71 research outputs found

    Deep MOS Spectroscopy of NGC 1316 Globular Clusters

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    The giant elliptical galaxy NGC 1316 is the brightest galaxy in the Fornax cluster, and displays a number of morphological features that might be interpreted as an intermediate age merger remanent (\sim3 Gyr). Based on the idea that globular clusters systems (GCS) constitute genuine tracers of the formation and evolution of their host galaxies, we conducted a spectroscopic study of approximately 40 globular clusters (GCs) candidates associated with this interesting galaxy. We determined ages, metallicities, and α\alpha-element abundances for each GC present in the sample, through the measurement of different Lick indices and their subsequent comparison with simple stellar populations models (SSPs).Comment: 5 pages, 3 figure

    A novel method for quantifying femoral neck anteversion: A case study in extinct and extant sloths

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    Extinct sloths represent a wide range of morphological, locomotor, and body size variation. Researchers have examined femoral neck angle in two dimensions to hypothesize locomotor behaviors in this group; however, this measure does not account for femoral neck anteversion. Here, we present a new method for quantifying femoral neck anteversion angle, in addition to femoral neck angle, to capture the 3D position of the femoral head/neck. Femora of extant (n = 21; Bradypus and Choloepus) and extinct (n = 49; Acratocnus, Megalocnus, Neocnus, and Parocnus) sloths were surface scanned and their surface models used to calculate three angles of femoral neck anteversion and femoral neck angle. Femoral neck anteversion was calculated as the angle between the femoral neck axis and the geometric axis of the femoral condyles (GA), the 35% cross section axis, and a trochanter axis. Femoral neck angle was calculated as the angle between the femoral neck and shaft axes. Genera were compared using ANOVAs with post hoc multiple comparisons for each angle. Femoral neck angle and femoral neck anteversion relative to the cross section were also analyzed. Significant differences among genera exist for all angles, (p \u3c .001) but not all angles separate all genera. Femoral neck and anteversion angles typically yield different results, demonstrating the utility of analyzing both angles. The GA and cross section angles are highly correlated in sloths, with the exception of comparisons among Megalocnus, Parocnus, and Neocnus, suggesting morphological variation in the distal femur. While this method was applied to sloths, it has broad applicability to mammalian groups

    Craniofacial Fluctuating Asymmetry in Gorillas, Chimpanzees, and Macaques

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    Objectives Craniofacial fluctuating asymmetry (FA) refers to the random deviations from symmetry exhibited across the craniofacial complex and can be used as a measure of developmental instability for organisms with bilateral symmetry. This article addresses the lack of data on craniofacial FA in nonhuman primates by analyzing FA magnitude and variation in chimpanzees, gorillas, and macaques. We offer a preliminary investigation into how FA, as a proxy for developmental instability, varies within and among nonhuman primates. Materials and Methods We generated 3D surface models of 121 crania from Pan troglodytes troglodytes, Gorilla gorilla gorilla, and Macaca fascicularis fascicularis. Using geometric morphometric techniques, the magnitude of observed FA was calculated and compared for each individual, sex, and taxon, along with the variation of FA across cranial regions and for each bilateral landmark. Results Gorillas and macaques exhibited higher and more similar magnitudes of FA to each other than either taxon did to chimpanzees; variation in magnitude of FA followed this same trend. No significant differences were detected between sexes using pooled data across species, but sex did influence FA magnitude within taxa in gorillas. Further, variation in FA variance across cranial regions and by landmark was not distributed in any particular pattern. Conclusion Possible environmentally induced causes for these patterns of FA magnitude include differences in growth rate and physiological stress experienced during life. Developmental stability may be greatest in chimpanzees in this sample. Additionally, these results point to appropriate landmarks for future FA analyses and may help suggest more urgent candidate taxa for conservation efforts

    List of species from Hispaniola

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    Based on literature evaluation by Sam Turvey

    Data from: Anthropogenic extinction dominates Holocene declines of West Indian mammals

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    The extensive postglacial mammal losses in the West Indies provide an opportunity to evaluate extinction dynamics, but limited data have hindered our ability to test hypotheses. Here, we analyze the tempo and dynamics of extinction using a novel data set of faunal last-appearance dates and human first-appearance dates, demonstrating widespread overlap between humans and now-extinct native mammals. Humans arrived in four waves (Lithic, Archaic, Ceramic, and European), each associated with increased environmental impact. Large-bodied mammals and several bats were extinct by the Archaic, following protracted extinction dynamics perhaps reflecting habitat loss. Most small-bodied rodents and lipotyphlan insectivores survived the Ceramic, but extensive landscape transformation and the introduction of invasive mammals following European colonization caused further extinctions, leaving a threatened remnant fauna. Both large- and small-bodied nonvolant mammals disappeared, reflecting complex relationships between body size, ecology, and anthropogenic change. Extinct bats were generally larger species, paralleling declines from natural catastrophes

    Quaternary Bat Diversity in the Dominican Republic

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    Velazco, Paúl M., O'Neill, Hannah, Gunnell, Gregg F., Cooke, Siobhán B., Rimoli, Renato, Rosenberger, Alfred L., Simmons, Nancy B. (2013): Quaternary Bat Diversity in the Dominican Republic. American Museum Novitates 2013 (3779): 1-20, DOI: 10.1206/3779.2, URL: http://www.bioone.org/doi/abs/10.1206/3779.
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