First occurrence of fossil shrimps (crustacea, decapoda) in the Ipubi Formation (Lower cretaceous, Araripe Basin)

The Ipubi Formation of the Araripe Basin is an important gypsum cretaceous reserve whose environment had resulted in the deposition of evaporites with narrow black shale lenses. In this work, we present the first occurrence of caridean for the dark shale levels of the Ipubi Formation. The analyzed specimen, although not achieving a detailed taxonomic determination, is a very important one because it is the first decapod crustacean found in this formation. We believe the specimen LPU-0918/A and B, is a caridean because of its second abdominal somite having a strongly rounded pleura in the base and it apparently overlaps the first and the third. The knowledge about fossil shrimps is still sparse, and the information presented here can be valuable to the understanding of the evolutive history of the carideans.

阿拉里佩盆地的伊普比地层是一处重要的石膏岩性白垩纪储备区，其环境条件导致蒸发岩与狭窄的黑页岩层沉积。在本研究中，我们首次发现了伊普比地层中暗色页岩层的甲壳类动物。所分析的样本，尽管未能实现详细的分类鉴定，但极具重要性，因为它是在该地层中首次发现的十足目甲壳类动物。我们认为样本LPU-0918/A和B属于甲壳类动物，因为其第二腹节基底具有明显圆润的侧板，且似乎与第一和第三腹节重叠。关于化石虾类的知识仍较为匮乏，此处所提供的信息对于理解甲壳类动物的演化历史具有重要意义。