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The Romualdo Formation, Aptian-Albian of the Araripe Basin, is known for the extraordinary preservation of its paleoichthyofauna. The majority of the studies performed on the basin are descriptive, so this study aims to analyze morphological adaptations in the paleoichthyofauna of the Romualdo Formation, seeking to understand how they influenced the life habits of fishes. To conduct the paleoecological study, 117 specimens were selected among 13 different taxa and used for the investigation of types of dentition, mouth orientation, and body morphology. A cluster analysis was carried out using morphometric data of body morphology, resulting in three groups based on the similarity index among the species. The morphology of most of the paleoichthyofauna, like Rhacolepis buccalis and Vinctifer comptoni, was adapted to swimming in high-energy environments and continuous swimming. Others, such as Araripelepidotes temnurus, presented a morphology adapted to surviving in low-energy environments, and few, like Brannerion sp. and Neoproscinetes penalvai, could perform maneuverability moves due to a deep, laterally flattened body and well-developed fins. The mouth orientation, as well as the body morphology, was of great importance to the inferences about the living zone and feeding habits of the fishes, suggesting that most inhabited the middle of the water column and were generalists regarding their feeding zone. Moreover, the types of dentition or lack thereof helped to infer food diversity and a possible food web. Therefore, the ecomorphological attributes showed some degree of morphological variations in the paleoichthyofauna, reflecting different swimming habits in environments of varied energy. The study also revealed a range of explored food resources, and the association among the fishes allowed the proposition of a rather complex food web.

This manuscript presents a biostratigraphic analysis based on non-marine palynomorphs and ostracods during the interval corresponding to the Aptian - lower Albian (local Alagoas stage) in the Jatoba Basin, northeastern Brazil. The data used for the analysis were from 179 samples collected in core 2-JSN-01-PE, which was drilled in the locality of Serra Negra, municipality of Ibimirim, Pernambuco. Of the 179 samples collected and prepared, only 23 presented ostracods, whereas 64 levels were carriers of organic waste, which aided in the biostratigraphic correlation of the studied core. From the palynological data, it was possible to identify the upper limit of the Inaperturopollenites turbatus (P-260) palynozone and the Sergipea variverrucata (P-270) palynozone and the lower limit of the Complicatisaccus cearensis (P-280) palynozone in the core 2-JSN-01-PE. Among the palynozones, the upper limit of P-260, whose record is difficult to track in northeastern Brazil and has been identified only in the Sergipe/Alagoas basin, and the limit of P-270 and P-280 in the Jatoba Basin, which had not yet been identified, can be highlighted. From the data based on non-marine ostracods, it was possible identify the “ Cytheridea ”? spp. ex. Group 201/218 Biozone (herein designated Damonella grandiensis ), code 011. Such record in the Jatoba Basin is represented for a diverse fauna when compared with the record of monospecific fauna initially proposed in the Sergipe/Alagoas Basin.

Up to date, at least 50 species of Crocodylomorpha are known in Brazil. Those species are distributed in a temporal range from the Triassic to the present day. However, Crocodylomorpha records from the Brazilian Jurassic are quite scarce, and they have been often considered as lacking enough information for a proper systematic identification. In this study, we describe new Crocodylomorpha specimens, collected in Ibimirim city, Pernambuco state, Northeast of Brazil, where outcrops of the Alianca Formation (Upper Jurassic), Jatoba Basin, have been recorded. The specimens are represented by teeth, frontal plate, vertebrae, and osteoderms. Despite fragmented, these Crocodylomorpha remains allowed us, based mainly on morphological evidence in the teeth, to visualize intermediate characteristics between the Goniopholididae and Teleosauridae. The present work reveals the high, and still little explored, paleontological potential of the Alianca Formation in the understanding of the Brazilian Jurassic.

The Cassiopidae family belongs to a group of gastropods of the Tethyan Realm, whose origin and dispersion are related a transgression of the Tethys Sea during the Early Cretaceous. The Romualdo Formation in the Araripe Basin, located in Northeast Brazil, presents fossil assemblages with echinoids, bivalves and cassiopid gastropods, indicating a marine sedimentation at the top of the formation. This research reveals three new species of this fauna: Gymnentome (Craginia) beurleni sp. nov., ‘Pseudomesalia’ (‘Pseudomesalia’) mennessieri sp. nov and ‘Pseudomesalia’ (‘Pseudomesalia’) santanensis sp. nov. We also review two other species: Craginia araripensis Beurlen, 1964 and Gymnentome romualdoi Beurlen, 1964 , which we reclassify taxonomically as Paraglauconia (Diglauconia) araripensis and Gymnentome (Gymnentome) romualdoi, respectively; Paraglauconia (Diglauconia) lyrica Maury, 1936 and Gymnentome (Gymnentome) carregozica Maury, 1936 were the first recorded species in the Araripe Basin. The occurrence of these cassiopid gastropod fauna in other basins, such as Sergipe, Potiguar and Parnaiba, indicate the influence of waters coming from the north through the Tethys Sea in the Aptian–Albian and in the marginal continental basins of the Brazilian Northeast.

Benthic macroinvertebrate fossils can be seen towards to the top of the Romualdo Member of the Santana Formation, in the Araripe Basin, Northeast Brazil, and can provide paleoenvironmental and paleobiogeographical information regarding the Cretaceous marine transgression which reached the interior basins in Northeast Brazil. We analyse taphonomic characteristics of macroinvertebrate concentrations of two outcrops (Torrinha and Torre Grande) within the municipality Araripina, Pernambuco, in order to enhance our understanding of the Cretaceous paleoenvironment in the western portion of the Araripe Basin. At the outcrop Torrinha, proximal tempestitic taphofacies were identified. These predominantly consist of ceritid, cassiopid, and later, naticid gastropods as well as undetermined bivalves. Given this lack of variability it can be deduced that there were no significant paleoenvironmental changes during the successive stages tempestitic sedimentation. In the Torre Grande outcrop distal to proximal tempestitic taphofacies were identified from the base to the top respectively pointing to a decrease in paleodepth. Asides from the macroinvertebrates present in Torrinha, there are also echinoids – unequivocal evidence for marine conditions. These occurrences appear to be restricted to Romualdo Member outcrops in the Araripina municipality (the Southeast portion of the Araripe Basin) confirming a previously published hypothesis suggesting that the Cretaceous marine transgression originated from the neighbouring Parnaiba Basin to the west. This study identified marine molluscs of a similar age to those in the Romualdo Member's equivalent rock units in the Parnaiba and Sergipe-Alagoas (SE-AL) basins suggesting a marine connection between these basins and the Araripe Basin during the Early Cretaceous.

Pleistocene sites with mammals in Brazil are commonly recorded from limestone or dolomite caves, outcrops at rivers and creeks, coastal plain lagoon deposits, rock shelters, and natural tanks. This work presents a new late Pleistocene site containing bones and footprints of mammals. The footprints are assigned to llama (Lamaichnum), cervid (Pecoripeda), horse (Hippipeda), and at least one megamammal (?Toxodon), constituting the northernmost record for the late Pleistocene of South America and the first record from Brazil. Mammals are related to fluvial environments along with treeless vegetation during a sub-humid climate, in a region currently dominated by a semiarid biome.

So far, there are at least 22 species of fossil turtles formally described for Brazil, with the Araripe Basin being the second largest in Mesozoic diversity with five species, losing only to the Bauru Group, with six species. The material presented here refers to three fossil turtles (DGEO-CTG-UFPE 8470, DGEO-CTG-UFPE 8471, DGEO-CTG-UFPE 8932) from Romualdo, an Albian Formation of the Araripe Basin (Cretaceous), collected in municipalities of Pernambuco (PE). The DGEO-CTG-UFPE 8470 specimen was identified as Araripemys barretoi Price, 1973, and DGEO-CTG-UFPE 8471 and DGEO-CTG-UFPE 8932 as Cearachelys placidoi Gaffney et al., 2001, the first occurrence of this taxon in the state of Pernambuco. DGEO-CTG-UFPE 8470 and DGEO-CTG-UFPE 8932 are the first Testudines described from the municipality of Exu, (PE).