Paleobiology Research Articles

High-resolution estimates of temporal mixing within shell beds: the evils and virtues of time-averaging

This study quantifies the fine structure of time-averaging by using large samples of dated shells collected from within individual strata. Time-averaging results in both good and bad news for interpreting bioclastic deposits.Nine samples of shells were collected from four Holocene cheniers on the Colorado Delta (Gulf of California) and 165 shells of the bivalve Chione fluctifraga were dated using 14C-calibrated amino acid racemization (D-alloisoleucine/L-isoleucine). The age range of shells within samples averages 661 years and, in seven out of nine samples, exceeds 500 years. The sample standard deviation ranges from 73 to 294 years and averages 203 years, far exceeding the dating errors (≪100 years) and potential variation in the life span of Chione (<10 years). Time-averaging is homogeneous among strata within cheniers but varies significantly among cheniers. Age-distributions of dated shells indicate that at 50-year resolution, the samples provide a continuous and uniform record for the entire interval. The actual sample completeness (63.6%) is very close to that predicted by simulations of sampling a 100% complete, uniform record (67.3%).The bad news is that, no matter how carefully collected, data from shell beds may not be suitable for studying processes on timescales shorter than 102 to 103 years; explanations for faunal change that invoke reasoning or models derived from a strictly ecological point of view may rarely be justifiable. Also, notable differences in temporal resolution between the shell beds of seemingly identical origin imply that paleontological patterns (e.g., species diversity) may be affected by cryptic variation in time-averaging. The comparison of our data with time-averaging estimates obtained from other cheniers at coarser sampling resolutions indicates that pooling of samples (analytical time-averaging) can significantly reduce the temporal resolution of paleontological data.The good news is that shell beds can record the optimal type of time-averaging: where paleobiological data are a time-weighted average of the faunal composition from the spectrum of environments that existed during the entire interval of time. Samples from single strata provide a long-term record that is representative of the predominating environments. Within the range of 14C dating, shell beds can provide a complete, high-resolution record, and thus may offer exceptional insights into the environmental and climatic changes of the last 40 thousand years.

Book review: Ammonoid paleobiology: From anatomy to ecology

Book review: Ammonoid paleobiology: From anatomy to ecology

Form, Function and Palaeobiology: Preface

Form, Function and Palaeobiology: Preface

A Tribute to Martin D. Brasier: Palaeobiologist and Astrobiologist (April 12, 1947-December 16, 2014).

A Tribute to Martin D. Brasier: Palaeobiologist and Astrobiologist (April 12, 1947-December 16, 2014).

Taphonomic and paleobiological preliminary notes on the burial found in the monastery of Ss. Ilario and Benedetto-Dogaletto Di Mira (Venica, Italy)

Taphonomic and paleobiological preliminary notes on the burial found in the monastery of Ss. Ilario and Benedetto-Dogaletto Di Mira (Venica, Italy)

Taphonomic and paleobiological preliminary notes on the burial found in the monastery of Ss. Ilario and Benedetto-Dogaletto Di Mira (Venica, Italy)

Taphonomic and paleobiological preliminary notes on the burial found in the monastery of Ss. Ilario and Benedetto-Dogaletto Di Mira (Venica, Italy)

A New Early Miocene Penguin Skull from Patagonia: Taxonomic and Paleobiological Value

Fil: Acosta Hospitaleche, Carolina Ileana Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Division Paleontologia Vertebrados; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata; Argentina

Osteohistology of the Triassic Archosauromorphs Prolacerta, Proterosuchus, Euparkeria, and Erythrosuchus from the Karoo Basin of South Africa

ABSTRACT The South African non-archosauriform archosauromorph Prolacerta and the archosauriforms Proterosuchus, Erythrosuchus, and Euparkeria were important constituents of the Early to early Middle Triassic Karoo ecosystem following the end-Permian mass extinction. We present new data on the osteohistology of these stem archosaurs and provide insight into their paleobiology. Bone tissues of the Early Triassic Prolacerta contain a poorly defined fibro-lamellar complex, with parallelfibered bone in some regions, whereas the contemporaneous Proterosuchus exhibits rapidly forming uninterrupted fibrolamellar bone early in its ontogeny, which becomes slow forming lamellar-zonal bone with increasing age. The early Middle Triassic Erythrosuchus deposited highly vascularized, uninterrupted fibro-lamellar bone throughout ontogeny, whereas the growth of the contemporaneous Euparkeria was relatively slow and cyclical. When our data are combined with those of previous studies, preliminary results reveal that Early an...

The Paleobiological revolution: essays on the growth of modern paleontology

The Paleobiological revolution: essays on the growth of modern paleontology

Paleobiology: Catching evolution in the act

Paleobiology: Catching evolution in the act

The Sauropods: evolution and paleobiology

The Sauropods: evolution and paleobiology

The Sauropods: Evolution and Paleobiology. Kristina A. Curry Rogers, and Jeffrey A. Wilson, editors

The Sauropods: Evolution and Paleobiology. Kristina A. Curry Rogers, and Jeffrey A. Wilson, editors

The paleobiology of rarity: some new ideas

The paleobiology of rarity: some new ideas

Paleobiology: Plenty of dinosaurs yet to be found

Paleobiology: Plenty of dinosaurs yet to be found

Paleobiology: Role of gastroliths in digestion questioned

Paleobiology: Role of gastroliths in digestion questioned

Paleobiology: Oh, what a sticky web they wove

Paleobiology: Oh, what a sticky web they wove

Paleobiology of the Archean

Paleobiology of the Archean

Palaeobiology in mammoth form

Palaeobiology in mammoth form

Reef Processes in the Long View

Reef Evolution . Rachel Wood. Oxford University Press, Oxford, 1999. 426 pp. $100, £55. ISBN 0-19-854999-7. Paper, $37.50, £22.50. ISBN 0-19-857784-2. Wood's overview of reef processes, primarily from a geological perspective, provides an admirable synthesis that will have a substantial impact on all who study reefs, biologists and geologists alike.

Evolution of Starfishes: Morphology, Molecules, Development and Paleobiology

Evolution of Starfishes: Morphology, Molecules, Development and Paleobiology