Journal of South American Earth Sciences ( IF 1.8 ) Pub Date : 2022-09-06 , DOI: 10.1016/j.jsames.2022.104021 Hanna Carolina Lins de Paiva, Valéria Gallo, Mauro Cavalcanti
Opportunities to examine the structure of paleocommunities are extremely rare, due to the incompleteness of the fossil record. Regarding the Morro do Chaves Formation, there are many studies about the fauna and flora since 1870. However, paleoecological data are relatively scarce. According to the most recent study, the palynological records of the Morro do Chaves Formation were related to a disturbed paleoenvironment, caused by marine incursions in the northern sector of the Sergipe-Alagoas Basin during Lower Cretaceous. Thus, this paper aims to analyze the paleoecological relationships of the paleocommunity of fishes in the Morro do Chaves Formation, as the possible responses to the paleoenvironmental disturbances. From the basic matrix of abundance data for four fish orders found in 11 pelitic levels, similarity matrices were computed, using the Bray-Curtis distance coefficient. Cluster analysis by the unweighted pair-group method using arithmetic averages (UPGMA) was performed on these matrices, for grouping the levels. The advantages of multivariate analysis in paleoecological studies are also discussed. In addition, the Morro do Chaves Formation is composed of active piscivorous predators, benthophagous and planktiphagous fishes. The aulopiform fishes probably acted as top-down regulators in the paleocommunity, controlling the local fish populations. Mawsonia and “Lepidotes” are usually recorded in similar outcrops and inferred to be associated fauna. While Mawsonia likely possesses a sit-wait strategy, “Lepidotes” would be a relatively more active predator.
中文翻译:
巴西东北部塞尔希佩-阿拉戈斯盆地 Morro do Chaves 组下白垩统(Barremian)鱼类群落的古生态学
由于化石记录的不完整,检查古社区结构的机会极为罕见。关于 Morro do Chaves 组,自 1870 年以来对动植物群的研究较多,但古生态学资料相对较少。根据最近的研究,Morro do Chaves 组的孢粉记录与下白垩纪塞尔希佩-阿拉戈斯盆地北部的海洋侵入造成的扰乱古环境有关。. 因此,本文旨在分析 Morro do Chaves 组鱼类古群落的古生态关系,作为对古环境扰动的可能反应。根据在 11 个泥质层中发现的四种鱼目丰度数据的基本矩阵,使用 Bray-Curtis 距离系数计算相似矩阵。通过使用算术平均值 (UPGMA) 的未加权对组方法对这些矩阵进行聚类分析,以对水平进行分组。还讨论了多变量分析在古生态学研究中的优势。此外,Morro do Chaves 组由活跃的食鱼捕食者、底栖鱼类和浮游鱼类组成。蝶形鱼可能在古社区中充当自上而下的调节者,控制着当地的鱼类种群。Mawsonia和“ Lepidotes ”通常记录在类似的露头中,并被推断为相关的动物群。虽然Mawsonia可能拥有坐等策略,但“ Lepidotes ”将是一种相对更活跃的捕食者。