Apparent sixth sense in theropod evolution: The making of a Cretaceous weathervane

Objective Two separate and distinctive skills are necessary to find prey: Detection of its presence and determination of its location. Surface microscopy of the dentary of albertosaurines revealed a previously undescribed sensory modification, as will be described here. While dentary “foramina” were previously thought to contain tactile sensory organs, the potential function of this theropod modification as a unique localizing system is explored in this study. Method Dentary surface perforations were examined by surface epi-illumination microscopy in tyrannosaurine and albertosaurine dinosaurs to characterize their anatomy. Fish lateral lines were examined as potentially comparable structures. Result In contrast to the subsurface vascular bifurcation noted in tyrannosaurines (which lack a lateral dentary surface groove), the area subjacent to the apertures in albertosaurine grooves has the appearance of an expanded chamber. That appearance seemed to be indistinguishable from the lateral line of fish. Conclusion Dentary groove apertures in certain tyrannosaurid lines (specifically albertosaurines) not only have a unique appearance, but one with significant functional and behavior implications. The appearance of the perforations in the dentary groove of albertosaurines mirrors that previously noted only with specialized neurologic structures accommodating derived sensory functions, as seen in the lateral line of fish. The possibility that this specialized morphology could also represent a unique function in albertosaurine theropods for interacting with the environment or facilitating prey acquisition cannot be ignored. It is suggested that these expanded chambers function in perceiving and aligning the body relative to the direction of wind, perhaps a Cretaceous analogue of the contemporary midwestern weathervane

Odyssey in the evolution of a paleopathologist

A recent report suggesting perceived limitations of and opportunities in the study of paleopathology suggested the importance of incorporation of scientific methodologies. It seems reasonable to also explore how those methodologies are developed and, indeed, how one approaches paleopathology as a science. The development of one such paleopathologist is delineated from his serendipitous observations to application of hypothesis generation and subsequent testing approach developed during basic medical science education. This approach resulted in recognition of how much he thought he knew was actually contrary to the facts. A critical factor was the collaborative approach with specialists in other fields, wherein linguistic confusion was overcome and perspectives refined by point–counterpoint analysis of hypotheses. The limited reliability of tertiary information was clearly exposed through examination of primary sources – original articles rather than what might be referred to as "meta-analyses". It became clear that linguistics was not the only challenge; application of techniques had to be observed and validated. Without validation one might obtain precision (method repeatedly reveals same results) but at the expense of accuracy (assurance that the method actually assesses the question). Paleontological studies are generally limited to examination of organisms and their traces. Archeologically based studies incorporate additional sources of information (e.g., historic), but are no less subject to such semantic and methodological issues. Proof of concept studies provided new windows to recognition not only of disease but to previous anatomical challenges (e.g., localization of direct muscle attachment sites and distribution). Trans-phylogenetic representation of disease falsified speculation that "evolution" would preclude analysis through time. Pathology is an intrinsic component of life and transcends both species and time. Knowledge gained in a given species and time can be applied to similar disease manifestations in other species in modern time. Once speculations were tested and either verified or falsified, paleo-epidemiologic approach allowed identification of patterns of spread and even application of that knowledge to recognition of human migration patterns. Proof of concept studies provided new windows to recognition not only of disease but to previous anatomical challenges (e.g., localization of direct muscle attachment sites and distribution)

A new spontaneous model of fibrodysplasia ossificans progressiva.

Fibrodisplasia ossificante progressiva (FOP) é uma doença genética caracterizada por uma acentuada, progressiva e aparentemente incontrolável ossificação dos tendões, ligamentos, faciais e músculos estriados da formação de osso heterotópico resultando na imobilização em cadeiraa de rodas por 30 anos. Estudos mais avaçados relacionados a sua gestão foi sempre comprometida pela falta de um modelo animal natural. Esqueletos de mamíferos “Defleshed” foram examinados para demonstrar a evidência de formação de osso heterotópico. O cervo-rato do sudeste asiático do gênero Tragulus foi diagnosticado por possuir uma bainha ósseas cobrindo a parte inferior das costas e na região da coxa consistente com a definição clínica da FOP. Esta deposição óssea heterotophica está presente em todos os machos adultos, incluindo os obtidos selvagens e zoológico de animais desta linhagem. Nós relatamos o primeiro exemplo conhecido de natural de fibrodisplasia ossificante progressiva (FOP) em um mamífero não-humano. Tragulus pode oferecer a oportunidade de examinar muitos dos atributos mais importantes da doença experimentalmenteFibrodysplasia ossificans progressiva (FOP) is a genetic disorder characterized by relentlessly progressive and seemingly uncontrollable progressive ossification of tendons, ligaments, fascia, and striated muscle with heterotopic bone formation resulting in immobilization and wheel chair confinement by age 30. Progress in its management has been compromised by lack of a natural animal model. Defleshed mammal skeletons were examined for evidence of heterotopic bone formation. The Southeast Asian mouse deer of the genus Tragulus was found to have an osseous sheath covering the lower back and upper thigh region consistent with the clinical definition of FOP. This heterotophic bone deposition is present in all adults males, including both wild obtained and zoo bred animals. We report the first known example of spontaneous, naturally occurring fibrodysplasia ossificans progressiva (FOP) in a non-human mammal. Tragulus may offer the opportunity to examine many of the disease’s most significant attributes experimentally

The oldest record of aquatic amniote congenital scoliosis

This research was supported by the National Science Center (Narodowe Centrum Nauki, www.ncn.gov.pl), Poland, project no. 2011/ 01/N/ST10/06989 granted to D. Surmik. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.We report the first occurrence of congenital scoliosis in an early Permian aquatic parareptile, Stereosternum tumidum from Paraná state, Brazil. The spine malformation is caused by a congenital hemivertebra. These observations give insight into the biomechanical aspects of underwater locomotion in an axial skeleton-compromised aquatic amniote. This is the oldest record of a hemivertebra in an aquatic animal.National Science Center (Narodowe Centrum Nauki, www.ncn.gov.pl

Tuberculosis-like respiratory infection in 245-million-year-old marine reptile suggested by bone pathologies

An absence of ancient archaeological and palaeontological evidence of pneumonia contrasts with its recognition in the more recent archaeological record. We document an apparent infection-mediated periosteal reaction affecting the dorsal ribs in a Middle Triassic eosauropterygian historically referred to as ‘Proneusticosaurus’ silesiacus. Highresolution X-ray microtomography and histological studies of the pathologically altered ribs revealed the presence of a continuous solid periosteal reaction with multiple superficial blebs (protrusions) on the visceral surfaces of several ribs. Increased vascularization and uneven lines of arrested growth document that the pathology was the result of a multiseasonal disease. While visceral surface localization of this periosteal reaction represents the earliest identified evidence for pneumonia, the blebs may have an additional implication: they have only been previously recognized in humans with tuberculosis (TB). Along with this diagnosis is the presence of focal vertebral erosions, parsimoniously compared to vertebral manifestation of TB in humans

Two types of bone necrosis in the Middle Triassic Pistosaurus longaevus bones: the results of integrated studies

Avascular necrosis, diagnosed on the basis of either a specific pathological modification of the articular surfaces of bone or its radiologic appearance in vertebral centra, has been recognized in many Mesozoic marine reptiles as well as in present-day marine mammals. Its presence in the zoological and paleontologic record is usually associated with decompression syndrome, a disease that affects secondarily aquatic vertebrates that could dive. Bone necrosis can also be caused by infectious processes, but it differs in appearance from decompression syndrome-associated aseptic necrosis. Herein, we report evidence of septic necrosis in the proximal articular surface of the femur of a marine reptile, Pistosaurus longaevus, from the Middle Triassic of Poland and Germany. This is the oldest recognition of septic necrosis associated with septic arthritis in the fossil record so far, and the mineralogical composition of pathologically altered bone is described herein in detail. The occurrence of septic necrosis is contrasted with decompression syndrome-associated avascular necrosis, also described in Pistosaurus longaevus bone from Middle Triassic of Germany

Tuberculosis-like respiratory infection in 245-million-year-old marine reptile suggested by bone pathologies

An absence of ancient archaeological and palaeontological evidence of pneumonia contrasts with its recognition in the more recent archaeological record. We document an apparent infection-mediated periosteal reaction affecting the dorsal ribs in a Middle Triassic eosauropterygian historically referred to as ‘Proneusticosaurus’ silesiacus. High- resolution X-ray microtomography and histological studies of the pathologically altered ribs revealed the presence of a continuous solid periosteal reaction with multiple superficial blebs (protrusions) on the visceral surfaces of several ribs. Increased vascularization and uneven lines of arrested growth document that the pathology was the result of a multi- seasonal disease. While visceral surface localization of this periosteal reaction represents the earliest identified evidence for pneumonia, the blebs may have an additional implication: they have only been previously recognized in humans with tuberculosis (TB). Along with this diagnosis is the presence of focal vertebral erosions, parsimoniously compared to vertebral manifestation of TB in humans

New tomographic contribution to characterizing mesosaurid congenital scoliosis

The presence of a pathology in the vertebral column of the early Permian mesosaurid specimen ZPAL R VII/1, being one of the oldest amniotic occurrences of congenital scoliosis caused by a hemivertebra, was recently recognized. Here we provide CT data to further characterize the phenomenon. The affected hemivertebra is wedged (incarcerated) between the preceding and succeeding vertebrae. The neural canal is misshapen but continuous and the number of dorsal ribs on each side of the specimen corresponds with the number of the vertebrae, documenting its congenital (homeobox-related) derivation