Cranial morphology ofMartes foinaandM. martes(Mammalia, Carnivora, Mustelidae): The role of size and shape in sexual dimorphism and interspecific differentiation

Abstract

Landmark based morphometrics was used to investigate sexual dimorphism and interspecific differentiation in the mustelids Martes foina and M. martes, which are typical sexual size dimorphic species. Analyses were run on 192 specimens of M. foina and 36 specimens of M. martes from central and northern Italy, by recording 19 and 40 landmarks on the dorsal skull and on the palate, respectively. Results indicate that both size and shape are important components of skull dimorphism in males and females of the two species. The skull of the stone marten males is larger, has a narrower postorbital constriction and larger molars than in females. These differences and the partial least square analysis run on shape variable and stomach contents of one sample suggest that stone marten males are better adapted to catch and kill live prey, while females seem to prey upon easier-to-catch food. Shape features involved in sexual dimorphism are similar to those involved in interspecific variation, but the two species differ also in the relative size of their canines, carnassial and molar teeth, which are likely related to different ways of acquiring and processing preys.

Quantifying the age- and sex-dependent morphological variation in two syntopic mustelids: Martes martes and Martes foina

“…Our results confirm sexual size dimorphism in favor of males for both species, for all traits we measured. More interestingly, our results showed that sexual size dimorphism was clearly more pronounced in PM than in SM, which is consistent with some studies (Moors, 1980;Reig and Ruprecht, 1989;Reig, 1992), but not with others (Loy et al, 2004). As previously suggested (Reig, 1992), lower sexual dimorphism in SM than in PM might be explained as a result of the more generalist behavior of SM (resulting in less intra-specific competition), with respect to habitat and food selection.…”

“…The species dimorphism was also more pronounced in females than in males. These results are in contradiction with previous studies which found larger skull, hence size, in PM than in SM (Reig and Ruprecht, 1989;Loy et al, 2004). In Italy, Loy et al (2004) even suggested that the larger SM skull design showed a higher adaptation toward hypercarnivory, assuming that PM was less carnivorous.…”

“…This hypothesis has been rejected by Reig (1992), Holmes and Powell (1994) but supported by Delibes (1983), Dayan et al (1989) and Daylan and Simberloff (1994). Obviously, relative sizes of the two species vary noticeably from one region to another within their sympatric range (Reig, 1992;Loy et al, 2004). On the sub-sample of adults, SM showed significantly larger measurements than PM of the same sex, at the notable exception of the posterior foot length and the head-and-body length for which results were not significant.…”

Multivariate and geometric morphometrics in the analysis of sexual dimorphism variation in Podarcis lizards

“…However, in recent years the development of geometric morphometrics has allowed the direct study of shape variation (Bookstein, 1984;Rohlf, 1990;Rohlf and Slice, 1990;Corti, 1993;Adams and Rohlf, 2000;Adams et al, 2004). Although the application of geometric morphometrics in SD studies still needs to be explored, some authors report interesting SD patterns revealed by the application of such techniques in various animal taxa (Hood, 2000;Rosas and Bastir, 2002;Loy et al, 2004;Rufino et al, 2004;Valenzuela et al, 2004;Bruner et al, 2005). Until the present, geometric methods have not been extensively applied to study the external morphology of lizards, and very few authors have applied such methods in reptiles (Monteiro et al, 1997;Claude et al, 2003;Marugá n-Lobón and Buscalioni, 2003;Manier, 2004;Bruner et al, 2005;Stayton, 2005;Vidal et al, 2005).…”

Morphometric analysis of the kingfisher cranium (AVES)

“…The centroid size of each specimen was extracted from the dorsal and the ventral projection of the cranium using tpsRelw (Rohlf 2002), and size differences among the families were evaluated through a one-way analysis of variance. The accuracy of the centroid size as an estimate of total size (Loy et al 2004) was tested by regression of the centroid size onto body weights obtained from Fry et al (1992). Chr: characters; 0-4: Codes.…”