Ontogenetic trajectories of septal spacing and conch shape in the Late Cretaceous gaudryceratid ammonoids: implications for their post‐embryonic palaeoecology
Ontogenetic trajectories of septal spacing and conch shape in the Late Cretaceous gaudryceratid ammonoids: implications for their post‐embryonic palaeoecology
复制标题
白垩纪晚期高角角菊石的间隔间距和海螺形状的个体发育轨迹：对其胚胎后古生态学的影响
DOI：
10.1111/pala.12587
复制
发表时间：
2022
期刊：
影响因子：
2.6
通讯作者：
Wani Ryoji
中科院分区：
文献类型：
--
作者：
Kawakami Yoshitaka;Uchiyama Naomi;Wani Ryoji
在这项研究中，我们分析了个体发育轨迹的间隔之间的连续室的gaudryceratid菊石，Gaudryceras tenuiliratum，这是收集在Tomamae和米卡萨地区的北海道，日本。细脉地老虎个体发育过程中间隔间距的变化趋势为：间隔间距在第30个间隔处由增大到减小，在第70个间隔处逐渐减小，在第110个间隔处逐渐增大。螺体膨胀率（WER）的个体发育轨迹也表明，当螺体直径约为5-7 mm时，WER由下降趋势变为上升趋势。这个海螺直径对应于第二个周期的结束增加到减少隔膜间距发生在约30个隔膜之前，在这一点上，G. tenuiliratum可能从浮游生物过渡到nektobenthic习惯。两个地区的间隔间距和海螺形状的个体发育轨迹没有显著差异，这意味着晚白垩世菊石的间隔间距的个体发育轨迹模式依赖于分类而不是环境，尽管这需要进一步研究来自北海道以外地区的G. tenuiliratus。
In this study, we analysed the ontogenetic trajectories of septal spacing between succeeding chambers of the gaudryceratid ammonoid,Gaudryceras tenuiliratum, which were collected in the Tomamae and Mikasa areas of Hokkaido, Japan. The ontogenetic trajectories of septal spacing inG.tenuiliratumdemonstrate a general trend: two cycles of increasing to decreasing septal spacing until about the 30th septum, gradually decreasing septal spacing until about the 70th septum, and then gradually increasing septal spacing at least until about the 110th septum. The ontogenetic trajectories of the whorl expansion rate (WER) in our specimens also demonstrated that a decreasing trend changed into an increasing trend at a conch diameter ofc. 5–7 mm. This conch diameter corresponds to the end of the second cycle of increasing to decreasing septal spacing occurring before about the 30th septum, at which pointG.tenuiliratumpossibly transitioned from planktic to nektobenthic habits. No significant differences were detected in the ontogenetic trajectories of septal spacing and conch shape between the two areas, which implies that the ontogenetic trajectory patterns of septal spacing in the Late Cretaceous ammonoids were taxonomy‐dependent rather than environment‐dependent, although this should be further examined withG.tenuiliratumcollected from areas outside of Hokkaido.