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35-533: The Cerro Fortaleza Formation , in older literature described as Pari Aike Formation , is a Late Cretaceous geologic formation of Campanian to Maastrichtian age (although it has formerly been reported to be Cenomanian to Santonian ) of the Austral Basin in southern Patagonia , Argentina . The sandstones of the formation were deposited in a fluvial environment . The formation has an estimated thickness of 460 metres (1,510 ft) and overlies

70-653: A northward course towards Asia. In the Southern Hemisphere, Australia and Antarctica seem to have remained connected and began to drift away from Africa and South America. Europe was an island chain. Populating some of these islands were endemic dwarf dinosaur species. In the Late Cretaceous, the hadrosaurs , ankylosaurs , and ceratopsians experienced success in Asiamerica (Western North America and eastern Asia). Tyrannosaurs dominated

105-572: A pneumatic opening. Caiuajara was assigned to the Tapejaridae , more precisely the Tapejarinae . It shares several traits with the tapejarids, such as a crest running from the front snout to the back of the head; an elongated nasoantorbital fenestra occupying over 40% of total skull length; and a large boss on the front edge of the coracoid. A typical tapejarine trait is the down-turned snout tip. A cladistic analysis showed that Caiuajara

140-482: A skull and postcrania of at least three juveniles; CP.V 1025: a thighbone; CP.V 1026: a thighbone; CP.V 1450: a slab containing at least fourteen juveniles; CP.V 2003: a skull with lower jaws and articulated wing elements; UEPG/DEGEO/MP-4151: a slab with two skulls and postcrania; and UEPG/DEGEO/MP-4152: a snout with postcrania. Most specimens are part of the collection of the Centro Paleontológico of

175-404: A snout and finger phalanges; CP.V 999: a partial skull; CP.V 1001: a slab with a partial skull, lower jaws and postcrania of at least three individuals; CP.V 1003: a partial skull and symphysis; CP.V 1004: a snout; CP.V 1005: a partial crested skull with the complete mandibula; CP.V 1006: a partial crested skull lacking the snout combined with postcrania; CP.V 1023: a snout and postcrania; CP.V 1024:

210-440: A snout and limb bones; CP.V 868: a snout, wing elements and other postcrania; CP.V 869: a vertebral column, right arm, coracoid, breastbone, wing phalanges, belly ribs, pelvic elements and a right thighbone; CP.V 870: a shoulder girdle with the humeri; CP.V 871: a right shoulder girdle with right arm elements; CP.V 872: s partial skeleton including the skull, lower jaws, right arm, neck vertebrae and additional limb elements; CP.V 873:

245-536: A very different dinosaurian fauna, with most predators being abelisaurids and carcharodontosaurids ; and titanosaurs being among the dominant herbivores. Spinosaurids were also present during this time. Birds became increasingly common, diversifying in a variety of enantiornithe and ornithurine forms. Early Neornithes such as Vegavis co-existed with forms as bizarre as Yungavolucris and Avisaurus . Though mostly small, marine Hesperornithes became relatively large and flightless, adapted to life in

280-459: Is a possible sister species of Tupandactylus . In 2014, Caiuajara was the geologically youngest known tapejarid (aside from the possible tapejarid Bakonydraco galaczi ) and also the most southern one known. This expansion of their known range was seen as an indication that tapejarids had a global distribution. Moreover, Caiuajara is the first pterosaur found in the south of Brazil. A phylogenetic analysis conducted in 2019 by Kellner (one of

315-479: Is it particularly evident that a true systematic decline was ever in place, especially with the discovery of smaller pterosaur species. Several old mammal groups began to disappear, with the last eutriconodonts occurring in the Campanian of North America . In the northern hemisphere, cimolodont , multituberculates , metatherians and eutherians were the dominant mammals, with the former two groups being

350-484: The Universidade do Contestado . The largest individuals of Caiuajara had an estimated wingspan of 2.35 meters (7.7 ft). The species had a large toothless head with, in adult individuals, an enormous shark fin-shaped crest on the snout. The describing authors established several distinguishing unique traits, autapomorphies . The tip of the snout is strongly oriented to below, at 142 to 149°, relative to

385-692: The Anita Formation , while it is overlain by the La Irene Formation . These formations are considered Campanian and Maastrichtian in age, respectively, making the Cerro Fortaleza Formation aged between them. The giant titanosaurs Puertasaurus and Dreadnoughtus , the megaraptoran Orkoraptor , Austrocheirus isasii , and the ornithopod Talenkauen have been recovered from the formation alongside turtles and crocodiles. Late Cretaceous During

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420-564: The Deccan Traps , both of which have been firmly dated to the time of the extinction event. In theory, these events reduced sunlight and hindered photosynthesis , leading to a massive disruption in Earth's ecology . A much smaller number of researchers believe the extinction was more gradual, resulting from slower changes in sea level or climate . Caiuajara Caiuajara is an extinct genus of tapejarid pterosaur from

455-513: The Early Cretaceous period ( Aptian to Albian stages) of Brazil . It is known from a single type species , Caiuajara dobruskii . In 1971, the labourers Alexandre Dobruski and his son João Gustavo Dobruski found pterosaur fossils in a field near Cruzeiro do Oeste in the south of Brazil, in the state of Paraná . The finds were in 2011 brought to the attention of paleontologists Paulo C. Manzig and Luiz C. Weinschütz. In 2014,

490-418: The type species Caiuajara dobruskii was named and described by Paulo Manzig , Alexander Kellner , Luiz Weinschütz , Carlos Fragoso , Cristina Vega , Gilson Guimarães , Luiz Godoy , Antonio Liccardo , João Ricetti and Camila de Moura . The generic name refers to the geological Caiuá Group and the related genus Tapejara . The specific name honors the discoverers. The holotype , CP.V 1449 ,

525-497: The Argentine form Pterodaustro , were by the describers seen as proof of a gregarious lifestyle, Caiuajara living in colonies. The many specimens also allowed to determine a growth series, the first such an ontogenetic sequence for pterosaurs of which it is nearly certain that it really represented a single species. The age of the exemplars can be determined, not just from size but also by the degree of ossification, especially of

560-859: The Cretaceous Period derived from the German name Kreidezeit , and T is the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). The event marks the end of the Mesozoic Era and the beginning of the Cenozoic Era. "Tertiary" being no longer recognized as a formal time or rock unit by the International Commission on Stratigraphy ,

595-850: The K-T event is now called the Cretaceous—Paleogene (or K-Pg) extinction event by many researchers. Non- avian dinosaur fossils are found only below the Cretaceous–Paleogene boundary and became extinct immediately before or during the event. A very small number of dinosaur fossils have been found above the Cretaceous–Paleogene boundary, but they have been explained as reworked fossils , that is, fossils that have been eroded from their original locations then preserved in later sedimentary layers. Mosasaurs , plesiosaurs , pterosaurs and many species of plants and invertebrates also became extinct. Mammalian and bird clades passed through

630-617: The Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Due to plate tectonics , the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia . India maintained

665-455: The attachments of the main flight muscles, are not less developed, attaining a size of 38 to 40% of the humeral shaft length. This suggests that they were precocial , taking wing almost as soon as they hatched; parental care must have been limited. This might have been typical of all derived pterosaurs. The snout crest however, strongly changed during growth. It became much taller and also much more steeply inclined, from about 115° to 90°. Although

700-524: The boundary with few extinctions, and evolutionary radiation from those Maastrichtian clades occurred well past the boundary. Rates of extinction and radiation varied across different clades of organisms. Many scientists hypothesize that the Cretaceous–Paleogene extinctions were caused by catastrophic events such as the massive asteroid impact that caused the Chicxulub crater , in combination with increased volcanic activity , such as that recorded in

735-403: The breastbone, the long bones and the wrist, and the fusion of the shoulder blade and coracoid into a scapulocoracoid . It showed that juvenile individuals, the smallest specimens of which have a wingspan of about 65 centimeters (26 in), generally had the same proportions as adults. Especially important is that their humeri are not proportionally smaller and their humeral deltopectoral crests,

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770-629: The describers of Caiuajara ) and colleagues recovered Caiuajara within the tribe Tapejarini , sister taxon to sister taxon to three other genera: Europejara , Tapejara , and Tupandactylus . Azhdarchidae Chaoyangopteridae Keresdrakon vilsoni Thalassodromeus sethi Tupuxuara leonardii Caupedactylus ybaka Aymberedactylus cearensis Eopteranodon lii "Huaxiapterus" benxiensis "Huaxiapterus" corollatus Sinopterus dongi Europejara olcadesorum Caiuajara dobruskii Tapejara wellnhoferi Tupandactylus imperator The habitat of Caiuajara

805-415: The edge of the upper jaw. The rear ascending branches of the premaxillae on their midline form an elongated bony rim projecting to below into the nasoantorbital fenestra, the large skull opening in the side of the snout. In the concave upper rear of the symphysis, the fronts of the lower jaws grown together, a rounded depression is present. The front outer edge of the quadrate shows a longitudinal groove. Below

840-411: The front part of the nasoantorbital fenestra, a depression is present in the upper jaw edge. Additionally, Caiuajara shows a unique combination of traits that are themselves not unique. The lower edge of the eye socket is rounded. At a maximal occlusion, the gap between the upper and lower jaw is wider than with other tapejarines. The pteroid on its bottom surface shows a conspicuous depression lacking

875-468: The lake was likely inhabited by the pterosaurs for a great length of time, although it is also possible they visited the lake during regular migrations. Fossil plants — tapejarids are often assumed to have been herbivores — have not been found, so there are no direct indications about the food source. Likewise, remains of invertebrates have not been discovered. The large concentrations of fossils, among pterosaurs very rare and only equaled by those found of

910-664: The large predator niche in North America. They were also present in Asia, although were usually smaller and more primitive than the North American varieties. Pachycephalosaurs were also present in both North America and Asia. Dromaeosaurids shared the same geographical distribution, and are well documented in both Mongolia and Western North America. Additionally therizinosaurs (known previously as segnosaurs) appear to have been in North America and Asia. Gondwana held

945-636: The most common mammals in North America. In the southern hemisphere there was instead a more complex fauna of dryolestoids , gondwanatheres and other multituberculates and basal eutherians ; monotremes were presumably present, as was the last of the haramiyidans , Avashishta . Mammals, though generally small, ranged into a variety of ecological niches, from carnivores ( Deltatheroida ), to mollusc-eater ( Stagodontidae ), to herbivores (multituberculates, Schowalteria , Zhelestidae and Mesungulatidae ) to highly atypical cursorial forms ( Zalambdalestidae , Brandoniidae ). True placentals evolved only at

980-540: The numerous teleost fishes, which in turn evolved into new advanced and modern forms ( Neoteleostei ). Ichthyosaurs and pliosaurs , on the other hand, became extinct during the Cenomanian-Turonian anoxic event . Near the end of the Cretaceous Period, flowering plants diversified. In temperate regions, familiar plants like magnolias , sassafras , roses , redwoods , and willows could be found in abundance. The Cretaceous–Paleogene extinction event

1015-407: The open sea. Though primarily represented by azhdarchids , other forms like pteranodontids , tapejarids ( Caiuajara and Bakonydraco ), nyctosaurids and uncertain forms ( Piksi , Navajodactylus ) are also present. Historically, it has been assumed that pterosaurs were in decline due to competition with birds, but it appears that neither group overlapped significantly ecologically, nor

1050-463: The skeleton are present. The bones have been three-dimensionally preserved, not compressed, but are only rarely articulated. The individuals found are often juveniles; adult animals are much rarer, only represented by two skulls and three humeri. Good specimens have been assigned as paratypes , the more fragmentary ones have been referred. The paratypes are: CP.V 865: a snout, rear of the mandibula, right jugal, vertebrae, ribs and metatarsals; CP.V 867:

1085-401: The snout as a whole also became more massive, the snout tip inclination relative to the jaw edge remained the same. At the back of the skull an additional projection developed. Furthermore, the dentary crest on the lower jaw strongly increased in size. No specimens have been found lacking the snout crest, indicating that Caiuajara was in this respect not sexually dimorphic and casting doubt on

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1120-433: The very end of the epoch; the same can be said for true marsupials . Instead, nearly all known eutherian and metatherian fossils belong to other groups. In the seas, mosasaurs suddenly appeared and underwent a spectacular evolutionary radiation. Modern sharks also appeared and penguin-like polycotylid plesiosaurs (3 meters long) and huge long-necked elasmosaurs (13 meters long) also diversified. These predators fed on

1155-412: Was a desert with dunes. The layers in which the fossils were found had been deposited in a lake in the desert; probably the bones had been exposed at the surface around the lake for a time and were then by storms blown into it, eventually sinking to the bottom. Possibly the same storms caused many individuals to die together; this could also have been the result of droughts. A succession of layers shows that

1190-537: Was a large-scale mass extinction of animal and plant species in a geologically short period of time, approximately 66  million years ago (Ma). It is widely known as the K–T extinction event and is associated with a geological signature, usually a thin band dated to that time and found in various parts of the world, known as the Cretaceous–Paleogene boundary (K–T boundary). K is the traditional abbreviation for

1225-533: Was found in a sandstone layer of the Goio-Erê Formation , of Early Cretaceous age, in the Paraná Basin . It consists of a partial skeleton including the skull, lower jaws, neck vertebrae and wing elements. Many hundreds of bones have been discovered, concentrated in several bone beds, and representing at least forty-seven individuals but probably many more. In the total assembly, all elements of

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