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.
A recently discovered Norian outcrop in Poręba, Poland, has yielded numerous well‐preserved turtle remains. These, together with historical materials from Germany, enabled the identification of two ...new proterochersid taxa: Proterochersis porebensis sp. nov. from Poland and Keuperotesta limendorsa gen. et sp. nov. from Germany. Moreover, two problematic taxa, Proterochersis intermedia Fraas, 1913; and Murrhardtia staeschei Karl & Tichy, 2000; are shown to be conspecific with Proterochersis robusta Fraas, 1913. New diagnoses for the family Proterochersidae Nopcsa, 1923 and all included taxa are provided. Proterochersids are of great importance to turtle phylogeny because of their age (they comprise the oldest fully shelled turtle species known to date) and their still‐debated phylogenetic position (classically they are considered the basalmost Pleurodira, but in some analyses they are placed on the stem of Testudinata). Newly discovered plesiomorphic aspects of the anatomy of these three species included in the phylogenetic analysis demonstrate that they are not only the oldest, but are also the most basal fully shelled turtles. The unique features of their shell (e.g. the first thoracic rib unreduced and costal‐bearing, and the osseous contact between the carapace and sacral vertebra) are of special significance for future research of the earliest stages of turtle shell evolution. This is the first contribution focused solely on the new, phylogenetically informative, and important characters of this group since the initial description of P. robusta more than 100 years ago.
Neoplasms are common across the animal kingdom and seem to be a feature plesiomorphic for metazoans, related with an increase in somatic complexity. The fossil record of cancer complements our ...knowledge of the origin of neoplasms and vulnerability of various vertebrate taxa. Here, we document the first undoubted record of primary malignant bone tumour in a Mesozoic non-amniote. The diagnosed osteosarcoma developed in the vertebral intercentrum of a temnospondyl amphibian, Metoposaurus krasiejowensis from the Krasiejów locality, southern Poland.
A wide array of data collected from gross anatomy, histology, and microstructure of the affected intercentrum reveals the tumour growth dynamics and pathophysiological aspects of the neoplasm formation on the histological level. The pathological process almost exclusively pertains to the periosteal part of the bone composed from a highly vascularised tissue with lamellar matrix. The unorganised arrangement of osteocyte lacunae observed in the tissue is characteristic for bone tissue types connected with static osteogenesis, and not for lamellar bone. The neoplastic bone mimics on the structural level the fast growing fibrolamellar bone, but on the histological level develops through a novel ossification type. The physiological process of bone remodelling inside the endochondral domain continued uninterrupted across the pathology of the periosteal part.
Based on the results, we discuss our case study's consistence with the Tissue Organization Field Theory of tumorigenesis, which locates the causes of neoplastic transformations in disorders of tissue architecture.
Abstract
The turtle locomotor system is heavily modified owing to the severe impact of development of the shell on the body plan of these reptiles. Although limb and girdle osteology of the earliest, ...Triassic turtles is relatively well understood in general, the exact impacts of variability, ontogeny and preservation (e.g. deformation) on the observed morphologies have rarely been considered in detail. Here, we describe in detail and document the osteology and intraspecific variability of the limbs and girdles of Proterochersis spp., the basalmost true turtles (Testudinata). We also provide a synthesis of currently available data and detailed comparisons with other Triassic stem turtles to gain a better understanding of the diagnostic value of the early turtle appendicular skeleton and to pave the way for future biomechanical and functional studies. Our data suggest that Proterochersis spp. could be at least partly aquatic and could change their preferred habitat during ontogeny, with larger (and, presumably, older) specimens presenting more characters suggestive of a more terrestrial environment.
The shell of the oldest true turtle (Testudinata) branch (Proterochersidae) from the Late Triassic (Norian) of Poland and Germany was built in its anterior and posterior part from an osteodermal ...mosaic which developed several million years after the plastron, neurals and costal bones. We provide the most detailed description of the shell composition in proterochersids to date, together with a review of the shell composition in other Triassic pantestudinates. A scenario of early evolution of the turtle shell is proposed based on new data, and the possible adaptive meaning of the observed evolutionary changes is discussed. These observations are consistent with the trend of shell simplification previously reported in turtles. Several aspects of proterochersid shell anatomy are intermediate between Odontochelys semitestacea and more derived turtles, supporting their stem phylogenetic position. Three additional ossifications were sutured to xiphiplastra and pelvis in Proterochersis spp. and at least in some individuals the nuchal bone was paired. The peripherals, suprapygals, and pygal bone are most likely to be of osteodermal origin and homologous to the proterochersid shell mosaic.
Bromalites (coprolites and possibly some cololites) from a turtle-dominated fossil assemblage from the Upper Triassic of Poland were studied. Bromalites collected at the Poręba site are grouped ...within four morphotypes (A, B, C, and D) attributable to sharks, medium-sized omnivorous or carnivorous tetrapods (likely turtles), sizable carnivorous archosaurs (likely theropods) and an indeterminate big herbivorous tetrapod (possibly dicynodonts or aetosaurs), respectively. Food residues, abundant eggs (possibly of parasites), and microorganisms were found within the materials. Several lines of evidence suggest that at least part of the type B specimens might have been produced by turtles, since (a) turtles are the prevailing tetrapods in the assemblage (over 4/5 of tetrapod bone remains), (b) coprolites are of adequate size, and (c) they appear to have been produced by a carnivore of a low metabolic rate, as seen in extant turtles. The content of the type B specimens would imply that the Late Triassic turtle Proterochersis porebensis was partly piscivorous, but possibly complemented its diet with a more diversified foodstuff, including plants. Semiaquatic habit of Proterochersis porebensis might also provide a taphonomic explanation of the relative abundance of turtle remains at the Poręba site, Poland. Shark bromalites and coprolite specimens attributable likely to theropod dinosaurs also contain abundant fish remains. Origin and classification of spiral and scroll bromalites left by fish are discussed in addition.
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•Studied coprolites provide information on a turtle-dominated Late Triassic ecosystem.•Coprolites were produced by sharks, turtles, theropods, and a sizable herbivore.•Carnivores fed predominantly on fish in this fluvial environment.•The turtle Proterochersis porebensis was likely omnivorous and semiaquatic.•Life habits of early turtles were similar to those typical of extant taxa.
Abstract
The Late Cretaceous Bagaraatan ostromi, described by Osmólska in 1996, is one of the most enigmatic theropod dinosaurs. The holotype possesses a peculiar combination of features, which ...Osmólska suggested were indicative of a primitive position among theropods that could not be resolved further. Other researchers have pointed to affinities with either derived bird-like coelurosaurs or tyrannosaurids. Here, we reanalyse all material collected by Osmólska, which reveals it to be a chimaera of multiple theropod taxa. The femur, tibiotarsus, one pedal phalanx, and most of the bones undescribed in Osmólska’s paper are identified as Caenagnathidae indet. The mandible, cervical vertebrae, pelvis, tail, and one pedal phalanx, which we consider the holotype of B. ostromi, show tyrannosaurid affinities, which are here supported by phylogenetic analyses. We find only two potentially unique diagnostic features of the Bagaraatan holotype: double surangular foramina and a horizontal ridge on the lateral surface of the postacetabular process of the ilium. Both, however, may be ontogenetically or intraspecifically variable, and thus we conclude that the holotype of B. ostromi represents an indeterminate tyrannosaurid. The small size of the holotype and its possession of many features known to characterize juvenile Tyrannosaurus rex indicate that the skeleton belongs to a juvenile, which is one of the smallest juvenile tyrannosaurids currently known.
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