Archive

Conodonts from the early Ordovician Horn Valley Siltstone in the Amadeus Basin, Northern Territory, Australia, are described and illustrated. Samples were collected from limestone beds within the unit at two easily accessible localities. Twenty-two multi-element species belonging to seventeen genera are described. One new genus (Jumudontus) and eight new species (Acodus buetefueri, Drepanoistodus pitjanti, Erraticodon patu, Jumudontus gananda, Prioniodus amadeus, Protoprioniodus aranda, Protoprioniodus nyinti, and Protoprioniodus vapu) are proposed.

• Read more about Early Ordovician conodonts from the Horn Valley Siltstone, central Australia

The problematical genus Koninckopora is one of a number of fossil dasycladacean algae which possess micritic microstructures. The microstructure of the carbonate which encrusted Koninckopora is compared with microstructures of other plant and invertebrate groups which are known to have transformed from aragonite to calcite. It is concluded that the encrusted parts of Koninckopora were originally composed of calcite not aragonite. Koninckopora thus differs from all living calcareous dasycladaceans and probably most fossil forms.

• Read more about Ultrastructure and early diagenesis of the Viséan alga Koninckopora

Re-evaluation of belemnites belonging to the suborder Diplobelina Jeletzky, 1965 has resulted in erection of the new genera Vectibelus (based on Conoteuthis vectensis Spath, 1939) and Chalalabelus (based on Conoteuthis renniei Spath, 1939). A specifically indeterminate representative of Chalalabelus is described from the Barremian of Speeton, England. The genera Vectibelus gen. nov. and Conoteuthis d'Orbigny, 1842 are characterized by thin, skin-like guards, which are different from the stout, adapically rounded guards of Chalalabelus gen. nov. and Diplobelus Zittel, 1868. C.

• Read more about Lower Cretaceous diplobelinid belemnites from the Anglo-Paris Basin

The partial left jaw ramus of a large amphibian, from the Low Main Seam (Middle Coal Measures) of Newsham, Northumberland, is described for the first time. It is attributed to Anthracosaurus russelli Huxley and represents a previously unknown region of the jaw. The surangular crest is unlike that of other embolomerous anthracosaurs, the articular is widely exposed and the surangular restricted anteriorly by the depth of the adjacent dentary. The long posterior coronoid bears teeth of characteristic form and structure. A new restoration of the whole jaw of Anthracosaurus is presented.

• Read more about A jaw ramus of the Coal Measure amphibian Anthracosaurus from Northumberland

The brachiopod Stegerhynchus Foerste, 1909 occurs in Silurian strata in Canada, the U.S.A., the U.S.S.R., Gotland, and the United Kingdom. Review of the literature shows that Rhynchonella whitii praecursor Hall, 1863 is the true type species of Stegerhynchus.

• Read more about The Silurian brachiopod Stegerhynchus

Platychonia magna (d'Orbigny), a lithistid sponge previously regarded as a calcisponge (Cupulo-spongia magna), forms small bioherms in rocks of Upper Bathonian age (sub-zone of Clydoniceras hollandi), at Saint-Aubin-sur-Mer on the Normandy coast. In addition to the main frame-builder, four subsidiary faunal groups are preserved. These are: (i) encrusting organisms which attached to the sponge fronds and gave the reef additional strength; (ii) byssate and pedically attached filter-feeding nestlers; (iii) vagile strollers which predated, scavenged, or grazed; (iv) borers.

• Read more about Ecology of sponge reefs from the Upper Bathonian of Normandy

Revision of the Upper Cenomanian ammonites from Anjou and the Vendee in Western France including those described by A. de Grossouvre (1912), shows that two faunas are present. A lower assemblage including Pseudocalycoceras? cf. lattense (Thomel), Thomelites aff. sornayi (Thomel), and rare Calycoceras naviculare (Mantell) comes from the Marnes a Ostracees, and can be correlated with similar faunas in Sarthe, the Paris Basin, and southern England. Above, the Sables a Catopygus obtusus yields Sciponoceras gracile (Shumard), Metengonoceras dumbli (Cragin), Proplacenticeras cf.

• Read more about Upper Cenomanian ammonites from Anjou and the Vendée, Western France

Accurately constructed models of ammonoid shells were used in experiments on floating orientations. These experiments show that inflated shells of the cadicone type float stably, with or without liquid in the final chambers. Highly compressed involute shells are unstable unless the last two chambers contain liquid. The highly evolute shell type, represented by Dactylioceras, floats on its side when empty and vertically when the last four chambers contain liquid.

• Read more about Floating orientations of cephalopod shell models

Cranial remains of a labyrinthodont amphibian Doragnathus woodi gen. et sp. nov., from localities in the Visean and Namuriun of the Scottish Carboniferous, are described. The structure of ihe lower jaw resembles that of the earliest known Amphibia, but its dentition is unusual, comprising large numbers of strongly incurved, closely spaced marginal teeth together with it row of small needle-like coronoid teeth. The relationships of Doragnathus are discussed. A spceimen of Doragnathus from Pitcorthie represents the earliest recorded labyrinthodont in the British Carboniferous.

• Read more about A new labyrinthodont amphibian from the Carboniferous of Scotland

A description is given of the presacral vertebrae and ribs of a lysorophid amphibian from the Middle Coal Measures (Westphalian B) of Northumberland. The specimen is the earliest lysorophid yet described and is the first certainly identifiable member of the group to be recorded from any horizon outside North America. An isolated presacral vertebra from an unknown Coal Measures horizon at Low Moor, West Yorkshire, may represent additional evidence of lysorophids in the British Carboniferous.

• Read more about A lysorophid amphibian from the Coal Measures of northern England