bluuebunny/crossref_metadata_2025_split huggingface dataset:
A chemical–mineralogical classification of common plutonic rocks and associations
Authors: Debon F. , Le Fort P. 
Published: November 2011

ABSTRACTA classification is proposed, based mainly on major element analytical data plotted in a coherent set of three simple chemical-mineralogical diagrams. The procedure follows two complementary steps at two different levels. The first is concerned with the individual sample: the sample is given a name (e.g. granite, adamellite, granodiorite) and its chemical and mineralogical characteristics are determined. The second one is more important: it aims at defining the type of magmatic association (or series) to which the studied sample or group of samples belongs. Three main types of association are distinguished: cafemic (from source-material mainly or completely mantle-derived), aluminous (mainly or completely derived by anatexis of continental crust), and alumino-cafemic (intermediate between the other two types). Subtypes are then distinguished among the cafemic and alumino-cafemic associations: calc-alkaline (or granodioritic), subalkaline (or monzonitic), alkaline (and peralkaline), tholeiitic (or gabbroic-trondhjemitic), etc. In the same way, numerous subtypes and variants are also distinguished among the aluminous associations using a set of complementary criteria such as quartz content, colour index, alkali ratio, quartz–alkalies relationships and alumina index.Although involving a new approach using partly new criteria, this classification is consistent with most of the divisions used in previous typologies. The method may also be used in the classification of the volcanic equivalents of common plutonic rocks.
Stratigraphical palaeontology of the Westphalian of the Ayrshire Coalfield, Scotland
Authors: Brand P. J. 
Published: November 2011

ABSTRACTA brief account of the stratigraphy of the Westphalian (Upper Carboniferous) of the Ayrshire Coalfield is given. Older rocks are found to be overlain by Westphalian strata of differing age in various parts of the coalfield. A correlation of the coal seams known by numerous local names in various areas of the coalfield is shown. The vertical distribution of species of non-marine bivalves is illustrated and the faunas associated with various horizons discussed. The presence of variants of Anthraconaia pulchella Broadhurst at more than one horizon is noted. The lateral distribution of species at given horizons is examined and it is shown that elements of the overall fauna of an horizon may be absent in parts of the coalfield. The occurrence of marine bands in the succession is noted and their distribution discussed. It is suggested that during the Aegiranum Marine Band incursion the northern and north-western parts of the coalfield were nearer a land mass. A new stratigraphical name, the Bogton Marine Band is proposed. The band occurs within the Upper Similis-Pulchra Chronozone.
The earliest known (Namurian A, E1) haplolepids (Osteichthyes: Actinopterygii)
Authors: Lowney Karen A. 
Published: November 2011

ABSTRACTTwo new genera and species of haplolepids (Chondrostei), Protohaplolepis scotica and Blairolepis loanheadensis, are described from the ironstones of Loanhead, Midlothian (Namurian A, E1); this represents the earliest known record of the family. Protohaplolepis scotica (= Traquair's nomen nudum “Eurylepis scoticus”) shows many features in common with Westoll's hypothetical haplolepid “common ancestor X”, and is possibly ancestral to the Haplolepis–Microhaplolepis line within the family. Blairolepis loanheadensis, known only from a skull roof, shows greater similarities to Parahaplolepis and Pyritocephalus, but differs from these genera in having separate dermopterotics and parietals. Two subfamilies, the Haplolepinae and the Parahaplolepinae, are suggested to reflect the distinct evolutionary lines within the family.A new species, Parahaplolepis westolli, is also described from Newsham, Northumberland (Westphalian B). This species shows a close resemblance to the American species Parahaplolepis tuberculata from Linton, Ohio.A brief discussion of the evolutionary history of the family is presented, along with a summary of its stratigraphical and geographical distribution.
Introduction to the palaeontology of the Dinantian of Foulden, Berwickshire, Scotland
Authors: Wood S. P. , Rolfe W. D. Ian 
Published: November 2011

ABSTRACTThe Foulden Site of Special Scientific Interest is one of the few Cementstone Group localities that yields significant fauna and flora. Excavations in 1980 and 1981 removed a 1·3 m2 slab of the Fish Bed for laboratory study of the vertical and spatial distribution of the biota. Layer by layer analysis revealed an almost mutually exclusive relationship between the vertical distribution of the palaeoniscoid fishes and malacostracan crustaceans, as well as a horizon crowded with juvenile acanthodians. Elongate elements of this biota showed slight preferred orientations at that prolific horizon. Some 27 m of strata including the Fish Bed, Plant Bed and Shell Bed are recorded in detail, and their biota noted. Interim results of work on the main groups collected are summarised in associated papers in this part of Transactions. Brief reports are given here on the euryhaline marine bivalve mollusc Modiolus latus (Portlock), a rare durophagous bradyodont shark tooth and an Eogyrinus-like amphibian scute.
Malacostracan Crustacea from the Dinantian of Foulden, Berwickshire, Scotland
Authors: Briggs D. E. G. , Clarkson E. N. K. 
Published: November 2011

ABSTRACTTheTealliocarisandCrangopsispreviously recorded from Foulden are shown to beBairdops elegansandBelotelson traquairi, respectively. This locality thus yields the oldest KnownBairdops. The two species are confined to the lower Carboniferous sedimentary basin S of the Southern Uplands massif. Elsewhere, these genera are thought to characterise the nearshore marine fauna. The reciprocal relationship noted between malacostracans and actinopterygians may therefore be a function of fluctuating salinity.
A vermiform problematicum from the Dinantian of Foulden, Berwickshire, Scotland
Authors: Almond John E. 
Published: November 2011

ABSTRACTA unique specimen of an unusual elongate segmented compression fossil, Polylurida aenigmatica n. gen., n. sp., is described and illustrated. The bilaterally-symmetrical, dorsoventral structure (c. 6·5 cm long × 0·8 cm maximum width) narrows towards both ends and is subdivided into approximately 19 similar tapering segments, showing no evidence of tagmosis, appendages or an internal gut. The segments are covered with a substantial papillose organic cuticle, each segment bearing towards one end a pair of transverse calcareous bars. These bars are perforated by simple canals filled with strands of dark organic material which traverse their whole thickness and flare out superficially to form pores on both their lower and upper surfaces. Internal horizontal lamination of the bar material suggests an episodic accretionary pattern of skeletal growth. The bars appear to represent internal skeletal structures and are restricted to one side (dorsal or ventral) of the body, where the adjacent cuticle is locally thickened to form a corresponding series of discrete paired densely papillose transverse bands. Although Polyurida may be an unusual segmented worm, its singular suite of characters and lack of data prevent assignment to any higher taxon.
Acanthodian and coelacanth fish from the Dinantian of Foulden, Berwickshire, Scotland
Authors: Forey P. L. , Young V. T. 
Published: November 2011

ABSTRACTAcanthodians are represented by numerous young and poorly cranially ossifiedAcanthodes ovensiWhite, the earliest known acanthodid. Study of the smallA. ovensitogether with the type series shows that squamation begins posteriorly, and spreads anteriorly along an initially triangular front, as inA. bridgeiZidek.Gyracanthussp. occurs at several horizons in the sequence. The coelacanth remains include the first articulated specimen known from Foulden, but preservation only allows an assignment to cf.Rhabdoderma. Although these taxa are distinctive, resemblances to other taxa occur only in generalised features. Hence, unlike the Foulden actinopterygian fish, the acanthodians and coelacanths cannot be used to suggest closer affinities with any other fish of this age, on which information is sparse.
Rhizodont crossopterygian fish from the Dinantian of Foulden, Berwickshire, Scotland, with a re-evaluation of this group
Authors: Andrews S. M. 
Published: November 2011

ABSTRACTMaterial of crossopterygian fishes from Foulden, Berwickshire, is important in including the first known entire specimen giving a clear picture of the body form of the Family Rhizodontidae (sensuAndrews 1973). This group is specialised in having numerous subsidiary lateral lines on the body, a ventrally expanded shoulder girdle, fins with peculiar stiffened structure, the pectorals forming greatly enlarged paddles and other fins being reduced in size. The Foulden remains fall into large and small size-ranges occurring largely at different levels in the sequence, but although these may represent growth in one taxon the available parts of the body are mostly complementary. Separate preliminary descriptions of the two size-ranges are therefore given, the small complete form being named?Strepsodus anculonamensissp. nov., and the large form remaining unnamed pending further study. An abridged historical account of previously named rhizodont genera (Rhizodus, Strepsodus, SauripterusandPycnoctenion) is given in order to explain why the new Foulden form(s) cannot at present be generically assigned more closely. A revised diagnosis of the Family Rhizodontidae leads to a discussion of the functional morphology and mode of life of fish of this type. Analogies with modern forms indicate that, like some sharks and crocodiles, they may have fed by tearing flesh off large prey, rotating or shaking against its inertia. Ways in which variously shaped rhizodont teeth (recurved, sigmoid etc.) may have functioned are suggested. Addenda deal with (1) the possible occurrence at Foulden of a large lungfish and (2) (after considering primitive and advanced rhizodont features) the renaming ofRhizodus ornatusTraquair 1878 from higher in the Scottish lower Carboniferous, as the type of a new genus,Screbinodus.
Structure and habits of living branchiopod crustaceans and their bearing on the interpretation of fossil forms
Authors: Fryer Geoffrey 
Published: November 2011

ABSTRACTBranchiopods are primitive crustaceans whose history extends back at least to the Devonian, yet some are highly successful today. Most fossil branchiopods do not show many features that lead to an understanding of function, but the Devonian lipostracan Lepidocaris is an exception. Recent work on living branchiopods, especially anostracans and anomopod cladocerans, enables Lepidocaris to be considered as a living animal. Work on extant anostracan nauplii also makes it possible to deduce how its larval stages swam and collected food.Other early crustaceans are briefly considered and comments are made on the concept of “living fossils”. While rates of morphological and genomic evolution are often discordant, the concept is still useful. Some branchiopods, such as the Notostraca, display remarkable morphological stasis: on the basis of morphology, a Triassic and a present-day form appear to be conspecific. The latter may be referred to as a “living fossil”.The outstanding morphological stasis of the crustacean nauplius is noted. Its existence in Cambrian times, deducible from its distribution among modern taxa, has been confirmed by Müller's finds. Such stasis, involving part of the genome of organisms whose adults display enormous adaptive radiation, has persisted with relatively small modifications since before the commencement of the entire radiation of vertebrates.
Swimming in Crustacea
Authors: Hessler Robert R. 
Published: November 2011

ABSTRACTAn analysis of swimming in living crustaceans is presented in order to elucidate the range of ways this function has been achieved, and to reveal the principles which constrain it. The study focuses onGnathophausia ingens, a primitive, bathypelagic malacostracan that swims with thoracic exopods and pleopods. These structures consist of a muscular peduncle and one or two flagella that are fringed with setulate setae. The basic motion is rowing with the limb and setal fan extended on the power stroke and flexed on recovery.A survey of other crustaceans shows that rowing with this type of swimming structure dominates throughout, although paddles often replace the flagella. Particularly pervasive is the large relative area of setae, whose effectiveness must stem from the ability to extend and flex passively and from the high drag generated on the power stroke by the setules at low Reynolds numbers.A review of reconstructions of Palaeozoic trilobites and marrellomorphs reveals the likelihood that if swimming was the function of the exites, they operated inefficiently or were employed in other methods as well. Sculling and drag reduction on the recovery stroke through feathering rather than flexion are possible alternatives. The more common occurrence of paddle-like limb shafts and blade-like marginal structures in other Palaeozoic arthropods is also noted.
Modes of life of arthropods from the Burgess Shale, British Columbia
Authors: Briggs D. E. G. , Whittington H. B. 
Published: November 2011

ABSTRACTThe modes of life of twenty three species of arthropods from the Shale are reviewed, with special reference to locomotion and feeding. Six groups are recognised, predatory and scavenging benthos, deposit-feeding benthos, scavenging and possibly predatory nektobenthos, deposit-feeding and scavenging nektobenthos, nektonic filter-feeders, and a miscellaneous sixth group that includes a questionable example of parasitism and a species that doubtfully grazed on algae. These animals had but limited powers of walking, digging, raking or swimming. Within these limitations a range of morphological adaptations and modes of feeding had been evolved, by Middle Cambrian time, a range comparable to that found in Recent marine forms. Arthropods in the Shale dominated, in numbers of individuals and possibly in biomass, a fauna dwelling above, on and in a muddy substrate at a depth of about 100 m.
Gross morphology and the mode of life of two species of lobster from the Lower Cretaceous of England:Meyeria ornata(Phillips) andMeyerella magna(M'Coy)
Authors: Simpson Martin I. , Middleton Richard 
Published: November 2011

ABSTRACTMacrurous decapod crustaceans are generally uncommon and are often incompletely preserved. However, at certain horizons in the Speeton Clay (Ryazanian–Albian) and Atherfield Clay (Lower Aptian) of Yorkshire and the Isle of Wight respectively, macrurans form the dominant element of the fauna. Two species in particular,Meyeria ornata(Phillips) andMeyerella magna(M'Coy), are not only very common in these formations, but are also very well preserved. Recent collections have yielded a large number of specimens of both species. This material is examined with the aid of SEM techniques, gross morphology is discussed, and the details of the exoskeletons are compared. In the case ofM. magna, examples are figured which show traces of a colour pattern and the effects of regeneration on the first pereiopods. A discussion is included of the possible function of the appendages inM. magnaandM. ornata, and of their other, unique features. Finally, the mode of life of both species is inferred from a consideration of their morphology, and of the evidence from their preservation, distribution and relationships with associated faunas.
Moulting in phacopid trilobites
Authors: Speyer Stephen E. 
Published: November 2011

ABSTRACTPhacopid trilobites, unlike most trilobites, lack functionally articulated libregenae. This distinction presumably dictated ecdysial strategies which were fundamentally different from those forms with sutured cephala.Phacops rana(Green) andGreenops boothi(Green) from the Middle Devonian Hamilton Group (New York) are preserved in circumstances which illustrate certain aspects of their moulting behaviour. Undisturbed exuviae display five different moult patterns; these suggest two basic modes of exuviation in phacopid trilobites (Body-upright and Body Inversion Moult Procedures).Certain Hamilton beds yield clusters ofPhacopscomprising complete and/or moulted remains. Complete trilobites in body clusters display varied orientations which, when considered in conjunction with exuvial patterns in moult clusters, suggest ecdysial procedures that involved body inversion and erratic tergal contractions (Body Inversion Moult Procedures). Ensembles where in thoracopygidia are upright and outstretched indicate hyperextension of the thorax and disarticulation of the cephalo-thoracic suture (Body-upright Moult Procedures).Phacopsmoult ensembles are characterised by inverted and tightly recurved thoracopygidia, whereasGreenopsensembles comprise outstretched, usually upright thoracopygidia with cephala that are frequently upright. Classic ‘Salterian’ patterns are uncommon inPhacops ranaand have not been recognised inGreenops boothi.Variations in moult procedure are attributed to differences in functional morphology and substrate consistency.
Cyrtoctenus wittebergensissp. nov. (Chelicerata: Eurypterida), a large sweep-feeder from the Carboniferous of South Africa
Authors: Waterston C. D. , Oelofsen B. W. , Oosthuizen R. D. F. 
Published: November 2011

ABSTRACTCyrtoctenus wittebergensissp. nov. is described from a unique holotype from the Witteberg Group of the Cape Supergroup. It is a giant hibbertopteroid eurypterid having combs and specialised movable spines of crytoctenid type (Størmer & Waterston 1968) on the more distal podomeres of the second to fourth prosomal appendages. The function of the combs and their associated movable spines is discussed and it is suggested that together they formed a unique adaptation of eurypterid structures to sweep filter-feeding, the combs forming the filters and the spines the cleaners. The digestive tract is remarkably preserved and shows a spiral valve, posterior to the stomach, which is interpreted as an adaptive feature in this large arthropod to increase the absorptive area of the gut.The new evidence provided by the South African specimen has required the re-interpretation of the disarticulatedCyrtoctenusspecimens previously described from Europe.Disjecta membrarecently obtained from the Tournaisian of Foulden, Berwickshire, which may belong toCyrtoctenus, are described and show characters previously unknown in Scottish material but similar to certain features in the South African specimen.The taxonomic relationships within the Hibbertopteroidea are discussed in the light of the new combination of characters found inC. wittebergensis. Two families are recognised in the superfamily, the Hibbertopteridae, includingHibbertopterusandCampylocephalus, and the new family Cyrtoctenidae which is here erected to includeCyrtoctenus, Dunsopterusand possibly alsoHastimima.
Biomechanical approaches to eurypterid cuticles and chelicerate exoskeletons
Authors: Dalingwater John E. 
Published: November 2011

ABSTRACTMicrostructural features of eurypterid cuticles are analysed from a biomechanical viewpoint: some fibrous elements are now considered to resemble the macrofibres of extant arthropod cuticles; possible preferred orientation zones inMycteropsare related to directional stresses; pore canals are not viewed as acting as crack-stoppers but laminae (sensuDennell 1978) may have served this function. Could some eurypterids have walked on land?—this problem is approached by using extantLimulusas a model. It leads on to the use of scaling exponents to determine the limits that possessing an exoskeleton places on the size of land arthropods: moulting may be the limiting factor. Possible critical factors limiting the size of aquatic arthropods are discussed briefly.
The use of models in the understanding of Cambrian arthropod morphology
Authors: Bruton David L. , Jensen Aage , Jacquet René 
Published: November 2011

ABSTRACTLarge scale models in polyester and araldite have been made of Sidneyia, Leanchoilia and Emeraldella from the Middle Cambrian, Burgess Shale. Details are given of how the models have been produced and used in functional morphology studies, particularly with respect to walking in Sidneyia.
Some controversial aspects of the morphology and anatomy of Ostenocaris cypriformis (Crustacea, Thylacocephala)
Authors: Pinna Giovanni , Arduini Paolo , Pesarini Carlo , Teruzzi Giorgio 
Published: November 2011

ABSTRACTThe present work deals with the structure of the cephalic part, traces of the digestive system and gills of Ostenocaris cypriformis (Thylacocephala). The structure of the cephalic part has provoked the most substantial controversy since it has been interpreted as being formed by a pair of enormous compound eyes or as a sac structure that we have called the cephalic sac. Particular attention has been devoted to the minute structure of the cephalic sac. Structures that we have previously termed ‘microsclerites’ can be readily observed, but are by no means easy to interpret.In many specimens, the basal part of the cephalic area contains abundant traces of alimentary residues. The area thus appears to be part of the digestive system. Our observations do not enable us to give a definitive picture of the anatomical organisation of these animals but do lead to substantial corrections of previously proposed interpretations.
Conchyliocarida, a class of fossil crustaceans: relationships to Malacostraca and postulated behaviour
Authors: Secretan Sylvie 
Published: November 2011

ABSTRACTConchyliocarida, from the Jurassic of France, have a conch-like carapace enclosing the whole body. The number of their somites, identified by the visible appendages, excludes them from Malacostraca. Caridean-like characters, including the large lamellar gills, bring them nearer to Malacostraca, end exclude them from other Classes. Their large functional compound eyes and the morphology of their limbs suggest a benthic life and predatory behaviour.Conchyliocarida are represented by several forms at La Voulte sur Rhône, which are compared and contrasted to related forms elsewhere.