Examination of statocysts of scyphomedusae and cubomedusae to clarify phylogenetic relationships and to develop a method for the age determination of medusae

盘形水母（Scyphozoa）和箱形水母（Cubozoa）具有复杂的感觉器官（rhopalia），其中含有无机晶体（平衡石）。在申请人Ilka Sötje博士的参与下，对一些物种中这些晶体的化学组成、晶体学和形态进行了研究，并在几份出版物中显示了不同分类群之间的一些差异。继续进行的研究将有助于确定水母的分类关系，例如，根口水母（Racostomeae）内部有争议的关系，尚待用分子方法加以澄清。箱形水母和盘形水母的耳石应进行比较检查。到目前为止，它们被分为两个不同的类群（类），但可能比目前假设的更密切相关。这两个类群的成年动物的耳石有一个非常不同的形态，但最近的调查表明，关于两个群体的年轻标本的耳石形态的相似之处;这将在本申请的上下文中详细检查。详细分析不同年龄组的水母的耳石将导致水母的年龄测定方法的发展。水母的凝胶状身体根据环境条件的不同而缩小和生长。因此，水母的大部分身体部位不能用于年龄测定，但水母发育过程中耳石数量和大小的变化可以用于年龄测定。年龄的确定是研究种群动态的基础，对于阐明观察到的世界范围内水母大量出现的原因至关重要。

Disc-shaped jellyfish (Scyphozoa) and box jellyfish (Cubozoa) have complex sense organs (rhopalia), which contain anorganic crystals (statoliths). The chemical composition, the crystallography and the morphology of these crystals in some species have been examined and some differences between the distinct taxa were shown in several publications with participation of the applicant, Dr. Ilka Sötje. Continuing examinations shall contribute to the identification of taxonomical relationships of jellyfish, for example the disputed relationships within the root-mouth jellyfish (Rhizostomeae), which have yet to be clarified with molecular methods. The statoliths of the box jellyfish and the disc-shaped jellyfish shall be examined in comparison. To date, they have been grouped into two different taxa (classes), but are presumably more closely-related to each other than is presently assumed. Statoliths of full-grown animals of both taxa have a very different morphology, but recent investigations have shown similarities regarding the statolith morphology in young specimens of both groups; this shall be examined in detail in the context of this application.The detailed analysis of statoliths in medusae of different age groups shall lead to the development of an age-determination method for jellyfish. The gelatinous body of jellyfish is shrinking and growing depending on environmental conditions. Therefore, most body parts of the medusa cannot be used for age determination, but changes in the number and size of the statoliths during medusa development can be used for age-determination. The determination of age is the basis for studies of population dynamics and is crucial for the elucidation of the reasons for the observed worldwide increase in mass occurrences of jellyfish.