GA3 induced flowering in Podophyllum hexandrum Royle: A rare alpine medicinal herb

Podophyllum hexandrum Royle, an important alpine herb, is the source of highly valued podophyllotoxin. The effect of some plant growth substances (GA₃, BAP & ABA), uniconazole (an inhibitor of GA biosynthesis), and a combination of GA₃ and uniconazole were examined in respect to influence on sprouting in rhizomes of P. hexandrum and on induction of flowering at a lower altitude. Amongst the various chemicals tested, GA₃ had a marked effect resulting in uniform sprouting and also induced flowering in about half of the treated rhizomes. While BAP also promoted early sprouting, delayed sprouting was seen in rhizomes treated with ABA. Uniconazole treatment, either alone or with GA₃ was found to inhibit flowering and also resulted in reduced plant height. GA₃ treatment of rhizomes from plants that was maintained for up to 30 months at a lower altitude also induced flowering thus replacing the normal chilling requirement of plants. These results suggest that treatment of GA₃ could be effectively used for inducing uniform sprouting and flowering in rhizomes of P. hexandrum grown at lower altitudes.     

The lectotype of Sphenobaiera Ikorfatensis (Seward) Florin, a ginkgophyte from the Lower Cretaceous of western Greenland

Use of the genus Sphenobaiera Florin for deeply divided ginkgoalean leaves lacking a petiole is discussed. The type material of the species Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous at Ikorfat in West Greenland is diagnosed, redescribed and the lectotype designated. The cuticle, which is described and figured in detail for the first time, shows the leaf to be amphistomatic and allows previous identifications of Sphenobaiera ikorfatensis in Lower Cretaceous floras from Siberia and China to be confirmed.     

An Early Devonian arthropod fauna from the Windyfield cherts, Aberdeenshire, Scotland

New terrestrial and freshwater arthropods are described from the Windyfield cherts, a suite of silicified sinters deposited 700m north‐east of the Rhynie cherts and part of the same Early Devonian hot‐spring complex. The diverse assemblage consists of Heterocrania rhyniensis (Hirst and Maulik, 1926a), here recognized as a euthycarcinoid; scutigeromorph centipede material assigned to Crussolum sp.; the crustacean Lepidocaris; trigonotarbid arachnids; a new arthropod of myriapod affinities named Leverhulmia mariae gen. et sp. nov.; and the distinctively ornamented arthropod cuticle of Rhynimonstrum dunlopi gen. et sp. nov. The Leverhulmia animal preserves gut content identifying it as an early terrestrial detritivore. Abundant coprolites of similar composition and morphology to the gut contents of the euthycarcinoid crowd the matrix. Chert texture, faunal associations, and study of modern analogues strongly suggest that the terrestrial arthropods were ubiquitous Early Devonian forms with no particular special adaptation to localized conditions around the terrestrial hot‐spring vents. The aquatic arthropods represent biota from ephemeral cool‐water pools in the vicinity of the hot‐spring vents.     

Facies pattern and genesis of the Jebel Rheris biostromes (Givetian,Eastern Anti-Atlas,Morocco)

Summary During Givetian times, the Jebel Rheris area was situated in a transitional zone at the northern margin of Gondwana, between the emerged Ougnate High in the north and the Mader Basin in the south. A facies pattern developed from stacked or amalgamated coral-stromatoporoid biostromes in the northern near-shore area to an alternating biostrome–crinoidal grainstone succession, which passed over a low angle slope setting towards the south to a pure crinoidal grainstone facies with abundant slumping structures. Finally in the south, a basinal turbiditic facies evolved. In the shallow sea, biostromes probably developed due to the lack of a ‘binder guild’ in the fossil community, which hampered the establishment of mound-like structures, stable enough to resist high-energy storm events. Repeated termination of the coral-stromatoporoid growth is attributed to transgressions. During suitable conditions, colonisation of the sea floor proceeded in three phases: a) cluster settlement; pioneer communities, mostly consisting of tabulate corals and domical to bulbous stromatoporoids, started growing in laterally delimited clusters; b) lateral dispersion; from these centres, settlement prograded laterally, until large areas of the sea-floor were covered; c) vertical accretion; the organisms more and more grew on each other, causing a homogeneous vertical expansion. A significant difference of this up to 200 m thick biostrome—crinoidal grainstone succession compared to continuously growing reefs is the fact that communities repeatedly had to start with the colonisation stage, thus could not reach a mature or climax stage.     

桂林上泥盆统的串管海绵

串管海绵的Amblysiphonella属在桂林地区融县组的发现,填补该属在晚泥盆世地质历程中的空白。在此之前,国内、外已出版地质文献中未记载该属在泥盆系发现的种。     

A New Genus of Rhynchonellid Brachiopod from the Lower Triassic of South China and Implications for Timing the Recovery of Brachiopoda After the End-Permian Mass Extinction

A new genus, Meishanorhynchia , is proposed based on new material from the Lower Triassic of the Meishan section, South China. It is of a late Griesbachian age based on both associated biozones (ammonoids and bivalves) and radiometric dates of the intercalated volcanic ash beds. Comparison with both Palaeozoic and Mesozoic–Cenozoic-related genera suggests that it may represent the first radiation of progenitor brachiopods in the aftermath of the end-Permian extinction. The lowest brachiopod horizon that contains the genus is estimated to be about 250.1 ± 0.3 Ma. This implies that the initial stage of recovery of Brachiopoda in the Early Triassic was probably about 1.3 ± 0.3 myr after the major pulse of the end-Permian mass extinction (dated as 251.4 ± 0.3 Ma). This is in agreement with Hallam's expectancy that biotic recovery typically begins within one million years or so of major mass extinctions, in contrast to current views on the end-Permian extinction event which propose that the recovery of most if not all biotic groups in the Early Triassic was severely delayed and only began about five million years after the end-Permian extinction.     

Favositidae (Tabulata) from Emsian to Middle Devonian limestones of the Tamworth Group (N.S.W., Australia)

Several different species and species groups of the familiy Favositidae from the Emsian and Middle Devonian limestones of the Tamworth Group (N.S.W., Australia) are described. The Emsian Sulcor Limestone Member yieldedFavosites sp. aff.F. basalticus (Goldfuss, 1826),Favosites sp. aff.F. salebrosus Etheridge, 1899,Favosites stellaris Chernyshev, 1937,Squameofavosites nitidus (Chapman, 1914),Sq. bryani (Jones, 1937),Pachyfavosites rariporosus Dubatolov, 1963, andP. tumulosus Yanet, 1965. The Middle Devonian Moore Creek Limestone Member yieldedFavosites ex gr.goldfussi D’Orbigny, 1850, exclusively. In the Emsian limestones occur favositids in a wide array of different facies, with most being found in stratified biostromes and in bedded nodular limestones. In the Middle Devonian most favositids are found in nodular and lumpy limestones which occur at the base and at the top of some successions      

Oceanography and reefs of recent and Paleozoic tropical epeiric seas

Summary The Java Sea, one of the few modern tropical epeiric seas, is used as an analogue to examine oceanography, stratigraphy, and reefs of Devonian strata in the Appalachian and Michigan Basins. Nearshore patch reefs and offshore “pinnacle” reefs occur in both the Java Sea and the Emsian-Eifelian Onondaga Formation in the Appalachian Basin. Nearshore patch reefs also occur in the Eifelian Formosa Reef Limestone in the Michigan Basin. The Java Sea is characterized by quasi-estuarine circulation, in which runoff and rainfall exceed evaporation. Nutrient and organic matter influx from land and from estuarine upwelling contribute to organic rich facies during transgressions and sea level highstands. Similarly, we propose that high runoff from the Appalachian Mountains and from the Laurentian craton contributed to slightly reduced salinity in the Appalachian basin, including possible density stratification during Middle Devonian highstands. By contrast, the Michigan Basin was characterized by antiestuarine circulation, in which evaporation exceeded combined runoff and rainfall. Contemporaneous Emsian-Eifelian strata in the Michigan Basin are dolomite and dolomitic limestone, rather than cherty and muddy limestone typical of the Appalachian basin. Reef composition generally reflects oceanographic circulation regime within the epicontinental seas we examine. Nearshore reefs of the modern Java Sea and the Onondaga Formation (Appalachian Basin) are dominated by multilobate submassive, dendroid, and phaceloid corals, and virtually no platy corals or tabular stromatoporoids. Multilobate and phaceloid corals are better able to accommodate muddy sedimentation. By contrast, offshore pinnacle reefs of the Java Sea and nearshore reefs of the Formosa Reef Limestone are dominated by platyAcropora (modern) or tabular and laminar stromatoporoids (Devonian). The scarcity of tabular stromatoporoids, and the dominance of phaceloid corals and dendritic branching corals, in the Onondaga Formation (Appalachian Basin) are herein explained by localized high productivity conditions driven by quasi-estuarine circulation, rather than cool water. Quasi-estuarine circulation or localized topographic upwelling leading to highly productive coastal environments may be responsible for other Paleozoic examples of apparent cool-water carbonate deposition within the tropics, including the Ordovician of Eastern Canada.     

Distribution,habitat and conservation status of desert pupfish (Cyprinodon macularius) in the Lower Colorado River Basin,Mexico

In order to better determine the currentstatus of desert pupfish populations (Cyprinodon macularius macularius) in the LowerColorado River Basin of Mexico, bimonthly fishsampling and habitat evaluations were carriedout from September 1996 to August 1997 in sixlocalities of Baja California and Sonora.Desert pupfish were collected using minnowseines and traps. Four sampling sites are inSonora, in shallow marginal habitats of theCiénega Santa Clara (Hunters' Camp, Outletof the Welton-Mohawk channel, El Doctor andFlor del Desierto) and two are in BajaCalifornia (Cerro Prieto and streams south ofCerro Prieto). The most abundant fish speciessampled was native desert pupfish (C.macularius, 59%) followed by sailfin molly(Poecilia latipinna, 19%), redbellytilapia (Tilapia cf. zilli, 10%) and western mosquito fish (Gambusiaaffinis, 7%). Significant temporalfluctuations in distribution and abundance ofdesert pupfish populations, as previouslyreported for these populations, was againdocumented. The main anthropogenic factorsaffecting distribution and abundance of desertpupfish populations in the Mexican portion ofthe Lower Colorado River Basin are progressivealteration of aquatic and riparian habitats, aswell as presence of exotic fishes that havecaused the displacement or elimination ofnative fish populations. Both habitat andpresence of the desert pupfish populations inthe study area are controlled by theperiodicity, quality and volume of dischargesinto the Mexican portion of the basin from theUnited States.     

New bryozoans from the Devonian of Afghanistan and the Carboniferous of Iran

A new family, Vidronovellidae, with a new genus, Vidronovella, and its type species V. fastigata sp. nov., and a new species, Europora gerirudensis, are described from the Famennian of Afghanistan, and the new species Primorella iranica, Heloclema magnificum, and Worthenopora elbursensis are described from the Viséan of Iran.