1Dept. Biological Sciences, Ohio Northern University, 2Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine
April 18, 2020 , Platinum Ballroom
This project explores skeletal properties and linear dimensions in Lagothrix to evaluate sexual dimorphism, and whether subspecies/species from neighboring regions are similar. Skeletal properties include limb bone midshaft cross-sectional cortical areas estimated from radiographs. Linear dimensions include head+body lengths obtained from either literature sources (available upon request) or the on-line databases of the American Museum of Natural History, the Field Museum of Natural History, and the National Museum of Natural History.
Analysis includes genus and subspecies levels, and uses Mann-Whitney tests to determine p-values. At the genus level, Lagothrix males are greater in body mass than females (p-value 0.01, N = 11 males, 12 females). Males also have longer bodies (p-value 0.02, N = 55, 49), and humeral midshaft cross-sectional cortical area is greater in males (p-value 0.02, N = 4, 6). At the subspecies/species level, poeppigii males have longer head+body lengths than females (p-value 0.02, N = 13, 9). Comparing subspecies/species to each other, cana females are shorter in head+body length than the other females (p-values less than 0.02, N = 9 or more). Lugens males are longer in head+body length than males of either lagothricha or cana, and poeppigii males are longer than lagothricha males (p-values less than 0.05, N = 10 or more).
In conclusion, Lagothrix demonstrates sexual dimorphism in greater body size in males. Among subspecies/species, data do not group taxa that literature and museum sources suggest are neighbors. More information is needed regarding ancestral distribution patterns of Lagothrix.