Giants and dwarves: Reconstructing the evolution of size and life histories within Myriapoda

多足类动物的代表，即蜈蚣、千足虫及其近亲，通常被认为是生活在土壤和落叶层中的相当小的动物。尽管多足类动物的种类远远少于昆虫类，但蜈蚣和千足类动物是现代动物群的重要组成部分。它们扮演着重要的生态角色，例如，作为分解者或令人印象深刻的捕食者，这只是两个例子。现代多足纲动物的大多数代表体型都在毫米范围内，而体型更大的多足纲动物生活在热带地区，最大体长略高于30厘米。因此，更令人惊讶的是，在古生代晚期，特别是在石炭纪（约3.59 - 2.99亿年前），这一群体的化石代表达到了2米的体型。在多足纲动物体型的背景下，特别有趣的是比较最大的代表，节肢动物的唯一化石代表，和最小的代表，刚毛千足动物（多xenida）。后者既存在于现代动物群中，也存在于保存在不同年代（1.3亿至1500万年前）琥珀中的化石中。尽管它们的体型差异很大，但这两个群体被认为是姐妹群体，因此显然在体型上发生了强烈的进化变化。本研究从两个方面进行了探讨：一是对腕骨千足虫与多尾千足虫姐妹类群关系的支持，二是腕骨千足虫体型随时间的变化。比较化石大小的一个挑战是，小的代表可能只是不成熟的。因此，我们将把那些尚未拥有完整段数的阶段包括在我们的比较中。这种不成熟的阶段可以在现代和某些谱系的化石代表中被识别出来（例如岩石生物或多xenidae），并以此识别出不同的阶段。当这些阶段进行比较时，个体发生变异，即个体发育过程中的变异，就可以得到纠正。对这些从1.3亿年前到今天的发现进行调查和分析，将有助于更好地了解生态功能的变化。

Representatives of the group Myriapoda, i.e. centipedes, millipedes, and their relatives, are generally known as rather small animals living in the soil and leaf litter. Even though the group Myriapoda comprises far less species than, for example, the group Insecta, centipedes and millipedes are important components of the modern fauna. They fulfil important ecological roles, for example, as decomposers or impressive predators to name just two examples. While the majority of modern representatives of Myriapoda has a body size within the millimetre range, much larger ones live in the tropics, with a maximum length of slightly more than 30 centimetres. Hence, it is even more astonishing that during the late Palaeozoic, especially in the Carboniferous (ca. 359–299 million years ago), fossil representatives of this group reached body sizes of up to two metres. Of special interest in the context of body size in Myriapoda is the comparison of the largest representatives, the exclusively fossil representatives of Arthropleuridea, and the smallest representatives, bristly millipedes (Polyxenida). The latter occur both in the modern fauna and as fossils preserved in ambers of different ages (from 130 to 15 million years ago). Despite their significant size difference, both groups have been suggested to be sister groups, hence apparently strong evolutionary changes in body size occurred. We explore two aspects: the support for a sistergroup relationship between Arthropleuridea and Polyxenida, and the size changes of bristly millipedes through time. A challenge in the comparison of size in fossils is that small representatives could simply be immatures. Therefore, we will include those stages into our comparisons which do not yet have the full segment number. Such immature stages can be recognised for modern and also for fossil representatives of certain lineages (e.g. Lithobiomorpha or Polyxenidae) and with this be identified to distinct stages. When these stages are compared, the ontogenetic variation, i.e. the variation during individual development, can be corrected. The investigations and analyses of these finds from 130 million years ago to today will provide for a better understanding of the changes in ecological functions through time.