Fig. 4. Histograms showing the distribution of m1 (A) and m3 (B) size in Gandheralophus gen. nov. specimens of the two Pakistan species described here: G. minor and G. robustus (solid bars). The holotype of each species falls in the modal class. Comparison to a mixed male and female sample of the North American reference species, Hyracotherium tapirinum (Cope, 1875) (open bars; after Gingerich 1981) shows that the variability of Gandheralophus specimens is too great to represent a single species. Empirically, mammalian species have natural−log (length X width) ranges of 0.4 units (mean ± 2 standard deviations; Gingerich 1981). Each species shown here fits within a 0.4−unit range. Distributions of size of G. minor and G. robustus are strongly bimodal. Taken together they would have a range of 0.55 units (2.90 to 3.45) for m1 and of 0.80 units (3.45 to 4.25) for m3. Thus G. minor and G. robustus represent separate species.

Published as part of Missiaen, Pieter & Gingerich, Philip D., 2012, New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia, pp. 21-34 in Acta Palaeontologica Polonica 57 (1) on page 27, DOI: 10.4202/app.2010.0093, http://zenodo.org/record/12779648