BackgroundBasal iguanodontian dinosaurs were extremely successful animals, found in great abundance and diversity almost worldwide during the Early Cretaceous. In contrast to Europe and Asia, the North American record of Early Cretaceous basal iguanodonts has until recently been limited largely to skulls and skeletons of Tenontosaurus tilletti.Methodology/Principal FindingsHerein we describe two new basal iguanodonts from the Yellow Cat Member of the Cedar Mountain Formation of eastern Utah, each known from a partial skull and skeleton. Iguanacolossus fortis gen. et sp. nov. and Hippodraco scutodens gen. et sp. nov. are each diagnosed by a single autapomorphy and a unique combination of characters.Conclusions/Significance Iguanacolossus and Hippodraco add greatly to our knowledge of North American basal iguanodonts and prompt a new comprehensive phylogenetic analysis of basal iguanodont relationships. This analysis indicates that North American Early Cretaceous basal iguanodonts are more basal than their contemporaries in Europe and Asia.

Recently discovered specimens of the marsupial Herpetotherium merriami (Stock and Furlong, 1922) from the John Day Formation, Oregon, are described. The species was previously known only from a single (type) specimen. These additional specimens have allowed for a revised diagnosis of the species based on the presence of an additional stylar cusp on the upper molars, as well as the relative size of the stylar cusps. This new material also allows for an examination of the variability within the species and establishes a time range for the species, which extends through most of the Arikareean (late Oligocene: Ar1–Ar3: late Rupelian-Aquitanian). Herpetotherium merriami is distinct within the genus because it is among the larger of the species, but one of the latest occurring, whereas the general pattern of the genus is a reduction in size through time.

Fishers are elusive carnivorans, with few occurrences in the fossil record. The origin and early evolution of fishers is unclear, but they likely originated in Asia. A new record of Pekania from the Rattlesnake Formation of Oregon represents the earliest known occurrence of a fisher, more than 5 million years earlier than other records in North America. This specimen has an unambiguous derived trait shared with other members of the genus, an external median rootlet on the upper carnassial. The age of this new find is inferred to be between 7.05 and 7.3 Ma, through radiometric and magnetostratigraphic dating. This age is supported by the presence of specimens of a shrew, Sorex edwardsi, and a rhinoceros, cf. Teleoceras, found at the same locality, as well as a rabbit, Hypolagus cf. vetus, and a tapir nearby, all of which are well known from early Hemphillian deposits. This find indicates that fishers were in both North America and Asia in the late Miocene, around the time of their divergence from other members of the clade as estimated from genetic data. Although it is over 7 million years old, this species shows remarkable similarity to extant P. pennanti, highlighting the highly conservative nature of gulonine mustelids. The Rattlesnake specimen is more robust than other fisher species, possibly representing something close to the ancestry of all fishers.

he creation of highly functional, durable, and low-cost ultrasound phantoms is an important part in the development of any ultrasound training program. Although ultimately falling short of the reference standard of using standardized patients for training purposes, gelatin-based phantoms are excellent substitutes in the early stages of ultrasound education. These phantoms can allow the early learner an opportunity to master the basic principles of sonography and knobology before moving on to, or in conjunction with, standardized patients or clinical situations. Objectives-The goal of this study was to investigate the durability and longevity of gelatin formulas for the production of staged ultrasound phantoms for education.Methods-Gelatin phantoms were prepared from Knox gelatin (Kraft Foods, Northfield, IL) and a standard 10%-by-mass ordinance gelatin solution. Phantoms were durability tested by compressing to a 2-cm depth until cracking was visible. Additionally, 16 containers with varying combinations of phenol, container type, and storage location were tested for longevity against desiccation and molding. Once formulation was determined, 4 stages of phantoms from novice to clinically relevant were poured, and clinicians with ultrasound training ranked them on a 7-point Likert scale based on task difficulty, phantom suitability, and fidelity.Results-On durability testing, the ballistic gelatin outperformed the Knox gelatin by more than 200 compressions. On longevity testing, gelatin with a 0.5% phenol concentration stored with a lid and refrigeration lasted longest, whereas containers without a lid had desiccation within 1 month, and those without phenol became moldy within 6 weeks. Ballistic gelatin was more expensive when buying in small quantities but was 7.4% less expensive when buying in bulk. The staged phantoms were deemed suitable for training, but clinicians did not consistently rank the phantoms in the intended order of 1 to 4 (44%).Conclusions-Refrigerated and sealed ballistic gelatin with phenol was a cost-effective method for creating in-house staged ultrasound phantoms suitable for large-scale ultrasound educational training needs. Clinician ranking of phantoms may be influenced by current training methods that favor biological tissue scanning as easier.

No abstract