caa a22 4500 378934813 CHVBK 20180305123638.0 cr unu---uuuuu 161128e20041001xx s 000 0 eng 10.1515/mamm.2004.018 doi (NATIONALLICENCE)gruyter-10.1515/mamm.2004.018 Development of tusks and associated structures in Mesoplodon bidens (Cetaceae, Mammalia) [Elektronische Daten] [Colin D. Macleod, Jerry S. Herman] This study examined the development of the tusks and associated skeletal structures in a series of 18 specimens of Sowerby's beaked whale (Mesoplodon bidens) from Scotland. The relative position of the tusks along the length of the mandible was found to move from 23% of mandible length from the anterior extremity in the smallest animal to around 37% in adults, due to a lengthening of the symphyseal region. A previously undescribed sexual dimorphism was noted, a bony abutment, or ossicular dental support, situated directly posterior to the erupted tusks of adult males. Ontogenetic changes associated with male maturity include an increase in tusk length, an increase in the length of the alveolus, a high level of wear on tusks, an increase in the depth of the mandible posterior to the alveolus, an increased level of mesorostral ossification and an overall thickening of the rostrum and the symphyseal region of the mandible. The tusks are presumed to be used in intraspecific aggressive interactions and the ossicular dental support may counteract backward and outward forces on them as they cut through an opponents flesh, while the thickening of the rostrum and mandible may reduce the risk of damage when the two animals make contact. Copyright 2004, Walter de Gruyter Cetacea nationallicence tusks nationallicence growth nationallicence sexual dimorphism nationallicence Macleod Colin D. 1. Department of Zoology, School of Biological Sciences, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ (United Kingdom) aut Herman Jerry S. 2. Department of Geology and Zoology, National Museums of Scotland, Chambers Street, Edinburgh EH1 1JF (United Kingdom) aut Mammalia Walter de Gruyter 68/2-3(2004-10-01), 175-184 0025-1461 68:2-3<175 2004 68 mamm https://doi.org/10.1515/mamm.2004.018 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/mamm.2004.018 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Macleod Colin D. 1. Department of Zoology, School of Biological Sciences, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ (United Kingdom) aut NATIONALLICENCE 700 1- Herman Jerry S. 2. Department of Geology and Zoology, National Museums of Scotland, Chambers Street, Edinburgh EH1 1JF (United Kingdom) aut NATIONALLICENCE 773 0- Mammalia Walter de Gruyter 68/2-3(2004-10-01), 175-184 0025-1461 68:2-3<175 2004 68 mamm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter