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A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil
Abstract
The skull of a new, and highly unusual crested dinosaur with an elongate rostrum is the first dinosaur to be named from the Santana Formation of NE Brazil. Irritator challengeri gen. et sp. nov was most likely a maniraptoran dinosaur, but its affinities to other maniraptorans remain to be established. Unique features for Irritator include the pattern of tooth replacement, a highly reduced supratemporal fenestra, extreme lateral compression of the rostrum and a saggital crest comprised of the frontal and parietal bones. Irritator was most probably a piscivore. A land link between South America and the dinosaurian faunal province of North America and Asia is indicated, probably via Africa.
... Premaxillae and braincase material are also known for the recently described Riparovenator milnerae and Ceratosuchops inferodios (Barker et al., 2021), and a snout and further isolated cranial elements, including a braincase, have been referred to Suchomimus tenerensis (Sereno et al., 1998;Hendrickx et al., 2016;Sereno et al., 2022), but the latter three taxa lack detailed osteological descriptions. Other specimens mainly include partial snouts (Kellner Campos, 1996;Taquet and Russell, 1998 The spinosaurid Irritator from the Araripe Basin of north-eastern Brazil was initially briefly described and assigned to Maniraptora by Martill et al. (1996). The authors examined the specimen with aid of computed tomography (CT), revealing that the upper jaw was artificially elongated, but, due to the technical limitations of CT devices at that time, little anatomical detail could be gathered from the scans. ...
... In the same year, Kellner (1996) suggested that Irritator represents a spinosaurid, which was later supported in a more detailed description of the specimen by Sues et al. (2002), after the skull had been more completely prepared. The spinosaurids Irritator and Angaturama limai, both from the Romualdo Member of the Santana Formation (as formerly considered, see below) of Brazil, were described within a period of one month (Martill et al., 1996;Kellner and Campos, 1996). It was hypothesized that both taxa may represent fragments of the same skull (Sereno et al., 1998), since they come from the same area and strata and represent largely complementary portions of the skull. ...
... The number of teeth in the maxilla of Irritator, as well as the identification of the preserved teeth (and thus the total number of teeth originally present in the maxilla) have been contentious. Martill et al. (1996) stated in the diagnosis of the taxon that more than 11 teeth were present in the maxilla, and later mentioned that the snout "bears at least 16 large teeth" (Martill et al., 1996: 6), though they did not clarify if this was the total number of preserved teeth or the estimated number of teeth in one maxilla. Sues et al. (2002) identified nine teeth in the left and 10 tooth positions in the right maxilla and suggested that the total number of maxillary teeth was at least 11. ...
... Currently, the law in force is The Federal Law of Archaeological, Artistic and Historic Monuments and Zones, published in 1972 [46]. The Instituto Nacional de Antropología e Historia, [26], ( publication retracted by publisher), (b) SMNK PAL 3828, holotype of the pterosaur Ludodactylus sibbicki [28], (c) SMNK 2344 PAL holotype of the pterosaur Tupandactylus navigans [95], (d ) SMNS 58022 holotype of the dinosaur Irritator challengeri [30] (e) SMNK PAL 3804, holotype of the crocodyliform Susisuchus anatoceps [96], ( f ) private collection BMMS BK 2-2, holotype of the putative legged-snake Tetrapodophis amplectus [27], currently interpreted as an aquatic lizard [33], photograph by Michael Caldwell. Abbreviations: SMNK, State Museum of Natural History Karlsruhe, Germany; SMNS, State Museum of Natural History Stuttgart. ...
... This fact, together with the absence of reported exportation permits, leads us to consider that these fossils may have been purchased (figure 5). Some publications state that the fossils were 'obtained from a quarry workman' [92] or 'from a fossil digger' [93] and eight publications [28,30,[94][95][96][97][98][99] directly acknowledge that the specimen was purchased. ...
... The latter can be exemplified by a case from the Araripe Basin itself. Martill et al. [30] studied an illicitly acquired, artificially 'enhanced' specimen from Brazil and only discovered these heavy modifications during the course of their work. The case left the authors so 'irritated' that they decided to express this frustration in the name of the new taxon: Irritator challengeri. ...
Scientific practices stemming from colonialism, whereby middle- and low-income countries supply data for high-income countries and the contributions of local expertise are devalued, are still prevalent today in the field of palaeontology. In response to these unjust practices, countries such as Mexico and Brazil adopted protective laws and regulations during the twentieth century to preserve their palaeontological heritage. However, scientific colonialism is still reflected in many publications describing fossil specimens recovered from these countries. Here, we present examples of ‘palaeontological colonialism’ from publications on Jurassic–Cretaceous fossils from NE Mexico and NE Brazil spanning the last three decades. Common issues that we identified in these publications are the absence of both fieldwork and export permit declarations and the lack of local experts among authorships. In Mexico, access to many fossil specimens is restricted on account of these specimens being housed in private collections, whereas a high number of studies on Brazilian fossils are based on specimens illegally reposited in foreign collections, particularly in Germany and Japan. Finally, we outline and discuss the wider academic and social impacts of these research practices, and propose exhaustive recommendations to scientists, journals, museums, research institutions and government and funding agencies in order to overcome these practices.
... Given the strong evidence for aquatic behaviour in the skeletal (and particularly cranial) anatomy of these dinosaurs, it follows that the brain and nervous system may be expected to exhibit specialisations for aquatic foraging or swimming. Schade et al. (2020) described the endocranial anatomy of the South American spinosaurine Irritator challengeri (SMNS 58022) from the Romualdo Formation (Lower Cretaceous: Aptian) of Brazil (Arai & Assine, 2020;Martill et al., 1996;Sues et al., 2002). Irritator shares similarities with the endocasts of other non-maniraptoran theropods and possesses unexceptional hearing capabilities; more interesting is the tentative evidence from the inner ear that suggest an ability to rapidly move and tightly control ventral movements of the head that may have aided in the capture of small, agile prey such as fish (Schade et al., 2020). ...
The digital reconstruction of neurocranial endocasts has elucidated the gross brain structure and potential ecological attributes of many fossil taxa, including Irritator, a spinosaurine spinosaurid from the "mid" Cretaceous (Aptian) of Brazil. With unexceptional hearing capabilities, this taxon was inferred to integrate rapid and controlled pitch-down movements of the head that perhaps aided in the predation of small and agile prey such as fish. However, the neuroanatomy of baryonychine spinosaurids remains to be described, and potentially informs on the condition of early spinosaurids. Using micro-computed tomographic scanning (μCT), we reconstruct the braincase endocasts of Baryonyx walkeri and Ceratosuchops inferodios from the Wealden Supergroup (Lower Cretaceous) of England. We show that the gross endocranial morphology is similar to other non-maniraptoriform theropods, and corroborates previous observations of overall endocranial conservatism amongst more basal theropods. Several differences of unknown taxonomic utility are noted between the pair. Baryonychine neurosensory capabilities include low-frequency hearing and unexceptional olfaction, whilst the differing morphology of the floccular lobe tentatively suggests less developed gaze stabilisation mechanisms relative to spinosaurines. Given the morphological similarities observed with other basal tetanurans, baryonychines likely possessed comparable behavioural sophistication, suggesting that the transition from terrestrial hypercarnivorous ancestors to semi-aquatic "generalists" during the evolution of Spinosauridae did not require substantial modification of the brain and sensory systems.
... Abelisauroids, carcharodontosaurids and spinosaurids may have been theropod trackmakers of the Rio do Peixe basins. Some of the large theropod tracks are possibly attributed to large and very large (8e17 m long; Hendrickx et al., 2015) Spinosauridae, although they are only recognized from the fossil record in the Aptian deposits of the Araripe basin (Martill et al., 1996;Kellner and Campos, 2000;Sues et al., 2002) and Cenomanian of São Luís basin (Medeiros, 2006). The Carcharodontosauridae, medium-size to very large allosauroid theropods (6e14 m long; Hendrickx et al., 2015) are known from South America after the Valanginian (Novas et al., 2005;Coria et al., 2020). ...
The dinosaur tracks in the Rio do Peixe basins (Lower Cretaceous, Rio da Serra-Aratu stages) occur in at least 39 individual tracksites through approximately 98 stratigraphic levels in the western part of the State of Paraíba, Brazil. The Triunfo basin (one of the four Rio do Peixe basins) is a 480 km² asymmetric graben, located in the counties of São João do Rio do Peixe, Uiraúna, Poço, Brejo das Freiras, Triunfo, and Santa Helena, controlled by a NE transcurrent fault system. To date, only four isolated footprints and two incomplete trackways have been identified in the Antenor Navarro Formation. Among the isolated footprints, three probably belong to theropods. One incomplete trackway consists of just two digitigrade, rounded digits, suggesting they were made by a small ornithopod. In this study we describe a new ichnosite, located at Sítio Pereiros, São João do Rio do Peixe county, Paraíba State. The one and a half meter thick succession of fine-grained sandstones, siltstones, mudstones and shales with ripple marks, climbing ripples and mud cracks of the Sousa Formation reveals a bedding plane with three trackways, with a total of 19 tridactyl, mesaxonic footprints. These trackways are interpreted as produced by theropods, two large and one smaller. In these beds there are also ostracods, spinicaudatans (conchostracans), and fragments of microvertebrates (fish scales, teeth and bones). The Sítio Pereiros ichnosite represents a deposition in a floodplain area, with temporary aerial exposure of the superficial sediments in which tracks were impressed. The ichnofauna from this locality increases knowledge of the theropod fauna from the Triunfo basin and the distribution of the dinosaur tracks throughout the interior basins of Northeastern Brazil.
Description of these new theropod tracks permits evaluation of the behavior of these three theropods, including inferences about trackmaker speed and the type of gait of the three animals, and also of their possible size. This is the 40th ichnosite in the Rio do Peixe basins, extending analysis of the types of trackmaker associations present at such ichnosites, as well as the dinosaur diversity represented at each of them. New interpretations are presented about the environments, and the relationship between the various groups represented in this region in the Early Cretaceous.
... Os dinossauros não avianos da Formação Romualdo são representados por cinco espécies de Theropoda, incluindo os espinossaurídeos Irritator challengeri e Angaturama limai e os coelurossaurídeos Santanaraptor placidus, Mirischia assymetrica e Aratasaurus museunacionali, sendo apenas este último reconhecido nas concreções carbonáticas dos folhelhos negros na porção inferior da unidade, enquanto todos os demais foram identificados em rochas da porção superior. Aratasaurus museunacionali constitui o primeiro coelurossauriano basal reconhecido na Bacia do Araripe, sendo sugestivo de que este grupo era amplamente distribuído durante o Cretáceo Inicial (Kellner & Campos, 1996;Martill et al., 1996;Kellner, 1999;Aureliano et al., 2018;Sayão et al., 2020). Diferentes autores consideraram a possibilidade de os restos de Angaturama limai representarem a terminação anterior do rosto de Irritator challengeri (Sereno et al., 1998;Sues et al., 2002). ...
O rifteamento do Gondwana resultou em mudanças importantes na
composição química e distribuição de nutrientes dos oceanos, além de ter contribuído para modificações na circulação de massas de água, o que acarretou na abertura de novos espaços ecológicos. Com a reativação de sistemas de falhas do embasamento durante a ruptura, tem-se a formação de lagos de riftes perenes e temporários, por vezes alimentados por incursões fluviais. Além disso, os pulsos de incursões marinhas durante os eventos de transgressão no final do Cretáceo Inicial também geraram importantes modificações na biota da Bacia do Araripe. A gênese desses novos ecoespaços resultou em grandes transformações bióticas, criando novas possibilidades para o surgimento, a diversificação e a extinção de espécies em um curto espaço temporal. As rochas da Bacia do Araripe registram este momento em que ficam evidentes as relações intrínsecas entre as alterações dos espaços ecológicos e as consequentes biotas registradas em ambientes continentais e marinhos. A integração entre os dados sedimentológicos, estratigráficos e paleontológicos
das rochas da Bacia do Araripe permite categorizar três biotas, Missão Velha, Crato e Romualdo, produtos das dinâmicas tectônicas globais associadas à ruptura do Gondwana e suas decorrentes variações climáticas e oceanográficas. Essas biotas apresentam registros paleobiológicos singulares, com animais e vegetais abundantes, diversificados e muitas vezes de caráter endêmico. Muitos dos fósseis identificados são espécies com preservação
excepcional, que possibilitam o entendimento de aspectos-chave para a evolução biológica e a relação com as espécies viventes.
... In the Lower Cretaceous of South America, the unambiguous presence of Spinosauridae Stromer 1915(sensu Sereno et al. 1998) has only been confirmed in Brazil so far (Martill et al. 1996;Sues et al. 2002;Sales et al. 2016). Compared to those of other theropod dinosaurs, spinosaurid tooth crowns show a reduction in labiolingual compression and distal curvature (e.g., Charig and Milner 1997;Ruiz-Omeñaca et al. 1998), making them superficially similar to those of certain crocodyliforms (e.g., Holtz 1998;Sereno et al. 1998;Rayfield et al. 2007;Amiot et al. 2010). ...
We describe the first crocodyliform tooth found in continental deposits from the Quebrada Monardes Formation (Lower Cretaceous) at Cerro La Isla, Atacama Region, northern Chile. Though the fossil (SGO.PV.1160) is poorly preserved, the enamel surfaces clearly bear tightly-packed apicobasal ridges. Comparisons of SGO.PV.1160 with the dental morphology of taxa that it may belong to suggest a hitherto unknown pholidosaurid or, more likely, notosuchian. Therefore, the tooth crown is here provisionally identified as belonging to an indeterminate mesoeucrocodylian, pending future discoveries of more complete material. This find increases our knowledge of the fauna in the Lower Cretaceous deposits of Cerro La Isla, as well as the importance of the fossil site, since pholidosaurids have not been reported from Chile, while if it proves to be notosuchian, it may represent one of the earliest known taxa of the group in South America, and the entire world.
... Their fossils have been found in South America (Brazil), Africa (particularly North Africa), Europe (Portugal, Spain, England), Asia (China, Thailand, Laos), and Oceania (Australia) (e.g., Kellner and Campos 1996;Benton et al. 2000;Sues et al. 2002;Medeiros 2006;Buffetaut et al. 2008; Barrett et al. 2011;Bittencourt and Langer 2011;Kellner et al. 2011;Hendrickx et al. 2016;, with no occurrences in North America. In Brazil, spinosaurid remains include three species from the northeast: Angaturama limai (Kellner and Campos 1996) and Irritator challengeri (Martill et al. 1996; redescribed by Sues et al. 2002), both from the Romualdo Formation (Albian), as well as Oxalaia quilombensis (Kellner et al. 2011) from the Alcântara Formation (Cenomanian; Góes and Rossetti 2001). performed a reinterpretation of spinosaurids' craniodental features and concluded that Angaturama and Irritator would fall between Baryonychinae and Spinosaurinae regarding their morphological similarities, with Oxalaia closer to other African Spinosaurinae. ...
Despite being poorly known from limited skeletal remains as teeth and a few postcranial material, spino-saurid remains have been reported from two different Lower Cretaceous localities in Brazil, with three officially proposed taxa up to now: Angaturama, Irritator and Oxalaia. Here, we report the first record of a spinosaurid pedal ungual from the Itapecuru Formation, Parnaíba Basin, Lower Cretaceous rocks of Maranhão State. The specimen retains a quite flat ventral surface that is proportionally almost two times broader than its proximal depth, which is a feature also found in Spinosaurus. Moreover, size inferences are made for this immature specimen.
... The Araripe Basin in northeastern Brazil -a region of low socioeconomic status -where 'Ubirajara' was found has suffered from illicit fossil trafficking for decades 4,5 . In fact, some foreign researchers openly admit to having obtained Araripe fossils from commercial sources or fossil dealers (for example, the dinosaur Irritator challengeri, the crocodilian Susisuchus anatoceps and the pterosaurs Ludodactylus sibbicki, Lacusovagus magnificens, Unwindia trigonus and Tupandactylus navigans [6][7][8][9][10][11] ). In one notorious case, researchers even conceded they were "deceived by the fossil dealers" 9 . ...
To the Editor — The dinosaur fossil ‘Ubirajara jubatus’ was allegedly exported from Brazil in 1995 and is currently held by State Museum of Natural History Karlsruhe (SMNK) in Germany. It has attracted the attention of the scientific community not only because of its intrinsic interest but also for the controversy surrounding its export from Brazil, which has put into question the legal and ethical context of this work and led to the removal of the publication. Note that ‘Ubirajara jubatus’ is no longer a valid scientific name due to this retraction, hence its appearance in quotation marks here. ‘Ubirajara’ is far from a unique case of an illegally acquired and exported fossil residing in a foreign museum. The Araripe Basin in northeastern Brazil — a region of low socioeconomic status — where ‘Ubirajara’ was found has suffered from illicit fossil trafficking for decades. In fact, some foreign researchers openly admit to having obtained Araripe fossils from commercial sources or fossil dealers (for example, the dinosaur Irritator challengeri, the crocodilian Susisuchus anatoceps and the pterosaurs Ludodactylus sibbicki, Lacusovagus magnificens, Unwindia trigonus and Tupandactylus navigans). In one notorious case, researchers even conceded they were “deceived by the fossil dealers”. Many of the illicit fossils, some of which are holotypes (specimens used to designate new species), are stored in German museums. Like many other Latin American countries, Brazil adopted rigid laws...
... Fossil discoveries within the past three decades have revealed an unexpected diversity of tetanuran theropod dinosaurs from Cretaceous localities in the Southern Hemisphere landmasses, especially South America (e.g., Bonaparte 1991;Coria and Salgado 1995;Kellner and Campos 1996;Martill et al. 1996;Novas 1997Novas , 1998Novas and Puerta 1997;Kellner 1999;Naish et al. 2004;Makovicky et al. 2005Makovicky et al. , 2012Novas and Pol 2005;Novas et al. 2005Novas et al. , 2008aNovas et al. , 2008bNovas et al. , 2012Coria andCurrie 2006, 2016;Martínez and Novas 2006;Martinelli and Vera 2007;Sereno et al. 2008;Kellner et al. 2011;Porfiri et al. 2011aPorfiri et al. , 2018Agnolín et al. 2012;Apesteguía et al. 2016;Motta et al. 2016Motta et al. , 2020Coria et al. 2020; see reviews in Novas et al. 2013;Ezcurra and Novas 2016). Among the most enigmatic of these predominantly Gondwanan tetanuran clades is Megaraptora, definitively represented in South America by the Argentinean Late Cretaceous species Aerosteon riocoloradensis (Sereno et al. 2008), Megaraptor namunhuaiquii (Novas 1998;Calvo et al. 2004;Porfiri et al. 2007aPorfiri et al. , 2007bPorfiri et al. , 2008Porfiri et al. , 2014Paulina-Carabajal and Porfiri 2018), Murusraptor barrosaensis (Coria and Currie 2016;Paulina-Carabajal and Currie 2017;Aranciaga Rolando et al. 2019), Orkoraptor burkei (Novas et al. 2008a), and Tratayenia rosalesi , as well as multiple taxonomically indeterminate (e.g., Aranciaga Rolando et al. 2015Novas et al. 2019;Ibiricu et al. 2020) or as-yet undescribed (e.g., Porfiri et al. 2011b;Casal et al. 2019;Méndez et al. 2019) specimens. ...
We describe two partial postcranial skeletons belonging to the enigmatic theropod dinosaur clade Megaraptoridae from the Upper Cretaceous (lower Cenomanian-upper Turonian) Bajo Barreal Formation of southern Chubut Province, central Patagonia, Argentina. The specimens are assigned to Megaraptoridae due to their possession of multiple anatomical features that are considered synapomorphies of that predatory dinosaur group, such as a greatly enlarged, laterally compressed ungual of manual digit I that possesses asymmetrical lateral and medial vascular grooves. Overlapping elements of the two skeletons are nearly identical in morphology, suggesting that they probably represent the same taxon, a large-bodied theropod that was previously unknown from the early Late Cretaceous of southern South America. The Bajo Barreal specimens constitute the most ancient unquestionable records of Megaraptoridae from that continent, and exhibit particularly strong osteological resemblances to penecontemporaneous megaraptorids from the Winton Formation of Australia. Phylogenetic analysis recovers the unnamed Bajo Barreal taxon as the earliest-diverging South American megaraptorid and the oldest-known representative of this clade that likely attained a body length of at least seven meters and a mass of at least one metric ton. Overall, the balance of the evidence suggests that megaraptorids originated in eastern Gondwana (Australia) during the Early Cretaceous, then subsequently dispersed to western Gondwana (South America) during the mid-Cretaceous, where they attained substantially larger body sizes, ultimately coming to occupy the apex predator niches in their respective habitats.
In the palaeogeographical context of the opening of the South Atlantic Ocean at the end of the Early Cretaceous, we document here the first microvertebrate fauna recorded from the Aptian deposits of Gadoufaoua, Niger. A systematic study of the fauna has resulted in a significant expansion of the existing faunal list and increase our knowledge of the palaeobiodiversity of the Gadoufaoua fossil site. Some taxa were previously recorded (lungfishes, crocodilians, chelonians, etc.), but several new taxa are described here for the first time, including the first occurrence of a stem-boreosphenidan mammal in Africa for this time-interval. In addition, chondrichthyans, pterosaurs and lissamphibians are documented. The analysis of taxonomic diversity and preservation of the fossils confirms a floodplain depositional environment (more precisely channel-type), in a higher velocity flow regime than previously thought based on studies of the macrofauna. To confirm the depositional environment inferred by the state of preservation of the fossils, a preliminary comparison with the fauna of similar age from the Santana Formation (Brazil) has been undertaken. The hypothesis of a communication between Africa and South America during the Aptian, as had already been demonstrated based on studies of the macrofauna, is strengthened.
Tyrannosaurids are a well-supported clade of very large predatory dinosaurs of Late Cretaceous Asiamerica. Traditional dinosaurian systematics place these animals within the infraorder Carnosauria with the other large theropods (allosaurids, megalosaurids). A new cladistic analysis indicates that the tyrannosaurs were in fact derived members of the Coelurosauria, a group of otherwise small theropods. Despite certain gross cranial similarities with the large predators of the Jurassic and Early Cretaceous, the Late Cretaceous tyrannosaurids are shown to be the sister group to ornithomimids and troodontids, which share a derived condition of the metatarsus. This clade is found to be nested within Maniraptora, which is a more inclusive taxon than previously recognized. The atrophied carpal structure found in tyrannosaurids and ornithomimids is derived from a maniraptoran condition with a large semilunate carpal, rather than from the plesiomorphic theropod morphology.
The taxa “Carnosauria” and “Deinonychosauria” (Dromaeosauridae plus Troodontidae) are shown to be polyphyletic, and the Late Jurassic African form Elaphrosaurus is found to be the sister taxon to Abelisauridae rather than a primitive ornithomimosaur. Purported allosaurid-tyrannosaurid synapomorphies are seen to be largely size-related, present in the larger members of both clades, but absent in smaller members of the Tyrannosauridae. The remaining giant tetanurine theropods (Megalosaurus and Torvosaurus) were found to be progressively distant outgroups to an allosaurid-coelurosaur clade. The inclusion of the Tyrannosauridae within Maniraptora suggests a major adaptive radiation of coelurosaurs within Cretaceous Asiamerica comparable to contemporaneous radiations in various herbivorous dinosaurian clades.
The theropod families Abelisauridae and Noasauridae appear closely related because of shared derived characters such as the short anterior area of the maxilla, the small or absent preantorbital fenestra, the quadrate fused to the quadratojugal, and cervical vertebrae with vestigial neural spines and hypertrophied epipophyses. The families appear linked to Ceratosauridae and are interpreted as Ceratosauria. They are very different from the clade Allosauridae‐Tyrannosauridae as well as from other Laurasian theropods.The geographic distribution of the Abelisauridae possibly includes Africa, India, South America and southern Europe, and they are generally associated with titanosaurid sauropods. It is considered that they are endemic to Gondwana, and the presence of abelisaurids in Europe may be the result of a migratory event from Africa.It is suggested that the Baharija theropods may be more related to the abelisaurs than to the tyrannosaurs.
A major question in Mesozoic biogeography is how the land-based dinosaurian radiation responded to fragmentation of Pangaea. A rich fossil record has been uncovered on northern continents that spans the Cretaceous, when continental isolation reached its peak. In contrast, dinosaur remains on southern continents are scarce. The discovery of dinosaurian skeletons from Lower Cretaceous beds in the southern Sahara shows that several lineages of tetanuran theropods and broad-toothed sauropods had a cosmopolitan distribution across Pangaea before the onset of continental fragmentation. The distinct dinosaurian faunas of Africa, South America, and Asiamerica arose during the Cretaceous by differential survival of once widespread lineages on land masses that were becoming increasingly isolated from one another.