O novo artigo publicado no PeerJ reforça a vida agitada e perigosa do dinossauro carnívoro Allosaurus fragilis.
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| Esqueleto original de Allosaurus fragilis |
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| Escápula de Allosaurus fragilis |
Novas perspectivas sobre o estilo de vida de Allosaurus (Dinosauria: Theropoda) com base noutro espécime com múltiplas patologias
Os terópodes (dinossauros carnívoros) adultos de grande porte são frequentemente encontrados com numerosas patologias. Um grande e quase completo, espécime provavelmente adulto de Allosaurus do Howe Stephens Quarry, Formação Morrison, Wyoming, mostra várias patologias. Ossos patológicos incluem o dentário esquerdo, duas vértebras cervicais, uma cervical e várias costelas dorsais, a escápula esquerda, o úmero esquerdo, ísquio direito, e duas falanges do pé. Estas patologias podem ser classificadas da seguinte forma: a quinta vértebra cervical, escápula, várias costelas e ísquio estão traumátizadas, e um calo na falange II-2 é traumático-infecciosa. Traumaticamente elementos fraturados expostos ao movimento frequente (por exemplo, a escápula e as costelas) mostram uma tendência a desenvolver pseudartroses em vez de calo. As patologias na quarta cervical são mais susceptíveis de serem idiopática, e no úmero esquerdo é infecciosa ou idiopática, enquanto pedal esquerdo falange IV-1 é classificada como idiopática. Com excepção do ísquio, todos os elementos patológicos traumáticas / traumáticas infecciosa mostrar evidências inequívocas de cura, o que indica que as respectivas patologias não causou a morte desse indivíduo. Alinhamento das patologias na escápula e de costelas do lado esquerdo sugere que tudo pode ter sido causado por um único evento traumático. A fratura isquiática pode ter sido fatal. A ocorrência de múltiplas patologias traumáticas novamente sublinha que terópodes de grande porte experimentou lesões frequentes durante a vida, o que indica um estilo de vida predatório activo. Sinais de infecções são escassas e restringidas localmente, indicando o sucesso na prevenção da disseminação de agentes patogénicos, como é o caso nos répteis existentes (incluindo as aves).
New insights into the lifestyle of Allosaurus (Dinosauria: Theropoda) based on another specimen with multiple pathologies
Abstract:
Adult large-bodied theropods are often found with numerous pathologies. A large, almost complete, probably adult Allosaurus specimen from the Howe Stephens Quarry, Morrison Formation (Late Kimmeridgian–Early Tithonian), Wyoming, shows multiple pathologies. Pathologic bones include the left dentary, two cervical vertebrae, one cervical and several dorsal ribs, the left scapula, the left humerus, right ischium, and two left pedal phalanges. These pathologies can be classified as follows: the fifth cervical vertebra, the scapula, several ribs and the ischium are traumatic, and a callus on the shaft of the left pedal phalanx II-2 is traumatic-infectious. Traumatically fractured elements exposed to frequent movement (e.g. the scapula and the ribs) show a tendency to develop pseudarthroses instead of callus healing. The pathologies in the lower jaw and a reduced flexor tubercle of the left pedal phalanx II-2 are most likely traumatic or developmental in origin. The pathologies on the fourth cervical are most likely developmental in origin or idiopathic, that on the left humerus is infectious or idiopathic, whereas left pedal phalanx IV-1 is classified as idiopathic. With exception of the ischium, all traumatic / traumatic-infectious pathologic elements show unambiguous evidences of healing, indicating that the respective pathologies did not cause the death of this individual. Alignment of the scapula and rib pathologies from the left side suggests that all may have been caused by a single traumatic event. The ischial fracture may have been fatal. The occurrence of multiple traumatic pathologies again underlines that large-bodied theropods experienced frequent injuries during life, indicating an active predatory lifestyle, and their survival perhaps supports a gregarious behavior for Allosaurus. Signs of infections are scarce and locally restricted, indicating a successful prevention of the spread of pathogens, as it is the case in extant reptiles (including birds).
Foth C, Evers S, Pabst B, Mateus O, Flisch A, Patthey M, Rauhut OWM.(2015) New insights into the lifestyle of Allosaurus (Dinosauria: Theropoda) based on another specimen with multiple pathologies. PeerJ PrePrints3:e824v1 http://dx.doi.org/10.7287/peerj.preprints.824v1
Adult large-bodied theropods are often found with numerous pathologies. A large, almost complete, probably adult Allosaurus specimen from the Howe Stephens Quarry, Morrison Formation (Late Kimmeridgian–Early Tithonian), Wyoming, shows multiple pathologies. Pathologic bones include the left dentary, two cervical vertebrae, one cervical and several dorsal ribs, the left scapula, the left humerus, right ischium, and two left pedal phalanges. These pathologies can be classified as follows: the fifth cervical vertebra, the scapula, several ribs and the ischium are traumatic, and a callus on the shaft of the left pedal phalanx II-2 is traumatic-infectious. Traumatically fractured elements exposed to frequent movement (e.g. the scapula and the ribs) show a tendency to develop pseudarthroses instead of callus healing. The pathologies in the lower jaw and a reduced flexor tubercle of the left pedal phalanx II-2 are most likely traumatic or developmental in origin. The pathologies on the fourth cervical are most likely developmental in origin or idiopathic, that on the left humerus is infectious or idiopathic, whereas left pedal phalanx IV-1 is classified as idiopathic. With exception of the ischium, all traumatic / traumatic-infectious pathologic elements show unambiguous evidences of healing, indicating that the respective pathologies did not cause the death of this individual. Alignment of the scapula and rib pathologies from the left side suggests that all may have been caused by a single traumatic event. The ischial fracture may have been fatal. The occurrence of multiple traumatic pathologies again underlines that large-bodied theropods experienced frequent injuries during life, indicating an active predatory lifestyle, and their survival perhaps supports a gregarious behavior for Allosaurus. Signs of infections are scarce and locally restricted, indicating a successful prevention of the spread of pathogens, as it is the case in extant reptiles (including birds).
Foth C, Evers S, Pabst B, Mateus O, Flisch A, Patthey M, Rauhut OWM.(2015) New insights into the lifestyle of Allosaurus (Dinosauria: Theropoda) based on another specimen with multiple pathologies. PeerJ PrePrints3:e824v1 http://dx.doi.org/10.7287/peerj.preprints.824v1
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