Сообщество, посвящённое ра Below are the 18 most recent journal entries recorded in the "Сообщество, посвящённое ра" journal:
April 20th, 2014
04:44 pm
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Gondwanasuchus

 Gondwanasuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous Adamantina Formation of Brazil. The type species is Gondwanasuchus scabrosus.

 80 миллионов лет назад на юго-востоке современной Бразилии обитало множество разнообразных крокодилов. Некоторые из них так вошли в роль сухопутных хищников, что начали всерьез конкурировать с динозаврами-тероподами. Одного из таких "динокроков" описали недавно бразильские палеонтологи.

 Большие глаза, тонкая морда и обнаженные острые зубы – так выглядел при жизни Gondwanasuchus scabrosus, кузен современных крокодилов, принадлежавший крокодиломорфному семейству Baurusichidae. Несмотря на относительно небольшие размеры, он был сильным и прожорливым хищником.

 Отлично сохранившиеся череп и нижнюю челюсть этого животного из бассейна Бауру исследовали профессор федерального университета Triangulo Mineiro (UFTM) Тьяго Марино и научный сотрудник университета Рио-де-Жанейро (UFRJ) Фабиано Иори. По их данным, гондваназух жил на суше, в условиях сухой и жаркой полупустыни. При длине порядка 1,3 метра весил этот сухопутный крокодиломорф около 18 килограммов. Таким образом, он был чуть меньше и в два раза легче современной собаки породы сенбернар.

 Между собой ученые прозвали объект своего исследования "мясником". "Отметим, что его глазницы скошены, и он мог хорошо видеть то, что находится впереди. Сжатые с боков зубы на передней и задней кромках зазубрены наподобие ножа для мяса, так что этот парень вполне оправдывал свое прозвище", рассказал Марино.

 "Высота морды превосходит ее ширину, что типично для сухопутных животных, продолжает палеонтолог. – Такое строение позволяло кусая, отрывать части добычи. Лапы, в отличие от современных настоящих крокодилов, были подведены под тело почти вертикально, что обеспечивало более быстрое передвижение по суше".

 Очень любопытными оказались зубы Gondwanasuchus scabrosus. Они сжаты с боков и зазубрены, приближаясь по форме к зубам некоторых хищных динозавров. Кроме того, они несли несколько вертикальных борозд, повышающих устойчивость к поломке.

 "Он не был похож на крокодилов или аллигаторов, потому что его череп был высоким, а у тех и у других он широкий и низкий. Этот крокодиломорф явно не был водным хищником. Ноздри расположены по бокам черепа, что опять же указывает на сухопутный образ жизни", говорит Марино. Больше всего гондваназух напоминал комодского варана, также ведущего наземный образ жизни и способного отрывать большие куски добычи, откусывая их. Однако, в отличие от комодского варана, гондваназух охотился на мелких животных и, возможно, не брезговал падалью.

 Профессор палеонтологии университета Бразилиа (UnB) Рикардо Пинта объяснил, почему Gondwanasuchus не был динозавром. "Он принадлежит к группе крокодиломорфов, не очень разнообразной, зато дожившей до наших дней. В прошлом сухопутные крокодиломорфы были довольно успешными", сообщил профессор. Открытие очередного ископаемого, по его словам, помогает исследователям реконструировать сценарии прошлого и таким образом лучше представить себе историю развития жизни на Земле. Особенно любопытным оказалось то, что в местности, где обитал гондваназух и еще шесть других видов крокодиломорфов из его семейства, было довольно мало хищных динозавров.

 "Вполне возможно, что крокодиломорфы просто лучше сохранялись в этих местах, и они были более многочисленны, чем плотоядные динозавры. Но разнообразие форм крокодилов и их образ жизни удивили нас. Они занимали самые разные экологические ниши. G. scabrosus, например, имел прекрасное бинокулярное зрение, которое помогало ему точно оценивать расстояние до жертвы перед нападением. Такие адаптации имели и некоторые хищные динозавры. Вполне возможно, что крокодиломорфы вытеснили динозавров из экологической ниши среднеразмерных хищников, и именно поэтому остатки последних так редки в этих местах. Бассейн Бауру в меловом периоде был землей крокодиломорф", подчеркнул, в свою очередь Марино.

 Стоит отметить, что в честь бассейна Бауру было названо семейство сухопутных крокодиломорфов Baurusuchidae, особенно обильных в этом регионе и особенностями строения напоминавших динозавров-тероподов. Ранее бразильские палеонтологи уже описали отсюда четрехметрового Stratiotosuchus maxhechti, охотившегося на своих динозавров, и двухметрового Campinasuchus dinizi с клыками, сделавшими бы честь саблезубому тигру.

 Название рода образовано от древнего суперконтинента Гондвана и греческого слова "suchus" - крокодил. Видовое имя в переводе с латыни обозначает шероховатый или зазубренный.

 Гондваназух был современником титанозавров, которые считаются одними из самых крупных сухопутных животных. Их вес мог достигать 100 тонн. Ископаемые остатки помогают нам восстановить древнюю историю Земли. Например, благодаря тому, что окаменелости некоторых животных находят в разных частях света, мы смогли узнать о распаде Гондваны. Мелкие окаменелости используются геологами, например, при поисках нефти, помогая им в определении возраста горных пород.


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March 30th, 2014
07:03 pm
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Yacarerani

 Yacarerani (meaning "first Yacare" in Guaraní) is an extinct genus of Late Cretaceous notosuchian crocodylomorph. Fossils have been found in 2002 from central Bolivia in Amboró National Park and are Turonian-Santonian in age. The genus was recently described in 2009 in the Journal of Vertebrate Paleontology. The material represents two individuals and was found in association with eggs that are thought to have been part of a nest. Yacarerani was a small crocodylomorph at around 80 centimetres (31 in) in length. It may have lived in small groups, creating burrows to lay eggs in.

 The dentition of Yacarerani, like many other notosuchians, is heterodont, with different tooth morphologies in different parts of the jaws. Two teeth in the lower jaw project forward from the tip, resembling the incisors of a rabbit. Other teeth, situated posteriorly, are cusped and adapted for grinding or chopping food such as tubers or small arthropods. In the lower jaw, the dentary tooth rows merge posterior to the anterior dentary teeth. The same is true for the upper tooth rows, which merge on the palate.

 Yacarerani presents similar teeth morphology to Adamantinasuchus navae, a crocodylomorph from Adamantina Formation, Bauru Group, Brazil.


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05:54 pm
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Stratiotosuchus

 Stratiotosuchus (from Greek, στρατιώτης (stratiōtēs, "soldier") and σοῦχος (suchos, "crocodile")) is an extinct genus of baurusuchid mesoeucrocodylian from the Adamantina Formation in Brazil. It lived during the Late Cretaceous. The first fossils were found in the 1980s, and the type species Stratiotosuchus maxhechti was named in 2001. A hyperpredator, it and other baurusuchids may have filled niches occupied elsewhere by theropod dinosaurs.

 Stratiotosuchus has a deep, laterally compressed skull 470 millimetres (1.54 ft) long. It reached up to 4 metres in length, making it about the same size as Baurusuchus. The teeth are ziphodont, meaning that they are laterally compressed, curved, and serrated. Like other baurusuchids, Stratiotosuchus has a reduced number of teeth: three in its premaxilla and five in its maxilla. When the jaw is closed, the teeth of the upper jaw overlie those of the lower jaw and shear closely together. Stratiotosuchus has one large caniniform tooth in its premaxilla, and several large maxillary teeth behind it. An enlarged fourth dentary tooth in the lower jaw also forms a canine, and is visible when the jaw is closed.

 Like all crocodyliforms, Stratiotosuchus was quadrupedal. Unlike the sprawling gait of crocodilians living today, Stratiotosuchus is thought to have been a fully erect quadruped. The transition from a sprawling, low to the ground posture in the ancestors of Stratiotosuchus to an erect, elevated posture involved a significant transformation of the limbs, hips, and shoulders.

 Large crests are present over the acetabulum, or hip socket, stabilizing the hip in what is known as a pillar-erect stance (the acetabular crest lies like a shelf on top of the femur to form a pillar). The ischium bone, which extends backward from the hip, has a large projection that in life would serve as a strong attachment site for the puboischiotibialis muscle. The puboischiotibialis is also present in living crocodilians and is used primarily to keep the legs upright in what is known as a high walk, in which they hold their legs underneath them while walking. The puboischiotibialis is very weak in living crocodilians, so they cannot sustain a high walk for very long. Stratiotosuchus is thought to have had a much stronger puboischiotibialis, allowing it to have a permanent upright stance.

 Stratiotosuchus also has a relatively straight femur bone; while the bone is somewhat twisted along its length, the degree of torsion is not as high as that of other crocodyliforms. The shape of the femur is more similar to that of rauisuchids and poposaurids, which were early crocodile relatives that are known to have had erect gaits. The femur even shares similarities with those of early theropod dinosaurs, which were fully bipedal. When compared to crocodilians, the top of the femur of Stratiotosuchus is rotated toward the front, so that the femoral head faces backward rather than medially inward. This position restricts the movement of the hindlimbs along a forward-backward or parasagittal axis. Muscles that attach to the side of the leg in crocodilians would have attached to the back of the leg in Stratiotosuchus, enabling a powerful backward extension of the hind leg.

 The arm socket faces backwards and downwards from a bone in the shoulder girdle called the coracoid, suggesting that the arms were held beneath the body. The large articular surface on the head of the humerus implies that the arms had a wide range of movement, but restricted to a parasagittal axis. The deltopectoral crest on the front of the humerus would have anchored large arm muscles to bring the arm forward while walking. Modern crocodilians also have a deltopectoral crest, but it is positioned laterally and anchors to muscles that pull the arms up to the sides, not forward. The muscle thought to have facilitated forward movement in Stratiotosuchus is called the deltoideus clavicularis; it is also present in modern crocodilians, which use it for high walking.

 Other features that suggest an erect posture are tightly clustered metacarpals forming narrow hands well-suited for walking and a backward-projecting calcaneal tuberosity in the ankle, which would have attached to muscles that fixed the lower limb in a parasagittal axis. A backward-projecting calcaneal tuberosity is present in most early crocodilian relatives, including those that are thought have sprawling gaits, yet modern crocodilians have more laterally projected tuberosities impeding a parasagittal orientation of the hind foot.

 The first known fossil of Stratiotosuchus was a nearly complete skeleton, cataloged as DGM 1477-R. It was found by paleontologist José Martin Suárez in the town of Irapuru in São Paulo State in 1988. This skeleton and all other specimens of Stratiotosuchus come from the Adamantina Formation, which is either Turonian-Santonian in age (about 85 million years old) or Campanian-Maastrichtian in age (about 70 million years old). DGM 1477-R includes a nearly complete skull, partial lower jaw, vertebral column, and limb bones. The skeleton was identified as that of a baurusuchid, closely related but distinct from Baurusuchus pachechoi, which had been known since 1945. Stratiotosuchus maxhechti was named in 2001 on the basis of this skeleton, designated the holotype of the species. Stratiotosuchus means "soldier crocodile" in Greek, and the species name honors paleontologist Max K. Hetch.

 Further preparation of DGM 1477-R revealed that two individuals were present in the same block of sandstone, as indicated by two extra leg bones, an extra fragment of the hip, and extra metatarsals. They are the same size as the other bones, suggesting that the second individual was equal in body size to the first.

 Stratiotosuchus has been recognized as a baurusuchid since it was first described in 1988. In 2004, Baurusuchidae was even defined as the most recent common ancestor of Baurusuchus and Stratiotosuchus and all of its descendants; thus, the definition of Baurusuchidae relies on the inclusion of Stratiotosuchus. Stratiotosuchus and Baurusuchus both belong to a large clade called Metasuchia, which includes living crocodilians and many extinct relatives extending back into the Jurassic. However, the exact position of Stratiotosuchus and Baurusuchus within Metasuchia is still uncertain. Below are several possibilities that have been uncovered in various phylogenetic analyses:

 Baurusuchidae is grouped with the family Sebecidae in a clade called Sebecosuchia.

 Sebecids are closer to Neosuchia (the group including modern crocodilians), while baurusuchids are either basal metasuchians or deeply nested within Notosuchia, a large clade of extinct metasuchians.

 Baurusuchidae is polyphyletic, with Stratiotosuchus and Baurusuchus positioned as basal metasuchians while other baurusuchids are placed in the clade Sebecia along with sebecids. This also makes Sebecosuchia polyphyletic.

 Montefeltro et al. (2011) found support for baurusuchids as advanced notosuchians, and divided the family into two subfamilies, Baurusuchinae and Pissarrachampsinae. Stratiotosuchus belonged to Baurusuchinae along with Baurusuchus.

 Another phylogenetic analysis of baurusuchids was conducted by Riff and Kellner (2011). Their analysis placed Stratiotosuchus and Baurusuchus deep within Notosuchia, as the sister taxon of the family Sphagesauridae.

 Based on the types of deposits in the Adamantina Formation, Stratiotosuchus most likely lived alongside a river system with many small ephemeral lakes.

 With a fully erect stance, Stratiotosuchus has many features convergent with theropod dinosaurs, which are fully bipedal. In Stratiotosuchus, a roughly surfaced region on the upper part of the femur is analogous to the accessory trochanter common to tetanuran theropods. These projections are thought to have anchored the same muscle, called the puboischiofemoralis internus pars dorsalis. A crest on the forward edge of the tibia is similar to those seen in early theropod dinosaurs. The articular surface of the tibia that attaches to the femur is laterally compressed, which is unlike the more circular surface in living crocodilians and more like that of a theropod dinosaur. On the hip of Stratiotosuchus, a depression on the ilium is convergent with the brevis fossa of dinosaurs, and the small bump anchoring the puboischiotibialis muscle is convergent with the obturator tubercle of maniraptoriform theropods.

 Along with anatomical similarities, Stratiotosuchus and other baurusuchids are thought to have had lifestyles very similar to those of theropod dinosaurs. While many small carnivorous crocodyliforms are known from the Adamantina Formation, Stratiotosuchus and Baurusuchus are believed to have been the only large carnivores the Adamantina ecosystem. Decades of paleontological exploration in these deposits have uncovered only a few theropod dinosaur bones, so it appears that baurusuchids like Stratiotosuchus occupied the niche of top predators in the absence of these dinosaurs. A nearby Cretaceous deposit in Argentina called the Neuquén Group also contains baurusuchids, but they are much smaller than Stratiotosuchus and were likely out-competed by the wide range of theropod dinosaurs known from these deposits. In the absence of large theropods, carnivores like Stratiotosuchus may have fed on large herbivorous titanosaurs, including Adamantisaurus, Aeolosaurus, Gondwanatitan, and Maxakalisaurus.

 Pseudosuchians superficially resembling Stratiotosuchus were the top predators of the Triassic period, until they were decimated by the Triassic–Jurassic extinction event and replaced by large theropods. The appearance of Stratiotosuchus and other baurusuchids marks a brief recovery of this top position during the Late Cretaceous.


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05:41 pm
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Uruguaysuchus

 Uruguaysuchus is an extinct genus of crocodylomorph from the Late Cretaceous of Uruguay. It was related to Simosuchus and Malawisuchus. It was of small to moderate size reaching a length of 120 cm.

 Type specimen: CA (unnumbered), a partial skeleton (A complete skull, mandible, right forelimb, 18 vertebrae, both ilia and partial right hindlimb, as well as a few associated osteoderms). Its type locality is Guichón (water well), which is in an Aptian/Santonian fluvial sandstone in the Guichón Formation of Uruguay.

 Uruguaysuchus is a small mesoeucrocodylian known from several partial skeletons and skulls from the Guichón Formation (middle Cretaceous, Uruguay). Several authors have pointed out derived similarities of this taxon with different basal notosuchian genera, highlighting its importance for mesoeucrocodylian phylogeny and biogeography. However, the holotype is only partially prepared and has not been available for study for many years. Thus, phylogenetic studies have included this form based on the original description, thereby resulting in a large amount of missing data in the character scorings of this taxon. Here, we describe a new specimen from the type locality consisting of a partial skull, lower jaw and cervical vertebrae which can be referred to U. aznarezi. The new specimen allows for the recognition and scoring of several characters previously unknown for this taxon, thus providing a more extensive diagnosis, as well as new information for understanding its phylogenetic relationships. These characters are congruent with the morphology present in basal notosuchians. The relationships of Uruguaysuchus are tested through a cladistic analysis using a recently published data set including the new information. The phylogenetic results differ from previous analyses, recovering this taxon as the sister group of the Araripesuchus clade. U. terrai is considered a juvenile individual of U. aznarezi.


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March 26th, 2014
10:41 am
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Simosuchus

 Simosuchus (meaning "pug-nosed crocodile" in Greek, referring to the animal's blunt snout) is an extinct genus of notosuchian crocodylomorphs from the Late Cretaceous of Madagascar. It is named for its unusually short skull. Fully grown individuals were about 0.75 metres (2.5 ft) in length. The type species is Simosuchis clarki, found from the Maevarano Formation in Mahajanga Province.

 The teeth of S. clarki were shaped like cloves (maple leaves), which coupled with its short and deep snout suggest it was not a carnivore like most other crocodylomorphs. In fact, these features have led many palaeontologists to consider it an herbivore.

 Simosuchus was small, about 0.75 metres (2.5 ft) long based on the skeletons of mature individuals. In contrast to most other crocodyliforms, which have long, low skulls, Simosuchus has a distinctively short snout. The snout resembles that of a pug, giving the genus its name, which means "pug-nosed crocodile" in Greek. The shape of skulls differs considerably between specimens, with variation in ornamentation and bony projections. These differences may be indications of sexual dimorphism. The front portion of the skull, or preorbital area, is angled downwards. Simosuchus likely held its head so that the preorbital area was angled about 45° from horizontal. The teeth line the front of the jaws and are clove-shaped. At the back of the skull, the occipital condyle (which articulates with the neck vertebrae) is downturned. 45 autapomorphies, or features unique to Simosuchus, can be found in the skull alone.

 In most respects, the postcranial skeleton of Simosuchus resembles that of other terrestrial crocodyliforms. There are several differences, however, that have been used to distinguish it from related forms. The scapula is broad and tripartite (three-pronged). On its surface, there is a laterally directed prominence. The deltopectoral crest, a crest on the upper end of the humerus, is small. The glenohumeral condyle of the humerus, which connects to the pectoral girdle in the shoulder joint, has a distinctive rounded ellipsoid shape. The limbs are robust. The radius and ulna of the forearm fit tightly together. The front feet are small with large claws, and the back feet are also reduced in size. There is a small crest along the anterior edge of the femur. On the pelvis, the anterior process of the ischium is spur-like.

 Most of the spinal column of Simosuchus is known. There are eight cervical vertebrae in the neck, at least fifteen dorsal vertebrae in the back, two sacral vertebrae at the hip, and no more than twenty caudal vertebrae in the tail. The number of vertebrae in the tail is less than that of most crocodyliforms, giving Simosuchus a very short tail.

 Like other crocodyliforms, Simosuchus was covered in bony plates called osteoderms. These form shields over the back, underside, and tail. Unusually among crocodyliforms, Simosuchus also has osteoderms covering much of the limbs. Osteoderms covering the back, tail, and limbs are light and porous, while the osteoderms covering the belly are plate-like and have an inner structure resembling spongy diploë. Simosuchus has a tetraserial paravertebral shield over its back, meaning that there are four rows of tightly locking paramedial osteoderms (osteoderms to either side of the midline of the back). To either side of the shield, there are four rows of accessory parasagittal osteoderms. These accessory osteoderms tightly interlock with one another.

 The first specimen of Simosuchus clarki, which served as the basis for its initial description in 2000, included a complete skull and lower jaw, the front of the postcranial skeleton, and parts of the posterior postcranial skeleton. Five more specimens were later described, representing the majority of the skeleton. Many isolated teeth have also been found in the Mahajanga Basin. Most remains of Simosuchus were found as part of the Mahajanga Basin Project, directed by the Université d'Antananarivo and Stony Brook University. Material was usually found in clays that were part of flow deposits in the Anembalemba Member of the Maevarano Formation.

 Simosuchus was first considered to be a basal member of the clade Notosuchia, and was often considered to be closely related to Uruguaysuchus from the Late Cretaceous of Uruguay and Malawisuchus from the Early Cretaceous of Malawi. Later phylogenetic studies have placed it closer to the genus Libycosuchus and in a more derived position than some other notosuchians such as Uruguaysuchus. In its initial description by Buckley et al. (2000), Simosuchus was placed in the family Notosuchidae. Its sister taxon was Uruguaysuchus, and the two were allied with Malawisuchus. These taxa were placed in Notosuchidae along with Libycosuchus and Notosuchus. Most of the following phylogenetic analyses resulted in a similar placement of Simosuchus and other genera within Notosuchia. Turner and Calvo (2005) also found a clade including Simosuchus, Uruguaysuchus, and Malawisuchus in their study.

 The phylogenetic analysis of Carvalho et al. (2004), based on different character values than previous studies, produced a very different relationship among Simosuchus and other notosuchians. Simosuchus, along with Uruguaysuchus and Comahuesuchus, were placed outside Notosuchia. Simosuchus was found to be the sister taxon of the Chinese genus Chimaerasuchus in the family Chimaerasuchidae. Like Simosuchus, Chimaerasuchus has a short snout and was probably herbivorous. Both genera were placed outside Notosuchia in the larger clade Gondwanasuchia. Uruguaysuchus, previously considered to be a basal notosuchian and a close relative of Simosuchus, was placed in its own family, Uruguaysuchidae, also outside Notosuchia. Malawisuchus was found to be a member of Peirosauroidea, specifically a member of the family Itasuchidae.


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10:09 am
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Pissarrachampsa

 Pissarrachampsa (meaning "piçarra [the local name for the sandstones it was recovered from] crocodile") is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It is based on a nearly complete skull and a referred partial skull and lower jaw from the CampanianMaastrichtian-age Vale do Rio do Peixe Formation of the Bauru Group, found in the vicinity of Gurinhatã, Brazil.

 Pissarrachampsa is known from a nearly complete holotype skull with the tip of the snout eroded away. The end of the snout and the bottom of the palate are also represented by a second fossil. Like other baurusuchids, it has a deep skull that narrow in front of the eyes and wider at the back, giving it a roughly triangular shape when viewed from above. The snout is not as narrow as other related baurusuchids, however. At around 70% the length of the entire skull, the snout is also short in comparison to those of other crocodyliforms. Like other baurusuchids, Pissarrachampsa has an enlarged caniniform tooth in the upper jaw. Including the enlarged caniniform, there are four teeth implanted in the maxilla, less than other baurusuchids. A groove extends behind the last of the maxillary teeth. While other baurusuchids have more teeth implanted this groove, Pissarrachampsa likely lost these teeth, giving it a reduced dentition. A deep notch between the maxillae and premaxillae provides room for an enlarged fourth dentary tooth in the lower jaw when the mouth is closed. Another large dentary tooth fits into a hole at the back of the upper jaw. Except for the fourth dentary tooth, no teeth in the lower jaw are visible when the mouth is closed.

 The nostrils are positioned at the tip of the snout and face forward. They are found in a depressed region called the circumnarial fossa. Thick palpebral bones overly the eyes. The supratemporal fenestrae, two large holes on the skull roof, are almost the same size as the eye sockets and are roughly triangular in shape. The thick anterior and medial rims of the supratemporal fenestrae are a diagnostic feature of Pissarrachampsa. At the back of the skull are four quadrate fenestrae, small depressions that Pissarrachampsa shares with other notosuchians. In Pissarrachampsa, these fenestrae are visible when the skull is viewed from the side, but in other baurusuchids, they are hidden within a deep notch in the back of the skull. The pterygoid wings extend down from the bottom of the skull as two large triangular pieces of bone. A deep depression on each wing serves as another diagnostic characteristic of the genus. Another unique feature can be found underneath the back of the skull; four holes called Eustachian foramina provide an opening for the Eustachian tubes, and in Pissarrachampsa the outer or lateral pair are larger than the inner or medial pair.

 Интересную находку удалось обнаружить простому муниципальному служащему из маленького городка в одном из бразильских штатов Минас-Жерайс еще в 2008 году. Ранее этой находкой никто не интересовался. Но недавно об этом узнали палеонтологи из Университета Сан-Паулу и канадского Университета Макгилла.
Когда ученые увидели окаменелый скелет, они поняли, что это необычный представитель отряда крокодиломорф. В ходе детального изучения останков, было установлено, что их возраст составляет более 70 миллионов лет, а найденный вид принадлежит к семейству баурузухид (Baurusuchidae). Еще одним интересным моментом, который привлек внимание ученых, было то, что голова найденного крокодила, больше походила на голову собаки, чем на голову современных крокодилов.

  Стоит отметить, что наука уже давно признала большие различия между представителями семейства баурузухид и другими крокодиломорфами. До недавнего времени баурузухии были прекрасно изучены и описаны во многих трудах по палеонтологии. Но теперь, ученые получили целый череп крокодила, принадлежавшего к неизвестному ранее виду. Этого представителя корокодиломорф назвали Pissarrachampsa sera.

  Со слов одного из ученых проводивших исследования останков этого ископаемого Ханса Ларсона стало понятно, что современная наука не располагает глубокими знаниями об этом виде, а лишь только предположениями об их анатомическом строении и способе жизни. На основе анализа данных полученных в ходе исследования останков крокодиломорфа, ученые предположили, что представители семейства баурузухид были высокого роста, имели увеличенные клыки в пасти и долговязое, подвижное тело.
 
  Кроме того, было сделано предположение о том, что способ жизни этих животных напоминал способ жизни диких собак. К такому выводу ученые пришли после детального изучения количества и размеров зубов. Эти крокодиломорфы могли охотиться на животных такого же размера, что и они сами, примерно от 4 до 6 метров в длину. Данные животные благодаря своему стереоскопическому зрению, могли точно определить расстояние до жертвы, а затем догнать ее на своих удлиненных ногах.

  Нельзя оставить без внимания и другие предположения ученых, о том, что найденные останки могли принадлежать динозавру. Но такое предположение крайне сомнительно, поскольку найденный череп имеет признаки, характерные для крокодиломорф позднего мелового периода.

 После сравнения Pissarrachampsa sera с другими баурузухиями, палеонтологи обнаружили большие отличия в строении нового вида. "Мы имеем дело с исключительно далеко расходящимися линиями крокодиловых. Предстоит найти еще много окаменелостей, чтобы связать этого крокодиломорфа с его предшественниками и потомками в процессе эволюции”, – убежден один из авторов исследования Фелипе Монтефельтро (Felipe Montefeltro).


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March 24th, 2014
09:26 pm
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Pakasuchus

 Pakasuchus kapilimai  — ископаемый крокодиломорф, который был найден в восточной Африке.

 Останки рептилии (скелет и череп) найдены при раскопках в рифтовой долине Руква на юго-западе Танзании (Rukwa Rift Basin). Возраст оценивается от 80 до 110 миллионов лет назад. Находка была сделана ещё в 2008 году во время совместной международной экспедиции, созданной при поддержки Национального научного фонда США и Национального географического общества как часть проекта Rukwa Rift Basin Project.

 Длина этого крокодиломорфа составляла около полуметра. Предположительно паказух питался насекомыми. Большую часть своего времени этот ящер проводил на суше, о чём говорит расположение ноздрей (они находятся спереди черепа, а не сверху, как у современных крокодилов). Уникальным отличием от современных рептилий является чёткое дифференцирование зубов.

 Pakasuchus is a genus of notosuchian crocodyliform distinguished by its unusual mammal-like appearance, including mammal-like teeth that would have given the animal the ability to chew. It also had long, slender legs and a doglike nose. Pakasuchus lived approximately 105 million years ago, in the mid-Cretaceous. Fossils have been found from the Rukwa Rift Basin of southwestern Tanzania, and were described in 2010 in the journal Nature. The type species is P. kapilimai. Pakasuchus means "cat crocodile" (paka meaning "cat" in Kiswahili) in reference to its cat-like appearance and probable behavior.

 Pakasuchus was around 50 centimetres (20 in) long. Like all notosuchians, it was an active terrestrial animal. It probably hunted small prey such as insects. It had a short, broad skull somewhat similar in shape to a cat. Unlike living crocodilians, Pakasuchus had distinctive heterodont teeth that varied in shape throughout its jaws. There are large, sharp teeth near the front of the jaws, and broad molar-like teeth at the back of the mouth. While multicuspid teeth are seen in many other notosuchians such as Simosuchus and Yacarerani, they are most complex in Pakasuchus. The molar-like teeth show a level of complexity that matches that of mammals, being able to occlude, or fit with one another, and provide sharp shearing edges for slicing food.

 Pakasuchus also differed from modern crocodilians, and many other crocodyliforms, in the reduction of osteoderms covering the body. Small, reduced osteoderms overlie the dorsal vertebrae, but fewer in number and are not as large as those of other notosuchians. However, caudal osteoderms still covered the tail. The loss of osteoderms on the body and retention of them on the tail is unique among crocodyliforms.

 А complete skeleton of Pakasuchus was found in 2008 in southwestern Tanzania by an international research team funded by the National Science Foundation and the National Geographic Society as part of the Rukwa Rift Basin Project. Remains from six other individuals were later uncovered. The specific name honors Saidi Kapilima, one of the leaders of the Rukwa Rift Basin Project and who helped in the excavation of the specimens.

 The most complete specimen includes a nearly complete skull. Because the jaws were closed in this specimen, some of the teeth were obscured. The describers of the specimens used X-ray computed tomography scanning, or CT scanning, to image the teeth. This provided a detailed view of the animal's dentition that could not normally be observed in the  complete skeleton of Pakasuchus was found in 2008 in southwestern Tanzania by an international research team funded by the National Science Foundation and the National Geographic Society as part of the Rukwa Rift Basin Project. Remains from six other individuals were later uncovered. The specific name honors Saidi Kapilima, one of the leaders of the Rukwa Rift Basin Project and who helped in the excavation of the specimens.

 The most complete specimen includes a nearly complete skull. Because the jaws were closed in this specimen, some of the teeth were obscured. The describers of the specimens used X-ray computed tomography scanning, or CT scanning, to image the teeth. This provided a detailed view of the animal's dentition that could not normally be observed in the specimen.

 Pakasuchus was probably very mammal-like in behavior as well as appearance. The molariform teeth are well suited to shearing food like modern mammalian carnivores. In fact, the teeth are so similar to those of mammals that it has led paleontologist Greg Buckley to state "If only isolated teeth had been discovered, without the skull, it is very likely that some of the molariform teeth would have been mistaken for a mammal's."

 The relative lack of osteoderms on the body may have been an adaptation for an active terrestrial lifestyle, as it would have lightened the animal. However, the retention of osteoderms on the tail is hard to explain, as they would have been quite heavy. The long legs and slender build would also have made Pakasuchus more agile.

 Notosuchians were widespread across Gondwana throughout the Cretaceous. Pakasuchus, as well as many other notosuchians, would have filled ecological niches in these areas that were otherwise occupied by mammals in the northern continents. Mammals were relatively uncommon in Gondwana at the time, making it possible for notosuchians to occupy a similar niche.

 The Rukwa Rift Basin is known for a rich vertebrate fauna that existed during the Cretaceous. During the Early Cretaceous, the basin was part of a large river system with braided channels and low-lying vegetated floodplains. Several dinosaurs are known from the basin that would have lived alongside Pakasuchus, including large sauropods and theropods. Aquatic crocodyliforms inhabited the rivers along with turtles and fishes.

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08:58 pm
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Notosuchus

 Notosuchus (/ntəˈsjuːkəs/; 'southern crocodile') is an extinct genus of South American notosuchian crocodylomorph. It was terrestrial, living approximately 85 million years ago in the Coniacian or Santonian stages of the Late Cretaceous.

 Notosuchus was relatively small, reaching 1.5 m (5 ft) in length and a weight of 36 kg. Remains have been found in the Bajo de la Carpa Formation in Patagonia, Argentina. First named in 1896, Notosuchus was the first known notosuchian. The type species is N. terrestris. A second species, N. lepidus, was named in 1957.

 A paper published in 2008 by Fiorelli and Calvo described new remains of the type species N. terrestris. In it, the authors suggested that the skull would have supported a short trunk, or "hog's snout" as well as fleshy upper and lower lips. The anteriorly directed nares and the absence of a bony nasal septum (which presumably indicates cartilaginous tissue serving its place) provide evidence for a trunk-like snout, while striations on the surface of the nasal bones and the lower jaw most likely acted as attachment points for the nasolabial muscles and the depressor muscle, respectively. Additionally, the authors suggested that a lateral rim on the dentary as well as numerous aligned neurovascular foramina are evidence of soft cheek-like muscular tissue. The function of the trunk was likely used for searching for food by sniffing the ground in a manner similar to extant suids and peccaries, while the cheeks would aid in mastication by preventing food loss.


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March 23rd, 2014
07:53 pm
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Morrinhosuchus

 Morrinhosuchus is an extinct genus of notosuchian crocodyliform from the Late Cretaceous Adamantina Formation of Brazil. It is known from a mandible and a portion of the front of the skull collected from the municipality of Monte Alto in São Paulo state. Morrinhosuchus refers to Morrinho de Santa Luzia, a hill nearby the collection site of the holotype, while luziae refers to the chapel of Santa Luzia, which is located on top of the hill.

 The skull and jaws are posteriorly broad but narrow significantly toward the front. The teeth at the back of the jaw are bulbous in shape and circular in cross-section (this shape is only found in one other notosuchian, Mariliasuchus, also from the Adamantina Formation). The mandible arches upward. The symphysis, or area where the two sides of the lower jaw meet, is formed mostly by the mandibles but also partly by the splenials. The skull preserves an antorbital fenestra, or opening in front of the eyes. The nasal, a bone at the top of the skull behind the nostrils, is relatively long. There is also a small notch at the contact between the premaxilla and the maxilla near the front of the snout.

 Morrinhosuchus can be distinguished from Mariliasuchus on the basis of several unique features. For example, there is a gap between the maxilla and the palatine bone around the midline of the palate. The palate itself is also wider than that of Mariliasuchus. While the teeth of the two genera are very similar, their number and placement in the jaw differs slightly. Morrinhosuchus has seven post-caniniform teeth while Mariliasuchus has only six. There are also differences in the shape of the rostrum between the two genera, as Morrinhosuchus has a higher, more pointed snout with less constriction than in Mariliasuchus.

 The Adamantina Formation, which is Turonian to Santonian in age, was deposited in semi-arid conditions around 95 million years ago. Morrinhosuchus was found in an outcrop of reddish sandstone with carbonate nodules, concretions, and areas of intense bioturbation. The Adamantina Formation is part of the larger Bauru Basin, from which several other notosuchians have been found. These include Sphagesaurus, Mariliasuchus, Adamantinasuchus, Armadillosuchus, and Baurusuchus.


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06:48 pm
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Mariliasuchus

 Mariliasuchus ("Marilia crocodile") is an extinct genus of Late Cretaceous notosuchian mesoeucrocodylian found near Marilia, Brazil. The first bone remains were found and collected in 1995 by Brazilian paleontologist William Nava, in red rocks from Adamantina Formation. Four years later, it was described as "Mariliasuchus amarali", by Brazilian palaeontologists Ismar de Souza Carvalho and Reinaldo J. Bertini.

 Its type species M. amarali, in honour of Sérgio Estanislaw do Amaral, Brazilian naturalist. A second species, M. robustus, was named in 2007.

 Several specimens of M. amarali have been found close to eggs, eggshells and coprólites to date:

  • UFRJ DG 50-R (holotype): a partially complete and articulated skeleton, including a nearly complete skull and partially preserved axial and appendicular skeletons. It belongs to a juvenile specimen.
  • UFRJ DG 105-R
  • UFRJ DG 106-R
  • MZSP-PV 50
  • MZSP-PV 51
  • MN 6298-V
  • MN 6756-V
  • URC R 67
  • URC R 68
  • URC R 69
  • MPM 114 Ic V - 4 eggs
  • MPM 115 R
  • MPM 116 R
  • MPM 117 R
  • MPM 119 R

 Abbreviations:

  • UFRJ - Universidade Federal do Rio de Janeiro, Brazil
  • MZSP - Museu de Zoologia da Universidade de São Paulo, Brazil
  • MN - Museu Nacional, UFRJ, Brazil
  • URC - Museu de Paleontologia e Estratigrafia "Prof. Dr. Paulo Milton Barbosa Landim" Unesp, Rio Claro, SP, Brazil
  • MPM - Museu de Paleontologia de Marília, SP, Brazil
  •  All of these specimens have been recovered in a road cut, 10 km south from the city of Marilia, in outcrops known as "Estrada Velha" pto. 1 and 2. They come from the upper part of the Adamantina Formation, indicating a Late Cretaceous (possibly Campanian/Maastrichtian) age.

     A phylogenetic analysis done by Zaher et al. (2006) found Mariliasuchus amarali to share a close relationship with Comahuesuchus. Andrade et al. (2006), while studying the palate and choanae of some mesoeucrocodylians, reached this same conclusion. Though no name was given to this clade in either publication, it is referred in this article as Comahuesuchidae.

     Mariliasuchus, unlike modern crocodylians, was an animal of terrestrial habits (though see below). Its nostrils were located on the front of the skull, unlike modern crocodiles, in which the nostrils face upwards, to help the animal breathe while its almost completely submerged. Furthermore, the eyes in M. amarali are faced laterally (in modern crocodiles they face upwards). It had a very modified dentition, differentiated in incisiforms, caniforms and molariforms. Strangelly, in particular, were the anterior-most teeth, which were directed horizontally rather than vertically. The function of this strange arrangement is not yet clear, but Vasconcellos et al. (2002) made comparisons with the dentition of pigs, indicating that their dietary preferences may be convergent. It also had strong jaw muscles, indicating a good degree of mandibular activity.

     There seems to be a significant degree of variation between specimens of M. amarali. Some of this is related to ontogenetic variation, but some may also suggest sexual dimorphism, or even that some of the specimens assigned to this species belong to a different animal.

     Ontogenetic studies done by Vasconcellos and Carvalho (2005) concluded that during its growth, the skull of M. amarali individuals becomes shorter and the skull more resistant, while being laterally compressed. In adulthood, the orbit has a less circular arrangement than in younger individuals.

     The postcranial skeleton of Mariliasuchus amarali displays a mixture of traits similar to those present in the skeleton of Cretaceous terrestrial crocodyliform Notosuchus and traits present in aquatic eusuchian crocodyliform, including living crocodilians. Nobre and Carvalho (2013) inferred that Mariliasuchus did not have an erect or semi-erect posture, but rather a sprawling posture and, possibly, had amphibian habits similar to those of living crocodilians.

     Notosuchidae is a Gondwanan family of notosuchians. They were small-bodied terrestrial crocodyliforms that lived during the Late Cretaceous.


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    06:28 pm
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    Comahuesuchus

     Comahuesuchus is an extinct genus of notosuchian crocodylomorph from the Late Cretaceous of Argentina. It was described by palaeontologist José Bonaparte in 1991.

     The type species is C. brachybuccalis.

     The holotype of C. brachybuccalis is MUCPv-202.

     Comahuesuchus is the name-sake of the clade Comahuesuchidae. Sereno et al. (2003) suggested that Comahuesuchus and Anatosuchus are both comahuesuchids, but work by Martinelli and Andrade et al. (2006), has suggested that A. minor is not a comahuesuchid. Comahuesuchus seems instead to be more closely related to Mariliasuchus.


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    March 16th, 2014
    06:44 pm
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    Chimaerasuchus

     Chimaerasuchus ("chimera crocodile") is an extinct genus of Chinese crocodyliform from the Early Cretaceous. The four teeth in the very tip of its short snout gave it a "bucktoothed" appearance. Due its multicusped teeth and marked heterodonty, it is believed to have been an herbivore.

     Древние крокодилы, обитавшие на нашей планете вместе с динозаврами, были куда более широко распространены, чем сейчас. В те далекие времена среди них встречались и огромные океанические формы с плавательными перепонками на лапах, и наземные формы с длинными конечностями, которые могли бегать за своей добычей и даже лазать на деревья. Недавние находки ученых свидетельствуют о том, что в те времена жили на Земле даже крокодилы-вегетарианцы.

     Несколько лет назад в Китае были обнаружены останки мелкого крокодила мелового периода, который получил латинское имя Chimaerasuchus (крокодил-химера) благодаря своим весьма причудливым широким и тупым зубам, которые больше напоминали коренные зубы млекопитающих. Такие зубы да еще короткая тяжелая морда позволили предположить, что рептилия питалась растениями. В скором времени были сделаны и другие подобные находки. Другой крокодил мелового периода, найденный на Мадагаскаре и названный Simosuchus (от греч. simo – свиной нос, пятачок), обладал коротким квадратным рылом и округлыми зубами с зубчатым краем. Подобные зубы встречались у растительноядных динозавров, а сейчас их можно увидеть у игуан.

     Совершенно не удивительно, что в меловом периоде с его огромным разнообразием хищных рептилий некоторые крокодилы небольших размеров «решили», напротив, стать вегетарианцами. Хотя при этом им пришлось избегать встреч со своими более крупными и кровожадными сородичами.

     Chimaerasuchidae ("Chimera crocodiles") is a family of mesoeucrocodylians. It was erected as a clade in 2004 by Carvalho et al and included Chimaerasuchus from the Early Cretaceous of China and Simosuchus from the Late Cretaceous of Madagascar. The validity of the clade has been questioned in later studies that found the two genera to be more distantly related.

     In the phylogenetic analysis of Carvalho et al, the family contained Chimaerasuchus and Simosuchus, two genera of small (~1 metre long), possibly herbivorous crocodyliforms from the Cretaceous. Both had short-snouted heads with multicusped teeth. Carvalho et al placed Chimaerasuchidae within a new clade of mesoeucrocodylians called Gondwanasuchia. It was the sister taxon of Notosuchimorpha, another newly erected clade that contained notosuchias, sebecosuchians, and peirosaurids.

     The Carvalho et al. (2004) paper phylogeny did not include neosuchians in the analysis. Neosuchians and notosuchians are the two major clades of mesoeucrocodylians. When neosuchians are included in analyses with Simosuchus and Chimaerasuchus, the two genera do not appear as sister taxa (Pol 2003; Candeiro & Martinelli 2006). In fact Chimaerasuchus has been found to be the sister taxon of Sphagesaurus. Sphagesaurus is often assigned its own family, Sphagesauridae. If Chimaerasuchus belongs to Shagesauridae, Chimaerasuchidae would be a junior synonym of Sphagesauridae. This is because Sphagesauridae was named before Chimaerasuchidae, and under ICZN rules, the oldest name has priority.

     In a recent contribution, Marinho & Carvalho (2007) did a revision of Sphagesauridae and noticed that Chimaerasuchus does not have any of the synapomorphies of this family that was originally erected by Kuhn (1968). In this new paper, the authors propose an emended diagnosis for the Sphagesauridae, pointing new synapomorphies for this taxon and propose that the Chimaerasuchidae would be a valid family in spite of the poor phylogenetic analysis of Carvalho et al. (2004) paper.


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    06:30 pm
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    Campinasuchus

     Campinasuchus is an extinct genus of baurusuchid mesoeucrocodylian from Minas Gerais State of Brazil.

     Campinasuchus is known from four partial skulls from the Honorópolis District of the Adamantina Formation, Bauru Basin, dating to the Turonian or the Santonian stage of the late Cretaceous, about 93.5-83.5 million years ago. The specimens were collected at Três Antas Farm, Campina Verde County of the Minas Gerais State. The holotype CPP 1235 consists of a well preserved posterior skull and partial rostrum, and the paratypes, CPP 1234, partial skull, CPP 1236, nearly complete rostrum and CPP 1237, partial skull (including mandible) and associated postcranial skeleton. Campinasuchus is the fifth baurusuchid species from the Adamantina Formation to date.

     Campinasuchus, like other baurusuchids, was a fully terrestrial predator. It has a deep and laterally compressed skull with large, blade-like teeth. Compared to other baurusuchids, it has a very short, low snout. It is much narrower than the back of the skull. Its upper margin is also lower than the back of the skull, giving the head a slightly sloping profile (other baurusuchids have high snouts that are level with the rest of the skull). The third maxillary tooth of the upper jaw and the fourth dentary tooth of the lower jaw are greatly enlarged. A small pit on the premaxilla accommodates the first tooth of the mandible when the jaws are closed. This pit is positioned between the first and second premaxillary teeth. A deep notch forms the boundary between the premaxilla and maxilla, and provides an opening for the large fourth dentary tooth of the lower jaw. The supratemporal fenestrae, holes at the back of the skull, are relatively small. In other baurusuchids, the fenestrae are almost as large as the eye sockets.

     Campinasuchus was first named by Ismar De Souza Carvalho, Vicente De Paula Antunes Teixeira, Mara Lúcia Da Fonseca Ferraz, Luiz Carlos Borges Ribeiro, Agustín Guillermo Martinelli, Francisco Macedo Neto, Joseph J. W. Sertich, Gabriel Cardoso Cunha, Isabella Cardoso Cunha and Partícia Fonseca Ferraz in 2011 and the type species is Campinasuchus dinizi. The generic name is derived from Campina in reference to Campina Verde County in which Campinasuchus was found, and suchus, Latinized from the Greek souchos, an Egyptian crocodile god Sebek. The specific name honours the owners of the farm where the specimens were excavated: Izonel Queiroz Diniz Neto and the families Diniz and Martins Queiroz.


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    Baurusuchus

     Baurusuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It was a terrestrial predator and scavenger, about 3.5 to 4 metres (11 to 13 ft) long and 80 to 100 kilograms (180 to 220 lb) in weight. Baurusuchus lived during the Turonian to Santonian stages (90-83.5 million years ago) of the Late Cretaceous Period, in Adamantina Formation, Brazil.[2] It gets its name from the Brazilian Bauru Group ("Bauru crocodile"). It was related to the earlier-named Cynodontosuchus rothi, which was smaller, with weaker dentition (Bonaparte, 1996). The three species are B. pachechoi (Price, 1945), B. salgadoensis (Carvalho et al., 2005) (named after General Salgado County in São Paulo, Brazil) and B. albertoi (Nascimento & Zaher, 2010) (named after Dr. Alberto Barbosa de Carvalho, Brazilian paleontologist). Its relatives include the similarly sized Stratiotosuchus from the Adamantina Formation, and Pabweshi, from the Pakistani Pab Formation.

     B. salgadoensis is seen as a terrestrial predator, living in hot and arid climate. The position of the external nares was unsuited for an amphibious lifestyle like in modern crocodilians and the snout and teeth are laterally compressed like in theropods. Both of this supports the terrestrial hypothesis. The hot environment hypothesis is based on the lifestyle of modern crocodilians and the stratigraphy of Baurusuchus. B. salgadoensis was found in fine massive sandstones which are interpreted as a floodplain area in hot and arid climate. Baurusuchus was likely able to dig holes for finding water in dry seasons or, like modern alligators do, for thermoregulation. The occurrence of very complete skeletons in correlated stratigraphic levels supports this. Such a strategy would have made it less water-bound than most modern crocodiles, allowing it to live in more continental climate. The strongly bent pterygoids suggest a powerful bite and that Baurusuchus could close it's jaw very quickly. The skull and teeth morphology (biology) indicates that the biting strategies of Baurusuchus were similar to a komodo dragon which include ambushing the prey, biting it and pulling back the serrated, blade-like teeth. Baurusuchus likely played an important role in it's ecosystem, competing with the abelisaurids for food.

     Баурузух - сухопутный крокодиломорф позднего мелового периода из местности Бауру (Бразилия).

     Тяжелый, мощный, уплощенный с боков череп, скорее предназначенный, для продирания сквозь густую кустарниковую растительность, нежели чем для охоты в водной среде. Возможно, конкурировал с хищными динозаврами (абелизавридами).

     Удивительная особенность этой рептилии – на черепе явные признаки строения, свойственные только крупным плотоядным динозаврам: это antorbital fenestra – широкое отверстие между ноздрями и глазницами, которое появилось еще у архозавров в раннем Триасовом периоде, этот признак сохранили птицы, но полностью утратили современные крокодилы.

     Кроме того баурузух отличался невысокими гребнями сверху черепа. Строение крестцовых позвонков явно свидетельствует об успешном приспособлении к активному перемещению по суше.

     Имел высокие грацильные (почти собачьи по строению) лапы. Специалисты в 2010 году предположили, что по строению передних конечностей вполне был способен в засушливые периоды вырывать достаточно глубокие ямы в поисках воды

     Sebecosuchia is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group first appeared in the Late Cretaceous with the baurusuchids and went extinct in the Miocene with the last sebecids. Fossils have been found primarily from South America but have also been found in Europe, North Africa, and Asia. Some recent studies have separated Baurusuchidae and Sebecidae, making Sebecosuchia polyphyletic, but others have retained it as a valid grouping.

     Sebecosuchia was first constructed in 1946 by American paleontologist Edwin Colbert to include Sebecus and Baurusuchidae. Sebecus, which had been known from South America since 1937, was an unusual crocodyliform with a deep snout and teeth that were ziphodont, or serrated and laterally compressed. The family Baurusuchidae was named the year before and included the newly described Baurusuchus, which was also a South American deep-snouted form.

     More recently, other crocodyliforms have been assigned to Sebecosuchia that cannot be placed into either family. These include the genera Eremosuchus, named in 1989, and Pehuenchesuchus, named in 2005. They are usually considered to be more basal sebecosuchians than the sebecids and baurusuchids.

     Baurusuchidae is a Gondwanan family of mesoeucrocodylians that lived during the Late Cretaceous. It is a group of terrestrial hypercarnivorous crocodilians from South America (Argentina and Brazil) and possibly Pakistan. Baurusuchidae has been defined as a clade containing the most recent common ancestor of Baurusuchus and Stratiotosuchus and all of its descendants. It may, however, be polyphyletic, as recent phylogenetic analyses have placed Baurusuchus within Notosuchia and other baurusuchids within the more distantly related clade Sebecia. A recent study of the family finds it monophyletic by including the South American genera Baurusuchus, Cynodontosuchus, Pissarrachampsa, Stratiotosuchus, and Wargosuchus. Other traditional baurusuchids like Pabwehshi are excluded. The recently named Campinasuchus is also included in the family. Baurusuchids have been placed in the suborder Baurusuchia, and two subfamilies have been proposed: Baurusuchinae and Pissarrachampsinae.

     Several genera have been assigned to Baurusuchidae. Baurusuchus was the first, being the namesake of the family. Remains of Baurusuchus have been found from the Late Cretaceous Bauru Group of Brazil in deposits that are Turonian - Santonian in age. In addition to Baurusuchus, five other South American crocodyliforms have been assigned to Baurusuchidae: Campinasuchus, Cynodontosuchus, Pissarrachampsa, Stratiotosuchus, and Wargosuchus. Cynodontosuchus was the first known baurusuchid, named in 1896 by English paleontologist Arthur Smith Woodward, although it was only recently assigned to Baurusuchidae. Wargosuchus was described in 2008.[3] Cynodontosuchus and Wargosuchus are known only from fragmentary remains. Both genera are from the Santonian of Argentina.

     A fourth genus, Stratiotosuchus, was assigned to Baurusuchidae in 2001. Fossils have been found from the Turonian - Santonian of Brazil. Pabwehshi is the youngest genus that has been assigned to Baurusuchidae, and is from the Maastrichtian of Pakistan. It was named in 2001 but has since been reassigned as a basal member of Sebecia.

    A new genus, Campinasuchus, was assigned to the family in May, 2011. It is known from the Turonian-Santonian Adamantina Formation of the Bauru Basin of Brazil. Soon after, the new genus Pissarrachampsa was named from the Campanian–Maastrichtian Vale do Rio do Peixe Formation, also in the Bauru Basin.


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    Armadillosuchus

     Armadillosuchus is an extinct genus of sphagesaurid crocodylomorph. It was described in February 2009 from the Late Cretaceous Bauru Basin of Brazil. Armadillosuchus length was estimated on 2 m (7 ft) with a weight of 120 kg.

     Sphagesaurids share a number of mammal-like features in their teeth and jaws, although they are unrelated to mammals. Armadillosuchus is especially mammal-like in that it had heavy body armor characterized by flexible bands and rigid shields that covered its back, less like the traditional osteoderms that line the backs of most crurotarsans and more like that of a modern armadillo (hence the genus name meaning "armadillo crocodile"). Because of its unique morphology, it is believed to have had a terrestrial and quite possibly fossorial lifestyle.

     90 млн лет назад по территории современной Бразилии ползали двухметровые крокодилы, покрытые костяным панцирем. Необычная рептилия предпочитала засушливый климат и разгрызала жертв мелкими зубками.

     Бразильские палеонтологи обнаружили близ Сан-Паулу череп, ребра и лапу «самого экзотического крокодила из найденных на сегодняшний день».

     Эта похожая на броненосца рептилия жила 90 млн лет назад, в меловом периоде. Шея и верхняя часть ее спины были защищены костными пластинами. В длину животное достигало 2 м, а весило около 120 кг, пишет Reuters.

     Кости необычного крокодила были впервые найдены в 2005 году. За это время ученым из университета Рио-де-Жанейро удалось реконструировать скелет и облик животного. У него была узкая короткая пасть с мелкими зубами, которые, как полагают ученые, являются результатом приспособления к питанию определенным видом добычи. Каким именно — палеонтологи пока не выяснили. Они уверены лишь в одном: двухметровый архозавр был хищником.

     Палеонтолог Измар де Соуза Карвальо, представлявший скелет и макет этой древней рептилии на пресс-конференции в Рио-де-Жанейро, охарактеризовал крокодила как «уникального, нигде более на планете не найденного». Ученые определили эту рептилию в новый род — Armadillosuchus (крокодил-броненосец). Видовое название животного (Armadillosuchus Arrudai) образовано от фамилии профессора Тадеу Арруды, который первым наткнулся на кости хищника.

     Этот крокодил был похож на современных броненосцев не только внешним видом, но и условиями обитания. «Кости армадиллозуха найдены лишь в центре штата Сан-Паулу, что удивительно: ведь это опровергает мысль, что крокодилы обитают лишь в жарком и влажном климате. В этом случае мы имеем дело с крокодилами, которые жили в сухом, аридном климате», — отметил де Соуза. Палеонтологи полагают, что 90 млн лет назад средняя дневная температура на территории современной Бразилии превышала 45 градусов, при этом водоемы здесь были редкостью.

     Результаты исследования бразильских палеонтологов опубликованы в журнале Journal of South American Earth Science.

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    March 8th, 2014
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    Araripesuchus

     Araripesuchus is a genus of extinct crocodyliform that existed during the Cretaceous period of the late Mesozoic era some 125 to 66 million years ago. Five species of Araripesuchus are currently known. They are generally considered to be notosuchians (belonging to the clade Mesoeucrocodylia), characterized by their varied teeth types and distinct skull elements. Its length was about 1-1.8 m (3.3-6 ft) with a weight of 40 kg (90 lbs). Araripesuchus can be distinguished by their laterally bulged edges of the snout, with the bulge being the most prominent around the area of an enlarged maxillary tooth. There are five valid species within this genus.

     The genus was coined in 1959 with the description of the type species Araripesuchus gomesii, a notosuchian crocodylian from the famed Santana Formation of Brazil. The holotype used to describe the genus, 423-R is currently in the care of the Divisao de Mineralogia e Geologia do Departamento Nacional da Producao Mineral in Rio de Janeiro. 423-R consists of a single skull articulating with part of a lower jaw. A more complete specimen, AMNH 24450 is held by the American Museum of Natural History. A second species, Araripesuchus wegeneri was described in 1981. This species was discovered from Early Cretaceous deposits of Niger on the African continent, as opposed to the South American paleodistribution of the other species in the genus. The type specimen for the species, GDF-700 consisting of a few, fragmentary jaw elements, reside at the Museum National d'Histoire Naturelle in Paris. Araripesuchus patagonicus was described from a patagonian specimen (MUC-PV 269) in 2000. Another species to be assigned to the genus, was Araripesuchus buitreraensis, described in 2005. This species was described from a single skull (MPCA-PV 235) retrieved from Late Cretaceous deposits in what is now Argentina. At 130 millimeters, the skull is the largest Araripesuchus specimen discovered to date. A fifth species, Araripesuchus tsangatsangana was described in 2006. This species' type specimen was discovered from latest Late Cretaceous deposits from the African island of Madagascar. Analysis of this specimen solidifies the position of A. wegneri as a member of the genus. A. tsangatsangana is the geologically youngest known of this genus.

     There are currently six recognized species within the genus Araripesuchus: A. patagonicus, A. buitreraensis, A. tsangatsangana, A. wegeneri, A. rattoides and the type species A. gomesii. The placement of the first African species discovered, A. wegeneri was questioned for a while by various authors. Ortega et al. argued for the assignment of the errant species to another genus based on phylogenetic analysis. Further analysis, combined with the discovery of the second African species A. tsangatsangana has shed more light on the placement of A. wegeneri within the genus. When analyzed together, the African species support the inclusion of all five known species into the same genus.

     The genus was originally assigned by Price to the family Uruguaysuchidae in the original 1959 description. This classification was followed by Buffetaut in 1981 with the description of A. wegeneri also within the same family. However, in their 2000 description of A. patagonicus, Ortega et al. avoided placing the species within the family. Instead, it was simply noted that Uruguaysuchus was a possible close relative of the genus.

     Ortega et al. and several other studies place Araripesuchus outside Notosuchia. In some phylogenetic analyses, it is placed closer to the clade Neosuchia, which includes modern crocodilians. In most recent analyses, however, Araripesuchus is placed as a basal notosuchian. The phylogenetic analysis of Soto et al. (2011) joined Araripesuchus with Uruguaysuchus, reinstating the family Uruguaysuchidae. This family was found to be the most basal group of Notosuchia. 

     Araripesuchus remains have been recovered from the continents of South America and Africa suggesting a Gondwanan origin for the evolution of the genus. At around the time of Araripesuchus existence, South America and Africa were physically adjacent to each other. The various species evolved from the same stock in the general area, radiating outward from a yet-unidentified origin point. The presence of specimens from Madagascar further strengthens this evolutionary radiation mode.

     Крокодилы – самые крупные и известные хищные рептилии, дожившие до наших дней, в прошлом, в мезозое, были значительно более разнообразны и многочисленны. Они не только составляли конкуренцию своим ближайшим родственникам – динозаврам, но и охотились на них. Крокодилы населяли все континенты, но наиболее разнообразны были, судя по находкам палеонтологов, они были на территории Гондваны, суперконтинента, распавшегося в конце мезозоя.

     Именно из Южной Америки, Африки, Мадагаскара и Индостана, входивших в Гондвану, известно самое большое число разнообразных древних крокодилов. Теперь к ним прибавилось еще пять новых видов, обнаруженных американскими палеонтологами в Сахаре.

     Группа палеонтологов под руководством Пола Серено (Paul Sereno) из Чикагского университета (University of Chicago) на протяжении нескольких лет изучала остатки крокодилов на территории Марокко и Нигера. Им удалось обнаружить скелеты и отдельные кости крокодилов шести разных видов, обитавших на севере Африки в меловом периоде. Среди этих шести видов пять – новые, до сих пор исследователям не встречавшиеся. Судя по всему, в меловом периоде в этих местах крокодилы занимали множество экологических ниш и их разнообразие связано с пищевой специализацией.

     Все эти крокодилы жили в конце раннего и в начале позднего мела. Два из шести найденных крокодилов (Anatosuchus minor, Araripesuchus wegeneri) были обнаружены в отложениях нижнемеловой формации Эльрхаз (Elrhaz Formation) в Нигере. Эти отложения формировались в аптском и альбском веках раннего мела (Aptian-Albian). Остальные четыре вида (Araripesuchus rattoides, Kaprosuchus saharicus, Laganosuchus thaumastos, Laganosuchus maghrebensis) жили в сеноманском веке позднего мела (Cenomanian) на территории Нигера и Марокко. Их нашли в отложениях формации Эчкар в Нигере (Echkar Formation) и Кем-Кем (Kem Kem Beds) в Марокко. 

     Следующий крокодил, найденный палеонтологами, Araripesuchus wegeneri, уже был известен ученым. В 60-х годах ХХ века его окаменевшие кости нашли в Южной Америке, в Бразилии. Он, как и анатозухус, жил в конце раннего мела. Этого крокодила нельзя отнести к крупным видам, длина его черепа всего лишь около 10 сантиметров. От журналистов он получил прозвище DogCroc (КрокоПёс). Для такого названия были определенные основания, так как, во-первых, эти крокодилы жили и охотились стаями, во-вторых, некоторые зубы в их челюстях здорово напоминали собачьи, а кроме того эти животные имели длинные ноги и хорошо бегали.  

     В одном из блоков породы палеонтологи нашли сразу четыре хорошо сохранившихся скелета Araripesuchus wegeneri, погибших одновременно и захороненных рядом. Как и у большинства его родственников, спина и хвост Araripesuchus wegeneri были покрыты броней из костных пластинок. Но в случае опасности эти небольшие крокодилы явно полагались не на броню, а на скорость – строение их конечностей и позвоночника свидетельствуют о способности к быстрому бегу. Палеонтологи даже сравнили строение Araripesuchus wegeneri со строением австралийских морских крокодилов, способных бегать практически галопом и пришли к выводу, что арарипезухус был отличным бегуном.

     Очень необычными оказались зубы этого крокодила. Они заметно отличаются друг от друга по форме. Вероятно, что диета этих крокодилов была очень разнообразной, возможно, что в нее входили и какие-то растения.

     Палеонтологи обнаружили и неизвестного ранее ближайшего родственника Araripesuchus wegeneri, они назвали его Araripesuchus rattoides, у журналистов этот вид получил кличку RatCroc (КрокоКрыса). Он жил несколько позже своего родственника, в сеноманском веке позднего мела, 94-100 миллионов лет назад. К сожалению, палеонтологам удалось найти только несколько кусков челюстей этого крокодила, но и эти фрагменты позволили кое-что узнать о его образе жизни. Araripesuchus rattoides, как и его родственник, имел длину не больше метра. Он отличался от других крокодилов тем, что на его нижней челюсти два крупных передних зуба были сближены и направлены вперед, как зубы грызунов (у них, правда, выступающими являются зубы на верхней челюсти). Исследователи предполагают, что эти зубы Araripesuchus rattoides использовал для выкапывания добычи из земли или ила. 


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    February 16th, 2014
    02:18 pm
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    Anatosuchus

     Anatosuchus ("duck crocodile", for the broad, duck-like snout) is an extinct genus of notosuchian crocodylomorph discovered in Gadoufaoua, Niger, and described by a team of palaeontologists led by the American Paul Sereno in 2003, in the Journal of Vertebrate Paleontology. Its duck-like snout coincidentally makes it resemble a crocoduck.

     The type species of Anatosuchus is A. minor, in reference to its small body size. The holotype material (MNN GDF603), is a nearly complete skull with articulated lower jaws. It was discovered from the upper portion of the Elrhaz Formation and lower portion of Echkar Formation, indicating an Early Cretaceous (Late Aptian or Early Albian).

     In the initial description of Anatosuchus, it formed a clade with Comahuesuchus, within a less inclusve Notosuchia, also found to be monophyletic. However, further work proposed that Anatosuchus is not closely related to Comahuesuchus.

     As the specific name indicates, A. minor was a very small crocodylomorph, with an adult body length estimated at around 70 centimeters. It had a very broad, duck-like snout.

     

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    Adamantinasuchus

     Adamantinasuchus is an extinct genus of notosuchian crocodylomorph from the Late Cretaceous of Brazil.

     Ziphosuchia is a clade of mesoeucrocodylian crocodyliforms that includes notosuchians and sebecosuchians. First constructed in 2000, it was considered to include Notosuchus, Libycosuchus, and Sebecosuchia. In a 2004 phylogenetic study, it was defined as the most recent common ancestor of Notosuchus, Libycosuchus, and Baurusuchoidea and all of its descendants.

     Ziphosuchia is often considered to be the sister group of Neosuchia, a clade that includes modern crocodilians. Because the fossil range of Neosuchia extends back to the Early Jurassic with the family Goniopholididae, a ghost lineage of ziphosuchians dating back to that divergence point can be expected.

     Notosuchia is a suborder of primarily Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Cretaceous. Fossils have been found from South America, Africa, Asia, and Europe. Notosuchia was a clade of terrestrial crocodilians that evolved a range of feeding behaviours, including herbivory (Chimaerasuchus), omnivory (Simosuchus), and terrestrial hypercarnivory (Baurusuchus). It included many members with highly derived traits unusual for crocodylomorphs, including mammal-like teeth, flexible bands of shield-like body armor similar to those of armadillos (Armadillosuchus), and possibly fleshy cheeks and pig-like snouts (Notosuchus). The suborder was first named in 1971 by Zulma Gasparini and has since undergone many phylogenetic revisions.

     Notosuchians were generally small, with slender bodies and erect limbs. The most distinctive characteristics are usually seen in the skull. Notosuchian skulls are generally short and deep. While most are relatively narrow, some are very broad. Simosuchus has a broadened skull and jaw that resembles a pug, while Anatosuchus has a broad, flat snout like that of a duck.

     The teeth vary greatly between different genera. Many have heterodont dentitions that vary in shape across the jaw. Often, there are large canine-like teeth protruding from the front of the mouth and broader molar-like teeth in the back. Some genera, such as Yacarerani and Pakasuchus, have extremely mammal-like teeth. Their molars are complex and multicuspid, and are able to occlude or fit with one another. Some forms such as Malawisuchus had jaw joints that enabled them to move the jaw back and forth in a shearing motion rather than just up and down.

     A derived group of notosuchians, the baurusuchids, differ considerably from other forms. They are very large in comparison to other notosuchians and are exclusively carnivorous. Baurusuchids have deep skulls and prominent canine-like teeth.

     The clade Notosuchia has undergone many recent phylogenetic revisions. In 2000, Notosuchia was proposed to be one of two groups within the clade Ziphosuchia, the other being Sebecosuchia, which included deep snouted forms such as baurusuchids and sebecids. The definition of Notosuchia by Sereno et al. (2001) is similar to that of Ziphosuchia as it includes within it Sebecosuchia. Pol (2003) also includes Sebecosuchia within Notosuchia. More recently, a phylogenetic analysis by Larsson and Sues (2007) resulted in the naming of a new clade, Sebecia, to include sebecids and peirosaurids. Baurusuchidae was considered to be polyphyletic in this study, with Pabwehshi being a basal member of Sebecia and Baurusuchus being the sister taxon to the clade containing Neosuchia and Sebecia. Thus, Sebecosuchia was no longer within Notosuchia and not considered to be a true clade, while Notosuchia was found to be a basal clade of Metasuchia.


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