Prenatal Cranial Ossification of the Humpback Whale (Megaptera novaeangliae)
Prenatal Cranial Ossification of the Humpback Whale (Megaptera novaeangliae)
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DOI：
10.1002/jmor.20367
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发表时间：
2015-05-01
影响因子：
1.5
通讯作者：
Mueller, Johannes
中科院分区：
文献类型：
--
作者：
Hampe, Oliver;Franke, Helena;Mueller, Johannes
作为小型陆生有蹄类哺乳动物的后代，鲸鱼在其进化史上经历了巨大的转变，即在对水中生活的二次适应过程中进化出了解剖学、生理学和行为的广泛变化。然而，人们对鲸鱼个体发育知之甚少，这有助于确定关键进化事件的时间和顺序，例如鲸目动物耳朵的修饰。对于须鲸（Mysticeti）来说尤其如此，该群体包括座头鲸 Megaaptera novaeangliae。我们使用高分辨率 X 射线计算机断层扫描重新研究柏林自然博物馆库肯塔尔收藏的座头鲸胎儿，从而扩展了对其骨骼发生的历史描述，并首次提供了该物种的颅骨骨化序列。原则上，产前大翅目的骨化顺序遵循典型的哺乳动物模式，前真皮骨是头骨中的第一个骨化元素，从齿骨开始。与其他哺乳动物不同，外鼓室骨在早期就骨化。在这些早期产前标本的上颌骨和齿骨中都可以观察到牙槽结构，但缺乏牙齿的证据。尽管由于保护问题不太可能获得新的胚胎材料，但我们的研究表明，采用新技术重新检查现有标本仍然有望填补我们在鲸鱼进化和个体发育方面的知识空白。 J.莫菲尔。 276:564-582，2015 年。(c) 2015 年 Wiley 期刊公司。
Being descendants of small terrestrial ungulate mammals, whales underwent enormous transformations during their evolutionary history, that is, extensive changes in anatomy, physiology, and behavior were evolved during secondary adaptations to life in water. However, still only little is known about whale ontogenetic development, which help to identify the timing and sequence of critical evolutionary events, such as modification of the cetacean ear. This is particularly true for baleen whales (Mysticeti), the group including the humpback whale Megaptera novaeangliae. We use high-resolution X-ray computed tomography to reinvestigate humpback whale fetuses from the Kukenthal collection at the Museum fur Naturkunde, Berlin, thus, extending historic descriptions of their skeletogenesis and providing for the first time sequences of cranial ossification for this species. Principally, the ossification sequence of prenatal Megaptera follows a typical mammalian pattern with the anterior dermal bones being the first ossifying elements in the skull, starting with the dentary. In contrast to other mammals, the ectotympanic bone ossifies at an early stage. Alveolar structure can be observed in both the maxillae and dentaries in these early prenatal specimens but evidence for teeth is lacking. Although the possibility of obtaining new embryological material is unlikely due to conservation issues, our study shows that reexamination of existing specimens employing new technologies still holds promise for filling gaps in our knowledge of whale evolution and ontogeny. J. Morphol. 276:564-582, 2015. (c) 2015 Wiley Periodicals, Inc.