The Furongian (upper Cambrian) Alum Shale of Scandinavia: revision of zonation

The zonation of the Furongian Alum Shale in Scandinavia, based on olenid trilobites, is reviewed and revised. The current scheme is rooted in a detailed zonation introduced in the late 1950s with subzones that subsequently have been elevated to zonal rank. Ten of these zones are difficult to recognize in all Alum Shale districts, and a revised zonation is proposed, focused on unambiguous identification throughout Scandinavia. The difficulties in recognizing zones in some districts mostly relate to biofacies differentiation. Representatives of Ctenopyge are, for instance, common in palaeo-offshore areas, whereas pelturines are rare in these settings and vice versa in palaeo-inboard settings. The following modifications of the olenid zonation are proposed: the Olenus scanicus Zone is renamed the O. scanicus–O. rotundatus Zone; the Ctenopyge similis and Ctenopyge spectabilis zones are replaced by the Sphaerophthalmus modestus–Sphaerophthalmus angustus Zone; the Ctenopyge tumida Zone is renamed the Peltura acutidens–Ctenopyge tumida Zone; the Peltura scarabaeoides Subzone is restored (as a zone) and replaces the Ctenopyge bisulcata and Ctenopyge linnarssoni zones. The Parabolina heres megalops (Sub)Zone is reinstated and replaces the Peltura paradoxa Zone; the Acerocarina granulata and P. costata zones are combined as the Acerocarina granulata–Peltura costata Zone. In addition, the name Proceratopyge nathorsti–Simulolenus alpha Zone is suggested for the polymerid zone corresponding to the upper Miaolingian Agnostus pisiformis Zone. The proposed changes reduce the number of Furongian Zones to 23, allocated to six superzones. No subzones are recognized, but some zones can potentially be subdivided for improved local correlation. The stratigraphical ranges of all Furongian olenid trilobites and agnostoids described from Scandinavia are summarized.     

Productivity and Distribution of Trichoptera Larvae in a Colorado Mountain Stream

Summary From June 1968 to late May, 1969 collections of more than 20,600 immature Trichoptera were made from the St. Vrain River of Colorado. Agapetus sp., Arctopsyche grandis, Brachycentrus americanus, Ecclisomyia maculosa, Hydropsyche sp., Hydropsyche occidentalis, Helicopsyche borealis, Leptocella sp., Neothremma alicia, Rhyacophila acropedes, and Sortosa sp. were taken at eight sites ranging from 1565 to 3200 m in altitude. The Trichoptera of the St. Vrain exhibited a distinct altitudinal zonation with Zone I (1565 m) dominated by Leptocella, Hydropsyche sp., and Helicopsyche borealis; Zone II (1750 to 2350 m) was dominated by Brachycentrus americanus and Hydropsyche occidentalis; Zone III (2350 m) was considered a transitional area. In Zone IV (2650 m) and Zone V (2950 to 3250 m ) Neothremma alicia and Arctopsyche grandis were the most successful genera, respectively. Temperature is proposed as the major variable controlling attitudinal zonation.Standing crop productivity of Trichoptera was determined from timed collections and expressed as population density (number of organisms collected per 30 minutes) and organic biomass (dry organic matter represented by organisms collected per 30 minutes). Intermediate altitudes (2300 m) exhibited the lowest productivity but greatest species diversity. Highest productivity occurred below 1600 m but organic biomass was surprisingly high above 2900 m. Changes in productivity in relation to altitude are discussed in relation to temperature, food availability, severe flooding, and other variables. Productivity on a yearly basis was found to be greatest in spring and at minimum levels during autumn and early winter. The holometabolous life cycle of Trichoptera, temperature, and current seem to be the major governing factors of seasonal productivity.     

Tremadocian (Ordovician) biostratigraphy and graptolites at Dayangcha (Baishan,Jilin, NE China)

Based on a systematic study of Tremadocian graptolites from the Early Ordovician Yehli Formation at Dayangcha, Baishan of Jilin, NE China, a revised graptolite zonation is proposed for the Tremadocian rocks in the area. In ascending order, the graptolite zones include theRhabdinopora flabelliformis parabola Zone, theAnisograptus matanensis Zone, thePsigraptus jacksoni Zone and theAorograptus victoriae Zone. The first three zones are discussed with their definitions and durations clarified, whereas the last zone is introduced for the first time as a replacement of the formerAdelograptus-Clonograptus Zone. The entire Yehli Formation is considered to be older than the late Tremadocian Hunneberg Substage of Scandinavia, the latter being represented by the carbonate-dominated basal part of the overlying Liangchiashan Formation where no graptolites have so far been discovered. The Tremadocian succession in the Dayangcha area is regarded as being representative of the North China (Sino-Korea) Palaeoplate, and a correlation of the Tremadocian graptolite sequence with those of other continents is suggested. Nine species belonging toDendrograptus, Aspidograptus, Callograptus andAirograptus of the family Dendroidae, and eight species ofPsigraptus, Adelograptus, Aorograptus andKiaerograptus of the family Anisograptidae are described and some are revised in the present paper. Among the important revisions are the reconstructed proximal development ofPsigraptus jacksoni based on partially three-dimensional specimens from the area, and the complex thecal structures ofAspidograptus.      

Revision of Famennian-Tournaisian (Late Devonian – Early Carboniferous) conodont biostratigraphy of Sardinia,Italy

Conodont biostratigraphy of the Famennian and Tournaisian of Sardinia is provided on the basis of all data available in the literature. More than 130 conodont taxa documented from this time-interval allow recognition of nineteen conodont biozones. The zonation scheme adopted here is broadly similar to the standard zonation schemes used in the Upper Devonian and Lower Carboniferous, though a few variations are needed to better accommodate the species occurrences in Sardinia: the velifer Zone and the styriacus Zone have been reintroduced, even though with slightly different meanings than previously used; the Lower praesulcata Zone is expanded to include the Middle praesulcata interval. The Upper praesulcata Zone and the sulcata Zone are missing. All zones are described and discussed and a complete list of bioevents is provided.     

Hydraulic sorting of microbiota in calciturbidites— A dinantian case study from the rheinische schiefergebirge,Germany

Summary A calciturbidite bed from the lower part of the Kieselkalk Formation (late cd II) at Wallau, eastern Rheinisches Schiefergebirge, displays ideal grading of reworked calcareous shallow-water microbiota, ranging from plurimillimetric agglutinated foraminifers and fragments of calcareous algae (Koninckopora sp.) to plurimicronic calcispheres, radiolarians and sponge spicules. Microbiota derived from all levels of the platform. Correspondingly, several carbonate microfacies types could be discerned. The early diagenetic micrite base of the turbidite preserved the anoxic basinal facies. The turbidite bed belongs to Foraminiferal Zone 15 (V3bα), theAlbaillella cartalla Zone (radiolarian chronology), and is the Lower and part of the Uppertexanus Zone (standard conodont zonation). From the few published data on foraminifers, the Kieselkalk is thought to range from Mid Viséan V2b to Late Viséan V3b gamma.     

EARLY ORDOVICIAN CONODONTS FROM TARUTAO ISLAND,SOUTHERN PENINSULAR THAILAND

Abstract: Early Ordovician conodont faunas of the Thung Song Formation on Tarutao Island, southern peninsular Thailand, consist of 14 known species belonging to 17 genera, and eight undescribed species. Utahconus tarutaoensis and Filodontus tenuis are new species. Three conodont zones: the Rossodus manitouensis Zone, the Utahconus tarutaoensis Zone and the Filodontus tenuis Zone, in ascending order, are defined in the study sections. These are coeval with the interval from the Rossodus manitouensis Zone to the Acodus deltatus‐Oneotodus costatus Zone of the standard zonation in the North American Midcontinent. Based on the conodonts studied here and fossils previously reported from Tarutao Island, the Thung Song Formation is early Tremadocian to middle Arenig (Ibexian) in age. This formation is lithostratigraphically subdivided into the S1 to S5 members, and our study sections consist of the S1 to S3 members. These strata accumulated on a shelf in the Early Ordovician. The depositional environments of the limestones making up the S1 and S3 members were in deeper‐shelf conditions. Limestone and shale of the S2 member formed in a shallow‐water, high‐energy environment.     

Middle and Early Upper Devonian Miospore Zonations in Eastern Yunnan and the Significance of Their Stratigraphy

The Devonian marine and non marine deposits were widely distributed in East Yunnan, where rich marine faunas and floras were present. The Middle and early Upper Devonian miospores of Eastern Yunnan were also abundant and usually well- preserved. The present paper provides both analysis of qualitative and quantitative composition development of Middle and early Upper Devonian spore assemblage in Eastern Yunnan, and a palynological zonatlon containing four successive assemblage zones: 1.Zone of Calyptosporites velatus-Rhabdosporites langii (VL); 2. Zone of Archaeozonotriletes variabilis-Calyptosporites proteus (VP); 3. Zone of Geminospora lemurata-Cristatisporites triangulatus (LT); 4. Zone of Archaeoperisaccus ovalis-Lagenicula bullosum (OB). The Middle and early Upper Devonian spore assemblages of Eastern Yunnan may be compared with those in South China and West Qinling. The spore zonation possesses stratigraphical dating of the Devonian megafloras of the region, particularly those from the Middle and Upper Devonian. The proposed spore zonation is closely compared with that erected for the Middle and early Upper Devonian of Old Sandstone Continent and adjacent Region. Based on palynological data, the reconstruction of Paleogeography and Paleoecology are discussed.     

Neogene planktonic foraminiferal biostratigraphy and evolution: Equatorial to subantarctic, South Pacific

Detailed planktonic foraminiferal zonations have been established for the Neogene (Latest Oligocene through present) in six DSDP sites in the South Pacific ranging from equatorial to subantarctic latitudes (48°S). Two basic zonal schemes are readily recognized: tropical and temperate. The tropical zonation is best developed in DSDP Site 289 and the temperate zonation in Sites 206, 207A and 284. Tropical and temperate zonations can be linked by a warm subtropical scheme in Site 208, because this sequence includes a mixture of tropical and temperate elements. A site located close to the Subantarctic Convergence (Site 281) contains a zonation largely of temperate character, but the present of cooler elements and some differences in biostratigraphic ranges have required a slightly different biostratigraphic scheme.Although two broad schemes are recognized, none of the biostratigraphic sequences are identical between any of the sites. This reflects differences in biogeography, evolution and diachronous extinction at various latitudes during the entire Neogene. Diachronism in biostratigraphic ranges continue to create difficulties in correlation across such wide latitudes.Our detailed work has required the establishment of new biostratigraphic zonations in certain parts of the Neogene sequence and modifications in some other parts. Otherwise, previously established schemes are followed as closely as possible. In the temperate region, a new zonation has been established for the Early Miocene to early Middle Miocene. For the remainder of the Neogene the zonation of Kennett (1973) has been largely used. The tropical zonation of Blow (1969) is employed in the equatorial Site 289, but with further subdivisions for Zones N4 and N17. For areas intermediate between tropical and temperate latitudes (Site 208), a modified Early Miocene zonation is established based on changes in tropical and temperate elements.The zonal schemes are established on taxa that exhibit both diachronous and isochronous ranges across the latitudes. Zones that are at least partly diachronous include the Globigerinoides trilobus and Globorotalia miozea Zones of Early Miocene age; perhaps the Globorotalia mayeri Zone (its base) of the Middle Miocene; the Globorotalia conomiozea Zone of the Late Miocene; and the Globorotalia crassaformis Zone of the Early Pliocene.A large number of datum levels are recognized based on first evolutionary appearances or extinctions. The most widely applicable datums are as follows: latest Oligocene — Globigerinoides F.A.; Early Miocene — Globoquadrina dehiscens, F.A., Globorotalia kugleri L.A., Catapsydrax dissimilis L.A. and Praeorbulina glomerosa F.A.; Middle Miocene — Orbulina suturalis F.A., Globorotalia peripheroacuta F.A., Fohsella lineage L.A., Globorotalia mayeri L.A.; Late Miocene — “Neogloboquadrina” continuosa L.A., Globoquadrina dehiscens L.A., Globorotalia cibaoensis F.A.; Early Pliocene — Globorotalia puncticulata F.A., Globorotalia margaritae F.A.; Early Pleistocene — Globorotalia truncatulinoides F.A. A number of other datums are identified which assist with correlation over more restricted latitudinal ranges.The evolution of most Neogene planktonic foraminifera is now well established for a wide range of water masses. Evolutionary lineages are primarily centered in the temperate and tropical regions. Tropical lineages have recently been reviewed by Srinivasan and Kennett (1981) and are not discussed in detail here. However, Sphaeroidinellopsis seminulina is now considered to have evolved directly into S. paenedehiscens during the Late Miocene and S. subdehiscens Blow is considered to be junior synonym of S. seminulina.A new evolutionary lineage is recognized in the warm subtropics (Site 208) whereby Globigerina woodi woodi gave rise to Globigerinoides subquadratus via Globigerina brazieri. The discovery of this lineage clearly demonstrates that Globigerinoides is a polyphyletic “genus”. Another major phylogenetic lineage is recognized within the temperate globorotaliids of Early Miocene age as follows: “N.” continuosa → Globorotalia zealandica incognita → G. zealandica zelandica → G. praescitula → G. miozea. Although parts of this lineage have been recognized earlier, the entire phylogeny has previously been underscribed.A new Early to Middle Miocene lineage is recognized in the subantarctic to temperate areas which involve a transition from Globorotalia praescitula to G. challengeri n. sp. via intermediate forms.Two major Neogene globorotaliid lineages — the Menardella of the tropics and Middle Miocene to Recent forms of Globoconella of the temperate areas — are both considered to have evolved from Globorotalia praescitula beginning in the Early Miocene. This evolution initially was restricted to temperate areas but has since separated into distinctly tropical and temperate phylogenetic elements.     

Mite and insect zonation on a Marion Island rocky shore: a quantitative approach

This study provides the first quantitative analysis of the littoral and supralittoral insect and mite assemblages of sub-Antarctic Marion Island. Seventeen mite species (126,203 individuals) from 11 families were found on the shore at Macaroni Bay. Three families dominated the assemblages in both abundance and diversity: the Hyadesiidae, Ameronothridae and Halacaridae. Six insect species from three orders were found on the shore. Species richness increased from one in the littoral, to four and two species in the Mastodia and Caloplaca zones, respectively. The littoral chironomid midge Telmatogeton amphibius was the most abundant insect species, constituting 80% of all insects counted. Arthropod assemblages corresponded closely to the cryptogam-dominated zonation patterns previously identified for the Marion Island shore. This clear association between arthropod and cryptogam zonation patterns provided a clear indication of habitat specificity in many of the species, and a quantitative analysis of habitat specificity on a species by species basis supported this idea. The specificity of most species to the shore, which forms part of the epilithic biotope, is most likely a consequence of the considerable age of this biotope compared to the younger, post-glacial vascular vegetation. Tourist species, i.e. species transient to an assemblage, inflated species richness in zones and the distribution ranges of species across zones. It is suggested that previous qualitative analyses of shoreline arthropod communities may have overestimated species ranges and richnesses because of the inclusion of tourist species. It is suggested that if a sound understanding of patterns in, and processes underlying Antarctic arthropod assemblages is to be achieved, quantitative analyses must be expanded in the region. Accepted: 14 May 2000     

THE EARLY JURASSIC AMMONITE BADOUXIA FROM BRITISH COLUMBIA, CANADA

Abstract:  Most species of the Lower Jurassic ammonite genus Badouxia are restricted to the eastern Pacific where they are of fundamental importance to the Hettangian/Sinemurian ammonite zonation of North America. The fauna from the type area for the genus has been restudied and four species and two transitional forms are now recognized. Badouxia forticostata and Badouxia castlensis are new. Badouxia occidentalis (Frebold) and Badouxia oregonensis Taylor are placed in synonymy with Badouxia canadensis (Frebold). These major taxonomic changes and subsequent modification to the range of B . canadensis require revisions to the current zonation for the Western Cordillera of North America. The Oregonensis Zone is re-named the Mineralense Zone. The Canadensis Zone is abandoned and its previously defined Rursicostatum and Columbiae subzones are elevated to the level of full zones. Large samples indicate that most species of Badouxia display a remarkable range of continuously variable morphology. In addition, the genus shows some of the best-documented evidence of sexual dimorphism in Early Jurassic ammonites. Badouxia spans the Hettangian/Sinemurian boundary and based on the range of different species, five stratigraphic intervals are recognized. Intervals 1–3 correlate with the north-west European Angulata Zone. The majority of interval 4 and the whole of interval 5 correlate with the north-west European Bucklandi Zone. The age of the base of interval 4 is uncertain.     

Global radiolarian zonation for the Pliensbachian, Toarcian and Aalenian

Jurassic radiolarians from 220 samples in Queen Charlotte Islands, B.C., Williston Lake, B.C., east-central Oregon, Baja California Sur, southern Spain, Austria, Slovenia, Turkey, Oman, Japan and Argentina were studied in order to construct global zonation for the Pliensbachian, Toarcian and Aalenian stages. Well-preserved faunas from continuous stratigraphic sections in Queen Charlotte Islands provide the most detailed record for this time interval, and all collections are tied to North American ammonite zones or assemblages. Collections from nearly all other areas lack independent dating except for early Toarcian carbon-isotope dating in Slovenia and late Aalenian ammonites in Spain.A database of 197 widely distributed updated taxonomic species was used to construct a Unitary Association (UA) zonation for the interval. A global sequence of 41 UAs was obtained for the top of the Sinemurian to the base of the Bajocian. The first and the last UAs represent the Late Sinemurian and the Early Bajocian respectively. The remaining 39 UAs were merged into nine zones (four Early Pliensbachian, one Late Pliensbachian, one Early Toarcian, one Middle-Late Toarcian, and two Aalenian) according to prominent radiolarian faunal breaks and ammonite data. The new zones are the Canutus tipperi - Katroma clara Zone (latest Sinemurian/earliest Pliensbachian); Zartus mostleri - Pseudoristola megaglobosa, Hsuum mulleri - Trillus elkhornensis and Gigi fustis - Lantus sixi zones (Early Pliensbachian); Eucyrtidiellum nagaiae - Praeparvicingula tlellensis Zone (Late Pliensbachian); Napora relica - Eucyrtidiellum disparile Zone (Early Toarcian); Elodium pessagnoi - Hexasaturnalis hexagonus Zone (Middle and Late Toarcian); Higumastra transversa - Napora nipponica Zone (early Aalenian); and Mirifusus proavus - Transhsuum hisuikyoense Zone (late Aalenian). These zones can be correlated worldwide and link previously established UA zonations for the Hettangian-Sinemurian and the Middle to Upper Jurassic. The new zonation allows high-resolution dating in the studied interval and provides a solid basis for analyzing faunal turnovers and the paleobiogeography of Jurassic radiolarians.     

Cenomanian to Coniacian ostracodes from the Nkalagu area (SE Nigeria): biostratigraphy and palaeoecology

Ostracode faunas from three sections in the Nkalagu area, including the type section of the Nkalagu Formation, were analysed qualitatively and quantitatively. Based on the results, an ostracode zonation is proposed as follows: aCythereis sp. 2 Interval Zone (late Turanian to Coniacian), aCythereis vitiliginosa reticulata Interval Zone (Turonian) and aCytherella spp. Abundance Zone (Cenomanian). This zonation may be only of local (basin wide) character but should allow a micropalaeontological correlation of strata in the Lower Benue Trough. By comparison with sedimentological and palaeontological parameters, aCytherella dominated shelf/depleted oxygen-assemblage can be distinguished from aCythereis/Ovocytheridea dominated upper bathyal/suboxic to oxic-assemblage. The stratigraphic and palaeoecologic characteristics of the ostracode assemblages will be specified and presented in this contribution. Some of the species (Leguminocythereis sp.,Cytherella cf.comanchensis) are assumed to be replaced and to reflect the turbiditic activity in the area, resulting in carbonate deposits of economic significance.     

New records of Acari from the sub-Antarctic Prince Edward Islands

Sixty species of Acari are recorded from the sub-Antarctic Marion and Prince Edward Islands (the Prince Edward archipelago). Twenty of the 45 species collected on recent expeditions are new and currently undescribed. Other new taxa include a family of Mesostigmata, four new genera, and the first sub-Antarctic records of Cillibidae (Mesostigmata) and Eryngiopus (Prostigmata). Fifteen of the 31 species previously reported from the islands are confirmed, although eight of the previous accounts remain doubtful. The fauna, which shows a distinction between the shoreline and terrestrial components, comprises endemic, South Indian Ocean Province and sub-Antarctic mite species. Accepted: 18 July 1998     

中国海相早三叠世弓鲛鱼类(软骨鱼类)的首次报道——华南二叠系一三叠系界线上下鱼类序列研究之一

广西田东县作登下三叠统罗楼组产出弓鲛鱼类作登弓鲛Hybodus zuodengensis(Yang et al.)、乐氏弓鲛H.yohi(Yang et al.)和田东多尖齿鱼(新种)Polyacrodus tiandongensis sp.nov.,其中前二种化石以前曾被作为牙形类报道.这是弓鲛鱼类在中国海相早三叠世的首次报道.另外,本组还产出属种未定的硬骨鱼类化石(Osteichthyes gen.et sp.indet.).建立了我国海相早三叠世第一个鱼类带化石,作登弓鲛-乐氏弓鲛组合带(Hybodus zuodengensisH.yhoi AZ);伴生的有Neospathodushomeri-N.triangularis牙形类带化石,该带化石延续的时限为奥伦尼克阶(Olenekian)司帕斯期(Spathian)早期.     

中国海相早三叠世弓鲛鱼类(软骨鱼类)的首次报道——华南二叠系—三叠系界线上下鱼类序列研究之一

广西田东县作登下三叠统罗楼组产出弓鲛鱼类 :作登弓鲛Hyboduszuodengensis(Yangetal.)、乐氏弓鲛H .yohi (Yangetal.)和田东多尖齿鱼 (新种 )Polyacrodustiandongensissp .nov .,其中前二种化石以前曾被作为牙形类报道。这是弓鲛鱼类在中国海相早三叠世的首次报道。另外 ,本组还产出属种未定的硬骨鱼类化石 (Osteichthyesgen .etsp .indet.)。建立了我国海相早三叠世第一个鱼类带化石 ,作登弓鲛—乐氏弓鲛组合带 (Hyboduszuodengensis H .yohiAZ) ;伴生的有Neospathodushomeri N .triangularis牙形类带化石 ,该带化石延续的时限为奥伦尼克阶 (Olenekian)司帕斯期 (Spathian)早期。     

Abundance and seasonality of mid-altitude fellfield arthropods from Marion Island

Fellfield is an important habitat in both the Antarctic and sub-Antarctic. However, few studies have examined the abundance and seasonality of arthropods in sub-Antarctic fellfield habitats. Here, soil arthropod communities were sampled for over a full year in two distinct habitat components (rocky areas and Azorella selago cushions) in a mid-altitude fellfield on Marion Island. Species richness was relatively high (42 spp.) and consisted almost exclusively of indigenous species. Maximum mean annual density in the A. selago cushions was 16,000 individuals m⁻² for Eupodes minutus. In contrast, the highest density of any species in the rocky, inter-cushion areas was 700 individuals m⁻² for Halozetes fulvus. Quantitative analyses highlighted prominent differences in arthropod community structure between the two habitat components, despite the fact that most species were common to both of them. In general, arthropod abundances were lower in the fellfield compared with less extreme vegetation types in the sub-Antarctic, but were not dissimilar to those found in fellfield in the maritime Antarctic. In the Marion Island fellfield, arthropods either showed no pronounced seasonal peak in abundance, or a summer peak, although these patterns differed between habitat components within species, and between species. These data provide a firm quantitative foundation for further investigations of community patterns and seasonality in sub-Antarctic fellfield arthropods. Accepted: 10 June 2000     

Latest Cretaceous to Late Paleocene radiolarian biostratigraphy: A new zonation from the New Zealand region

The scarcity of records of Early Paleocene radiolarians has meant that while radiolarian biostratigraphy is firmly established as an important tool for correlation, there has been a long-standing gap between established zonations for the Cretaceous and from latest Paleocene to Recent. It has also led to considerable speculation over the level of faunal change across the Cretaceous/Tertiary (K/T) boundary. Consequently, the discovery of rich and diverse radiolarian assemblages in well-delineated K/T boundary sections within siliceous limestones of the Amuri Limestone Group in eastern Marlborough, New Zealand, is of great significance for biostratigraphy and K/T boundary research.This initial report is restricted to introducing a new latest Cretaceous to mid Late Paleocene zonation based on the radiolarian succession at four of these sections and a re-examination of faunas from coeval sediments at DSDP Site 208 (Lord Howe Rise). Three new Paleocene species are described:Amphisphaera aotea, Amphisphaera kina andStichomitra wero. Six new interval zones are defined by the first appearances of the nominate species. In ascending order these are:Lithomelissa? hoplites Foreman (Zone RK9, Cretaceous),Amphisphaera aotea n. sp. (Zone RP1, Paleocene),Amphisphaera kina n. sp. (RP2),Stichomitra granulata Petrushevskaya (RP3),Buryella foremanae Petrushevskaya (RP4) andBuryella tetradica (RP5). Good age control from foraminifera and calcareous nannofossils permits close correlation with established microfossil zonations. Where age control is less reliable, radiolarian events are used to substantially improve correlation between the sections.No evidence is found for mass extinction of radiolarians at the end of the Cretaceous. However, the K/T boundary does mark a change from nassellarian to spumellarian dominance, due to a sudden influx of actinommids, which effectively reduces the relative abundance of many Cretaceous survivors. An accompanying influx of diatoms in the basal Paleocene of Marlborough, together with evidence for an increase of total radiolarian abundance, suggests siliceous plankton productivity increased across the K/T boundary. Possible causes for this apparently localised phenomenon are briefly discussed.     

The life histories of Meridialaris chiloeensis (Demoulin, 1955) (Ephemeroptera: Leptophlebiidae) and Gigantodax rufescens (Edwards, 1931) (Diptera: Simuliidae) on a Magellanic sub-Antarctic island (55°S)

The life histories of Meridialaris chiloeensis (Demoulin, 1955) (Leptophlebiidae: Ephemeroptera) and Gigantodax rufescens (Edwards, 1931) (Simuliidae: Diptera) were studied in a Magellanic sub-Antarctic river in Navarino Island (55°S). Both species are distributed along the whole length of the watershed. Phenology was studied in the field for a period of 12 months between August 2009 and September 2010, at a site near the river's mouth (sea level). Cumulative degree-days were calculated along the gradient at five representative altitudinal locations, starting at the river's headwaters. Samples were obtained during January of 2010 at all the remaining altitudinal locations to assess possible changes in voltinism during the austral summer season through the watershed. Results show that M. chiloeensis and G. rufescens have a bivoltine and multivoltine life cycle, respectively, at sea level. Based on degree-days obtained and field observations at the remaining stations, possible voltinism patterns are discussed for both species along the altitudinal gradient. These species are proposed as suitable long-term indicators for climate change studies in the sub-Antarctic ecoregion of Magallanes, as monitoring their responses will be important in the interpretation of changes in ecosystem function, community structure, and distributions of aquatic taxa in this region of the world.     

The lichen genus Stereocaulon in Antarctica and South Georgia

Summary Six species of Stereocaulon and one unnamed taxon (close to S. glabrum) are reported from South Georgia, the maritime Antarctic islands and Antarctic Peninsula. S. caespitosum is new to the western sub-Antarctic. Variations in morphology and secondary chemistry are provided, and the ecology and geographical distribution in the sub-Antarctic and Antarctic biomes are given for each taxon.     

Food, reproduction and survival in mice on sub-Antarctic Marion Island

The house mouse Mus musculus is the most widespread introduced mammal on sub-Antarctic islands, where it may alter ecosystem function. Ambient temperature and food availability affect reproduction and survival for mice. It is unclear how these factors influence mouse demography in the sub-Antarctic, and we tested the influence of food experimentally on Marion Island. Using food supplementation trials, we did not alter reproduction or overwinter survival. Alternatively, we argue ongoing climatic change on Marion could increase mouse densities through summer, while increased winter survival may reduce population growth rates the following summer through density dependence. The overall influence of these apposing forces depends on their relative strengths but may limit changes in mouse numbers with ongoing changes in climate in the sub-Antarctic.