Morphological variability of baculum (os penis) in the polecat Mustela putorius

Abstract

MALECHA A. W., KRAWCZYK A. J., HROMADA M. 2009. Morphological variability of baculum (os penis) in the polecat Mustela putorius. Acta zoologica cracoviensia, # )(1-2): 115-120. Abstract. The study presents the morphological variation in three traits of the baculum (os penis) in the polecat (Mustela putorius Linnaeus, 1758), based on an analysis of 108 males (7 juveniles and 101 adults) collected in NE Slovakia between 1958-1978. Adult individuals had a significantly larger baculum (length, width and distal tip size) than juveniles. All three measured baculum traits correlated significantly with each other. However, these relationships only explained from 10% (width distal tip size relationship) up to 51% (length width relationship) of the variance between the studied traits. Therefore, evolutionary analysis based on baculum variation should take into account not only baculum size, but also base width, which may be a measure of baculum developmental stage. Moreover, coefficients of variation were 10.2%, 30.2% and 11.4%, respectively for length, width and distal tip size of the baculum, much greater than the known variation of cranial measurements. Therefore, more data on the variability among individuals, as well as between measured traits, are needed for a better understanding of the evolutionary processes which influence baculum size and shape.

Variability of the baculum in the red fox (Vulpes vulpes) from Slovakia

“…Finally, it should be concluded that the present results are in line with the aforementioned data obtained by other authors (e.g. Abramov 2002;Baryshnikov, BinindaEmonds, and Abramov 2003;Malecha, Krawczyk, and Hromada 2009;Krawczyk, Malecha, and Tryjanowski 2011;etc. ) and confirm that bacula are variable in size and structure.…”

“…On the contrary, the least variables were the length of the baculum and the length of sulcus urethralis. The data obtained are consistent with those given by Malecha, Krawczyk, and Hromada (2009). The latter authors showed that the most variable trait was the width of the baculum, but not the length of the baculum, as often used in comparative analyses (e.g.…”

“…in mechanical support and protection of the urethra from compression. Moreover, Kratochvíl and Kratochvíl (1976), Baryshnikov, BinindaEmonds, and Abramov (2003), Hromada (2009), andTryjanowski (2011) showed that the shape and the size of the baculum vary greatly between species, even between in closely related species, and therefore are widely used as diagnostic traits in taxonomy.…”

“…Several authors (Lariviére and Ferguson 2002;Ramm 2007;Krawczyk and Malecha 2009;Malecha, Krawczyk, and Hromada 2009;Krawczyk, Malecha, and Tryjanowski 2011) reported that the following three main adaptive hypotheses were advanced for the evolution of the baculum: the vaginal friction hypothesis, the prolonged intromission hypothesis, and the induced ovulation hypothesis. Lariviére and Ferguson (2002) tested these three hypotheses by using phylogenetically corrected methods and data on North American carnivores.…”

Morphological and biometrical comparisons of the baculum in the genus Nannospalax Palmer, 1903 (Rodentia: Spalacidae) from Turkey with consideration of its taxonomic importance

“…The comparative morphology of bacula exposes obvious differences among rodent species from the larger group Eutheria (Hooper, 1960;Lidicker and Brylski, 1987;Baryshnikov and Abramov, 1997;Benda and Tsytsulina, 2000;Adebayo et al, 2011). Therefore, the differences in the shape and the size of the bacula have been widely used as a tool for distinguishing closely related species and for determining the phyletic relationships among species (Hooper, 1960;Walton, 1968;Williams et al, 1980;Lidicker and Brylski, 1987;Simson et al, 1993;Çolak et al, 1998;Benda and Tsytsulina, 2000;Baryshnikov et al, 2003;Ferguson and Lariviere, 2004;Malecha, 2009). …”