To be or not to be heavier: The role of dermal bones in the buoyancy of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis.

Stereospondyli are a clade of large aquatic temnospondyls known to have evolved a large dermal pectoral girdle. Among the Stereospondyli, metoposaurids in particular possess large interclavicles and clavicles relative to the rest of the postcranial skel-eton. Because of the large size of these dermal bones, it was first proposed that they served as ballast during hydrostatic buoyancy control which assisted metoposaurids to live a bottom-dwelling mode of life. However, a large bone need not necessarily be heavy, for which determining the bone compactness becomes crucial for under-standing any such adaptation in these dermal bones. Previous studies on the evolu-tion of bone adaptations to aqu…

An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Abstract Background 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. Results A wide array of data collected from gross anatomy, histology, and microstructure of the affected intercentrum reveals th…

Pentadactyl manus of the Metoposaurus krasiejowensis from the Late Triassic of Poland, the first record of pentadactyly among Temnospondyli

Abstract Temnospondyli are commonly believed to have possessed four digits in the manus and five in the pes. However, actual finds of articulated autopodia are extremely rare. Therefore, an articulated, slightly incomplete forelimb skeleton with preserved manus of Metoposaurus krasiejowensis from the Late Triassic of Poland is important in providing new details about the structure and ossification sequence in the temnospondyl limb. The most important observation is the presence of five metacarpals in this specimen. This allows reconstructing the manus as pentadactyl. The number of phalanges and the distribution of distal articulation facets allow reconstruction of the digit formula as (2?)‐…

Additional file 7 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 7. Close-ups of osteocytes lacunae in the neoplasm-affected part of vertebral intercentrum showing their subspherical shapes.

Additional file 6 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 6. Photoscan of ground section of normal, non-altered anterodorsal vertebral intercentrum of Metoposaurus krasiejowensis, for comparative purposes, specimen number UOPB 00118 [1].

Triassic nursery? Evidence of gregarious behavior in juvenile pseudosuchian archosaurs as inferred by humeral histology of Aetosaurus ferratus (Norian; southern Germany)

Climatic influence on the growth pattern ofPanthasaurus maleriensisfrom the Late Triassic of India deduced from paleohistology

Metoposaurids are representatives of the extinct amphibian clade Temnospondyli, found on almost every continent exclusively in the Late Triassic deposits. Osteohistologically, it is one of the best-known temnospondyl groups, analyzed with a wide spectrum of methods, such as morphology, morphometry, bone histology or computed modelling. The least known member of Metoposauridae isPanthasaurus maleriensisfrom the Pranhita-Godavari basin in Central India, being geographically the most southern record of this family. For the first time the bone histology of this taxon was studied with a focus on the intraspecific variability of the histological framework and the relationship between the observed…

New skulls of the basal sauropodomorph Plateosaurus trossingensis from Frick, Switzerland: is there more than one species?

The Triassic basal sauropodomorph Plateosaurus trossingensis is well-known from mass accumulations at the German localities of Trossingen and Halberstadt and the Swiss locality of Frick, and is significant especially regarding its ta-phonomy and proposed developmental plasticity. These implications, however, rely on the assumption that this material derives from a single species, which has been questioned. Here we describe new skull material from Frick including eight complete and six partial skulls, more than doubling the number of known skulls of P. trossingensis. This exceptional sample size allows for gaining a deeper understanding of variability that may occur in a single species. The …

Variability of growth pattern observed in Metoposaurus krasiejowensis humeri and its biological meaning

Purpose Histological studies on temnospondyl amphibian bones remain rare. A systematic revision of the histology was applied for the purpose of testing the histovariability in the humeri and becoming new information about the growth pattern. Methods The present study includes 12 humeri of Metoposaurus krasiejowensis, which originate from the Late Triassic clay pit near Krasiejo´w, southwestern Poland. The specimens were scanned with a microCT and the histological thin-sections have been obtained with the standard petrographic method. Results The evaluation of the studied bones shows a uniform growth series resulting in one morphotype. Strikingly, the histological analysis reveals a greater …

Additional file 1 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 1. 3D model of ZPAL Ab III/2467.

Additional file 3 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 3. 3D model of pathologically-altered intercentrum, virtually extracted from microtomographic scans.

Additional file 4 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 4. 3D model of bone outgrowth, virtually extracted from microtomographic scans.

Additional file 5 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 5. 3D model of ZPAL Ab III/2467 with marked scanning planes.

Additional file 2 of An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis?

Additional file 2. Juxtaposition of the 3D model of ZPAL Ab III/2467 and 3D volumetric reconstructions of the remaining normal part of the pathologically-altered intercentrum and bone outgrowth (tumour).