Methods for Estimating the Volume of the Tympanic Bulla in the Big Hairy Armadillo Chaetophractus villosus (Mammalia, Xenarthra, Dasypodidae)

作者：Paula Basso Ana; Silvia Sidorkewicj Nora; Beatriz Casanave Emma

来源：International Journal of Morphology, 2017, 35(1): 128-132.

DOI：10.4067/s0717-95022017000100021

• Fossorial mammals
• Armadillos
• Middle ear
• Auditory bulla
• Non-destructive methods

Two methods of measurement of bullar dimensions (callipers and scaling from digital images) and subsequent application of four volume formulae (rectangular prism, cylinder, ellipse and elliptical cone) were tested to find the most appropriate non-destructive method for estimating the bullar volume in Chaetophractus villosus. Material for the study consisted in clean adult skull (n=22). Real volume was obtained from latex casts of the tympanic bulla. Each estimation was corrected by a factor based on the differences between the estimated and the real volumes. Highest accuracy (5-7 % of underestimation) and precision (coefficient of variation: 13.27 %) were obtained from callipers and application of rectangular prism, cylinder and ellipse formulae. The corresponding correction factors were 0.31, 0.39 and 0.58, respectively.

• 出版日期2017-3