The distribution of hydroid sibling species on hermit crabs in estuaries in the Gulf of Maine

Estuaries in the Gulf of Maine contain disjunct, isolated populations of a number of invertebrate taxa typically distributed only sound of Cape Cod. These estuarine populations may either be remnants of a southern fauna that were stranded by Quaternary changes in water temperature, or they may have been established more recently via larvae that entered the estuaries from the open ocean. We tested these hypotheses by examining the distribution of sibling species of hydroids that are symbiotic on paguriid hermit crabs. These crab-hydroid species pairs differ greatly in their ability to colonize new areas through the water column. The hermit crabs possess a planktonic larva that can disperse great distances, while the hydroids have a crawling planula larva that is extremely limited in its dispersal capabilities. Consequently, estuarine hermit crab populations that lack their native hydroid symbiont are likely to have originated by larval colonization. Hydroid sibling species were identified on the basis of MDH electromorphs. Species identifications were confirmed through a limited number of test matings with colonies of known species identity. In three out of the four estuaries that we examined, shells inhabited by the southern hermit crab,Pagurus longicarpus, were occupied only by the local northern hydroid,Hydractinia polyclina. This pattern is consistent with a more recent establishment of the hermit crab populations through larval dispersal or transport. However, in Casco Bay, shells inhabited byP. longicarpus were occupied by a mixture of the northern hydroid,H. polyclina, and the southern hydroid,H. symbiolongicarpus, that is associated withP. longicarpus throughout the southern part of its range. Thus, theP. longicarpus population in Casco Bay may either be a relict of a former, more broadly distributed population of this crab in the Gulf of Maine, or if recently established, is likely to have originated by the introduction of adult crabs with hydroid-covered shells.     

The cyclopoid copepods,Hemicyclops adhaerens andSaphirella sp., in the Damariscotta River estuary,maine, with a note to their possible relationship

During the 14-month collection period,Hemicyclops always appeared as naupliar stages andSaphirella as immature copepodite stages at 3 stations in the middle and lower estuary.Hemicyclops nauplii were abundant during late spring and summer, with a seasonal maximum of 7448/m³ in late spring at the upstream station.Saphirella stages were observed throughout the year, but higher population densities generally occurred in the summer and fall; the highest density was 3413/m³. Both species were usually more abundant upstream than downstream. The larvae may be life stages of a single bottom-dwelling species,Hemicyclops adhaerens.     

Dinosaur eggshells from the Santonian Milk River Formation of Alberta,Canada

The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous.     

Environmental application and phytotoxicity of anaerobic digestate from pig farming by in vitro and in vivo trials

Anaerobic digestate is a by-product from the biogas production which can be applied as replacement for mineral fertilizers. But digestate has both phytostimulating and phytotoxic effects on plants. Fertilizers toxicity and phytotoxicity should be measured to preserve the environment. The phytotoxicity of digestate from anaerobic digestion of swine manure was evaluated using several official protocols. Germination toxicity was tested on Pisum sativum L. and Lepidium sativum L., roots elongation on Hordeum vulgare L. and shoots elongation on Lactuca sativa L. To determine digestate growth toxicity, pot experiments were performed on two Solanum lycopersicum L. cvs. Digestate dilutions ranging from 5 to 30 % were tested in the different assays. Standard protocols were applied to non-standard species: Cichorium endivia L. (shoots elongation) and two Capsicum annuum L. cvs (pot trials). Digestate concentrations stimulating germination and early life stages were between 2 and 3 %. Pot trials suggested that during more advanced growth stages, digestate can be applied at 20–30 %. The main finding was that to minimize digestate phytotoxicity, direct contact with germinating seeds or young plants should be avoided. During plants late growth, digestate administration might be increased carefully to minimize salinity and ammonia excess. Soil samples from the pot trials were analysed at the starting, mid- and final experimental stages. Conclusion was that digestate utilization may have also a soil liming effect, increasing electric conductivity, pH and contrasting soil acidification.     

Triassic biochronology: State of the art and main problems

According to known resolution of the IUGS, the International Stratigraphic Commission entrusted its subcommissions with a task to prepare proposals for the official approval of boundaries between Phanerozoic stages. Specially organized working groups were later renamed as special teams for seeking the Global Stratotype Sections and Points (GSSP) for these boundaries. In 2001, the GSSP of lower boundary for the Induan Stage, the basal one in the Triassic System, was officially approved to be in the Meishan section of southern China. The selection appeared to be lame, because the Permian-Triassic boundary layers of the stratotype section are lacking ammonoids. As a result, this boundary is now based only on the first occurrence level (FO) of conodont species Hindeodus parvus. Soon, the proposal of Chinese paleontologists to consider the western Pingdingshan section in the Anhui Province as the GSSP for the lower boundary of the Olenekian Stage may win the official recognition. This boundary between the Olenekian and Anisian stages, which is placed at the FO of conodont species Neospathodus waageni is the least debatable. The Mt. Desli Caira section in northern Dobrogea (Romania) is most appropriate for its global stratotype. In contrast, the Anisian-Ladinian boundary appeared to be most disputable. The Subcommission on Triassic Stratigraphy should select one of three GSSP candidates proposed. The lower Carnian boundary traditionally drawn at the aon Zone base suffered some changes. It is proposed to place it at the FO of the ammonoid genus Daxatina with the GSSP in the Dolomites of Italy. The Norian and Rhaetian boundaries are under discussion.     

Balanoglossites ichnofabrics from the Middle Ordovician Volkhov formation (St. Petersburg Region, Russia)

The limestone succession of the Middle Ordovician Volkhov Formation in the St. Petersburg region (Russia) exposes numerous horizons with firm- and hardgrounds below omission surfaces, which contain trace fossils attributable to the ichnogenus Balanoglossites Mägdefrau, 1932. Although known from the literature since 75 years, such trace fossils were previously only informally described as “Korrosionsgruben”, “Karandashi”, or ascribed to different ichnotaxa such as Trypanites, Arenicolites and Pseudopolydorites. Owing to their complexity and often high bioturbation density, the morphology of these trace fossils is difficult to capture. Ichnofabrics containing Balanoglossites triadicus were studied in detail from sawn rock faces, broken rock blocks and sectioned slabs, including those from historical buildings in St. Petersburg. Accordingly, different trace-fossil elements can be revealed in dependence on the original substrate consistency, reflecting various stages of lithification: Mineral-stained and Trypanites-perforated hardground surfaces are bioeroded with long elongated grooves which are assigned to the ichnogenus Sulcichnus. Subtle openings lead into the partly lithified limestone where they branch into complex galleries of B. triadicus. They are characterized by J-, U- and Y-shaped shafts and multiply branched tunnels, which gradually continue into the underlying firmground. Other portions of the ichnofabric only exhibit biodeformational structures or the strongly compacted and branched burrow networks Labyrintichnus, which is due to the original soft sediment consistency. Balanoglossites ichnofabrics demarcate certain omission surfaces within the Dikari Limestone and can be traced for more than 300 km, supporting the regional lithostratigraphical correlation. The trace maker of B. triadicus and related trace fossils is interpreted to be a eunicid polychate with the ability to bioerode and burrow the sediment. The studied material from the Ordovician is similar to the Balanoglossites from the type area, the Triassic of Germany, in many respects. B. triadicus is a very common trace fossil in Ordovician and other Palaeozoic rocks of Baltoscandia and North America but so far has been seldom identified as such but instead is commonly confused with Thalassinoides, from which, however, it differs in several aspects.     

A new caraboid larva from the Middle Jurassic of China (Insecta: Coleoptera)

A new species of caraboid larva (Coleoptera, Adephaga), Carabilarva gongi sp. nov., is described based on a well-preserved specimen from the Middle Jurassic Daohugou deposits (in the upper part of Jiulongshan Formation) of Inner Mongolia, China. It is the fourth caraboid larva from the Mesozoic, and differs from the other three Mesozoic species mainly in having a longer body with shorter mandibles. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) show that this Daohugou fossil is preserved as carbonaceous compressions that lost the micro-structure, such as macrochaetae.     

New antlion species (Insecta,Neuroptera, Palaeoleontidae) from the Lower Cretaceous Crato Formation in northeastern Brazil

Two new palaeoleontid species, Baisopardus escuilliei sp. nov. and Baisopardus pumilio sp. nov., are described, based on compression fossils from the Crato Formation in northeastern Brazil. The external morphology, particularly the wing venations, are analysed and compared with all genera of Palaeoleontidae. The previously proposed synonymy of Baisopardus with Neurastenyx is discussed. Neurastenyx, proven to be a poorly known genus based on an incomplete type fossil, is limited to its sole type species as a Myrmeleontoidea incertae sedis nov. sit. Consequently the genus Baisopardus is restored and all the other species previously included in Neurastenyx are transferred into Baisopardus.     

Mechanisms of exsolution in omphacites from high temperature,type B,eclogites

The microstructural development during the transformation of omphacite into pyroxene-plagioclase symplectites has been studied in some eclogites from the Seve nappe, Central Scandinavian Caledonides. The omphacite transformation can be described as a discontinuous precipitation reaction that occurred in two clearly defined stages to produce a coarser type A, followed by a finer, type B symplectite. Each type has its distinctive chemistry. The combination of microstructural and chemical characteristics of the transformation is used to reconstruct the early stages of the cooling history of the eclogites. In addition, based on a classification of phase transformations according to growth processes, the continuous exsolution reaction reported in high-temperature omphacites is combined with the discontinuous reaction in a time-temperature transformation (TTT) diagram to produce a more unified view of the exsolution in the omphacites.     

Climatic speciation in Japanese ground crickets

The two species groups of ground cricket previously known as P. taprobanensis and P. fascipes are widely distributed from the tropical to temperate regions of East Asia. In the Japanese Islands they show parallel variations along a latitudinal gradient in both developmental and morphometric traits. The ovipositor length varies continuously from 44 to 28°N, but this cline is disrupted by an abrupt shortening farther south. The disruption is associated with changes in the life cycle from the presence to virtual absence of egg diapause and from a short-day to long-day type of nymphal photoperiodic response. It is inferred that the two different types of life cycle were selected for in the temperate and subtropical climates, respectively, and that this differential selection resulted in speciation. Since climatic adaptation seems to be the primary factor involved, this sort of divergence may be called “climatic speciation”.     

Fracture evolution and energy mechanism of deep-buried carbonaceous slate

In order to study the influence of confining pressure and water content on the mechanical properties, fracture evolution and energy damage mechanism of deep-buried carbonaceous slate, uniaxial and triaxial compression tests were carried out under natural and saturated states and acoustic emission monitored. The deep-buried carbonaceous slate samples were obtained at a depth of 1020 m from the Lanjiayan tunnel in Sichuan province, China, where the maximum in situ stress has been measured at 44.2 MPa. The results suggest that water has a significant softening effect on the strength and deformation characteristics of carbonaceous slate, but the effect decreases with an increase in the confining pressure. When both the confining pressure and water content are increased, the acoustic emission events and dissipated energy gradually increase at the pre-peak and post-peak stages. Thus, the AE evolution type seen in the natural state under low confining pressure usually presents as a main shock-type event, and it changes to a foreshock–main shock–after shock event when saturated and at high confining pressures. Based on the S-shaped energy evolution law, the damage evolution process of carbonaceous slate was analyzed. The damage stress thresholds σ _ea and σ _eb were obtained, which can be considered as the thresholds of the rock entering the energy-hardening and energy-softening stages. Finally, a new brittleness energy index BDE is proposed to describe the influence of confining pressure and water content on the damage mechanism of deep-buried carbonaceous slate.     

A preliminary study on mineralogical and chemical compositions of some chondrites falling in China

Samples are available from 37 stony meteorites falling in China. Twenty-two chondrites are examined in terms of chemical and mineral compositions, cosmogenic nuclides, formation and exposure ages, impact effect and chondrule textures. On the basis of chemical-petrologic features these chondrites are classified asE ₄ (Qingzhen),H ₅ (Jilin, Changde, Shuangyang, Anlong, Xinyi and Yangjang),L ₆ (Renqiu, Junan, Heze, Rugao and Nei Monggol) andLL ₆ (Dongtai). E ₄ is characterized by high iron and sulfur, with the former occurring mainly as Fe^o and FeS. FromH ₅ throughH ₆ toLL ₆, iron and nickel decrease gradually while FeO and the ratio of Fe silicate to total iron increase gradually. indicating a general increase in the orderE-H-L-LL in the degree of oxidation at the time of formation. E ₄ consists mainly of enstatite and, to much less extent, free SiO₂ but olivine is hardly to be found. The olivine proportions amount to 29.07, 41.98 and 51.36 percent inH ₅,L ₆ andLL ₆ respectively, with Fa increasing from 17 to 27 percent. Recrystallization has been noticed to different degrees inH ₄,H ₅,L ₆ andLL ₆ chondrites. The extent to which the original structure disappears and the boundaries of chondrules become indistinct decreases from type 6 through type 5 to type 4, reflecting different degrees of thermal metamorphism. Major minerals in the meteorites all exhibit signs of low to medium shock metamorphism. Specific activity, depth effect and orbit effect are also measured on some chondrites that have fallen in recent years and some new information has been obtained with respect to the orbit and source region for meteorite parent bodies in space. This results show that the environment of formation ofE group may be nearer to Mars than that ofO group. Each chemical group of chondrites has its own evolutionary history, and chondritets of different chemical groups may have originated from parent bodies of different compositions. Or owing to the differentiation caused by thermal melamorphism, various kinds of meteorites may be derived from a common parent body. From this argument it is suggested that five stages may be recognized during the formation process of chondrites.     

Structural control of the distribution of trace elements between silicates and hydrothermal solutions

Over several years many partition coefficients have been measured between framework silicates, sheet silicates and hydrothermal solutions. Only trace alkaline cations are considered in the present work. It is well known that the difference between ionic radii of the trace cation and the major cation is replaces is not satisfactory for a good correlation with the partition coefficients P_X. A structural parameter δ_c is therefore defined, taking into consideration the adaptation of the trace cation to the cavity in which it occurs. This cavity may be the entire site of the major element, or a part of this site in the case of small cations, or a structural cavity located out of the alkali-ion site. The adaptation parameter δ_c is the difference between the ionic radius of the trace cation and the radius of that cavity. This paper shows that the partition coefficient P_X of the trace alkali-ion from the hydrothermal solution is an exponential function of the adaptation parameter δ_c, whatever the silicate may be.     

Description of a new species of Offneria (Hippuritida,Caprinidae) from the lower Aptian of southeast Spain. Stratigraphic,evolutionary, palaeobiogeographic and palaeoenvironmental implications

A new species of Offneria (Caprinidae) Offneria prebetica nov. sp., is described from the Murcia region (Prebetic zone, SE Spain). Its type level is the upper Bedoulian. The key diagnostic character of the new species is the presence on the ventral side of the left valve of an inner row, or double row, of polygonal canals flanked by outer piriform canals with one or two orders of bifurcations. Offneria prebetica nov. sp. is the most advanced species of the genus. Cluster analysis shows the placement of the new species in the monophyletic group of European species, in agreement with its geographic location. Offneria appears to be the most prolific genus of the Caprinidae with species having contrasting ages and palaeobiogeographic distributions. Stratigraphic data from SE Spain indicate that the Offneria lineage was resilient to the environmental perturbations recorded during the late Bedoulian, Offneria prebetica nov. sp. may be used as a time marker for this interval, and its last occurrence was coeval with the “Mid-Aptian extinction event”.     

Fluid Inclusion,H-O,S, Pb and noble gas isotope studies of the Aerhada Pb-Zn-Ag deposit,Inner Mongolia,NE China

The Aerhada Pb-Zn-Ag deposit is located in the western segment of the Great Hinggan Range Ag-Pb-Zn-Cu-Mo-Au-Fe metallogenic belt in NE China. Orebodies occur mainly as vein type and are hosted by sandstone and siliceous slate. Three stages of primary mineralization, including an early arsenopyrite-pyrite-quartz, a middle polymetallic and silver sulfides-quartz and a late sphalerite-pyrite-calcite-fluorite are recognized. Four types of fluid inclusions have been identified in the ore-bearing quartz and fluorite veins, i.e., liquid-rich, gas-rich, three-phase CO₂ aqueous inclusions, and pure gas or liquid aqueous inclusions. Microthermometric studies on fluid inclusions reveal that homogenization temperatures from early to late stages range from 253° to 430 °C, 195° to 394 °C and 133° to 207 °C, respectively. Fluid salinities range from 2.9 to 14.0 wt.% NaCl equiv. The vapor composition of the ore fluid is dominated by H₂O, CO₂ and CH₄, with minor proportions of N₂. The fluid δ¹⁸O_H2O and δD_H2O values vary from +1.6 to +9.3‰ and −122 to −56‰, respectively, and reflect a magmatic fluid and a meteoric fluid dominant hydrothermal system for the early and late stages of mineralization, respectively. The calculated δ³⁴S_H2S values of hydrothermal fluids in equilibrium with sulfides range from +5.2 to +7.1‰, suggesting a mixed source for sulfur, i.e., the local magmatic and sedimentary rocks. The Pb isotope compositions of sulfides are similar to those of the local magmatic and sedimentary rocks, implying that lead and possibly silver relate to these sources. The noble gas isotope compositions of fluid inclusions hosted in ore minerals suggest that the ore-forming fluids were dominantly derived from a deep mantle source. Fluid mixing and dilution are inferred as the dominant mechanisms for ore deposition. The Aerhada Pb-Zn-Ag deposit can be classified as a medium to low temperature hydrothermal vein type deposit.     

Microvertebrates from the Rhaetian bone beds at Westbury Garden Cliff,near Gloucester,UK

Westbury Garden Cliff has been a noted site for Rhaetian bone beds for over a century. It is known especially as a source of excellently preserved bones of the small marine reptile Pachystropheus as well as other reptiles, and fishes. Further it is the type locality of the Westbury Formation, the lower half of the British Rhaetian (Penarth Group). It was also featured in a debate over lateral equivalence of the basal Rhaetian bone bed, with supposedly 5–6 m of pre-basal bone bed deposition. However, the bone beds at different localities are unlikely to be of exactly the same age, and the succession at Westbury Garden Cliff lacks the erosive base of the Westbury Formation seen elsewhere and so presumably started later, perhaps reflecting progressive inundation of the Welsh High, the nearest land. However, the main bone bed occurs in lenses up to 20 cm wide, and may represent hummocky cross stratification, evidence of storm bed deposition. Trace fossils in several sandstones include Selenichnites and Crescentichnus, evidence of shallow-water limulids ploughing the sediment for food, Lockeia, the living burrows of bivalves, and Chondrites burrow systems, suggesting subsequent stability of the sandstone beds.     

Early life stages of resident nekton in intertidal marshes

Variability in early life stages of species that are permanent residents of the estuarine nekton is poorly understood, especially in systems with extensive areas of emergent vegetation (e.g., salt marshes and mangroves). Sampling small mobile nekton in these shallow intertidal habitats presents a difficult methodological challenge. Simulated aquatic microhabitats (SAMs) were used to collect the early life stages of resident nekton that remained on the emergent marsh surface after it was exposed by the tide and could not be adequately sampled by traditional methods. Where the intertidal is a prominent areal component of the estuary, a large portion of young nekton could be overlooked using other common survey methods (e.g., plankton tows or block nets). Populations of young fishes and natant crustaceans were monitored for a year at 3-d to 6-d intervals from both low and high intertidal elevations within each of two marsh sites on Sapelo Island, Georgia, USA. Three species accounted for >99% of the 41,023 individuals collected. These were the killifishesFundulus heteroclitus (57.0%) andF. luciae (4.0%), and the daggerblade grass shrimp,Palaemonetes pugio (38.4%). YoungF. heteroclitus were used in field enclosure experiments to relate abundance data to actual areal densities. Average annual estimated density of young nekton on the surface of the intertidal marsh at low tide was 7.2 individuals m^?2. Early life stages of estuarine resident species, particularly those with demersal young, are not affected by the same physical processes influencing larval supply and recruitment variability in marine-spawned species. In salt marshes, biotic factors (e.g., adult reproductive activity, predation, and food limitation) may be more important as proximate causes of variation during the early life histories of resident nekton.     

AGN III—primordial activity in the nuclei of disk galaxies with pseudobulges

Observational data on the evolution of quasars and galaxies of various morphological types and numerical simulations carried out by various groups are used to argue that low-redshift (z < 0.5) quasars of types I and II, identified with massive elliptical and spiral galaxies with classical bulges, cannot be undergoing a single, late phase of activity; i.e., their activity cannot be “primordial,” and must have “flared up” at multiple times in the past. This means that their appearance at low z is associated with recurrence of their activity—i.e., with major mergers of gas-rich galaxies (so-called wet major mergers)—since their lifetimes in the active phase do not exceed a few times 10⁷ yrs. Only objects we have referred to earlier as AGN III, which are associated with the nuclei of isolated, late-type spiral galaxies with low-mass, rapidly-rotating “pseudobulges,” could represent primordial AGNs at low z. The black holes in such galaxies have masses M _BH < 10⁷ M _⊙, and the peculiarities of their nuclear spectra suggest that they may have very high specific rotational angular momenta per unit mass. Type I narrow-line (widths less than 2000 km/s) Seyfert galaxies (NLSyIs) with pseudobulges and black-hole masses M _BH < 10⁷ M _⊙ may be characteristic representatives of the AGN III population. Since NLSyI galaxies have pseudobulges while Type I broad-line Seyfert galaxies have classical bulges, these two types of galaxies cannot represent different evolutionary stages of a single type of object. It is possible that the precursors of NLSyIs are “Population A” quasars.     

U-spatial statistic data modeled on a probability diagram for investigation of mineralization phases and exploration of shear zone gold deposits

In Model-Based Objective Techniques, MBOT, the geochemists avoid using personal opinion in determination of threshold value. The two most important methods of MBOT are U-spatial statistic and modeling of probability diagram. The spatial coordination of the samples, as weight of measured values, is applied in the calculation of threshold value for anomaly separation.The U-spatial statistic data modeled on a probability plot is a new method in anomaly separation. This method is a combination of U-spatial statistic and modeling of probability plot and was used for the first time in this article. This new method provides the opportunity to identify different geological events that control the concentration variations in the lithogeochemical environments based on U-values. It is also possible to determine the number, type and intensity of these events. The results of using this method for Au element in a shear zone gold mineralized area, south western part of Saqez, Iran, led to identification of three mineralized areas. The epigenetic effects, as mineralization events, affected the concentrations in two stages with different intensity. Both of these stages are interpreted as hydrothermal fluid effects, but the second stage with higher intensity has led to probability anomalous areas.