In this study, the ontogenetic trajectories of septal spacing between succeeding chambers of five modern cuttlefishes, Sepia esculenta, S. lycidas, S. latimanus, S. pharaonic and Sepiella japonica, which were all wild‐caught around Japan, were analysed. The ontogenetic trajectories of septal spacing of all examined cuttlefishes demonstrate a decrease in septal spacing followed by an increase during the earliest ontogenetic stage. This trend is assumed to be related to hatching. After the rapid decrease and increase in septal spacing, species‐dependent trends occur irrespective of sex and locality. Based on cluster analyses of general trends recognized in each species, the five examined species can be categorized into two groups: (1) a group by S. pharaonis, S. esculenta and Sepiella japonica; and (2) S. latimanus and S. lycidas as more distant branching groups within the five examined species. This classification is concordant with some phylogenetic clades determined from DNA analyses. Therefore, we hypothesized that the ontogenetic trajectories of septal spacing among modern cuttlefishes are phylogenetically dependent. If this hypothesis holds in fossil cuttlefishes, the examination of ontogenetic trajectories of septal spacing would give new insight into the recognition not only of the life history but also of the phylogeny of fossil cuttlefishes.

中文翻译：

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现代乌贼的间隔间距的成因轨迹在系统发育上是依赖的

在这项研究中，隔间距的五个现代乌贼，接替室之间的个体发育轨迹乌贼，S. lycidas，S. latimanus，S.法老和曼氏无针粳稻进行了分析，这些分析在日本各地都是野外捕获的。所有检查的墨鱼的间隔间距的个体发育轨迹表明，在最早的个体发育阶段中，间隔间距减小，然后增加。假定该趋势与孵化有关。在间隔间距迅速减小和增加之后，不论性别和地点如何，都会出现物种依赖性的趋势。基于在每个种类所识别的一般趋势簇分析，五个检查种类可分为两组：（1）一组由S.蚁，S.星虫和曼氏粳稻; （2）沙门氏菌和lycidas作为五个被检查物种中较远的分支群体。这种分类与从DNA分析确定的一些系统进化进化枝一致。因此，我们假设现代墨鱼之间的间隔间隔的发育轨迹是系统发育相关的。如果这一假设在化石乌贼中成立，那么对间隔间隔的个体发生轨迹的检查将不仅对人们的生活史而且对化石乌贼的系统发育的认识提供新的见解。