Schnell Nalani K, Britz Ralf, Johnson G David
Department of Comparative Zoology, University of Tübingen, Germany.
J Morphol. 2010 Aug;271(8):1006-22. doi: 10.1002/jmor.10858.
In all stomiid genera there is an occipito-vertebral gap between the skull and the first vertebra bridged only by the flexible notochord. Morphological studies from the early 20th century suggested that some stomiid genera have 1-10 of the anteriormost centra reduced or entire vertebrae missing in this region. Our study reviews this previous hypothesis. Using a new approach, we show that only in Chauliodus, Eustomias and Leptostomias gladiator vertebral centra are actually lost, with their respective neural arches and parapophyses persisting. We present results from a comparative analysis of the number and insertion sites of the anteriormost myosepta in 26 of the 28 stomiid genera. Generally in teleosts the first three myosepta are associated with the occiput, and the fourth is the first vertebral myoseptum. The insertion site of the fourth myoseptum plays an important role in this analysis, because it provides a landmark for the first vertebra. Lack of association of the fourth myoseptum with a vertebra is thus evidence that the first vertebra is reduced or absent. By counting the occipital and vertebral myosepta the number of reduced vertebrae in Chauliodus, Eustomias and Leptostomias gladiator can be inferred. Proper identification of the spino-occipital nerves provides an additional source of information about vertebral reduction. In all other stomiid genera the extensive occipito- vertebral gap is not a consequence of the reduction of vertebrae, but of an elongation of the notochord. The complex structure and ontogeny of the anterior part of the vertebral column of stomiids are discussed comparatively.
在所有巨口鱼科属种中，颅骨与第一块脊椎骨之间存在枕椎间隙，仅由柔韧的脊索连接。20世纪早期的形态学研究表明，一些巨口鱼科属种在该区域最前端的椎体有1至10个椎体前部缩小或整个椎体缺失。我们的研究重新审视了这一先前的假设。采用一种新方法，我们发现只有在深海狗母鱼属、长吻鱼属和尖吻深海狗母鱼中椎体中心实际缺失，其各自的神经弓和副突仍然存在。我们展示了对28个巨口鱼科属种中的26个属种最前端肌隔数量和插入位点的比较分析结果。一般来说，硬骨鱼中前三块肌隔与枕骨相关，第四块是第一块脊椎肌隔。第四块肌隔的插入位点在该分析中起着重要作用，因为它为第一块脊椎提供了一个标志。因此，第四块肌隔与脊椎缺乏关联是第一块脊椎缩小或缺失的证据。通过计算枕骨和脊椎肌隔，可以推断出深海狗母鱼属、长吻鱼属和尖吻深海狗母鱼中缩小的椎体数量。对枕脊神经的正确识别提供了有关椎体缩小的额外信息来源。在所有其他巨口鱼科属种中，广泛的枕椎间隙不是椎体缩小的结果，而是脊索伸长的结果。我们对巨口鱼科脊椎柱前部的复杂结构和个体发育进行了比较讨论。
