os clitoridis; Baubellum; spectacled bear; Animals; Female; Male; Bone and Bones/anatomy & histology; Ursidae/anatomy & histology; Bone and Bones; Ursidae; Anatomy; Histology; Ecology, Evolution, Behavior and Systematics; Molecular Biology; Developmental Biology; Cell Biology
Abstract :
[en] The baubellum (os clitoridis) is a bone found in the clitoris of many female eutherian mammals and is homologous to the baculum in males. In contrast to the baculum, the baubellum has received very little attention regarding its morphological or interspecific diversity, or on hypotheses for its function. The presence of the baubellum in bears (Ursidae) has only been established and mentioned in the literature for the Ursus genus, and not for the other genera of bears. Moreover, no scaled photographs are available for baubella of this clade, and the sizes reported vary between sources. We hereby present and describe the baubellum of a spectacled bear (Tremarctos ornatus), providing a detailed account of baubella in a basal ursid species. The baubellum of Tremarctos is slightly bowed dorsally, with two small prominences at the distal apex. The length of the Tremarctos baubellum in this study is comparable to that of Ursus americanus (American black bear). We infer the specific shape, with longitudinal ridges, of the baubellum in Tremarctos could indicate a discrete function during copulation or sexual arousal. However, future studies, especially regarding the associated soft tissues, will be required to confirm whether this is indeed the case. Our study expands the understanding of baubella within Ursidae, providing new data (including a three-dimensional model) that can be used to further explore the morphological diversity and function of this enigmatic extra-skeletal bone.
De Ridder, Tim ; Department of Veterinary Sciences, Comparative Perinatal Development, University of Antwerp, Antwerp, Belgium ; Department of Biology, Functional Morphology Laboratory, University of Antwerp, Antwerp, Belgium
Goossenaerts, Ellen; Department of Veterinary Sciences, Comparative Perinatal Development, University of Antwerp, Antwerp, Belgium
Spruyt, Jonas; Centre for Research and Conservation, Royal Zoological Society of Antwerp, Antwerp, Belgium
Van Ginneken, Chris; Department of Veterinary Sciences, Comparative Perinatal Development, University of Antwerp, Antwerp, Belgium
Aerts, Peter; Department of Biology, Functional Morphology Laboratory, University of Antwerp, Antwerp, Belgium ; Department of Movement and Sports Sciences, University of Ghent, Ghent, Belgium
Maclaren, James ; Université de Liège - ULiège > Département de géologie > Evolution and diversity dynamics lab ; Department of Biology, Functional Morphology Laboratory, University of Antwerp, Antwerp, Belgium
Language :
English
Title :
First description of the baubellum in the spectacled bear Tremarctos ornatus (Mammalia: Ursidae).
The authors would like to thank Linda Van Elsacker (Zoological Director KMDA) for facilitating the collaboration of the KMDA with the University of Antwerp, and Joaquim Sanctorum for FleX\u2010CT scanning the specimen and for rendering the 3D model. We also thank Stephan Milz and Edward Fenton for their editorial work, and the three anonymous reviewers for their comments. No specific funding was sought for this study; financial support was provided for the 3D scanning by CoPeD lab (C.V.G). and FunMorph lab (P.A.). This work was conducted during the final Master's year of T.D.R., under the supervision of J.A.M. (FWO PD\u2010JR fellowship: 12V8422N).
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