Identification of relevant taxonomic and evolutionary units is a recurrent issue in the fossil record, all more for ancient fossils devoid modern equivalents such as conodonts. Extensive morphological variation has often led to description numerous species, subspecies or morphotypes, which may correspond end-member morphologies reached through ontogeny. The platform elements Late Devonian conod...

Premise of research. The flora the Maywood Formation, one only three Devonian floras previously recognized in western North America, is known from a brief report focused on stratigraphy and has never been characterized more detail. A detailed assessment this associated animal fossils implications for age depositional environments Formation plant biogeography.Methodology. Fieldwork at Cottonwood...

The study examines bioclastic carbonate contourites that arise from the broad spectrum of bottom-current related sedimentary processes ranging deposition to erosion. result intermittent accumulation sediment are thin and condensed successions with abundant hiatuses. Such deposits poorly known, since broadly accepted contourite-facies model, bi-gradational sequence, characterizes environments co...

BACKGROUND Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan ('shark') record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks...

Abstract. In the Late Devonian to earliest Mississippian, Svalbard was affected by a short-lived episode of deformation named Svalbardian Orogeny. This event resulted in intense folding and thrusting sedimentary successions. Deformation stopped prior deposition Carboniferous Permian strata Billefjorden Gipsdalen groups, which lie unconformably over folded strata. Later on, presumed structures w...