Quantifying morphological variability within extant mammalian species

Abstract

In this study we attempt to establish a baseline for measuring species variability in the palaeontological record by using linear regression analysis on sets of measurements from extant mammalian species (males and females within species). In particular, this study explores the standard error of the m-coefficient (s.e.m) , derived from linear regression analyses associated with equations of the form y = mx + c, to quantify the degree of morphological variability within extant mammalian species. The slope m generally centres around 1.00. Even though the species in this study range in size from small rodents to large ungulates, s.e'm values show a normal distribution around a mean of 0.035 . The approach outlined here has potential application in palaeontological contexts where there is uncertainty about any two specimens being conspecific.