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Alamosaurus sanjuanensis was originally described from a left scapula (USNM 10846) and right ischium (USNM 10847) discovered in the Late Cretaceous Ojo Alamo Formation of New Mexico in 1921 (USNM quarry 15560). In 1937 a second specimen was found in the North Horn Formation of Utah, consisting of a partial skeleton (USNM 15560), comprised of a mostly complete pelvis and caudal vertebral series, from the Late Cretaceous. A sacral complex with five vertebrae was observed in the field but was not collected. In 1966 James “Jim” Jensen of the Brigham Young University Earth Science Museum relocated the Gilmore quarry and found the sacrum, which, by then, had “rotted down into brown soil” and could not be recovered. Nearby, Jensen discovered the proximal heads of a humerus and femur and an isolated proximal caudal vertebra, none of which belonged to USNM 15560. Mike Morales and a team from the University of California at Berkeley discovered additional caudal vertebrae in the vicinity also, none of which belonged to the specimen collected by Gilmore. The specimens recovered by Jensen and Morales are significant because they indicate the presence of additional Alamosaurus specimens in the North Horn Formation. Additionally, the humerus is the most complete Alamosaurus humeral head yet discovered.
A growing trend, motivated in part by reported declines in pollinator populations, is the evaluation of pollinator population dynamics within urban habitats (McIntyre and Hostetler 2001, Cane et al. 2006, Kearns and Oliveras 2009, Bates et al. 2011, Gotlieb et al. 2011, Baldock et al. 2015). Along these lines, we collected preliminary data on bee communities in two degraded urban habitats on the Arizona State University campus (ASUT1 and ASUT2) and the semi-natural desert habitat at Piestewa Peak (PP) within the Phoenix area for five weeks. We predicted that areas sustaining a higher diversity of floral resources would yield a richer group of bee species. We determined that bee relative abundance was higher at the semi-natural site (PP) than either urban site (p=0.02, 0.04). Bee species diversity and richness was higher in the urban habitat than at the semi-natural site (PP) (p=0.04). High floral species richness in surrounding gardens is likely the underlying driver leading to increased bee species richness in the urban site. This report is an initial assessment of an ongoing long-term monitoring study of bees in urban Phoenix.
A five-year study to determine the status of the porcupine (Erithizon dorsatum) in the state of Arizona was conducted. Letters requesting the cooperation of several agencies and requesting the public to report any sighting of porcupines were gathered by staff and students of Eastern Arizona College. The main agency supporting this study was the Arizona Game and Fish Department. During the study 61 sightings were reported and the data from each report were analyzed to compare to previous studies by Taylor in the 1930s and Brown and Babb in 2007. Mountain lions appear to continue to be a limiting factor in controlling the population. The most significant factor documented in this study is the increase in the number of road kills. Taylor reported no road kills in the 1930s, Brown and Babb reported 21% of porcupines as road kills in 2007 and this study documented 41% as road kill. It is speculated that the increase in traffic along major highways and the slow pace of porcupines has increased this cause of death.
Age-size relationships of a species in any given population are variable due to local environmental and genetic variations across individuals. The aim of this study is to test an age-size model for the keystone Carnegiea gigantea (saguaro, Cactaceae), that establishes in cohorts, to assess its accuracy in reconstructing those cohorts. Monte Carlo simulation is used to generate a Carnegiea gigantea population based on parameters selected and then applies the age-size model to the population to ascertain its effectiveness. Individuals in a cohort of different sizes are generated, as would be expected in the real world, and a simulated empirical dataset is created. Variation in growth over time incorporates two sources of variability, (1) individual variability (e.g. genetic or microsite variations) as well as (2) population-wide variability (such as fluctuations in rainfall from year to year). Generally, older cohorts are more difficult to accurately estimate, but all cohorts are identifiable. Results suggest that the Drezner model for Carnegiea gigantea is robust for reconstructing periods of establishment. This test of the Drezner model using annual and individual multipliers can be applied to other age-size models to ascertain their effectiveness, particularly for cohort identification.