A rich insect fauna is found in the Cretaceous (Aptian) Nova Olinda Member of the Crato Formation in the Araripe Basin, northeastern Brazil. The Crato Formation was deposited close to the centre of the supercontinent Gondwana, prior to significant rifting. In this paper, we analyzed remains of 1135 insect specimens, representing 55 families, within two limestone facies of the Nova Olinda Member: pale yellow and dark gray limestones. We collected taphonomical data and assessed the paleoecological significance of insect faunas in terms of their distribution and interaction with the paleoenvironment. The insect fauna is dominanted by fully terrestrial taxa despite preservation in an aquatic paleoenvironment. Considering both facies, the distribution of insect families is similar throughout the Nova Olinda Member, which excludes possible overlapping of one entomofauna over another. The pale yellow limestones near the top of the section are richer in fossil insect content and show a higher incidence of aquatic and semiaquatic insects preserved in dorsoventral view compared to the dark gray limestones. This suggests that the Crato insects preserved in the pale yellow limestones experienced short transport distances or prolonged decay or both. In contrast, insects preserved in the dark gray limestones appear proportionally with higher degrees of disarticulation than those preserved in the pale yellow limestones, indicating that these insects underwent a higher degree of postmortem transport in the biostratinomic stage. Compared to descriptions of other Early Cretaceous assemblages, the taxonomic literature of Crato Paleoentomofauna shows distinct differences. The Yixian and Zaza formations are described as being dominated by beetles and wasps. The Crato Formation, however, is relatively richer in Paleoptera species. Both the sedimentary facies studied and the paleoentomological content reveal a complex ecosystem inserted in a depositional setting, similar to modern long-standing wetlands, and where periodically flooded zones were surrounded by dry lands with xeromorphic vegetation.

中文翻译：

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巴西克拉托组白垩纪 (Aptian) 昆虫区系的古生态学分析

巴西东北部阿拉里佩盆地克拉托组的白垩纪（阿普第安）新奥林达段发现了丰富的昆虫动物群。在发生重大裂谷之前，克拉托地层沉积在靠近冈瓦纳超大陆中心的位置。在本文中，我们分析了新奥林达段的两个石灰岩相（浅黄色和深灰色石灰岩）内的 1135 个昆虫标本遗骸，代表 55 个科。我们收集了埋藏学数据，并评估了昆虫区系的分布及其与古环境相互作用的古生态学意义。尽管昆虫区系保存在水生古环境中，但它们以完全陆生类群为主。考虑到这两个相，整个新奥林达段昆虫科的分布是相似的，这排除了一种昆虫动物群与另一种昆虫动物群可能重叠的情况。剖面顶部附近的浅黄色石灰岩昆虫化石含量更丰富，与深灰色石灰岩相比，背腹观保存的水生和半水生昆虫的发生率更高。这表明保存在浅黄色石灰岩中的克拉托昆虫经历了短距离运输或长时间腐烂或两者兼而有之。相比之下，保存在深灰色石灰岩中的昆虫比保存在浅黄色石灰岩中的昆虫成比例地具有更高程度的脱节，表明这些昆虫在生物分层阶段经历了更高程度的死后运输。与其他早白垩世组合的描述相比，克拉托古昆虫动物群的分类学文献显示出明显的差异。据描述，义县和扎扎地层以甲虫和黄蜂为主。然而，克拉托组的古翅目物种相对丰富。研究的沉积相和古昆虫学内容都揭示了沉积环境中插入的复杂生态系统，类似于现代长期存在的湿地，周期性洪水区域被旱地植被包围。