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A biostratigraphic and systematic study based on belemnites collected along with ammonites was performed on four sections in the Subalpine Basin (SE France): Lac du Castillon and La Baume (Castellane area), Galabrun and Grand Lara (Gap area). The specimens, originating from hemi-pelagic marl-limestone alternations in the lower part of the “Calcaires à Zoophycos” Formation, are dated from Middle Aalenian...
A previous study on the ammonitellas of Agoniatites vanuxemi (Hall, 1879) from the Middle Devonian Cherry Valley Limestone of New York State, USA, showed remarkable preservation of the internal morphology. In this paper, the ammonitellas of another ammonoid, a member of the Tornoceratidae, from the Cherry Valley Limestone are studied. The tornoceratids come from a weathered friable shale layer. The...
A rare occurrence of Phragmoceras imbricatum Barrande is recorded from moderately shallow marine Silurian sequences in the Carnic Alps (Austria). The specimen was collected from a condensed series of nautiloid-bearing wackestones/packstones which are documented as being one of the earliest levels of the Silurian Cephalopod Limestone Biofacies deposited along the North Gondwana margin. The presence...
Dense concentrations of juvenile ammonoids were recently discovered in the Upper Cretaceous Mancos Shale of east-central Utah. In this paper, we describe this remarkable fossil occurrence and propose a taphonomic model to explain it. Large accumulations of cephalopods are not uncommon in the stratigraphic record, though concentrations of juveniles are relatively rare. Lithologic, geochemical, and...
A new subgenus within the genus Goniocamax, Progoniocamax nov. subgen., is described. It includes the Late Turonian-Early Coniacian species “Actinocamax” surensis Naidin and Actinocamax intermedius Arkhangelsky. The new subgenus represents a transition between the genera Praeactinocamax and Goniocamax. It occurs in the Central Russian Subprovince. From a geographical point of view, it indicates the...
Complete ammonoid mouth parts including both mandibles and the radula are rare. A newly prepared specimen of Ceratites penndorfi of the late Anisian from the Franconian Muschelkalk reveals one such anaptychus-type jaw apparatus including several more or less clearly recognisable structures such as the shapes and proportions of the inner and outer lamellae of both mandibles. The lower mandible has...
Although the Early Palaeozoic cephalopod order Endocerida is generally regarded as monophyletic, alternative views have been expressed. These invoke origins from different lineages within the order Ellesmerocerida. To test these alternatives, various aspects of endocerid morphology (including conch shape, structure of the ectosiphuncle, form of the endosiphuncular deposits, nature of the apical portion...
Scaphitid ammonites (scaphites) are among the most common ammonites in the Upper Cretaceous of the U.S. Western Interior. We have examined species of Hoploscaphites from the Campanian and Maastrichtian Pierre Shale and Bearpaw Shale for clues about their mode of life and habitat. Like most other ammonites, scaphites exhibit determinate growth. The “morphogenetic countdown” begins at the point at which...
Grammoceratinae (Hildoceratidae, Ammonitina) abound in the Toarcian strata of many western Tethyan localities, especially the Subbetic and Lusitanian basins (of southern Spain and central western Portugal, respectively). They decline through the Aalenian and disappear by the lowermost Bajocian. The genera Asthenoceras, Vacekia (subgenera Vacekia and Nadorites) and Fontannesia are traditionally considered...
Maastrichtian cephalopods and a brachiopod were dredged from the Butakov, Fedorov, Kotsebu, Il’ichev, Govorov, Gelendzhik, and Ita-Mai-Tai guyots in the Magellan Seamounts. The ammonoids Hypophylloceras sp., Phyllopachiceras sp., Anagaudryceras? sp. A, Anagaudryceras? sp. B, Gaudryceras aff. propemite Marshall, Gaudryceras sp., and Pseudophyllites cf. indra (Forbes), and the single brachiopod Basiliolidae...
Narrow groove-like excavations on ammonoid and coiled nautiloid shells are rare in Upper Carboniferous units from Texas, USA. The morphological characteristics of the excavation grooves typically are confined to the ventral and ventrolateral parts of the outer whorl of the shell, are narrower than the length, and have irregular edges where small segments or chips of shells have been removed. Analysis...
Shells of chambered nautilus (Nautilus spp. Linnaeus and Allonautilus spp. Ward and Saunders) are well-known collectibles, traded across the globe from their Indo-Pacific origins. Live animals and a variety of products made from shells are also traded internationally. In preparation for the 15th Meeting of the Conference of the Parties to the Convention on International Trade in Endangered Species...
In the coleoid literature, the terminology of shell elements that are deposited on the external surface of the primary shell wall is inconsistent and confusing. Morpho- and phylogenetic interpretations have been therefore controversial. A strict layer-by-layer comparison of seventeen species from seven coleoid subgroups suggests that the coleoid shell is covered by either one (Diplobelida, Spirulida,...
Cluster analyses and non-metric multidimensional scaling of ammonoid assemblages from six successive Early Carboniferous time intervals (two Tournaisian, Viséan, and Serpukhovian) show that increasing provincialism is the main biogeographic trend through the period. While the assemblages from the Tournaisian to the early Late Viséan are globally similar in the tropical occurrences, dissimilarities...
While previous workers have argued persuasively that ammonoid workers should use cladistic approaches to reconstruct phylogeny, relatively few cladistic studies have been published to date. An essential yet challenging part of cladistic analysis is the selection of characters. Are certain types of characters more likely to show homoplasy? Are certain aspects of shell anatomy more likely to contain...
The skeletal structure, herein termed “connecting stripes”, is demonstrated in dried cuttlebones of Sepia (Acanthosepion) savignyi de Blainville from the Gulf of Aqaba, Red Sea, Eilat, Israel. This structure consists of segmented chitinous strip-like sheets covering the outside opening to the cuttlebone chambers. Scanning electron microscope images demonstrate that the connecting stripes are tightly...
Although the Bothremydidae are the most abundant and diverse group of turtles in the Upper Cretaceous fauna of Europe, the record attributed to the genus Elochelys was, until now, quite scarce. However, the revision of the specimens previously attributed to this taxon and the analysis of new material from the Spanish record significantly increase our knowledge of these turtles. Evaluation of the morphological...
The gephyrocapsids, main component of the Pleistocene calcareous nannofossil assemblages, are here discussed as biostratigraphical and paleoclimate tools. The occurrence of the genus Gephyrocapsa is quantitatively analysed in the core ODP 198-1209B, collected in the NW Pacific Ocean. The studied stratigraphic succession covers a time interval including the Middle Pleistocene Transition (MPT), a highly...
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