Virginia Museum of Natural History
Virginia Museum of Natural History
Hayward P.J.,University of Swansea |
Winston J.E.,Virginia Museum of Natural History
Journal of Natural History | Year: 2011
Thirty-two species of cheilostomate Bryozoa are described and illustrated from 26 stations sampled by the United States Antarctic Research Program, including 29 new species and two new genera. A further new genus is introduced for two species formerly attributed to Osthimosia Jullien, 1888. One station was located in the Ross Sea and three in the cold temperate South Pacific; 14 stations were sampled in the region of the Scotia Arc, south of the Antarctic Convergence, and eight from the subantarctic southwest Atlantic, mostly in the vicinity of Tierra del Fuego. Nine new species were present in the Antarctic samples, whereas those from the southwest Atlantic yielded 18 new species and the two new genera. Three of the new subantarctic species are attributed to genera formerly considered to be Antarctic endemics, while the two newly assigned species of Osthimosia are presently known only from Antarctic localities. © 2011 Taylor & Francis.
News Article | September 15, 2016
The species of alligator roaming Florida's swamps and golf courses may be millions of years older than previously thought, scientists from the University of Florida said. What's more, the sharp-toothed reptiles we see today may be almost biologically identical to their millennia-old ancestors — an incredibly rare trait for most living species, according to a pair of studies shared with Mashable this week. "What we saw 8 million years ago in Florida is virtually the same thing as what we have there today," Evan Whiting, the studies' lead author and a vertebrate paleontologist, said by phone from Gainesville. SEE ALSO: Greenland sharks could be the world's longest-living vertebrates Whiting and his research team compared the fossils of the American alligator (Alligator mississippiensis) with those of extinct alligator species. They found that the minute differences in each species' forms were instead just variations of the same singular species. Their findings extend the American alligator's lineage by about 6 million years, according to the study published in the Journal of Herpetology. Scientists had previously believed the species emerged about 2 million years ago, when the most recent Ice Age began. "To hit this exact set of features in the American alligator, and for them to keep such a huge presence in the area that's now the Southeast U.S. for 7 to 8 million years, is nothing short of spectacular," Alex Hastings, the assistant curator of paleontology at the Virginia Museum of Natural History, told Mashable. "The fact that their populations are doing pretty well today is a testament to their evolutionary success," said Hastings, who was not involved in the University of Florida studies. The Florida researchers also found that, millions of years ago, American alligators shared the Florida peninsula with a species of 20-foot-long crocodiles, according to a separate study in the journal Palaeogeography, Palaeoclimatology, Palaeoecology. While the crocs fed mostly on marine-based prey, the alligators stuck to freshwater or terrestrial sources — a trait that still persists in American alligators, which lack the salt-secreting glands needed to thrive in saltwater. The Alligator mississippiensis has proved resilient to naturally occurring changes in the climate and environment over millions of years. But in the modern era, the species' survival is increasingly at risk. Image: journal of herpetology/"Cranial Polymorphism and Systematics of Miocene and Living Alligator in North America" Florida's booming population and sprawling real estate have steadily destroyed the alligators' habitat in recent decades. The reptiles landed on the U.S. endangered species list in the late 1960s, although the species was removed in the 1980s after the population recovered thanks to habitat protection efforts. Encroaching on alligators' habitat has dangerous consequences for humans, as well. In June, an alligator killed a toddler visiting Walt Disney World in Orlando, marking the fourteenth deadly alligator attack in Florida since 2000. Human-caused climate change poses another serious threat to the American alligator. Florida's low-lying landscape and porous bedrock make it particularly vulnerable to rising sea levels and saltwater intrusion, which could destroy the gators' freshwater dwellings along with homes and communities across the peninsula. An American Alligator swims in Everglades National Park, Florida, on June 23, 2016. "With increasing sea levels, we may see the available habitat for American alligators disappear," Whiting said. As Florida sinks underwater and global temperatures warm, the alligator may move north over centuries to perhaps as far north as modern-day South Dakota and Nebraska, where Alligator mississippiensis likely originated. "These things could be recolonizing parts of the United States that they haven't occupied in millions of years," Hastings said.
Vieira L.M.,University of Sao Paulo |
Winston J.E.,Virginia Museum of Natural History |
Fehlauer-Ale K.H.,University of Sao Paulo
PLoS ONE | Year: 2012
Background: Bugula is a speciose genus of marine bryozoans, represented by both endemic and cosmopolitan species distributed in tropical and temperate waters and important to marine biologists because of the occurrence of many species in harbor and fouling communities, therefore as potential invaders. The southeastern Brazilian coast in the southern Atlantic hosts the highest known diversity of the genus, a status intimately associated with the intensity of collecting efforts. Methodology: Morphological data based on the examination of living specimens, scanning electron and light microscopic images, and morphometric analyses were used to assess the diversity of Bugula along the coastal areas of southern, northeastern, and southeastern Brazil. In this study, morphological species boundaries were based mainly on avicularian characters. For two morphologically very similar species, boundaries are partially supported by 16 S rDNA molecular data. Results: Nine species are newly described from Brazil, as follows: Bugula bowiei n. sp. (= Bugula turrita sensu Marcus, 1937) from the southern, northeastern, and southeastern coasts; Bugula foliolata n. sp. (= Bugula flabellata sensu Marcus, 1938), Bugula guara n. sp., Bugula biota n. sp. and Bugula ingens n. sp from the southeastern coast; Bugula gnoma n. sp. and Bugula alba n. sp. from the northeastern coast; Bugula rochae n. sp. (= Bugula uniserialis sensu Marcus, 1937) from the southern coast; and Bugula migottoi n. sp., from the southeastern and southern coasts. Conclusion: The results contribute to the morphological characterization and the knowledge of the species richness of the genus in the southwestern Atlantic (i.e., Brazil), through the description of new species in poorly sampled areas and also on the southeastern coast of that country. Additionally, the taxonomic status of the Brazilian specimens attributed to B. flabellata, B. turrita and B. uniserialis are clarified by detailed studies on zooidal and avicularia morphology. © 2012 Vieira et al.
Winston J.E.,Virginia Museum of Natural History |
Vieira L.M.,University of Sao Paulo
Zootaxa | Year: 2013
This paper describes 22 species of marine bryozoans found in the sand-grain-encrusting interstitial epifauna of the northeast coast of São Paulo state, Brazil: one new cyclostome, Disporella calcitrapa sp. nov., and 21 cheilostomes. Sixteen of the cheilostomes are new species, and three represent new genera. They are Ammatophora arenacea sp. nov., Discoporella gemmulifera sp. nov., Puellina caraguata sp. nov., Puellina tuba sp. nov., Rosulapelta rosetta gen. et sp. nov., Collarina spicata sp. nov., Hippothoa calcicola sp. nov., Trypostega ilhabelae sp. nov., Reptadeonella granulosa sp. nov., Drepano-phora irregularis sp. nov., Allotherenia sabulosa gen. et sp. nov., Bryopesanser tilbrooki sp. nov., Psammocleidochasma tridentatum gen. et sp. nov., Celleporina abstrusa sp. nov., Hippoporella castellana sp. nov., and Hippoporella sabulonis sp. nov. Other species found in this habitat, Alderina smitti, Cymulopora uniserialis, Vibracellina laxibasis, Akatopora leucocypha, and Smittipora sawayai, have previously been described. The family Cymuloporidae fam. nov. is erected for Cymulopora and Crepis. The occurrence in this habitat of living colonies of bryozoans more characteristic of larger sub-tidal shell substrata indicates the potential importance of an interstitial refuge in maintaining and dispersing encrusting bryozoan populations along continental shelves where larger substrata are absent or rare. Copyright © 2013 Magnolia Press.
Ivanov K.,Cleveland State University |
Keiper J.,Virginia Museum of Natural History
Biodiversity and Conservation | Year: 2010
The effects of forest edge on ant species richness and community composition were examined within an urbanized area of northeast Ohio. The ground-dwelling ant fauna was inventoried in three deciduous forest fragments that have resulted from human disturbance. We surveyed ants via leaf-litter extraction along 150 m transects positioned perpendicular to the forest edge. We collected 4,670 individuals from 14 genera and 29 species. Samples closest to the forest edge contained more species and accumulated species at a higher rate than did samples located in the forest interior. Our rarefied and expected richness estimates revealed a decline of species richness from edge to forest interior. The higher ant richness at the forest edge was due mostly to the presence of species characteristic of the neighboring open habitats. Although most of the typical forest ant species were represented equally at the edge and at the forest interior, a few responded to the presence of edges with changes in their relative abundance and frequency of occurrence. Forest edges had a higher proportion of opportunistic species and a lower proportion of cryptic ants, whereas interior locations exhibited a more even distribution among ant functional groups. In addition, we documented a community composition shift between the edge and the forest interior. Consistent with previous findings, we suggest that the edge effects are most pronounced within 25 m of the forest edge, which may have implications for the overall conservation of forest-dwelling fauna. © 2010 Springer Science+Business Media B.V.
Frost B.R.,University of Wyoming |
Evans K.A.,Curtin University Australia |
Swapp S.M.,University of Wyoming |
Beard J.S.,Virginia Museum of Natural History |
Mothersole F.E.,Curtin University Australia
Lithos | Year: 2013
Dunite from New Caledonia displays three types of serpentine-dominated veins. The earliest, type 1 veins are narrow (50-100μm wide) and rarely extend across more than a single olivine grain. They are lizardite, contain abundant brucite and never contain magnetite. Type 2 veins are 0.01 to 0.1mm wide, extend across several olivine grains and cut across the type 1 veins. They are lizardite, contain magnetite, often in vein interiors, and contain less brucite than type 1 veins. Type 3 veins are dominantly chrysotile, cm-scale, have a magnetite-rich core, and extend for meters or more. Analyses of two representative samples indicate that the type 1 veins have relatively Fe-rich serpentine (XMg=0.92) and brucite (XMg=0.82). These minerals are less magnesian than those in the type 2 veins; serpentine has XMg=0.93-0.94 and brucite has XMg=0.84. In the magnetite-rich core to the type 3 vein both serpentine (XMg=0.94-0.97) and one of the two brucite populations (XMg=0.94) are Mg-rich. Opx in harzburgite layers in these samples is cut by serpentine veins that are on the order of 0.05mm wide. The serpentine veins after Opx lack talc or magnetite and, as with veins cutting olivine, the older veins are more Fe rich (XMg=0.84) than the younger veins (XMg=0.90). We conclude that the formation of magnetite was accompanied by the extraction of iron from the early-formed serpentine and brucite.Thermodynamic calculations suggest that the type 1 veins formed in a rock-dominated system where the activities of FeO, MgO, and SiO2 were dictated by the compositions of olivine and orthopyroxene. In contrast the type 2 veins were formed in a more fluid-dominated system where the infiltrating fluid was relatively oxidizing and out of equilibrium with the original brucite-serpentine assemblage. Reduction of this fluid was accompanied by reaction of brucite and serpentine to magnetite and hydrogen. By producing magnetite, this reaction extracted iron from brucite and serpentine, making them both more magnesian. This would drive the brucite-serpentine-magnetite assemblage to higher oxygen fugacity, progressively decreasing the efficiency of the magnetite-forming reactions. © 2013 Elsevier B.V.
Hoffman R.L.,Virginia Museum of Natural History
Zootaxa | Year: 2011
The name Rondostreptus kiellandi is proposed for an undescribed genus and species of Spirostreptidae apparently endemic to the Rondo Plateau in southeastern Tanzania. It appears to have no close relatives among the known spirostreptid fauna of East Africa. Copyright © 2011. Magnolia Press.
Frost C.D.,University of Wyoming |
Frost B.R.,University of Wyoming |
Beard J.S.,Virginia Museum of Natural History
American Mineralogist | Year: 2016
Silica-rich granites and rhyolites are components of igneous rock suites found in many tectonic environments, both continental and oceanic. Silica-rich magmas may arise by a range of processes including partial melting, magma mixing, melt extraction from a crystal mush, and fractional crystallization. These processes may result in rocks dominated by quartz and feldspars. Even though their mineralogies are similar, silica-rich rocks retain in their major and trace element geochemical compositions evidence of their petrogenesis. In this paper we examine silica-rich rocks from various tectonic settings, and from their geochemical compositions we identify six groups with distinct origins. Three groups form by differentiation: ferroan alkali-calcic magmas arise by differentiation of tholeiite, magnesian calc-alkalic or calcic magmas form by differentiation of high-Al basalt or andesite, and ferroan peralkaline magmas derive from transitional or alkali basalt. Peraluminous leucogranites form by partial melting of pelitic rocks, and ferroan calc-alkalic rocks by partial melting of tonalite or granodiorite. The final group, the trondhjemites, is derived from basaltic rocks. Trondhjemites include Archean trondhjemites, peraluminous trondhjemites, and oceanic plagiogranites, each with distinct geochemical signatures reflecting their different origins. Volcanic and plutonic silica-rich rocks rarely are exposed together in a single magmatic center. Therefore, in relating extrusive complements to intrusive silica-rich rocks and determining whether they are geochemically identical, comparing rocks formed from the same source rocks by the same process is important; this classification aids in that undertaking. © 2016 by Walter de Gruyter Berlin/Boston.
Ivanov K.,Virginia Museum of Natural History
Journal of Hymenoptera Research | Year: 2016
The worldwide transfer of plants and animals outside their native ranges is an ever increasing problem for global biodiversity. Ants are no exception and many species have been transported to new locations often with profound negative impacts on local biota. The current study is based on data gathered since the publication of the "Ants of Ohio" in 2005. Here I expand on our knowledge of Ohio's myrmecofauna by contributing new records, new distributional information and natural history notes. The list presented here contains 10 species with origins in a variety of geographic regions, including South America, Europe, Asia, and Indo-Australia. Two distinct groups of exotics, somewhat dibimilar in their geographic origin, occur in Ohio: a) 3 species of temperate Eurasian origin that have established reproducing outdoor populations; and b) 7 tropical tramp species currently confined to man-made structures. Only Nylanderia flavipes (Smith, 1874) is currently seen to be of concern although its effects on local ant communities appear to be restricted largely to already disturbed habitats. A systematic sampling of disturbed areas, urban sites, plant nurseries and conservatories, where new arrivals can be expected, would extend and build upon our current knowledge of Ohio's exotic ant fauna. Copyright © 2016 Kaloyan Ivanov.
Winston J.E.,Virginia Museum of Natural History
Integrative and Comparative Biology | Year: 2010
Who needs to go to outer space to study alien beings when the oceans of our own planet abound with bizarre and unknown creatures? Many of them belong to sessile clonal and colonial groups, including sponges, hydroids, corals, octocorals, ascidians, bryozoans, and some polychaetes. Their life histories, in many ways unlike our own, are a challenge for biologists. Studying their ecology, behavior, and taxonomy means trying to "think like a colony" to understand the factors important in their lives. Until the 1980s, most marine ecologists ignored these difficult modular organisms. Plant ecologists showed them ways to deal with the two levels of asexually produced modules and genetic individuals, leading to a surge in research on the ecology of clonal and colonial marine invertebrates. Bryozoans make excellent model colonial animals. Their life histories range from ephemeral to perennial. Aspects of their lives such as growth, reproduction, partial mortality due to predation or fouling, and the behavior of both autozooids and polymorphs can be studied at the level of the colony, as well as that of the individual module, in living colonies and over time. © The Author 2010. Published oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.