bluuebunny/crossref_metadata_2025 huggingface dataset:
Palaeocology of Hard Substrate Faunas from the Cretaceous Qahlah Formation of the Oman Mountains
Authors: Wilson Mark A. , Taylor Paul D.
Published: November 2003

Skeletal encrusters and carbonate hardgrounds are rare in siliciclastic sands and gravels because of high levels of abrasion and sediment movement. An exception to this is the Maastrichtian Qahlah Formation of the Oman Mountains, a sequence of coarse siliciclastic sediments deposited on a shallow marine shelf above wavebase and at an equatorial palaeolatitude. This unit contains intercalated carbonate hardgrounds and other hard substrates which were encrusted and bored. The hard substrates, comprising carbonate and silicate clasts, calcareous bioclasts (mollusc shells and coral fragments) and wood, supported a diverse encrusting and boring fauna dominated in biomass by the oyster Acutostrea. There are twelve bryozoan species and at least two serpulid worm species, most living cryptically. Other encrusters on exposed surfaces include the agglutinated foraminiferan Placopsilina and several species of colonial corals. Borings in the carbonate clasts and shells are predominantly those of bivalves (Gastrochaenolites), with subsidiary clionid sponge (Entobia) and acrothoracican barnacle (Rogerella) borings. The woodgrounds are thoroughly bored by teredinid bivalves (Teredolites). Of the common substrate types, carbonate hardground clasts support the greatest number of taxa, followed by chert clasts, with limestone rockground pebbles being depauperate. Clast composition and relative stability probably explain these differences. Individual clasts probably had variable and typically long colonisation histories. Detailed palaeoecological interpretation is constrained by taphonomic loss, time‐averaging and clast transportation and reorientation. Evidence from the Qahlah Formation shows that tropical rocky‐shore biotas in the Cretaceous were not impoverished as previously believed.
Embryonic Ammonoid Shell Features: Intraspecific Variation Revisited
Authors: Rouget Isabelle , Neige Pascal
Published: November 2003

Two samples of ammonoids belonging to the Oppeliidae, Sublunuloceras virguloidesHecticoceras (Brightii) canaliculatum, are analyzed to estimate the intraspecific variability of embryonic shell features. The study of embryonic shell characters reveals two main shapes of protoconch, flattened and round. Prosiphons may be straight or slightly curved. New parameters for area are added to the linear parameters commonly found in the literature. Prosiphon length and caecum area vary greatly whereas protoconch and ammonitella diameter vary only slightly, and the ammonitella angle is almost constant. The protoconch‐to‐ammonitella size ratio behaves differently in each species, suggesting different patterns of embryonic growth. We compare our results with published data and discuss their significance for species determination and ontogenetic interpretation. The main finding is that intraspecific embryonic variation is greater than was previously believed.
Conodonts Meet Cladistics: Recovering Relationships and Assessing the Completeness of the Conodont Fossil Record
Authors: Donoghue Philip C. J.
Published: November 2003

A numerical cladistic analysis of the conodont family Palmatolepidae has been undertaken to determine the applicability of the technique to group‐wide systematic revision. Results suggest a new hypothesis of relationships that is considerably more parsimonious than trees compatible with existing hypotheses of relationships, or trees that are even loosely constrained stratigraphically. This may occur either because the fossil record is incomplete, because taxon sampling for the cladistic analysis is low, or because the most parsimonious trees approximate the true tree less well than do stratigraphically‐constrained trees (or because of a combination of these factors). Although more taxa and more characters would be preferable in choosing between these possibilities, the tree derived solely from morphological data is adopted. Thus, stratigraphic data can be used to test hypotheses of relationships and construct phylogenies; hypotheses of relationships can be used to test the completeness of the conodont fossil record. Existing schemes of classification within the Palmatolepidae are rejected because most groups within them are either polyphyletic or paraphyletic. A new scheme is presented. Character changes suggest correlated, progressive and mosaic evolution within the Palmatolepidae. Parsimony analysis of partitioned datasets indicates that more phylogenetic information can be recovered from S rather than P or M element positions, although data from all three positional groups are preferable to data from just one. Thus, multielement taxonomy is essential to the resolution of conodont interrelationships.
Protopteraspis Gosseleti (Vertebrata: Pteraspidomorphi: Heterostraci) from the Lower Devonian of Shropshire, England
Authors: Blieck Alain , Tarrant Peter R.
Published: November 2003

New Protopteraspis material from Shropshire is sufficiently similar to Protopteraspis leathensis from the Welsh Borderland, and the type‐species Protopteraspis gosseleti from France, to justify transfering P. leathensis to P. gosseleti. The Anglo‐Welsh, biostratigraphic leathensis Zone is changed to the Protopteraspis Zone (sensu Blieck and Janvier 1989). Possible lifestyles are discussed for Protopteraspis gosseleti.
The Machaeridian Lepidocoleus Sarlei Clarke, 1896, from the Rochester Shale (Silurian) of New York State
Authors: Högström Anette E. S. , Taylor Wendy L.
Published: November 2003

Eight new specimens and the holotype of Lepidocoleus sarlei Clarke, 1896 from Lagersta¨tten deposits within the Rochester Shale (Silurian, Wenlock) of New York are described to elucidate the morphology, function and construction of the scleritome. The material exhibits an unusual type of dorsal hinge with a pronounced antero‐posterior displacement between the two sides. Two specimens have an aberrant sclerite on the right side of segment eleven. One tightly enrolled specimen may demonstrate a method of defence with the stronger protected dorsal side oriented outwards. The presence of a segmented body plan is suggested, based on requirements for a functional spiral enrolment. Distinct anterior and posterior morphologies together with the pattern of rugae provide valuable help in reconstructing disarticulated lepidocoleids.
Evolutionary Trends in the Ornamentation of Cambrian Solenopleuropsine Trilobites
Authors: Javier Álvaro J. , Vizcaïno Daniel
Published: November 2003

A phylogeny of the Cambrian solenopleuropsine trilobites is constructed to evaluate the importance of differential speciation, extinction and developmental constraints in the evolutionary history of the clade. The transformation of the Pardailhania–Solenopleuropsis (Manublesia)–Solenopleuropsis (Solenopleuropsis) lineages occurred during the mid Caesaraugustian–early Languedocian interval, with all measured morphological variables exhibiting continuous and gradual changes. Several evolutionary trends show tendencies towards an increase in tuberculation and its complexity on the anterior part of the cephalon. A mid Caesaraugustian anagenetic tendency is related to the influence of constant environmental conditions, whereas a late Caesaraugustian–early Languedocian cladogenetic tendency seems to have been an adaptative response to unstable environments. The Solenopleuropsinae clade has a well‐preserved continuous fossil record over its full biogeographical range in the Mediterranean region. The sympatric evolution in centrally located populations (Mediterranean area) follows the model of phyletic gradualism, whilst a peripheral population in Avalonia gave rise (by allopatric speciation) to a distinct species, characterized by a variation in the relative size of the palpebral lobes, which may be evidence of a parallel evolution in the trends of ornamentation.
Musculature and Asymmetry in a Carboniferous Pseudo‐Bellerophontoidean Gastropod (Mollusca)
Authors: Peel John S.
Published: November 2003

A single pair of well‐preserved muscle attachment scars showing excellent detail on the umbilical surface is described in a supposed bellerophontoidean gastropod from the Carboniferous of Britain. Ontogenetic study reveals that the bilateral symmetry of the thick‐shelled adult masks an anisometric early growth stage, indicating that the gastropod is a pleurotomarioidean vetigastropod masquerading as a bellerophontoidean.
The Phylogeny and Systematics of Blind Cambrian Ptychoparioid Trilobites
Authors: Cotton Trevor J.
Published: November 2003

The paraphyletic trilobite suborder Ptychopariina includes a large proportion of Cambrian trilobite diversity and is probably ancestral to most groups of post‐Cambrian trilobites. Resolution of the phylogenetic relationships within the group is therefore crucial to a better understanding of the initial radiation of trilobites. The recognition of approaches that can successfully resolve the relationships of ptychoparioid taxa is an important first step towards this aim. Cladistic analysis was used to determine relationships within the Cambrian ptychoparioid trilobite family Conocoryphidae, and to test claims that the family is polyphyletic. Ninety‐seven characters were coded for 40 conocoryphid species and nine non‐conocoryphids. The results indicate that the family consists of four distantly related clades. Three are recognized here as distinct families, including an extensively revised Conocoryphidae, and the families Holocephalidae and Atopidae. The fourth clade is referred to the subfamily Acontheinae (Corynexochida) as the new Tribe Hartshillini. Analysis of the disparity of these four clades shows that they are significantly less morphologically variable than the original polyphyletic taxon, demonstrating the possible effects of taxonomic error on macroevolutionary studies of morphological disparity.
A New Species of Amphirhagatherium (Choeropotamidae, Artiodactyla, Mammalia) from the Late Eocene Headon Hill Formation of Southern England and Phylogeny of Endemic European ‘anthracotherioids’
Authors: Hooker Jerry J. , Thomas Katherine M.
Published: November 2003

A new species of artiodactyl, Amphirhagatheriumedwardsi sp. nov., is described from the Late Eocene (Priabonian) Headon Hill Formation of the Hampshire Basin, southern England. The Haplobunodontidae, in which Amphirhagatherium is usually placed, has recently been combined with the monotypic Choeropotamidae, both essentially European endemic families. New anatomical information is forthcoming from both the new species and recently published data on related species. A cladistic analysis of taxa included in the two families, the possible anthracotheriid Thaumastognathus and the enigmatic Tapirulus, was conducted to test the relationships implied by observed morphological similarities. The genus Anthracobunodon is shown to be paraphyletic and is here synonymized with Amphirhagatherium. Choeropotamus and Thaumastognathus are sister taxa nested with three species of Haplobunodon and Haplobunodon is paraphyletic and polyphyletic, but this clade is too weakly resolved internally for reliable taxonomic changes. LophiobunodonTapirulus are sister taxa nested with a fourth species of Haplobunodon. The synonymy of the Haplobunodontidae with the Choeropotamidae is upheld and close relationship of the family with the Anthracotheriidae is argued to be unlikely. Choeropotamids are inferred to have had mixed frugivorous and browsing herbivorous diets. They seem to have diversified in the northern parts of Europe, some terminal taxa having originated following southward dispersal.
A Rare, Larval‐founded Colony of the Bryozoan Archimedes from the Carboniferous of Alabama
Authors: Mckinney Frank K. , Burdick Dennis W.
Published: November 2003

Very few basal attachments of the spiralled fenestrate bryozoan Archimedes are known. A newly discovered specimen is interpreted to have grown on a thin cylindrical ephemeral substratum that extended above the sediment‐water interface, allowing paired spirals to develop and to extend in opposite directions when the colony was very small.
Evolutionary and Diagenetic Changes in the Chemico‐structure of the Shell of Cranioid Brachiopods
Authors: Cusack Maggie , Williams Alwyn
Published: November 2003

The laminar dorsal valve of living Neocrania consists of: a primary layer of rhombohedral tablets, composed of granular calcite and commonly forming slats orthogonal to the margin, associated with polysaccharides and a fibrous 60 kDa protein; and a secondary layer of spirally growing (10.4) rhombohedra, doped with the 60 kDa protein and interleaved with membranes of a fibrous 44 kDa protein. The ventral valve consists exclusively of a primary layer with the same composition and basic structure as that of the dorsal valve. Investigation of selected antecedents shows that the chemico‐structure of the Neocrania shell has been virtually unchanged since the first appearance of the stock in the Early Ordovician (Arenig). The greatest phylogenetic change affected the ventral valve that varied, even in Ordovician genera, from a film of calcitic blades to a complete succession of primary and secondary laminae. The most profound diagenetic changes occurred before the Late Cretaceous with proteins degrading into peptides that were dispersed, with the loss of less stable amino acids, during laminar recrystallization. Palaeozoic shells suffered further recrystallization but, even after pressure solution, the original laminar fabric was replicated long after it had lost its constraining organic membranes.
Rodents and Insectivores from the Upper Miocene of Molayan, Afghanistan
Authors: Sen Sevket
Published: November 2003

Although Molayan is the richest fossil mammal locality in Afghanistan, only a few species have been studied. This paper describes three rodents (Hystrix aryanensis sp. nov., Parapeolomys sp. and Pseudomeriones latidens sp. nov.) and one insectivore (Erinaceus sp.). Lithostratigraphical correlations and biostratigraphical studies in the Khurdkabul Basin provide evidence that the Molayan locality is younger than three other localities in this basin: Sherullah, Taghar and Ghazgay. In addition, the taxa described here, along with several species of large mammals from Molayan, permit correlations with the Siwalik succession in Pakistan to the east, and with European Neogene mammal ages to the west. The age of the Molayan fauna is concluded to be mid Turolian. Observations on the mammal faunas from the Khurdkabul Basin suggest that the altitude of the area, at present over 2000 m, was much lower during the late Miocene. Uplift of the basin probably occurred no earlier than the ?late Pliocene.
A Chondrophorine (Medusoid Hydrozoan) from the Lower Cretaceous of Chile
Authors: Bell C. M. , Angseesing J. P. A. , Townsend M. J.
Published: November 2003

Aysenspriggia apelegensis is a new genus and species of a chondrophorine (jellyfish‐like hydrozoan) from the Lower Cretaceous Apeleg Formation of southern Chile. Despite their modern abundance chondrophorines are rare in the fossil record. The Apeleg Formation was deposited in a deep‐water environment characterised by strong tidal currents. The fossils resulted from water‐logged pelagic floats settling to the sea bed during periods of tidal slack water. Burial of the rigid three‐dimensional chitinoid float resulted in preservation as imprints on the base of the overlying sandstone. Soft parts of the animal were not preserved. The palaeoenvironmental interpretation is in accordance with that of other records of chondrophorines, including those from the Ediacaran fauna, which are apparently characterised by a bimodal depth distribution. Like much of the Ediacaran fauna most chondrophorines are preserved as impressions on the base of sandstone beds.
A New Japygid Dipluran from the Lower Cretaceous of Brazil
Authors: Wilson Heather M. , Martill David M.
Published: November 2003

The first Mesozoic japygid (Hexapoda: Diplura), Ferrojapyx vivax gen. et sp. nov., is described from the Lower Cretaceous (Aptian) Crato Formation of north‐east Brazil. There are only two previously described occurrences of japygids in the fossil record: in Miocene or Pliocene onyx marble from Arizona and from the Carboniferous (Westphalian D) Francis Creek Shale of Mazon Creek, Illinois.
The Early Triassic ‘lizard’Colubrifer Campi: A Reassessment
Authors: Evans Susan E.
Published: November 2003

Colubrifer campi Carroll, 1982 is a small reptile represented by a single skeleton from the Lower Triassic of South Africa. Carroll attributed the genus to the Squamata, proposing that it was a derived lizard with reduced limbs. Re‐examination of the specimen permits a rather different interpretation of the skull. The holotype of Colubrifer is the skeleton of a small primitive procolophonian, almost certainly referable to the established South African genus Owenetta.
Revision Of Late Devonian (Famennian) And Some Early Carboniferous (Tournaisian) Crinoids And Blastoids From The Type Devonian Area Of North Devon
Authors: Lane N. G. , Maples C. G. , Waters J. A.
Published: November 2003

The crinoids and blastoids from the Pilton (Beds) Formation of the type Devonian of north Devonshire are revised. These fossils were monographed by the Rev. G. F. Whidborne in 1898, but have not been studied since that time. Recent studies on various groups of fossils from the Pilton and related rocks in North Devon confirm that the great majority of these fossils are Famennian, although three specimens from Fremington are probably Early Carboniferous (Tournaisian). We identify four blastoid taxa from a fauna that is sparse and poorly preserved; two spiraculates, one fissiculate, and one taxon unidentifiable at the ordinal level. Mesoblastus cf. M. crenulatus from the Gattendorfia Zone (Lower Carboniferous) near Fremington is the oldest known representative of this genus. The crinoid fauna is somewhat more diverse, but the preservation is equally poor. No changes are made in the flexible crinoids. Among camerate crinoids, one species is reassigned to Eumorphocrinus and one is retained in Actinocrinites. Specimens of some crinoids, such as Rhodocrinites and Megistocrinus, are so poorly preserved that certain identification was not possible. The hexacrinoid Adelocrinus, relegated to uncertainty for 150 years, is here shown to be a valid genus that is very similar to Arthroacantha, but not synonymous with it. Among the cladid crinoids, the dominant groups are those within the Superfamily Scytalocrinacea, which includes Bridgerocrinus, Sostronocrinus, and Scytalocrinus, all of which are placed in the new family Sostronocrinidae. One new species, Glossocrinus whidbornei, is named. Non‐pinnulate cladids, common in older Devonian rocks, do not occur. The fauna shows considerable similarity with faunas from eastern North America and Germany. It shows less resemblance to the extensive Famennian crinoid and blastoid fauna of north‐western China, despite some remarkable congruencies, especially the occurrence of very similar species of Actinocrinites in these widely separated areas.
Presence Of Nemathecia In Parachaetetes Asvapatii Pia, 1936 (Rhodophyta, Gigartinales?): Reproduction In ‘Solenoporaceans’ Revisited
Authors: Aguirre J. , Barattolo F.
Published: November 2003

Parachaetetes asvapatii is a very common algal species in the Palaeogene deposits of the Tethyan realm and has been considered as a member of the heterogeneous family Solenoporaceae. This attribution is exclusively based on features of the vegetative tissue, since no reproductive structures have ever been recovered. However, detailed analysis of Late Cretaceous–Eocene material from Turkey has revealed nemathecia‐like structures in one specimen attributable to P. asvapatii. These nemathecia are small wart‐like structures protruding on the thallus surface that formed by enlargement of the most peripheral cells of the plant. Nemathecia only occur in three families of the order Gigartinales (Rhodophyta): Rhizophyllidaceae, Peyssonneliaceae and Polyideaceae. Since reproductive structures are stable characters, the presence of nemathecia leads us to tentatively refer P. asvapatii and related species (probably Elianella elegans) to the Gigartinales.
Biology Of The Famennian Heterocoral Oligophylloides Pachythecus
Authors: Chwieduk Edward
Published: November 2003

Studies on the taxonomy and morphology of the Famennian heterocoral Oligophylloides have placed great emphasis on the character of the soft tissue, coloniality and distal development of the skeleton with regard to the construction of the wall. Here, the existence of soft tissue covering the entire skeleton of the colony is proposed. Thirty‐eight branching specimens have been found in addition to the predominant single fragments of corallites; these should be regarded as colonial with a well‐developed branching form. It is here proposed that the external wall grew not only at the distal end, and that its thickening did not result from the overlapping of tabulae, but was built independently of tabulae by the soft tissue covering the whole skeleton of the colony. The following new characteristics of Oligophylloides are described: a change in the position of septa, so‐called ‘septal shifting’, a rearrangement of the septal apparatus; the occurrence of aulos‐like structures; a groove ornamentation on the external wall; and the granular microstructure of the axial part of septa. A detailed study of Late Devonian Oligophylloides corals shows that O. tenuicinctus Róz˙kowska and O. pachythecus pentagonus Róz˙kowska are synonymous with O. pachythecus Róz˙kowska.
The West Gondwanan Occurrence Of The Hybodontid Shark Priohybodus, And The Late Jurassic–Early Cretaceous Age Of The Tacuarembó Formation, Uruguay
Authors: Perea Daniel , Ubilla Martín , Rojas Alejandra , Goso César A.
Published: November 2003

Priohybodus cf. P. arambourgi is reported for the first time from the Tacuarembó Formation of Uruguay. This species is a hybodontid shark known previously only from Upper Jurassic and Lower Cretaceous deposits of Saharan Africa and the Arabian Peninsula. The material (22 isolated teeth and a dorsal fin spine) was found in a thin bone bed, associated with abundant bone fragments, scales and teeth of semionotiform fishes and theropod dinosaurs. Until now, the age of the Tacuarembó Formation has been difficult to determine because its fossil content lacked useful biostratigraphic indicators. The finding of Priohybodus cf. P. arambourgi in that unit greatly expands the palaeobiogeographic range of the species, and allows us to propose a Late Jurassic–Early Cretaceous age for the Tacuarembó Formation.
The first record of xiphosurid (arthropod) trackways from the Saltwick Formation, Middle Jurassic of the Cleveland Basin, Yorkshire
Authors: Romano Mike , Whyte Martin A.
Published: November 2003

Trackways attributed to a xiphosurid (arthropod) maker are described for the first time from the Middle Jurassic Saltwick Formation, Ravenscar Group, of the Cleveland Basin, Yorkshire. The trackways are assigned to Kouphichnium aff. variabilis (Linck, 1949) and clearly demonstrate the heteropody and varied behaviour of the maker. Their occasional asymmetry indicates a slight rotation of the body relative to the direction of locomotion. The Saltwick Formation has generally been regarded as a coastal plain deposit, and the presence of xiphosurid tracks reinforces the suggestions of periodic marine influences.
Proximal structure and development in the Ordovician graptolite Parisograptus Chen and Zhang, 1996
Authors: Maletz Jörg , Zhang Yuandong
Published: November 2003

The proximal development of Parisograptus Chen and Zhang is described from three–dimensionally preserved specimens. The unique development features an origin of proximal thecae like a string of pearls vertically upon each other on the reverse side of the rhabdosome with the dorsal sides of the initial stipes placed side by side. The development differs strongly from that found in the superficially similar Arienigraptus in which the first thecal pairs grow downwards side by side, even though the rhabdosome shapes are quite similar. It represents a first step towards the development of a completely biserial rhabdosome and eventually leads to the biserial, monopleural glossograptids.
Overgrowth on ammonite conchs: environmental implications for the Lower Toarcian Posidonia Shale
Authors: Schmid–Röhl Annette , Röhl Hans–Joachim
Published: November 2003

Ammonites of the south–west German Posidonia Shale (Early Toarcian) are occasionally overgrown by bivalves, brachiopods or serpulids. Attachment to both sides of the conchs in some specimens suggests attachment during the ammonite's lifetime, with a pseudoplanktic mode of life for the epizoans. However, dense overgrowth restricted to the upper surface of some ammonite shells indicates post–mortem colonization. Our study shows that apart from oxygen supply as a main factor controlling benthic colonization, substrate consistency also played an important part. Unfavourable living conditions prevailed during deposition of the organic–rich sediments, excluding macrofauna in the benthic environment. However, less than 0.1 per cent of the ammonite conchs found during the excavation show overgrowth, indicating that pseudoplanktonism was an infrequently adopted strategy for inhabiting surface waters.
Systematics of the Late Carboniferous Medullosalean Pteridosperm Laveineopteris and Its Associated Cyclopteris Leaves
Authors: Cleal C. J. , Shute C. H.
Published: November 2003

Laveineopteris is emended to become a morphogenus for the vegetative parts of certain medullosalean pteridosperms that grew in the Westphalian (Late Carboniferous) tropical rainforests. The plant bore pinnate foliage as sun leaves and entire orbicular leaves (cyclopterids) as shade leaves. The cyclopterids were attached to the axis of the saplings and epiphyllously to the lower parts of the pinnate fronds. Species recognition is mainly by the macro–morphology of the pinnate fronds. However, species can also be distinguished based on the epidermal anatomy of both pinnate fronds and cyclopterids, in particular the distribution and detailed structure of the stomata and hydathodes. Laveineopteris first appeared in the lowland swamp forests of Europe during the early Langsettian (Westphalian A), and there were two principal species: L. loshii and L. tenuifolia. During the early Bolsovian (early Westphalian C), a variety of L. tenuifolia appeared that was adapted to both the lowland swamps, and the upland swamps of the intramontane basins (central Bohemia and Saar–Lorraine). The smaller–pinnuled L. rarinervis also first appeared in the Bolsovian and seems to have been restricted to the lowland swamps. The morphogenus Cyclopteris should be used only for cyclopterid fossils, where they cannot be related to the species of Laveineopteris, Callipteridium or Margaritopteris that originally bore them.
The lectotype of Sphenobaiera Ikorfatensis (Seward) Florin, a ginkgophyte from the Lower Cretaceous of western Greenland
Authors: Lydon Susannah J. , Watson Joan , Harrison Nicola A.
Published: November 2003

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.
Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous of Huolinhe, eastern Inner Mongolia, China
Authors: Ge Sun , Lydon Susannah J. , Watson Joan
Published: November 2003

Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous Huolinhe Formation in the Huolinhe coal–mining area, eastern Inner Mongolia, China, is identified, described and figured. Comparison with the type material of Sphenobaiera ikorfatensis (Seward) Florin from West Greenland confirms its identity. About 20 Chinese leaf specimens are known with well preserved cuticle which is closely similar to the Greenland leaves but more papillate. The palaeoclimatic and phytogeographic significance of the occurrence of this species is discussed in relation to the suggestion that West Greenland, north–east China and eastern Siberia were in the same phytogeographic region during the Lower Cretaceous.
Economic commodity or environmental crisis? An interdisciplinary approach to analysing the bushmeat trade in central and west Africa
Authors: Bowen‐Jones E , Brown D , Robinson E J Z
Published: November 2003

Bushmeat is a large but largely invisible contributor to the economies of west and central African countries. Yet the trade is currently unsustainable. Hunting is reducing wildlife populations, driving more vulnerable species to local and regional extinction, and threatening biodiversity. This paper uses a commodity chain approach to explore the bushmeat trade and to demonstrate why an interdisciplinary approach is required if the trade is to be sustainable in the future.
Climate variability and rural livelihoods: assessing the impact of seasonal climate forecasts in Lesotho
Authors: Ziervogel Gina , Calder Rebecca
Published: November 2003

Climate variability acutely affects rural livelihoods and agricultural productivity, yet it is just one of many stresses that vulnerable rural households have to cope with. A livelihood approach is used to assess the potential role that seasonal climate forecasts might play in increasing adaptive capacity in response to climate variability, using Lesotho as a case study. An examination of the assets and strategies that rural households employ enables a holistic assessment of the impact seasonal forecasts could have on rural livelihoods. This research thereby bridges macro‐level variability with local‐level impacts and adaptation to provide insight into the dynamics of forecast use and impact among vulnerable groups.
‘After‐the‐fact causality’: a different direction for cultural geography
Authors: Norton William
Published: November 2003

Cultural geography might benefit from consideration of radical behaviourism and from interpretation and application of the concepts of behaviour analysis. The basic concept is that of operant conditioning, referring to the environment reinforcing behaviours that are most adaptive and effective in achieving reinforcers and avoiding aversive stimuli. The concept of rule‐governed behaviour facilitates incorporation of cognition into behaviour analyses, accommodating the fact that many consequences are delayed. These concepts are applied in an analysis of nineteenth‐century Mormon settlement in the American West. This argument for an objectivist approach is laden with social scientific baggage not favoured in contemporary cultural geography.
Construction of a historical Water Pollution Index for the Mersey Basin
Authors: Burton L R , Howard A , Goodall B
Published: November 2003

The Mersey Basin has been significantly polluted for over 200 years. However, there is a lack of quantitative historical water quality data as effective water quality monitoring and data recording only began 30–40 years ago. This paper assesses water pollution in the Mersey Basin using a Water Pollution Index constructed from social and economic data. Methodology, output and the difficulties involved with validation are discussed. With the limited data input available the index approximately reproduces historical water quality. The paper illustrates how historical studies of environmental water quality may provide valuable identification of factors responsible for pollution and a marker set for contemporary and future water quality issues in the context of the past. This is an issue of growing research interest.
Levetiracetam and Partial Seizure Subtypes: Pooled Data from Three Randomized, Placebo‐controlled Trials
Authors: Leppik Ilo E. , Biton Victor , Sander Josemir W. A. , Wieser Heinz Gregor
Published: November 2003

Summary:  Purpose: To determine the effect of levetiracetam (LEV) on partial seizure subtypes (simple partial, complex partial, and secondarily generalized seizures) in patients with refractory epilepsy.

Methods: Pooled results from three placebo‐controlled trials were analyzed.

Results: A statistically significant reduction in the frequency of all partial seizures and all seizure subtypes was observed in the LEV group (p < 0.001 vs. placebo). The proportion of patients in whom secondarily generalized seizures could be prevented over and above the reduction of partial seizures was significantly greater in the LEV group as compared with placebo, with an odds ratio of 1.83 [95% confidence interval (CI), 1.10–3.05].

Conclusions: LEV reduces frequency of simple and complex partial seizures. In addition, it demonstrates a specific, independent reduction of secondarily generalized seizures.
The Role of Hippocampal Sclerosis in Topiramate‐related Depression and Cognitive Deficits in People with Epilepsy
Authors: Mula Marco , Trimble Michael R. , Sander Josemir W. A. S.
Published: November 2003

Summary:  Purpose: To clarify the role of hippocampal sclerosis (HS) in developing psychiatric and cognitive adverse events during therapy with topiramate (TPM) in patients with temporal lobe epilepsy (TLE).

Methods: We analyzed the data of 70 patients with TLE and HS and 128 patients with cryptogenic TLE matched for age, sex, starting dose, and titration schedule of TPM. They were selected from the first consecutive 431 patients started on TPM between 1995 and 1999.

Results: Patients with HS were more likely to develop cognitive adverse events (CAEs; p = 0.002) and depression (p = 0.018) and to be receiving a polytherapy regimen (p = 0.007). However, regression analysis demonstrated that only HS was a predictive factor for the occurrence of CAEs (OR = 2.4; p < 0.001) and depression (OR = 2.3; p = 0.02).

Conclusions: Patients with TLE and HS were more prone to develop CAEs and depression than were patients with cryptogenic TLE, during TPM therapy, despite the same titration schedule. The presence of HS and not duration of epilepsy or polytherapy regimen represented the main risk factor.
Vagal Nerve Stimulation Induces Intermittent Hypocapnia
Authors: Holmes Mark D. , Miller John W. , Voipio Juha , Kaila Kai , Vanhatalo Sampsa
Published: November 2003

Summary:  Purpose: To study whether respiratory alteration caused by vagal nerve stimulation (VNS) can change end‐tidal carbon dioxide (EtCO2) levels.

Methods: We performed polygraphic recordings including capnographic monitoring during daytime sleep on adults with VNS therapy.

Results: Ten of 13 patients showed VNS‐induced alterations in the frequency or amplitude of respiration. Five patients had a consistent increase in respiratory rate with a simultaneous, consistent and significant decrease (p < 0.01; 5–22%) in EtCO2 during VNS. Three subjects showed occasional decreases in EtCO2 during VNS, and two showed no clearly detectable VNS‐related EtCO2 changes.

Conclusions: Our findings suggest that VNS may alter brain CO2 levels through changes in respiration. Because carbon dioxide (CO2) has potent effects on various brain functions, it is possible that these transient CO2 changes may have an effect on the state transitions between interictal and preictal states.
Long‐lasting Anticonvulsant Effect of Focal Cooling on Experimental Neocortical Seizures
Authors: Yang Xiao‐Feng , Chang Jong Hee , Rothman Steven M.
Published: November 2003

Summary:  Purpose: Previous clinical and experimental observations have demonstrated that cooling the brain can rapidly terminate focal seizures. We wished to determine whether cooling at regular intervals could prevent or attenuate the development of seizures in a model of focal epilepsy.

Methods: We induced focal neocortical seizures in halothane‐anesthetized rats by the microinjection of 4‐aminopyridine (4‐AP) into the motor cortex. With a small thermoelectric device, the site of the 4‐AP injection was either cooled intermittently (PostCool) for 30 s every 2 min, starting 15 min after the 4‐AP injection, or precooled (PreCool) for 30 min before 4‐AP injection, by using the same 30‐s cooling cycle. Seizures were quantified in 30‐min observation periods for 1.5 h.

Results: The average durations of PostCool and PreCool seizures were shorter than those of controls (p < 0.001). In addition, total seizure duration was significantly reduced in both groups, compared with controls (p < 0.01). The ratio of the root mean square power during a seizure to power in the immediate preseizure period was reduced in both PostCool and PreCool groups (p < 0.001). The number of seizures significantly declined over a 30‐ to 60‐min period in both experimental groups, and by 60 min, no seizures were evident.

Conclusions: These experiments show that gentle cooling to 20°C is capable of markedly reducing subsequent seizure frequency and intensity. The effects in our model, which generates very frequent and intense ictal activity, were robust, suggesting that prophylactic cooling might be even more beneficial in clinical situations. The physiologic mechanism for this preventive effect requires elucidation.
Increased Persistent Sodium Currents in Rat Entorhinal Cortex Layer V Neurons in a Post–Status Epilepticus Model of Temporal Lobe Epilepsy
Authors: Agrawal Newton , Alonso Angel , Ragsdale David S.
Published: November 2003

Summary:  Purpose: Spontaneous seizures in rats emerge several weeks after induction of status epilepticus with pharmacologic treatment or electrical stimulation, providing an animal model for human temporal lobe epilepsy. In this study, we investigated whether status epilepticus caused changes in the function of voltage‐gated sodium channels in entorhinal cortex layer V neurons, a cellular group important for the genesis of limbic seizures.

Methods: We induced status epilepticus in rats, by using lithium‐pilocarpine, and then 2–12 weeks later, used whole‐cell voltage‐clamp to examine voltage‐activated sodium currents of acutely dissociated layer V neurons.

Results: Transient sodium currents of entorhinal cortex layer V neurons isolated from 9‐ to 12‐week post–status epilepticus rats were similar to currents in age‐matched controls; however, low‐threshold persistent sodium currents were significantly larger. This increase in persistent activity was not seen 2–3 weeks after pilocarpine treatment; thus it occurred after a delay comparable to the delay in the appearance of spontaneous seizures.

Conclusions: Increased persistent currents are expected to accentuate neuronal excitability and thus may contribute to the genesis of spontaneous seizures after status epilepticus.
Single‐unit Analysis of Substantia Nigra Pars Reticulata Neurons in Freely Behaving Rats with Genetic Absence Epilepsy
Authors: Deransart Colin , Hellwig Bernhard , Heupel‐Reuter Miriam , Léger Jean‐François , Heck Detlef , Lücking Carl Hermann
Published: November 2003

Summary:  Purpose: The substantia nigra pars reticulata (SNpr) is assumed to be involved in the control of several kinds of epileptic seizures, an assumption based mostly on neuropharmacologic evidence. However, only very few neurophysiological recordings from the basal ganglia support neuropharmacologic data. We investigated the electrophysiologic activity of SNpr neurons in rats with genetic absence epilepsy.

Methods: Electrocorticography (ECoG) and multi‐unit recordings using permanently implanted tetrodes were obtained in freely behaving rats. After spike sorting, auto‐ and cross‐correlation analysis was used to detect oscillatory neuronal activities and synchronizations.

Results: During interictal periods, neither oscillation nor synchronization could be observed in the firing patterns of SNpr neurons. At the beginning of the absence seizure, the firing rate increased significantly. The SNpr neurons started firing in bursts of action potentials. Bursts were highly correlated to the spike‐and‐wave discharges (SWDs) in the ECoG, mainly after the spike component of the cortical spike‐and‐wave complex. Moreover, pairs of SNpr neurons tended to fire synchronously. Before the end of the seizure, the firing rate decreased progressively, and the burst‐firing pattern ended at or before the end of the SWDs. Once the SWDs had stopped, the SNpr neurons resumed their basal firing pattern as before the seizure onset.

Conclusions: These results provide electrophysiologic evidence that firing patterns and synchronization of SNpr neurons are in phase with the occurrence of SWDs. The findings support the concept that nigral control mechanisms are involved in modulating the propagation of an ongoing generalized seizure.
Texture Analysis of Hippocampal Sclerosis
Authors: Bonilha Leonardo , Kobayashi Eliane , Castellano Gabriela , Coelho Giselle , Tinois Eduardo , Cendes Fernando , Li Li M.
Published: November 2003

Summary:  Mesial temporal lobe epilepsy (MTLE) is frequently associated with refractory seizures and pathologic features of hippocampal sclerosis (HS). Quantitative magnetic resonance imaging (MRI) techniques can improve the detection and quantification of HS. The objective of this study was to evaluate whether MRI texture analysis can detect hippocampal abnormalities in patients with pathologically proven HS.

Methods: Nineteen consecutive patients who underwent surgery for refractory unilateral MTLE and had HS diagnosed on histopathology (12 right and seven left) had their preoperative MRIs evaluated. We performed texture analysis in 3‐mm coronal T1‐IR MRIs, focusing on the hippocampal head, by using the software MAZDA. Data were compared with those of a group of 78 normal hippocampi from 39 healthy adult volunteers through multivariate analysis of variance and selection of the most significant texture parameters.

Results: Overall, almost all parameters of texture could discriminate the group of hippocampi with HS and the group of contralateral hippocampi from the group of normal hippocampi, but the post hoc comparison showed no differences between HS and contralateral hippocampi.

Conclusions: These results provide evidence of texture alteration in MRIs of hippocampi with HS and corroborate the hypothesis of bilaterality of hippocampal damage in patients with MTLE, but further studies are needed to investigate the lateralization power of texture analysis.
The Influence of Comorbid Depression on Seizure Severity
Authors: Cramer Joyce A. , Blum David , Reed Michael , Fanning Kristina ,   Epilepsy Impact Project Group
Published: November 2003

Summary:  Purpose: To determine the relation between depressive symptoms and seizure severity among people with epilepsy.

Methods: A postal questionnaire was used to survey a nationwide community sample about seizures and depression. The Seizure Severity Questionnaire (SSQ) assessed the severity and bothersomeness of seizure components. The Centers for Epidemiological Studies‐Depression scale categorized levels of depression.

Results: Respondents categorized as having current severe (SEV, n = 166), mild–moderate (MOD, n = 74), or no depression (NO, n = 443) differed significantly in SSQ scores (all p < 0.0001). People with SEV or MOD reported significantly worse problems than did those with NO depression for overall seizure recovery (mean, 5.3, 4.9, 4.5, respectively); overall severity (5.0, 4.5, 4.2); and overall seizure bother (5.3, 4.8, 4.4) (all p < 0.005). Cognitive, emotional, and physical aspects of seizure recovery also were rated worse among people with SEV than with NO depression (all p < 0.05). Symptoms of depression were significantly correlated with higher levels of all components of generalized tonic–clonic seizure severity (r = 0.33–0.48; all p < 0.0001), and partial seizures (r = 0.31–0.38; all p < 0.01).

Conclusions: Clinically depressed people with epilepsy reported higher levels of perceived severity and bother from seizures, as well as greater problems with overall seizure recovery than did nondepressed people experiencing similar types of seizures. The pervasive influence of depressive symptoms on reports of seizure activity suggests that people with epilepsy should be screened for depression. These data highlight the importance of detecting and treating depression among people with epilepsy.
The Significance of Ear Plugging in Localization‐related Epilepsy
Authors: Clarke Dave F. , Otsubo Hiroshi , Weiss Shelly K. , Chitoku Shiro , Chuang Sylvester H. , Logan William J. , Smith Mary‐Lou , Elliot Irene , Elizabeth W. Pang , Rutka James T. , Snead O. Carter
Published: November 2003

Summary:  Purpose: The localizing value of ear plugging in the treatment of auditory onset partial seizures, to our knowledge, has not been previously described. We propose that ear plugging is a clinical response to a sensory seizure manifested as an auditory hallucination and a tool for identifying the seizure focus in the auditory cortex on the superior temporal gyrus.

Methods: We report on three children who had prior epilepsy surgery for recurrent symptomatic localization‐related epilepsy and who, subsequent to their surgery, displayed stereotyped unilateral or bilateral ear plugging at the onset of partial seizures. We studied scalp video electroencephalography (VEEG), magnetoencephalography (MEG), and magnetic resonance imaging (MRI) in all three. Additionally, we used electrocorticography (ECoG) in two patients, intracranial VEEG monitoring in one patient, and functional MRI language mapping in two patients.

Results: All three patients plugged their ears with their hands during auditory auras that localized to the superior temporal gyrus and were followed by partial seizures that spread to a wider field, as shown on scalp and intracranial VEEG. All three patients had MEG interictal discharges in the superior temporal gyrus. One patient who was nonverbal and unable to describe an auditory phenomenon plugged the ear contralateral to where temporal lobe–onset seizures and MEG interictal discharges occurred.

Conclusions: Ear‐plugging seizures indicate an auditory aura and may also lateralize seizure onset to the contralateral temporal lobe auditory cortex. Stereotyped behaviors accompanied by epileptic seizures in children who have poor communication skills are important in the seizure semiology of localization‐related epilepsy.