nanjing Institute of Geology and Palaeontology, CAS.
Brand U.,Brock University |
Came R.E.,University of New Hampshire |
Affek H.,Yale University |
Azmy K.,Memorial University of Newfoundland |
And 2 more authors.
Chemical Geology | Year: 2014
Global climate change impacts marine ecosystems, directly and indirectly, especially in the Arctic and Antarctic. We show the first long-term (1920-2011) time-series of oceanographic change in Hudson Bay, an arctic marine ecosystem, based on coupled brachiopod-calcite stable and clumped isotope results. Long-term decrease in brachiopod δ13C parallels that of seawater-DIC in Hudson Bay, and after considering its seasonal sea ice coverage, it is similar to that of the 13C-Suess effect observed in the North Atlantic and other regions. Acidification of Hudson Bay seawater leads warming by about 10-20years, and with intensified warming from the 1970s to 2010s closely coupled to earlier sea-ice breakup. Post-industrial warming of Hudson Bay is initially slow, but in later years, faster and of greater magnitude than of the coeval global oceans. Our observations for the past 90years suggest that climate-forced change contributed to an average increase of about 0.1°C and 3.6°C in sea-surface water temperature of Hudson Bay over the first 50 and subsequent 40years, respectively. This 3.7°C post-industrial warming of Hudson Bay seawater is about six times the 0.67°C increase observed during the past 100years in global ocean sea-surface temperature, which is about double the postulated increase of about 2°C for polar regions. Our results are consistent with the general notion that polar marine environments, such as Hudson Bay, can serve as sensitive indicators of change in climate, and of change still to come for lower latitude ecosystems. © 2014 Elsevier B.V.
News Article | November 8, 2016
WINNIPEG, MANITOBA--(Marketwired - Nov. 8, 2016) - The Honourable Jim Carr, Minister of Natural Resources and Member of Parliament (Winnipeg South Centre), on behalf of the Honourable Mélanie Joly, Minister of Canadian Heritage, will make an announcement on Wednesday about The Manitoba Museum. Please note that all details are subject to change. All times are local. The details are as follows: Follow us on Twitter, YouTube, Facebook, Instagram and Flickr.
News Article | November 10, 2016
The Honourable Jim Carr, Minister of Natural Resources and Member of Parliament (Winnipeg South Centre), today announced $2.5 million in funding to The Manitoba Museum for its project "Bringing Our Stories Forward." Minister Carr made this announcement on behalf of the Honourable Mélanie Joly, Minister of Canadian Heritage. This funding, provided through the Canada Cultural Spaces Fund, will revitalize the Museum and enable it to provide visitors with a more interactive and engaging experience. The project will include the renovation and renewal of several galleries and the purchase of state-of-the-art digital equipment. "The Government of Canada understands the importance of art and heritage facilities, which is why we committed to making significant new investments in cultural infrastructure. Our support for the renewal of The Manitoba Museum will help ensure Canadians have better access to our history, now and for generations to come." "Each year, thousands of visitors of all ages walk through the doors of The Manitoba Museum eager to learn and discover the history of our province. It is an iconic heritage institution that needs to be maintained, and I am proud to announce the Government of Canada's support to its renewal project. I look forward to seeing the changes once construction is complete." -The Honourable Jim Carr, Minister of Natural Resources and Member of Parliament (Winnipeg South Centre) "We are very grateful to the Government of Canada for supporting the renewal of one of the province's most beloved cultural institutions-The Manitoba Museum. This investment will build Manitoba pride and ensure that stories of Indigenous peoples and immigration are updated and that the visitor experience is enriched. As the Museum looks ahead to its 50th anniversary and the province's 150th anniversary, the time is right to invest in The Manitoba Museum." - Jeoff Chipman, Campaign Chair, Bringing Our Stories Forward, The Manitoba Museum Follow us on Twitter, YouTube, Facebook, Instagram and Flickr.
Elias R.J.,University of Manitoba |
Young G.A.,The Manitoba Museum |
Lee D.-J.,Andong National University |
Bae B.-Y.,Seoul National Science Museum
Geological Society Memoir | Year: 2013
During the Late Ordovician, Cincinnatian, the epicontinental seas and continental margin of Laurentia provided habitats that were suitable for corals. Biogeographical differentiation occurred within this equatorially placed continent, when corals were introduced to areas that had fundamentally different environments. There were four biogeographical divisions, characterized by distinctive faunas that included some endemic taxa: the Red River-Stony Mountain Province, Richmond Province, Edgewood Province and the less well understood, informal 'Continental Margin' Area. In each division, the potential for diversification and the capacity for diversity were determined by factors such as the duration and size of the division, the amount of immigration, the extent of evolution and biogeographical differentiation, faunal responses to changes in sea-level and climate, and the complexity of the ecological structure. The development of multiple biogeographical divisions, each contributing to overall diversity, enhanced the 'Great Ordovician Biodiversification Event'. During the latest Ordovician mass extinction, there was a reduction of diversity and loss of biogeographical divisions within Laurentia. The divisions were terminated when their characteristic taxa disappeared, in response to major environmental changes associated with glaciation in Gondwana and subsequent global warming. © The Geological Society of London 2013.
Robson D.B.,The Manitoba Museum
Endangered Species Research | Year: 2010
Previous studies suggest that low seed production due to pollinator competition and seed predation may negatively affect the reproduction of the rare forb western silvery aster Symphyotrichum sericeum in Canada. Research was conducted to determine normal flower and seed production and the impact of seed predation, and to ascertain whether clipping surrounding vegetation and/or fertilizing with nitrogen stimulates flower and seed production in S. sericeum. Only 41% of all stems observed produced capitula, and less than 40% of the seeds in each capitulum were filled. Flower production was negatively correlated with percentage vascular plant cover and positively correlated with percentage cryptogamic cover. The main seed predator was a weevil (Anthonomus sp.) that destroyed about one-third of all capitula produced. None of the treatments applied (e.g. clipped, fertilized and clipped × fertilized) significantly increased stem height, the percentage of flowering stems or seed production over the control; clipping actually decreased stem height. Fertilizing was the only treatment that showed some promise as it increased the number of capitula per flowering stem. Flower and seed production in S. sericeum may be facilitated by the presence of other species that modify the microenvironment. Low flower and seed production of plants in Canada is likely due to limited soil resources and pollen, and seed predation. © Inter-Research 2010.
Robson D.B.,The Manitoba Museum
Botany | Year: 2014
In Canada, silky prairie-clover (Dalea villosa var. villosa (Nutt.) Spreng) is a nationally rare plant, growing only in sand dunes in Saskatchewan and Manitoba. Previous research indicates that this species is incapable of self-pollination, making it dependent on insect pollinators for successful reproduction. The insect visitor community to D. villosa in Spruce Woods Provincial Park (SWPP), Manitoba, was documented and compared with that of 13 co-flowering plants that share some of its insect visitors. In total, 29 insect taxa were observed feeding on nectar or pollen from D. villosa. Hymenoptera were the most frequent visitors, comprising 60.7% of the taxa and making 93.5% of all visits. The visitation rate per stem to D. villosa (0.0042 stems·min-1) was the second highest of all of the plants with which it was compared. The insect visitor diversity was 4.0 (Simpson's reciprocal index), and the constancy index was 0.72. The high visitation rate, diversity, and constancy to this species may be due to a lack of competition for pollinators. Over half of the insect visitor taxa (54%) and visits (68%) were by omnivorous insects, as opposed to herbivorous ones. This means that there is interconnectivity between a mutualistic network involving D. villosa and several antagonistic networks.
Robson D.B.,The Manitoba Museum
Botany | Year: 2010
Flower-visiting insect activity to the rare Symphyotrichum sericeum (Vent.) G.L. Nesom and the common Solidago nemoralis Ait. var. longipetiolata (Mack. & Bush) Pal. & Steyerm. was examined to detect compositional and temporal similarities. A hand pollination experiment was conducted to determine whether pollen was limiting seed set. Of the 31 insect taxa that visited these plants, Bombus bifarius Cresson was the most common visitor to both species. More insect visitors of the Halictidae and Bombyliidae were received by S. sericeum than S. nemoralis, which received more visitors of the Syrphidae and Tachinidae. The insect visitation rate was not significantly different between the two plant species. Solidago nemoralis was visited by fewer insect taxa per day than S. sericeum, but the constancy of its visitors was higher. The insect visitor composition changed over time, with B. bifarius ignoring S. sericeum plants initially, then visiting them more frequently as the number of receptive S. nemoralis capitula declined. Hand pollination increased seed set in the ear- liest flowering capitula of S. sericeum, but not for those flowering during the peak. This research shows that the quantity of insect visits to the rare plant is comparable with that of the common plant but that pollination quality may be lower, particularly for early blooming capitula.
Bizecki Robson D.,The Manitoba Museum
Botany | Year: 2013
Pollination facilitation can occur when plant species share pollinators. Whether facilitation occurs depends on the flowering period overlap (synchrony), number of shared insect visitors (similarity), quantity and quality of insect visits, and the subsequent impact on seed production. Western Silvery Aster (Symphyotrichum sericeum (Vent.) G.L. Nesom) is a rare, self-incompatible plant visited by a wide range of generalist insect species. There are 22 common plant species that may facilitate insect visitation to the rare plant by supporting shared pollinators. Plant species with low synchrony and high similarity with S. sericeum are potential facilitators. In contrast, plant species with high synchrony and similarity likely act as competitors as the aggregative response to increasing plant density was saturating, suggesting that synchronously flowering species do not increase insect visitations. Hymenoptera responded more strongly than Diptera to increases in flowering stem density. These data suggest that facilitation of insect visitation between plant species via a numerical response that extends the flower season is possible but not likely via an aggregative response. Restoration of S. sericeum may therefore be more successful if potentially facilitating plants are grown with it; further testing of the impact of potential facilitators on seed production in S. sericeum is required.