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La musculature peaucière de la tête chez un jeune Lamantin du Sénégal (Trichechus senegalensis Link 1795; Mammifère, Sirénien)
Author(s) -
Saban Roger
Publication year - 1975
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/j.1439-0264.1975.tb00639.x
Subject(s) - biology
Summary The cutaneous musculature of a young Manatee (Trichechus senegalensis Link, 1795; Mammals, Sirenia) Adaptation of the manatee to marine life and to a plant diet has markedly changed the cutaneous musculature of the head. Like whales the manatee lacks pelvic limbs and has an extensive cutaneous muscle of the trunk (m. panniculus carnosus) which also covers part of the head corresponding here to the m. platysma myoides of the other mammals. The muscle extends into the lateral parts of the overhanging upper lip, is very thick here and represents the m. zygomaticolabialis. As in whales whose skull is covered with thick skin, the occipitofrontal musculature has disappeared. The same is true for the musculature of the ear; only a connection between the m. platysma and the external acoustic meatus (pars auricularis) remains. The large upper lip with its pendulous lateral parts is thickened in addition by all the derivatives of the deep cervical sphincter (m. nasolabialis, m. maxillolabialis) and its very thick oral part. The oral part froms a ventral sling rostral to the fibrous plate situated under the chin, which, in conjunction with the mentalis and the mental part of the buccinatorius, seems to play a role in the prehension of plants in that it facilitates the grasp of the lateral part of the upper lip, The m. dilatator nasi together with the m. nasolabialis controls the opening and closing of the nostril similarly to what has been described for the hippopotamus.