Increased sampling reveals the complex evolution of sauropod dinosaur tooth replacement rates.

Unlike most herbivores, sauropod dinosaurs evolved simple teeth that were replaced rapidly. Sauropod craniodental morphology is conserved relative to that of many archosaur clades, but tooth breadth and replacement rate vary substantially. Two neosauropod clades, Titanosauria and Diplodocoidea, independently evolved both narrow-crowned teeth and high tooth replacement rates among a suite of other convergent features.

The evolution of maximum terrestrial body mass in sauropod dinosaurs.

The long-necked dinosaurs, sauropods, are famous for their extreme body sizes, evolving body masses several times greater than the next-heaviest terrestrial animals, elephant-like and rhinoceros- like mammals and 'duck-billed' dinosaurs. The pace of sauropod discovery has been exponential in recent decades, resulting in the recognition of sauropods as a global, ecologically diverse group of herbivorous dinosaurs comprising over 250 known species. However, limitations due to missing data from their patchy fossil record have so far limited studies of sauropod body-size evolution to less than half their known diversity.

Developmental strategies underlying gigantism and miniaturization in non-avialan theropod dinosaurs.

In amniotes, the predominant developmental strategy underlying body size evolution is thought to be adjustments to the rate of growth rather than its duration. However, most theoretical and experimental studies supporting this axiom focus on pairwise comparisons and/or lack an explicit phylogenetic framework. We present the first large-scale phylogenetic comparative analysis examining developmental strategies underlying the evolution of body size, focusing on non-avialan theropod dinosaurs.

Evolution of amniote dentine apposition rates.

In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent the upper limit of odontoblast activity in non-ever-growing teeth, a hypothesis supported by the lack of scaling between dentine apposition rates and body mass in Dinosauria. To determine the correlates and potential controls of dentine apposition rate, we assembled a dataset of apposition rates, metabolic rates and body masses for 80 amniote taxa of diverse ecologies and diets.

Correction: Evolution of high tooth replacement rates in theropod dinosaurs.

[This corrects the article DOI: 10.1371/journal.pone.

Evolution of high tooth replacement rates in theropod dinosaurs.

Tooth replacement rate is an important contributor to feeding ecology for polyphyodont animals. Dinosaurs exhibit a wide range of tooth replacement rates, mirroring their diverse craniofacial specializations, but little is known about broad-scale allometric or evolutionary patterns within the group. In the current broad but sparse dinosaurian sample, only three non-avian theropod tooth replacement rates have been estimated.

Redescription of Brachiosaurid Sauropod Dinosaur Material From the Upper Jurassic Morrison Formation, Colorado, USA.

Like many long-standing dinosaur taxa, Brachiosaurus altithorax from the Upper Jurassic Morrison Formation of North America suffers from taxonomic issues stemming from a relatively incomplete holotype. Lack of anatomical overlap has precluded definitive referral of important specimens, including a mostly complete skull discovered in 1883. We redescribe this skull and some other significant brachiosaurid specimens based on new preparation and computed tomographic (CT) data.

Scaling of statically derived osteocyte lacunae in extant birds: implications for palaeophysiological reconstruction.

Osteocytes are mature versions of osteoblasts, bone-forming cells that develop in two ways: via 'static' osteogenesis, differentiating and ossifying tissue in situ to form a scaffold upon which other bone can form, or 'dynamic' osteogenesis, migrating to infill or lay down bone around neurovasculature. A previous study regressed the volume of osteocyte lacunae derived from dynamic osteogenesis (DO) of a broad sample of extant bird species against body mass, the growth rate constant ( k), mass-specific metabolic rate, genome size, and erythrocyte size. There were significant relationships with body mass, growth rate, metabolic rate, and genome size, with the latter being the strongest.

A new fossil assemblage shows that large angiosperm trees grew in North America by the Turonian (Late Cretaceous).

The diversification of flowering plants and marked turnover in vertebrate faunas during the mid-Cretaceous transformed terrestrial communities, but the transition is obscured by reduced terrestrial deposition attributable to high sea levels. We report a new fossil assemblage from multiple localities in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale Formation in Utah. The fossils date to the Turonian, a severely underrepresented interval in the terrestrial fossil record of North America.

Precocity in a tiny titanosaur from the Cretaceous of Madagascar.

Sauropod dinosaurs exhibit the largest ontogenetic size range among terrestrial vertebrates, but a dearth of very young individuals has hindered understanding of the beginning of their growth trajectory. A new specimen of Rapetosaurus krausei sheds light on early life in the smallest stage of one of the largest dinosaurs. Bones record rapid growth rates and hatching lines, indicating that this individual weighed ~3.

Measurement, variation, and scaling of osteocyte lacunae: a case study in birds.

Basic issues surrounding osteocyte biology are still poorly understood, including the variability of osteocyte morphology within and among bones, individuals, and species. Several studies have suggested that the volume or shape of osteocytes (or their lacunae) is related to bone and/or organismal growth rate or metabolism, but the nature of this relationship, if any, is unclear. Furthermore, several studies have linked osteocyte lacuna volume with genome size or growth rate and suggested that osteocyte lacuna volume is unrelated to body size.

Osteology of Huabeisaurus allocotus (Sauropoda: Titanosauriformes) from the Upper Cretaceous of China.

Background: The Late Cretaceous titanosauriform sauropod Huabeisaurus allocotus Pang and Cheng is known from teeth and much of the postcranial skeleton. Its completeness makes it an important taxon for integrating and interpreting anatomical observations from more fragmentary Cretaceous East Asian sauropods and for understanding titanosauriform evolution in general.

Methodology/principal Findings: We present a detailed redescription of Huabeisaurus allocotus and a suite of anatomical comparisons with other titanosauriforms that demonstrate its validity via autapomorphies (e.

Evolution of high tooth replacement rates in sauropod dinosaurs.

Background: Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates.

Sauropod dinosaur osteoderms from the Late Cretaceous of Madagascar.

Osteoderms are bones embedded within the dermis, and are common to select members of most major tetrapod lineages. The largest known animals that bear osteoderms are members of Titanosauria, a diverse clade of sauropod dinosaurs. Here we report on two titanosaur osteoderms recovered from the Upper Cretaceous Maevarano Formation of Madagascar.

A nomenclature for vertebral fossae in sauropods and other saurischian dinosaurs.

Background: The axial skeleton of extinct saurischian dinosaurs (i.e., theropods, sauropodomorphs), like living birds, was pneumatized by epithelial outpocketings of the respiratory system.