Dawid Surmik

The oldest record of aquatic amniote congenital scoliosis

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.

A re-evaluation of the historical ‘dinosaur’ remains from the Middle-Upper Triassic of Poland

Abstract The so-called historical Polish discoveries of Triassic ‘dinosaurs’ have been repeatedly cited in papers and popular science books. Here, we re-evaluate each historical and purported Triassic dinosaur find from Poland. Additionaly, we describe several supposed ‘dinosaur’ bones collected by Polish geologists but only briefly mentioned: in regional geological journals, on collection labels, or in field notes. We attempt to assign all investigated specimens to the least inclusive taxon possible. Our revision indicates that part of this material represents non-dinosaur archosauromorph taxa. Most of the analysed specimens are fragmentary bones or isolated teeth and are indistinguishable from skeletal elements described from other well-known Triassic archosauromorph taxa. We conclude that fossils of dinosauriforms are present in the Upper Triassic of Silesia and Holy Cross Mountains. New analysis of Velocipes guerichi von Huene, 1932 holotype specimen from Kocury shows that it is the proximal part of fibula of a medium-sized theropod (or even neotheropod). Formally undescribed part of dinosauriform limb bone from the Holy Cross Mountains and V. guerichi from Silesia are the only identifiable dinosauromorph skeletal remains recognised in the Polish Triassic discovered prior to the description of Silesaurus opolensis Dzik, 2003 from the Upper Carnian of Krasiejów.

Unusual intraosseous fossilized soft tissues from the Middle Triassic Nothosaurus bone

Fossilized soft tissues, occasionally found together with skeletal remains, provide insights to the physiology and functional morphology of extinct organisms. Herein, we present unusual fossilized structures from the cortical region of bone identified in isolated skeletal remains of Middle Triassic nothosaurs from Upper Silesia, Poland. The ribbed or annuli-shaped structures have been found in a sample of partially demineralized coracoid and are interpreted as either giant red blood cells or as blood vessel walls. The most probable function is reinforcing the blood vessels from changes of nitrogen pressure in air-breathing diving reptiles. These structures seem to have been built of extensible muscle layers which prevent the vessel damage during rapid ascent. Such suspected function presented here is parsimonious with results of previous studies, which indicate rarity of the pathological modification of bones associated with decompression syndrome in Middle Triassic nothosaurs.

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.

The results of palaeontological excavations in the Sadowa Góra quarry (2012-14)

Abstract Palaeontological fieldwork (2012-14) in the Sadowa Góra quarry carried out under the auspices of the University of Silesia, within the framework of a research project supported by the National Science Centre, helped to document the taxonomic diversity of Middle Triassic marine vertebrates from the Cracow-Silesia region. Accumulations of fossil bones are correlated with storm deposition and are time-averaged

The large superpredators’ teeth from Middle Triassic of Poland

ABSTRACT An unusual large teeth, finding from time to time in marine sediments of Muschelkalk, Silesia, Poland indicate the superpredators occurrence. According to size and morphological features the teeth are similar to archosaurs or giant marine reptiles.

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.