Brachyurans played important ecological and evolutionary roles in the marine benthic communities of the past and were the components of the Mesozoic Decapod Revolution. Therefore, the search for their fossil remains is fundamental to understanding the composition, diversity, and ecological structure of Mesozoic marine benthic communities. Brachyuran remains are uncommon in the decapod record of the Aptian Romualdo Formation in the Araripe Basin. In this context, we recorded and described new occurrences of Exucarcinus gonzagai, preserved in shales from the middle portion of the Romualdo Formation, near the city of Jardim in the State of Ceará. Comparisons between these new specimens and former specimens from the Exu locality, State of Pernambuco, including the type material, allowed us to recognize, for the first time, three distinct ontogenetic stages (i.e., informally referred as I, II, and III). Throughout ontogenetic development, the carapace becomes wider and spinier. Stage III carapaces exhibit a large number of grooves, although the grooves are poorly impressed, and some are pitted. Growth also resulted in better-developed orbital lobes and fissures. In addition, the preservation of some anatomical structures is highly influenced by the carapace fossilization process (i.e., molds or cuticles), including the tubercles, grooves, and spines. Unfortunately, those characters that can vary according to ontogenetic development or fossilization are commonly used in the systematic and phylogenetic decisions of the group. Hence, it is advisable to consider these changes whenever possible to avoid the erection of taphotaxons and mistaken phylogenetic decisions.

Brachyurans 在过去的海洋底栖群落中发挥了重要的生态和进化作用，并且是中生代十足目动物革命的组成部分。因此，寻找它们的化石遗骸是了解中生代海洋底栖群落组成、多样性和生态结构的基础。Brachyuran 遗骸在阿拉里佩盆地的 Aptian Romualdo 组的十足目记录中并不常见。在这种情况下，我们记录并描述了Exucarcinus gonzagai 的新出现，保存在 Romualdo 组中部的页岩中，靠近塞阿拉州的 Jardim 市。这些新标本与伯南布哥州 Exu 地区的旧标本（包括类型材料）之间的比较使我们第一次认识到三个不同的个体发育阶段（即非正式地称为 I、II 和 III）。在整个个体发育过程中，甲壳变得更宽、更有刺。阶段 III 的甲壳表现出大量的凹槽，尽管凹槽的压痕很差，有些是有凹坑的。生长还导致了更好的眼眶裂片和裂隙。此外，一些解剖结构的保存受甲壳化石化过程（即霉菌或角质层）的影响很大，包括结节、凹槽和刺。很遗憾，那些可以根据个体发育或化石化而变化的特征通常用于群体的系统和系统发育决策。因此，建议尽可能考虑这些变化，以避免产生分类群和错误的系统发育决定。