Characterizing cryptic species: A morphometric analysis of craniodental characters in the dwarf galago genus Galagoides

ObjectivesThe true dwarf galagos of the genus Galagoides, G. demidoff and G. thomasi, are difficult to distinguish morphologically at a specific or subspecific level, and most taxonomic designations are based primarily on geographic localities. We used morphometrics to investigate the morphological diversity of the genus. Materials and MethodsWe conducted statistical analyses of 12 linear measurements on 290 Galagoides skulls housed in museums worldwide, and assembled body weights for 71 wild caught specimens. We examined sexual dimorphism and specific and subspecific distinctiveness using MANOVA, ANOVA, principle components analysis and canonical variate analysis. ResultsWe distinguished skulls identified as Galagoides demidoff and G. thomasi with approximate to 70% reliability, and demonstrated consistently different patterns of static allometry in craniodental variables. Variables supporting specific distinction included M-1 width, palate width at P-2, palate (snout) length, length of premaxillary tube, width across mastoids, and total skull length. The type specimens of G. orinus and G. rondoensis were significantly different from G. demidoff and G. thomasi, but grouped with them in a CVA including G. zanzibaricus and G. granti, although molecular studies indicate that their true affiliation is with the latter species. Subspecies within G. demidoff could not be distinguished using craniodental morphometrics. DiscussionGalagoides demidoff and G. thomasi can be distinguished relatively reliably, and are broadly sympatric across western and central Africa. Neither species showed evidence of sexual dimorphism in craniodental size or shape. Size variation has a greater influence on skull morphology in G. demidoff than it has on G. thomasi. Am J Phys Anthropol 158:288-299, 2015. (c) 2015 Wiley Periodicals, Inc.