The skull of most subterranean tooth-digging rodents is markedly affected by their digging mode. In the present study, we investigated the cranial variation in a strictly subterranean, highly specialized Afrotropical tooth-digger, Heliophobius argenteocinereus (Bathyergidae, Rodentia), using a geometric morphometric approach and evaluated the effect of different factors on size and shape differences among four populations. No evidence for sexual dimorphism was found in skull size or shape. The cranial shape variation was large and influenced mainly by the type of habitat (miombo woodland versus farmland and grassland) and the latitudinal gradient. The dorsal side of the skull appears to be more plastic and adaptable to local environments, as well as more independent of size, than the ventral side. Only the shortening of the rostrum is presumably an adaptive process independent of size that leads to an increase of efficacy of the tooth-digging apparatus in Heliophobius, whereas the increase in the in-force and the more procumbent incisors both comprise size-related changes caused by ontogenetic allometric growth.

The wood mouse Apodemus sylvaticus (Linnaeus, 1758) and the yel low-necked mouse A. flavicollis (Melchior, 1834) are two com mon spe cies of the sub ge nus Sylvaemus, which are wide spread in many Eu ro pean coun tries. A. flavicollis is a typ i cal for est-dwell ing ro dent pre ferring hab i tats with well de vel oped can opy cover (Marsh and Har ris 2000) while A. sylvaticus oc cu pies a broader spec trum of hab i tats, from early successional stages to park-like for est, avoid ing only con tin u ous for est stands (Hamar et al. 1966, Steiner 1968.Re cently, the sys tem at ics and phylogenetics of the ge nus Apodemus have been widely discussed (eg Filippucci et alques tions, es pe cially the phylo gen etic re la tion -[15] Acta Theriologica 51 (1): 15-27, 2006. PL ISSN 0001-7051 Morphometric study of two spe cies of wood mice Apodemus sylvaticus and A. flavicollis (Rodentia: Muridae): tra di tional and geo met ric morphometric ap proach Lenka BARÈIOVÁ and Miloš MACHOLÁN Barèiová L. and Macholán M. 2006. Mor phom etr ic stu dy of two spe cies of wood mice Apodem us sy lvat icus and A. flavi coll is (Ro dent ia: Mu rid ae): tra dit ional and geo met ric mor phom etr ic appro ach. Acta The riol ogi ca 51: 15-27. De part ment of Zo ol ogy, Fac ulty of Bi o log i cal Sci ences, Uni ver sity of South Bo he mia, Branišovská 31, 370 05 Èeské Budìjovice, Czech Re pub lic,

1. Morphometrics, the study of the variation and change in form amongst organisms, serves as a basic methodological tool in various fields of biological research, including systematics. Because it includes information about spatial relationships amongst anatomical landmarks, geometric morphometrics is more suitable for analyzing morphometric variation than methods based on distance measurements. 2. Geometric morphometrics allows us to answer general ecological and evolutionary questions about shape. 3. In this paper, landmark-based methods are described and illustrated, based on a dataset of measurements from 295 Apodemus mandibles, and the applications of such methods in the systematics of insectivores (Eulipotyphla) and rodents (Rodentia) are summarized.