The development of fossil sponge systematics is hindered by factors such as their low anatomical complexity and the low preservation potential of many characters used in the definition of extant sponge clades. Here we describe Calliospongia chunchengia gen. et sp. nov., a new sponge from the Lower Cambrian Chengjiang biota, which possesses a unique combination of characters. The skeleton of C. chunchengia is similar to those of leptomitid protomonaxonids in being composed of large spicules arranged longitudinally. However, it is distinct enough to belong in its own genus and even question a leptomitid affinity, because, unlike the members of this group, which usually have two categories of diactine spicules, its skeleton is entirely composed of triactines. The new taxon shares the presence of large megascleres with demosponges, hexactinellids and the ascosponges, suggesting an affinity to the total group of Silicea. It is also reminiscent of the hexactinellid-like reticulosans, showing a potential connection between two major types of Early Palaeozoic sponge body plans. A more accurate definition of the Cambro-Ordovician groups and the creation of a total evidence framework that integrates extinct and extant sponge morphology into the phylogenetic scenario derived from phylogenomics seem to be essential steps for the improvement of our understanding of early sponge evolution.

海绵化石系统学的发展受到诸如解剖复杂性低以及现存海绵进化枝定义中使用的许多特征的保存潜力低等因素的阻碍。在这里，我们描述了春城Calliosponia gen。等11月，一种来自下寒武统澄江生物群的新海绵，具有独特的特征组合。春城花的骨架与细叶原单轴纲类似，由纵向排列的大针状体组成。然而，它足够独特，属于自己的属，甚至质疑细线虫的亲和力，因为与该组的成员不同，该组的成员通常具有两类二线虫针，它的骨架完全由三线虫组成。这个新分类单元与desponges、hexactinellids和ascosponges共享大巨巩膜的存在，表明与Silicea总群的亲缘关系。它也让人想起六行网状动物，显示出早古生代海绵体结构的两种主要类型之间的潜在联系。对寒武纪-奥陶纪类群进行更准确的定义，并创建一个将灭绝和现存的海绵形态整合到系统发生学中的系统发育场景的总体证据框架，似乎是提高我们对早期海绵进化的理解的重要步骤。