Scaphitids rank among the commonest and best‐known Late Cretaceous ammonites, yet many aspects of their palaeobiology are still unresolved. Here, natural moulds and co‐occurring aptychi (calcitic coverings of the lower jaw) of Hoploscaphites constrictus crassus from the upper Maastrichtian of Poland are studied. For the first time in a scaphitid ammonite, growth marks are identified on the moulds and aptychi, which enable a reconstruction of the successive ontogenetic stages of the shell and aptychus. These are correlated to each other, allowing us to address two open issues in scaphitid palaeobiology: (1) estimation of individual growth rate and age; and (2) assessment of the aptychus as a possible protective operculum. As far as the growth rate of H. c. crassus is concerned, this accelerated rapidly at the onset of the mature body chamber formation and decelerated shortly before the cessation of growth. The resultant growth curve departs significantly from the generalized growth curve previously proposed for ammonites. In contrast, an age of five years at maturity, tentatively estimated here for H. c. crassus, conforms to the previous estimates for shallow‐water ammonites of comparable size. The role of the aptychus as an operculum is rejected for H. c. crassus, based on a significant misfit in size and shape between the aperture and aptychus recorded during ontogeny. These conclusions may probably be extended to closely related members of the European Hoploscaphites constrictus evolutionary lineage and to some other scaphitids with shells similar in size and shape to that of H. c. crassus.

中文翻译：

---

壳和aptychus生长的相关性提供了一个了解的Scaphitid炸药古生物学的见解。

Scaphitids属于最常见和最著名的白垩纪晚期铵盐，但其古生物学的许多方面仍未解决。在此，自然的模具和的共现aptychi（下颚的方解石覆盖物）Hoploscaphites constrictus克拉苏从波兰的上马斯特里赫特进行了研究。首次在鹰嘴豆科的亚mon石中，在霉菌和aptychi上发现了生长痕迹，这使得能够重建壳和aptychus的连续个体发育阶段。它们之间是相互关联的，这使我们能够解决舟鱼古生物学中的两个未解决的问题：（1）估计个体的生长速度和年龄；（2）评估aptychus作为可能的保护盖。就H. c。的增长率而言。crassus就其而言，在成熟的体腔形成开始时迅速加速，并在停止生长前不久减速。所得的生长曲线与先前提出的针对亚mon石的广义生长曲线明显不同。相比之下，此处暂定为H. c。的五岁。crassus，符合以前对可比大小的浅水炸药的估计。H. c。拒绝了aptychus作为小孔的作用。crassus，基于在个体发育过程中记录的光圈和aptychus在大小和形状上的明显不匹配。这些结论可能会扩展到欧洲霍普劳斯海豚的紧密相关成员进化谱系以及一些壳和壳大小与H. c。相似的scaphitids 。crassus。