The Late Palaeozoic brachiopod genus Jakutoproductus Kashirtsev 1959 and the Jakutoproductus verchoyanicus Zone,northern Yukon Territory,Canada

Shi, Guang R., 1994:03:28. The Late Palaeozoic brachiopod genus Jakutoproductus Kashirtsev 1959 and the Jakutoproductus verchoyanicus Zone, northern Yukon Territory, Canada. Alcheringa 18, 103–120. ISBN 0311-5518.

The familial and subfamilial position, species composition, and geographic distribution of the Late Palaeozoic productid genus Jakutoproductus Kashirtsev 1959 are reviewed. Jakutoproductus is placed in the subfamily Plicatiferinae Muir-Wood & Cooper 1960 of the family Plicatiferidae. Eighteen described species from the Russian Arctic. Mongolia, northeast China, and northern Yukon Territory, Canada are assigned to Jakutoproductus. The Jakutoproductus verchoyanicus Zone of late Sakmarian to Artinskian age, most likely early Artinskian (Aktastinian), here established is based on material from the Jungle Creek Formation, northern Yukon Territory, Canada, and is correlated with the following horizons in Russia: the Osennin Horizon in the Verchoyan Mountains, the lower Munugudjak Horizon of the Kolyma-Omolon Massif, the Hipkhoshin Suite of east Zabaikal, the lower Bhang Horizon of Taimyr, and an unnamed sandstone-shale unit on the north island of Novaya Zemlya.     

Late Devonian gastropods from the Canning Basin,Western Australia

Over 50 identifications of Tertiary pollen are reviewed. The pollen assemblages indicate rain-forest through most of the Tertiary, but the requisites for pollen preservation are biased towards the wetter climates.

The present day geographical affinities of the botanical groups are largely with taxa of the tropical zone and Australia-wide taxa. There is geographic variation in the fossil pollen assemblages when southeastern Australia is compared with Central Australia and Queensland.

The major changes in the fossil floras coincide with climatic change, indicating the influence of climate on the evolution of plant assemblages. The older phytogeographic concepts are inappropriate for the fossil record, especially when considered in conjunction with palaeoclimates and palaeogeography.

It is unfortunate that palynology has given little information of the evolution of floras in drier climatic regimes, or of the evolution of the eucalypts.     

Systematic position of two Early Devonian sinistral heterostrophic gastropods from the Garra Limestone,New South Wales

Two Early Devonian gastropod genera, Garraspira gen. nov. and Anoriostoma from the GarraLimestone, with sinistrally heterostrophic shells, share several shell features and are placed in the new tribe Anoriostomatini within the subfamily Agnesiinae. In contrast to the other members of the latter subfamily these genera represent a lineage in which the apertural slit was lost during evolution. This fact supports the opinion that the presence or absence of the apertural slit does not necessarily have significance for high-level taxonomy. Morphology of the gerontic whorl in Anoriostoma sinistra and Garraspira imtsitata suggests their limited mobility during the last ontogenetic stage.     

Fusulinoideans from the early Midian (late Middle Permian) Metadoliolina dutkevitchi-Monodiexodina sutchanica Zone of the Senkina Shapka section,South Primorye,Far East Russia

Fusulinoideans from the Metadoliolina dutkevitchi-Monodiexodina sutchanica Zone of the lower part of the Chandalaz Formation in the Senkina Shapka section in South Primorye, Far East Russia, are described. The fusulinoidean zone is assigned to the early Midian (=Capitanian: late Middle Permian) based mainly on the morphologie and biostratigraphic characteristics of Metadoliolina dutkevitchi. Previously, a Midian age has been established for the Metadoliolina dutkevitchi-Monodiexodina sutchanica Zone by the coexistence of Lepidolina species. However, the occurrence of Lepidolina with the two zonal species in this area has not been verified by the illustration of Lepidolina specimens. We examined a fusulinoidean-bearing sample from the Metadoliolina dutkevitchi-Monodiexodina sutchanica Zone, and three fusulinoidean species, Monodiexodina sutchanica, Pseudofusulina sp. and Metadoliolina dutkevitchi, are de-scribed and illustrated.     

New Early Triassic Lingulidae (Brachiopoda) genera and species from South China

Peng, Y. & Shi, G.R., June, 2008. New Early Triassic Lingulidae (Brachiopoda) genera and species from South China. Alcheringa 32, 149–170. ISSN 0311-5518.

Two new genera, Sinolingularia gen. nov. and Sinoglottidia gen. nov., together with three new species, Sinolingularia huananensis gen. et sp. nov., Sinolingularia yini gen. et sp. nov. and Sinoglottidia archboldi gen. et sp. nov., are described on the basis of a large collection of well-preserved specimens from several sections straddling the Permian – Triassic boundary in South China.     

Discovery of late Changhsingian (latest Permian) brachiopod Attenuatella species from South China

Cretaceous polar dinosaur faunas were taxonomically diverse, which suggests varied strategies for coping with the climatic stress of high latitudes. Some polar dinosaurs, particularly larger taxa such as the duckbill Edmontosaurus Lambe, 1917 Lambe, L. M. 1917. A new genus and species of crestless hadrosaur from the Edmonton Formation of Alberta. Ottawa Naturalist, 31: 65–73.  [Google Scholar], were biomechanically and energetically capable of migrating over long distances, up to 2600 km. However, current evidence strongly suggests many polar dinosaurs (including sauropods, large and small theropods, and ankylosaurs of New Zealand) overwintered in preference to migration. Certain groups also appear more predisposed to overwintering based on their physical inability (related to biomechanics, natural history, or absolute size) to migrate, such as ankylosaurs and many small taxa, including hypsilophodontids and troodontids. Low-nutrient subsistence is found to be the best overwintering method overall, although the likelihood that other taxa employed alternative means remains plausible. Despite wide distribution of some genera, species-level identification is required to assess the applicability of such distributions to migration distances. Presently, such resolution is not available or contradicts the migration hypothesis.     

Stromatolite recognition in ancient rocks: an appraisal of irregularly laminated structures in an Early Archaean chert-barite unit from North Pole,Western Australia

The word ‘stromatolite’ should only be applied to organosedimentary structures predominantly accreted by sediment trapping, binding and/or in situ precipitation as a result of the growth and metabolic activities of benthic, principally prokaryotic, micro-organisms. Structures of uncertain origin that resemble stromatolites should be called ‘stromatoloids’. This cautious approach would eliminate the currently common assumption that structures with mesoscopic morphological similarities to microbially accreted sedimentary structures must be biogenic, a misconception that hampers investigations into the antiquity of life.

A hierarchical series of meso- and microstructural attributes of stromatolites can be used to assign gradually increasing probabilities of biogenicity to stromatoloids. This method is particularly useful for interpreting ancient noncolumnar stromatoloids with poor microstructural preservation. In a range of Early Archaean pseudocolumnar, nodular and stratiform stromatoloids from North Pole studied using this method, none could be proved to be stromatolites and only a few are probable or possible stromatolites. As these stromatoloids closely resemble previously reported structures from North Pole interpreted as stromatolites, we consider that the evidence for the existence of life c. 3500 my ago at North Pole is less definitive than previously supposed.     

Early astogeny in the Catenicellidae (Bryozoa,Cheilostomata)

Examples of early astogeny in the species Carinatocella harmeri (Stach), Costaticella hastata (Busk) and Claviporella aurita (Busk) are discussed. The primary zoid differs in each species and if found fossil, only in C. hastata could this zoid be recognised as a bryozoan fragment. Analogous development in other Bryozoa is discussed.     

Evolution of the Concept of ‘Extracellular Matrix’ in the Brain

The question as to whether an extracellular matrix exists between cells in the adult brain has been debated since the end of the last century. In the early years, zones containing neuropil and glial processes were mistakenly believed to represent this substance. But Golgi's discovery of the “perineuronal net” paved the way for future study of the true extracellular matrix. In the 1950s, application of histochemical techniques established the existence of interstitial material between nerve cells. Unfortunately the similarity between the pericellular distribution of this material and Golgi's “pericellular nets” was overlooked. The detection of an extracellular volume fraction in the central nervous system furnished further indirect proof for the existence of an extracellular matrix in the brain. However, the repeated failure of electron microscopy to reveal a substantial space between cell processes undermined the acceptance of the concept of “extracellular matrix” in the central nervous system. Nowadays this concept has, however, been firmly established.