Araripe Basin Research Articles

On the phylogenetic affinities of the tapejarid pterosaur ‘Tupuxuara deliradamus’ from the Lower Cretaceous of Brazil

ABSTRACT ‘Tupuxuara deliradamus’ was originally described as a tapejarid pterosaur from the Lower Cretaceous Romualdo Formation (Albian) of the Araripe Basin, Northeastern Brazil, and was regarded later by other authors as an indeterminate azhdarchoid. Whereas its taxonomic status remains controversial, its phylogenetic affinities were never investigated under computational analyses. Moreover, after its original description, other putative coeval pterosaurs have been described from Brazil. In the present study, these data are combined and we reconstruct the phylogenetic affinities of ‘Tu. deliradamus’ for the first time. It is recovered within Tapejarinae, nesting as the sister taxon to Caupedactylus ybaka. This result challenges the former assignation to Thalassodrominae. The holotype of ‘Tu. deliradamus’ shares a suit of traits of tapejarines, such as the lacrimal process of jugal being posteriorly inclined, the posterodorsal margin of the nasoantorbital fenestra forming an abrupt bend level with the dorsal margin of the orbit, and inclination of the quadrate with relation to the jugal bar is approximately 150°. Unfortunately, the fragmentary condition of SMKN PAL 6410 hampers a reliable taxonomic assignment at species level. Nevertheless, the new data supports its assignation to Tapejarinae indet.

Taphonomy of fish, invertebrates and plant remains in the first Tethyan-South Atlantic marine ingression along Cretaceous rift systems in NE-Brazil

The Aptian–Albian Amargosa Bed, Tucano Basin, which was recently considered as a Konservat-Lagerstätten, is a relatively thin, siliciclastic-dominated succession of yellowish and grayish papyraceous shales. We analyzed the taphonomy of fishes, gastric ejecta, freshwater shrimps and conchostracans, euryaline ostracods, and plants. Fish biostratinomic signatures indicate point to changes in water alkalinity/salinity as their causa mortis, occasionally subject to weak currents. The preferential preservation of flexed shrimps and isolated pleons corroborates this interpretation. Conchostracans, recorded in distinct levels, indicate episodes of mass mortality, variable transport and temporal mixing, and at least one faunal change. During the fossilization, primary P and Ca from shrimps and fishes probably generated phosphates, which finally altered to Fe oxy-/hydroxides, yielding a mixed elemental composition, not expressed in other mineralogies than Fe oxy-/hydroxides. The original calcite of ostracod valves likely has been dissolved/replaced by a K-rich aluminosilicate, or by a precursor phase. Plants were preserved by Fe oxy-/hydroxides or by kerogenisation. Previous studies show that marine ingression of Tethyan waters into the central segment of the proto-South Atlantic gulf flooded the continental scale axial river system captured by the Tucano rift basin, affecting base level up to the Araripe Basin. Here it is interpreted that tributary river systems with relatively steeper stream gradients were less affected by marine transgression than the axial system, resulting in local freshwater riverine influx across the elongated epeiric sea developed over the interior rift basins of NE-Brazil, resulting in a mixed biota of distinct water salinities that alternate in the Amargosa Bed type-section.

New invertebrate sites and marine ingressions in the Romualdo Formation, Aptian-Albian, Araripe sedimentary basin, NE Brazil

Fossil invertebrates are relevant to the understanding of past environmental phenomena due to their sensitivity to abiotic conditions. This work identified fossiliferous associations in four localities of the Romualdo Formation, seeking to better characterize the depositional paleoenvironment of the unit during the Aptian-Albian, in the south-central portion of the Araripe Basin, NE Brazil. All the stratigraphic sections analyzed are located in mines in the Pernambuco state: Vale do Silício and Gregório (municipality of Araripina), VMB and Serrolândia (municipality of Ipubi). In total, 69 samples were collected, 2156 invertebrate specimens were analyzed, and 13 taxa were identified (Shrimp: Paleomattea deliciosa, Kellnerius jamacaruensis; Spinicaudata: Cyzicus brauni, Cyzicus pricei, Martinestheria codoensis, Estheriina costai; Gastropoda: Tylostoma ranchariensis, Paraglaugonia sp., Pseudomesalia (‘Pseudomesalia’) santanensis, indeterminate cassiopids, cerithids and naticids; and Bivalvia: Brachidontes araripensis). Using PAST v 4.04 software the specimens were clustered, based on taxa diversity and abundance, into three fossil associations (Cyzicus sp., Paleomattea deliciosa and Cassiopidae) whose paleoecological characteristics suggest a transitional paleoenvironment affected by transgressive events (marine incursion I and II). Spinicaudata characterize a transitional environment. The isolated presence of the decapods, in turn, reflects the first marine ingression. Finally, the Cassipiodae association, present in shell bed deposits, represents the second ingression. It can be noted that the invertebrate fauna presents variation in terms of temporal distribution along the analyzed sections, reflecting environmental instability in the paleoenvironment. The taphonomic characteristics are consistent with a shallow marine sedimentation environment, occasionally subject to storm action. The tethyan affinity of part of the fossils during the Aptian-Aptian, points to a marine ingression through the Parnaíba.

Pedogenesis on Jurassic formations in the Araripe Basin, northeastern Brazil: Weathering and parent material

The Araripe Basin is the largest sedimentary basin in the countryside of Northeast Brazil. Despite the wide diversity of lithostratigraphic, geomorphological, and paleontological studies, little is known about the pedogenesis and weathering. This study aimed to characterize the morphological, physical and chemical attributes, and the spectral behavior of soils in a toposequence over Jurassic formations of the Araripe Basin so as to identify the main pedogenetic processes, as well as their degree of weathering. A toposequence composed of four soil profiles was selected, described, and sampled in a semi-arid depression that is geologically composed of lacustrine (mudstones) and fluvial (sandstones) deposits. The variability of soil attributes such as color, texture, base saturation, clay activity, and spectral behavior (vis-NIR and MIR) reflects the predominant influence of the parent material on the relief factor. The values of Ki index (SiO2/Al2O3) and Fed/Fet ratio indicate a very low degree of weathering, conditioned by a dry climate. From the MIR spectra, absorption features associated with calcite, Mg-silicate, illite, and smectite-illite interstratifications were identified. These minerals were interpreted to have originated authigenically, formed from evaporation processes in lacustrine environments. Despite the smaller influence of the relief and the low action of pedogenetic processes, incipient evidence of clay translocation is observed in the upper third of the landscape.

New data about the shark fauna of the Brejo Santo formation, Late Jurassic of the Araripe Basin, Northeastern Brazil

The Late Jurassic fauna of the Araripe Basin is represented by chondrichthyans and osteichthyans (Actinopterygii and Sarcopterygii). At the present study, we describe new records of hybodontid shark from the Brejo Santo Formation (Upper Jurassic – Tithonian) and characterize their paleohistology. They are represented by a complete cephalic spine of Planohybodus sp., which indicates sexual dimorphism, being present only in male sharks; as well as by a dorsal spine, which is the most complete found so far for this formation. Microstructural analyzes were performed in the dorsal spine, indicating this specimen as a juvenile, early sub-adult individual, approximately one year old.

Calcareous nannofossils, biostratigraphy, and paleobiogeography of the Aptian/Albian Romualdo Formation in the Araripe Basin, North-Eastern Brazil

Calcareous nannofossils, biostratigraphy, and paleobiogeography of the Aptian/Albian Romualdo Formation in the Araripe Basin, North-Eastern Brazil

Gastropods Colour Patterns in Cassiopids and Naticids from Romualdo Formation, Araripe Basin, Northeast Brazil

The phylum Mollusca includes one of the most beautiful examples of colour patterns in present-day shells. However, they are rare in the fossil record because they demand excellent fossilization. In Brazil, colour patterns in fossil mollusk shells are recorded in gastropods Natica aff. bulbulus White, 1887 from the Riachuelo Formation (Aptian-Albian), Sergipe-Alagoas Basin. This paper presents the first gastropod shells from the Romualdo Formation with colour patterns, visible under natural and UV light, belonging to the families Naticidae and Cassiopidae, collected at Santo Antônio outcrop municipality of Exu, Pernambuco and, Pinheiro and Serra do Mãozinha sites, municipality of Missão Velha and Romualdo site, municipality of Crato, Ceará. Among the cassiopids more than 100 specimens were tested, with 1/3 of them showing a residual colour pattern under UV light exposure, after chemical preparation. They correspond to the species Paraglauconia (Diglauconia) araripensis (Beurlen, 1964), Paraglauconia (Diglauconia) lyrica Maury, 1934, Gymnentome (Gymnentome) carregozica (Maury, 1934) and Gymnentome (Gymnentome) romualdoi Beurlen, 1964. The colour pattern is virtually similar in both genera, with fluorescent stripes on a dark background, showing the taxonomic similarity between them. As for the naticids, about 20 specimens were collected and 15 show good preservation, observing the visible colour pattern under natural light in Natica sp. and Euspira sp.; both new taxa for the Araripe Basin. The residual colour pattern in naticids ranges from spiral stripes to sigmoidal lines and blotches of brown and yellowish tones on a paler background, as observed in fossil species of the same family in the Cenozoic. The new occurrences increase the fossiliferous diversity of mollusks of the Romualdo Formation and extend the understanding of the diversity of colouration patterns of Lower Cretaceous gastropods.

Palynofacies analyses of Santana Group, upper Aptian of the Araripe Basin, northeast Brazil: Paleoenvironmental reconstruction

We present the paleoenvironmental analysis based on sedimentary organic matter (SOM) of alluvial-lacustrine-transitional deposits that crop out in the east portion of the Araripe Basin, Ceará State, Brazil. Samples were collected from the Barbalha, Crato, Ipubi and Romualdo formations, Santana Group. For the palynofacies analyses, the kerogen categories were counted and grouped. The described SOM were subdivided into six groups: Structureless, which consists of resin and amorphous organic matter (AOM); Terrigenous, which consists of non-opaque biostructured-phytoclast; Opaque, which consists of equidimensional, lath and corroded of black color; Sporomorphs, which consist of spores and pollen grains; Freshwater, constituted by Botryococcus and Pediastrum microplankton and Marine elements, represented by dinoflagellate cysts and foraminiferal lining. The stratigraphic distribution of the seven palynofacies reflects a change from fluvial system to a lacustrine environment, as well as the first marine incursion on Serra da Mãozinha section (Crato Formation). In the top of the Santana Group recorded a transition from a lacustrine environment close to a fluvio-deltaic source to an estuarine system, marked by the presence of Subtilisphaera, during the late Aptian. The palynological data presented indicates that the entire Santana Group is of Aptian age considering the conspicuous presence of Sergipea variverrucata in the sections.

Transtensional tectonics during the Gondwana breakup in northeastern Brazil: Early Cretaceous paleostress inversion in the Araripe Basin

Intraplate deformation during the Mesozoic breakup of West Gondwana predominantly occurred along major ancient lithospheric discontinuities. The Precambrian Patos Shear Zone (PASZ) is an inherited lithospheric discontinuity in the interior of northeastern Brazil which is closely linked to the evolution of the Araripe Basin. In this study, unlike previous interpretations of purely extensional tectonics, we conducted stratigraphic and structural field mapping as well as paleostress reconstruction to demonstrate the role of intraplate transtensional tectonics during the Araripe Basin evolution. Limited to the north by the PASZ and associated with sinistral reactivation, a set of normal to oblique NE–SW faults constituting a transtensional horsetail structure generated the initial basin geometry. Stratigraphic records of this rift phase comprise the Jurassic to Early Cretaceous Brejo Santo, Missão Velha, and Abaiara formations. Paleostress reconstruction showed a NE–SW/subhorizontal σ1 axis, a vertical σ2 axis, and a NW–SE/subhorizontal σ3 axis, resulting in a sinistral transtensional tectonic regime, which was mainly governed by intraplate processes that reflected the opening of the Brazilian East Margin. The subsequent Aptian post-rift early phase was characterized by NE–SW reverse faults and a succession of normal to oblique normal faults striking NW–SE to WNW–ESE. This fault arrangement generated a new NW–SE transtensional basin, which controlled the Barbalha Formation and modified and partially preserved the previous NE-SW transtensional basin. Paleostress reconstruction showed a NW–SE/subhorizontal σ1 axis and NE–SW/subhorizontal σ3 axis for strike-slip faults but NE–SW extension for normal faults. This is related to a second dextral reactivation of the PASZ following propagation of intraplate stress during the opening of the Brazilian Equatorial Margin. In summary, tectonic evolution of the Araripe Basin was strongly influenced by stress propagation from the Gondwana breakup into intraplate settings, with two distinct reactivations of the PASZ pre-existing basement structures which results in a paleostress inversion during basin evolution.

Aptian ostracods from the Santana Group, Araripe Basin, Brazil

The Class Ostracoda provides a well preserved and diverse microfossil succession throughout the Aptian Santana Group, Araripe Basin, Brazil. The Santana Group, consisting of the Barbalha, Crato, Ipubi and Romualdo formations, records the post-rift sequence (Alagoas local stage) of the Gondwana break-up. The Alagoas Stage is characterised by ostracods grouped as Cytheridea? spp. 201–218 of which several have been identified as belonging to Pattersoncypris Bate and Damonella Anderson. From 2 well cores and 10 outcrops of the Santana Group, 25 taxa were identified, 5 of which are here newly described. Throughout the Santana Group, Pattersoncypris micropapillosa Bate and Damonella grandiensis Tomé, Lima Filho and Neumann were recovered. Restricted to the Barbalha Formation, Candonopsis? alagoensis Tomé, Lima Filho and Neumann and Pattersoncypris cucurves nov. sp are abundant. The Crato Formation shows higher ostracod diversity with Damonella grandiensis being the most abundant and associated with Cypridea araripensis Silva, Brasacypris subovatum Do Carmo, Coimbra, Whatley, Antonietto and Citon, Damonella pumila nov. sp., Pattersoncypris alta (Antonietto, Gobbo, Do Carmo, Assine, Fernandes and Silva), Zonocypris berthoui Piovesan, Melo, Cabral and Guzmán, Zonocypris dorsoconvexa Piovesan, Melo, Cabral and Guzmán, Ilyocypris coimbrai nov. sp., Neuquenocypris berthoui Colin and Dépêche, Neuquenocypris sp., Rhinocypris spinata nov. sp., Theriosynoecum silvai (Silva), Theriosynoecum sp., Timiriasevia? sp. and Alicenula martinsi (Silva). The Ipubi and Romualdo formations record abundant Pattersoncypris crepata (Do Carmo, Coimbra, Whatley, Antonietto and Citon) in association with P. alta, Pattersoncypris kroemmelbeini nov. sp., P. symmetrica (Krömmelbein and Weber) and Alicenula martinsi (Silva). Theriosynoecum colini Do Carmo, Coimbra, Whatley, Antonietto and Citon, Ilyocypris coimbrai nov. sp. and Rhinocypris spinata nov. sp. also occur in the Ipubi Formation.

First Mesozoic lungfish aestivation burrows of West Gondwana (Late Jurassic of Araripe Basin, northeastern Brazil)

An assemblage of cylindrical trace fossils that occur in the Late Jurassic Missão Velha Formation is presented and interpreted to be the casts of lungfish burrows. These small-sized casts are interpreted as passive siliciclastic sedimentation into abandoned excavations made by lungfish, suggesting their presence in the Missão Velha Formation paleofauna. The identification is based on their morphological similarity to previously identified and extant lungfish burrows. The cross-section of the burrows is very similar to the modern burrow morphology of the African lungfish Protopterus along its full vertical length, indicating lungfish aestivation, and supplemented by spatial clustering reflecting gregarious behavior. The burrow fillings occur in siltstone lithofacies intercalated with cross-stratified fluvial sandstones. These strata were deposited in a continental environment that includes braided fluvial channels, floodplains, and paleosols. Lungfish burrows have been used to infer the presence of seasonal droughts in the geologic past, and the occurrence of lungfish burrows in the Missão Velha Formation adds new insights into the Late Jurassic climate of the Araripe Basin. This climate provided sufficient moisture punctuated by seasonally dry periods, affording a habitat that supported lungfish aestivation behavior.

Provenance analysis of the Araripe intracontinental basin, northeast Brazil – Routes for proto-Atlantic marine incursions in northwest Gondwana

This study presents U-Pb dating of detrital zircons from sandstones of the Araripe basin (NE Brazil) assisting in the reconstruction of the Mesozoic paleogeography. In particular, we focus in the seaway connection between the Proto-Atlantic ocean and this intracontinental basin in northwest Gondwana.The new U-Pb age spectra of detrital zircon grains from the pre-Jurassic and Mesozoic clastic sequences of the Araripe Basin, along with paleocurrent, stratigraphic and structural data, demonstrate a significant change in provenance during the Later Jurassic to mid-Cretaceous. Six distinct provenance patterns are identified in the sequences, which may reflect the rapid evolution of the paleogeographic scenarios during tectono-sedimentary history of the northwest Gondwana rift-related basins throughout the onset to the opening of the Atlantic Ocean. Here, we propose an alternative model for paleogeography of the northwest Gondwana. In the Later Jurassic, the main source of terrigenous clastics to the Araripe Basin was the Paleozoic-Triassic sedimentary rocks of the Parnaíba Basin, which formed a prominent barrier to separate the Araripe Basin from the Mesozoic units of the Parnaíba Basin. In the mid-Aptian, erosion led to the retraction of the Parnaíba Paleozoic sedimentary units to the west, as the Precambrian terranes from the Borborema Province, to the northwest, became the main source for the Araripe Basin. The rapid rifting evolution show that the Rio Salgado Belt, from NE region, became topographically depressed, potentially initiating a link between the Araripe and the Potiguar basins. During late-Aptian, the Araripe Basin probably connected to the Proto-Equatorial Atlantic Ocean from the northeast, through the Potiguar Basin and associated grabens on the north. The present paleogeographical reconstruction may explain the occurrence of warm water adapted Tethyan fauna in the Araripe Basin, more plausible than previous hypothesis of a connection to Proto-South Atlantic Ocean.

The paleohistology of †Araripichthys castilhoi from the Lower Cretaceous of Araripe Basin, Northeastern Brazil: a typical case of basal teleost

ABSTRACT †Araripichthys castilhoi belongs to the paleo-ichthyofauna from the Aptian calcareous concretions of Romualdo Member, Santana Formation, Araripe Basin, northeast Brazil. It was originally placed within Beryciformes (Acanthomorphata) by a combination of plesiomorphic and apomorphic characters. Later, an anatomical review of †Araripichthys demonstrated the presence of several primitive characters (cf. presence of fin spines, orbitosphenoid, two supramaxillae, seven hypurals, autogenous hypurals 1 and 2, second ural centrum and first uroneural not fused, and cycloid scales) and aligned it with Clupeocephala. †Araripichthys was also considered closely related to †Acanthichthys (primitive Acanthomorphata), basically by the body shape resemblance. Other included †Araripichthys in †Protobramoidei (basal Clupeocephala) based on the absence of pelvic fins, presence of stout neural spines and scales partially covering the dorsal fin. The odd taxonomic history of †Araripichthys is directly related to its scarce number of available well-preserved specimens and concurrently its absence in a comprehensive phylogenetic analysis. Here we present a paleohistological study, an efficient tool to precise the taxonomic position of fossil fishes, especially in cases like that of †Araripichthys. Its paleohistology presents pseudolamellar bony tissues with stellate lacunae, filled by osteocytes with ramified cytoplasmic extensions. The star-shaped osteocytes of †Araripichthys are clearly characteristic of basal teleosts. Conversely, in the scarce Acanthopterygii taxa with cellular bone the osteocytes morphology is clearly distinct since their canaliculi are not regularly localized around these cells. The currently accepted synapomorphies for Elopomorpha, Clupeocephala, Acanthopterygii, and the already known anatomical data for †Araripichthys together with its paleohistology, corroborate its incertae sedis position within basal Teleostei.

Petrological Meaning of Ethnostratigraphic Units: Laminated Limestone of the Crato Formation, Araripe Basin, NE Brazil

Crato Formation, NE Brazil, consists of laminated limestones deposited in a lacustrine environment during the Early Cretaceous. The Nova Olinda Member, the lowest unit of the Crato Formation, is world-famous for their exceptionally well-preserved fossils. The Nova Olinda limestones have been economically exploited for centuries. Today, this commercial excavation still represents the main economic activity in the region. During the mining process, the quarry workers have developed an informal stratigraphic code to individualize the different beds in the quarries. Upward, the local workers recognize the succession as “lajão dos sete cortes”, “matracão", “lajão branco", “pão de milho”, “veio da paiba”, "veio doidão”, “lajão amarelo” and “veio do besouro”. Here, we used principles of ethnostratigraphy to verify the origin and validity of these informal stratigraphic nomenclatures by classifying them as ethnostra. For this, we applied a detailed petrographical analysis with thin sections and high-resolution X-ray techniques to characterize each ethnostratum. Our results suggest possible linkages between informal and formal stratigraphic nomenclatures in Nova Olinda Member. Finally, this study showed that ethnostratigraphy can be applied as an auxiliary tool in stratigraphic studies, in both, as an initial exploratory approach and as enhancing the relationship between the geologists and the local community.

Quantification of the spatial arrangement of structural lineaments and deformation bands: Implications for the tectonic evolution of the eastern border of the Araripe Basin, NE Brazil

Spatial arrangement regards the spatial position of brittle structures. Even though they are important for several industrial applications, quantification of their spatial arrangement remains a challenge. In this contribution, we quantify and compare the spatial arrangement of regional lineaments and deformation bands in the Eastern Araripe Basin, NE Brazil using the normalized correlation count method on topographic, aeromagnetic, and outcrop data. We have noticed irregular and random arrangements of topographic and aeromagnetic clusters of lineaments, while deformation bands are grouped. The use of topographic and aeromagnetic data represents a reliable way to investigate regions with limitations (topographic, climatic, or social) that make field data hard or impossible to acquire. Furthermore, we proposed a preliminary tectonic evolution model for the eastern border of the Araripe Basin.

High-resolution taphonomy and sequence stratigraphy of internally complex, bakevelliid-dominated coquinas from the Aptian Romualdo Formation, Araripe Basin, NE Brazil

The Aptian Romualdo Formation (Araripe Basin, NE Brazil) was deposited in a restricted epeiric sea, during the opening of the South Atlantic Ocean, with a coeval record to that in the Brazilian Pre-Salt succession. The upper part of the Romualdo Formation encompasses the Highstand Systems Tract of a third-order stratigraphic sequence, and contains shell beds interbedded with shale, siltstone, and fine-grained sandstone. Based on distinct taphonomic features (shell sorting, fragmentation, abrasion, rounding, and orientation), sedimentological criteria (shell abundance, type of matrix, sedimentary structures, and presence/absence of quartz grains), and stratigraphic attributes (bed thickness, geometry, contacts), the paleoenvironmental conditions and the bed-by-bed accumulation history of the coquinas is disentangled. Eight carbonate microfacies were recognized, including ostracod carbonate mudstone, bivalve-gastropod wackestone, gastropod-bivalve packstone, bivalve-gastropod grainstone, bivalve-gastropod floatstone, bivalve-gastropod rudstone, bakevelliid floatstone, and bakevelliid rudstone, which are organized in six, cm-thick shell concentrations. Mudstone and wackestone facies mark the settling of carbonate muds without significant bottom currents and wave action, probably below storm wave base, whereas packstone, floatstone, and rudstone, with fragmented, rounded, and oriented shells, were deposited in agitated waters, between the fair-weather and the storm wave bases. Ripple cross-laminated grainstone is interpreted as high-energy facies deposited above fair-weather wave base. The shell beds are internally complex and consist of cm-scale alternations of microfacies differing in packing, sorting, and composition. They tend to fine upwards within dm-thick shell beds, generating shallowing-upward facies sequences. The concentrations, the uppermost one with in situ bakevelliid shells in the top, record high-frequency base level oscillations influenced by eustasy and climate changes. These bioclastic accumulations originated by the superposition of sedimentologic and primary biologic processes (e.g., post-deposition meiofaunal bioturbation). The cm-thick, low-diversity shell beds are excellent examples of multiple-event carbonate deposits generated in a siliciclastic-dominated, restricted epeiric sea, revealing high-frequency cycles in proximal to distal restricted marine settings.

Early Cretaceous Ostracoda (Crustacea) from south-central Araripe Basin, Brazil, with descriptions of seven new species.

A systematic study is made of Early Cretaceous (late Aptian/earlyAlbian) ostracod assemblages from the Santo Antnio section. This section is characterized by sediment belonging to the post-rift sedimentary sequence of the Romualdo Formation in the southern-central region of the Araripe Basin, Brazil and represents on of the first marine ingression in the interior of the continent, during the beginning of the formation of the Atlantic Ocean. The Santo Antonio section presents ostracods in greater diversity than previously known. Nineteen samples were analyzed, yielding a total of 8,370 specimens. Fifteen taxa were identified, including six brackish ostracods: Pattersoncypris salitrensis, Pattersoncypris angulata, Pattersoncypris micropapillosa, Damonella grandiensis, Alicenula cf. leguminella and Theriosynoecum cf. quadrinodosum; and nine typically brackish-marine species, including seven new ones: Dicrorygma cf. minuta, Dicrorygma (Orthorygma?) dimorpha, Mongolianella aptianensis sp. nov., Mantelliana speculum sp. nov., Paracypris undulareventralis sp. nov., Microceratina retangularis sp. nov., Perissocytheridea oculusutilis sp. nov., Perissocytheridea poruslinearis sp. nov. and Perissocytheridea florisdorsalis sp. nov. Therefore, the detailed taxonomic study brings a new understanding of marine ostracods around the upper Aptian/lower Albian boundary of the Araripe Basin.

The Fossil Fishes of the “Rocha” Collection Housed in the Museu Nacional and the Types Described by Jordan & Branner in 1908

In 1908, D.S. Jordan J.C. Branner described the following species of fossil fishes from the Araripe Basin: Calamopleurus vestitus, Cearana rochae, Enneles audax, and Tharrias araripis. Such material of the “Rocha Collection”, that was made by Francisco Dias da Rocha (1869-1960), were passed on to the Government of the State of Ceará. In 1961, Carlos de Paula Couto, negotiated the donation of the paleontological collections for the Museu Nacional. We review herein the history of the fossil fishes of the “Rocha Collection” that was housed in the Museu Nacional in, with an emphasis on type material. The documents and literature were consulted, and the fossil fishes were examined and photographed. This material corresponds to 12 catalogue numbers, three of which are replicas of the type- material housed in the Department of Geology, California Academy of Sciences, in California. The remaining nine numbers encompass 27 specimens referring to original material. The represented taxa are: Vinctifer comptoni, Notelops brama, Cladocyclus gardneri, Rhacolepis buccalis, Tharrhias araripis, and Brannerion sp. The only type material found was Cearana rochae, currently a synonym of Tharrhias araripis. This historical rescue of the “Rocha” collection type material will facilitate the investigation of researchers studying the paleoichthyofauna of the Araripe Basin.

The ontogenetic growth of Anhangueridae (Pterosauria, Pterodactyloidea) premaxillary crests as revealed by a crestless Anhanguera specimen

ABSTRACT The Anhangueridae are a clade of toothed pterodactyloid pterosaurs, known from their characteristic anteriorly expanded premaxillae and conspicuous rostral sagittal premaxillary and dentary crests. Most known anhanguerids come from the Lower Cretaceous Romualdo Formation within the Araripe Basin of northeast Brazil. With four currently valid genera and several specimens referred to the clade, anhanguerids are the most abundant and diverse tetrapod group in the Romualdo Formation. However, some studies suggest this diversity may be overestimated, as many taxa have been diagnosed based on subtle differences in their premaxillary crests, a structure argued to be either ontogenetically variable or sexually dimorphic. Here we describe an anterior fragment of a gracile pterosaur rostrum that possesses the single diagnostic feature of Anhanguera (fifth and sixth pairs of dental alveoli smaller than the fourth and seventh), but lacks a sagittal crest. The affinities of the new fossil among other toothed pterosaurs were tested through both cladistic and geometric morphometric approaches, which allow referral of the new specimen to Anhanguera. The absence of a crest in the new specimen of Anhanguera suggests that this structure varies in terms of ontogeny and/or sex, and that perhaps it was influenced by sexual selection.

Presence of the Aspidorhynchidae Vinctifer longirostris in the Early Cretaceous of the Araripe Basin

ABSTRACT The family Aspidorhynchidae consists of six genera: Aspidorhynchus, Belonostomus, Vinctifer, Pseudovinctifer, Richmondichthys and Jonoichthys. The genus Vinctifer has three nominal species, as follows: V. comptoni, found in Brazil, Venezuela, Colombia, Antarctica and Equatorial Guinea; V. ferrusquiai, present so far in the Sabinal Formation (Mexico); and V. longirostris, until then restricted to the Marizal Formation, in the Tucano Basin (Brazil). The presence of Vinctifer longirostris in the dark shales of the Romualdo Formation, Araripe Basin (Brazil), which was only speculated in previous works, is confirmed herein. Moreover, we added new morphological diagnostic features for this species, which were not observed in the specimens described for the Marizal Formation. This new record expands the geographical distribution of the species and also contributes to a better understanding of the diversity of the paleoichthyofauna of the Araripe Basin.