Scydmobisetia gen. nov., the first definite Glandulariini from Upper Cretaceous Burmese amber (Coleoptera: Staphylinidae: Scydmaeninae)     

《Cretaceous Research》2016

The Glandulariini (=Cyrtoscydmini) includes about 60 genera comprising over 70% of the extant species of Scydmaeninae. This successful group is today very common and abundant in forests of all continents. However, while extinct representatives of much smaller extant tribes, as Clidicini, Eutheiini and Cephenniini, were described from Cretaceous deposits, named genera and species of Glandulariini were so far known only from much younger Baltic, Sicilian and Dominican ambers. Here we report the first genus and species of definite Glandulariini from the Upper Cretaceous Burmese amber, Scydmobisetia vetutissima Jałoszyński and Yamamoto, gen. and sp. nov. Scydmobisetia is the first known glandulariine beetle with a pair of very long vertexal sensilla chaetica, previously not found in this tribe, but common among unrelated Staphylinidae. The new genus shows similarities to the extant genera Anthicimimus, Sciacharis, Spinosciacharis and Horaeomorphus, but S. vetutissima has protibial modifications typical of males of some extant species of Euconnus. We discuss the apparent disproportion in the oldest fossil record of various tribes of scydmaenines as a result of identification problems, and not the lack of known fossils.  相似文献   

Cretaceous amber inclusions of Spain and Myanmar demonstrate early diversification and wide dispersal of Cephenniitae (Coleoptera: Staphylinidae: Scydmaeninae)     

《Cretaceous Research》2016

The taxonomic status of previously misplaced species of an ant-like stone beetle from Spanish amber (Albian) is clarified. Specimens of Kachinus magnificus (originally placed as incertae sedis within Scydmaenitae) were re-examined and their characters were found different from those of the type species of Kachinus from Myanmar amber. Consequently, Archeutheia gen. nov. is proposed to accommodate the Spanish species, resulting in Archeutheia magnifica comb. nov. Moreover, in a comprehensive phylogenetic analysis Archeutheia was placed as a sister group to extant Eutheia, within the tribe Eutheiini of Cephenniitae. A specimen of an undetermined genus from Myanmar amber clearly belonging in Cephenniini is also recorded. Both taxa represent the first definite Cretaceous Cephenniitae, a supertribe whose recent members are distributed on all continents but are especially diverse in the Oriental and East Palaearctic regions. This finding demonstrates a diversification of two presently most species-rich tribes of Cephenniitae already in Early Cretaceous. Archeutheia is strikingly similar to the extant species of Eutheia and Veraphis, showing male dimorphic characters (modified protrochanters) and antennal cavities characteristic of Palaearctic Eutheiini. This fact suggests a long morphological stability in the supertribe. A previously proposed hypothesis of an early presence of the Cephenniitae in the Northern Hemisphere is for the first time supported by the fossil record, and the palaeolocalities (western Europe and Southeast Asia) demonstrate a wide distribution of Cephenniitae in the Cretaceous and an early split of its ancestral lineage.  相似文献   

A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation,Alberta, Canada     

《Cretaceous Research》2016

A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds.  相似文献   

Environmental inequality and pollution advantage among immigrants in the United States     

《Applied geography (Sevenoaks, England)》2017

Environmental inequality scholarship has paid little attention to the disproportional exposure of immigrants in the United States (U.S.) to unfavorable environmental conditions. This study investigates whether new international migrants in the U.S. are exposed to environmental hazards and how this pattern varies among immigrant subpopulations (e.g., Hispanics, Asian, European). We combine sociodemographic information from the American Community Survey with toxicity-weighted chemical concentrations (Toxics Release Inventory) to model the relationship between toxin exposure and the relative population of recent immigrants across Public Use Microdata Areas (PUMAs, n = 2054) during 2005–2011. Results from spatial panel models show that immigrants tend to be less exposed to toxins, suggesting resilience instead of vulnerability. This pattern was pronounced among immigrants from Europe and Latin America (excluding Mexico). However, our results revealed that Mexican immigrants are disproportionately exposed to environmental hazards in wealthy regions.  相似文献   

A low resolution map of Europa from four occultations by Io     

James R. Vermilion  Roger N. Clark  Thomas F. Greene  Jon F. Seamans  William F. Yantis 《Icarus》1974,23(1):89-96

Analysis of three occultations of JII (Europa) by JI (Io) has resulted in a preliminary reflectivity map of JII for the hemisphere centered on longitude 324°, a measurement of 1483±20 km for the radius of JII, estimates of the event impact parameters, determination of the mid event times, and a visual geometric albedo, p_ν = 0.74, for JII. A fourth occultation light curve was used after derivation of the results to confirm their validity.  相似文献   

The balance between microzooplankton grazing and phytoplankton growth in a highly productive estuarine fjord   总被引：1，自引：4，他引：1  

Andrew W. Leising  Rita Horner  James J. Pierson  James Postel  Claudia Halsband-Lenk 《Progress in Oceanography》2005,67(3-4):366

During 24, three-day cruises to Dabob Bay, Washington State, USA, from February 4 to April 26, 2002, and February 4 to May 1 2003, we examined the relative growth and grazing rates of phytoplankton and microzooplankton using dilution experiments. Experiments were conducted over two time intervals: 8–10 h during the nighttime only, or 24 h from noon to noon. We used water from two depths during each cruise: from the surface mixed layer, and from a deep layer below the seasonal thermocline. During 2002, there was one mid-sized bloom consisting mainly of Thalassiosira spp. in early February, and a larger bloom in April comprised of two Chaetoceros spp. and Phaeocystis sp. During 2003, there were also two blooms, one in early February, which was again dominated by Thalassiosira spp., and a second larger bloom in mid-April, comprised mainly of Thalassiosira spp. and Chaetoceros spp. During all four of these blooms, and for both water source depths, specific grazing rates of microzooplankton were most often as high or higher than the calculated phytoplankton specific growth rates. The major microzooplankton categories that could have accounted for this were (1) a large Gyrodinium spp., (2) a group of fusiform-shaped mid-sized Protoperidinium species, and (3) three loosely defined taxonomic groups consisting of naked ciliates, tintinnids, and unidentified heterotrophic dinoflagellates. Based on our measurements, it appears that the microzooplankton community grazing pressure can often exert significant control on phytoplankton biomass, even during the extremely productive spring bloom periods and under several different diatom-dominated bloom types. These results suggest that even in highly productive estuarine ecosystems, which are often nurseries to economically important fisheries species, microzooplankton play a critical role and may significantly alter the availability and efficiency of transfer of energy to higher trophic levels.  相似文献   

Seasonal variation in the molt status of an oceanic copepod     

Catherine Lynn Johnson 《Progress in Oceanography》2004,62(1):15-32

The timing of diapause, or suppressed development, in the dominant California Current copepod Calanus pacificus was examined in two ways. Diapause timing was inferred from changes in the abundance of deep, diapausing C. pacificus over a full year at a station off southern California, USA. Jaw phase and ecdysteroid content, indicators of molt cycle status in C. pacificus, were also examined to determine if shifts toward early molt phases, as are observed in diapausing Calanus, were also found among surface C. pacificus during periods when the abundance of deep, diapausing C. pacificus was increasing. The abundance of diapausing C. pacificus in deep water increased from June to mid-October, then declined from October to March. The percentage of surface-living C. pacificus CV with postmolt jaws, the earliest jaw phase, was significantly higher from June to mid-October than at other times. The ecdysteroid content of surface-living C. pacificus CV was also significantly lower during June to mid-October than during late October to May. Both of these changes indicate a shift to earlier molt phases in surface-living C. pacificus CV during periods of onset of diapause. However, the molt status of surface CV was variable from June to mid-October, suggesting that preparation for diapause was spatially or temporally heterogeneous. Hypotheses about environmental cues that induce diapause were evaluated, although the effect of cues on possibly sensitive stages could not be considered. The abundance of diapausing C. pacificus increased during a period of warm upper water column temperature and generally high and declining photoperiod; however, evaluation of the cues inducing diapause was inconclusive.  相似文献   

Travails of the flying Dutchmen : Lloyd's standard form of salvage agreement and the US salvage industry     

Mark Cohen 《Marine Policy》1982,6(4):265-286

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Benthic macrofauna–habitat associations in Willapa Bay, Washington, USA   总被引：1，自引：0，他引：1  

Steven P. Ferraro  Faith A. Cole 《Estuarine, Coastal and Shelf Science》2007,71(3-4):491-507

Estuary-wide benthic macrofauna–habitat associations in Willapa Bay, Washington, United States, were determined for 4 habitats (eelgrass [Zostera marina], Atlantic cordgrass [Spartina alterniflora], mud shrimp [Upogebia pugettensis], ghost shrimp [Neotrypaea californiensis]) in 1996 and 7 habitats (eelgrass, Atlantic cordgrass, mud shrimp, ghost shrimp, oyster [Crassostrea gigas], bare mud/sand, subtidal) in 1998. Most benthic macrofaunal species inhabited multiple habitats; however, 2 dominants, a fanworm, Manayunkia aestuarina, in Spartina, and a sand dollar, Dendraster excentricus, in subtidal, were rare or absent in all other habitats. Benthic macrofaunal Bray–Curtis similarity varied among all habitats except eelgrass and oyster. There were significant differences among habitats within- and between-years on several of the following ecological indicators: mean number of species (S), abundance (A), biomass (B), abundance of deposit (AD), suspension (AS), and facultative (AF) feeders, Swartz's index (SI), Brillouin's index (H), and jackknife estimates of habitat species richness (HSR). In the 4 habitats sampled in both years, A was about 2.5× greater in 1996 (a La Niña year) than 1998 (a strong El Niño year) yet relative values of S, A, B, AD, AS, SI, and H among the habitats were not significantly different, indicating strong benthic macrofauna–habitat associations despite considerable climatic and environmental variability. In general, the rank order of habitats on indicators associated with high diversity and productivity (high S, A, B, SI, H, HSR) was eelgrass = oyster ≥ Atlantic cordgrass ≥ mud shrimp ≥ bare mud/sand ≥ ghost shrimp = subtidal. Vegetation, burrowing shrimp, and oyster density and sediment %silt + clay and %total organic carbon were generally poor, temporally inconsistent predictors of ecological indicator variability within habitats. The benthic macrofauna–habitat associations in this study can be used to help identify critical habitats, prioritize habitats for environmental protection, index habitat suitability, assess habitat equivalency, and as habitat value criteria in ecological risk assessments in Willapa Bay.  相似文献   

Unusual features of the distribution of Radon-222 in the bottom waters of the continental slope of the Mid-Atlantic Bight: Hydrodynamic implications     

Steven R. Carson  Pierre E. Biscaye   《Progress in Oceanography》2006,70(2-4):271

²²²Rn was measured in the near-bottom waters of the continental slope of the Mid-Atlantic Bight. Separate measurements of the ²²²Rn supported by dissolved ²²⁶Ra allowed the excess ²²²Rn that is derived from the underlying sediments to be distinguished. Measurements of production of ²²²Rn by the sediments were used to calculate fluxes of ²²²Rn from sediments that would be expected as a result of molecular diffusion. On the upper slope and on the lower slope excess ²²²Rn standing crops were, respectively, greater than and consistent with fluxes of radon from sediments by molecular diffusion as are typical of most ocean environments. On the middle slope, however, observed excess ²²²Rn concentrations and standing crops were significantly lower than what would be expected from the calculated fluxes from the underlying sediments. This unusual feature of low radon concentrations on the middle slope is referred to as the low-radon zone (LRZ). This LRZ was always present over several years and seasons, but was variable in intensity (excess-radon concentration and standing crop) and in location on the slope. Low concentrations of suspended particulate matter and low current velocities observed by others in the same region are consistent with low mixing as a possible cause of the LRZ. Radon profile shapes and recent work by others on near bottom mixing due to interactions between topography and internal waves, however, suggest that high mixing due to internal waves is a more likely cause of the LRZ.  相似文献