Search results for "Metoposaurus"
showing 5 items of 15 documents
Mandible histology in Metoposaurus krasiejowensis (Temnospondyli, Stereospondyli) from the Upper Triassic of Poland
2021
Recent studies that have systematically augmented our knowledge of dermal bones of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis have mostly focused on shoulder girdle elements and the skull. So far, histological data on the mandible are still scant. For the present study, two mandibles have been examined, using 50 standard thin sections. Dermal bones of the mandible reveal a uniform diploë structure, with the external cortex consisting of moderately vascularised, parallel-fibred bone, as well as a distinct alternation of thick zones and thinner annuli. Dense bundles of well-mineralised Sharpey’s fibres are seen in the external cortex over the entire length of the man…
Histological characteristics of the vertebral intercentra of Metoposaurus diagnosticus (Temnospondyli) from the Upper Triassic of Krasiejów (Upper Si…
2012
ABSTRACTOsteohistological characteristics of the large temnospondyl amphibian Metoposaurus diagnosticus from the Upper Triassic of Poland (Krasiejów locality) were determined using vertebral intercentra thin-sections from different regions and growth stages. The intercentra showed a trabecular structure in both the endochondral and periosteal domains. Endochondral ossification developed first, and the primary bone occurs near the periphery with a higher degree of remodelling in the centre. Periosteal bone deposition begins later; first on the ventral side, continuing laterally and finally onto the dorsal side. Periosteal growth rate was initially very rapid, and then subsequently decreased …
Long bone histology of Metoposaurus diagnosticus (Temnospondyli) from the Late Triassic of Krasiejów (Poland) and its paleobiological implications
2013
ABSTRACT Long bones of the temnospondyl Metoposaurus diagnosticus krasiejowensis from the Late Triassic of Krasiejow, Poland, were studied using histological analysis. Six femora, three humeri, a radius, and an ulna were prepared for thin-sectioning. In all bones, the dominant type of primary bone matrix is parallel-fibered bone with secondary, or rarely primary, deposition of lamellar bone inside vascular canals. Two small humeri and the smallest femur showed incipient fibrolamellar bone, which may be a character typical for juvenile individuals. The medullary region is filled with well-developed trabecular bone. The growth marks in all bones are organized as thick layers of highly vascula…
Unique growth pattern of Metoposaurus diagnosticus krasiejowensis (Amphibia, Temnospondyli) from the Upper Triassic of Krasiejów, Poland
2013
Morphology and bone histology of femora, tibiae, and fibulae of the temnospondyl Metoposaurus diagnosticus krasiejowensis from the Upper Triassic locality of Krasiejow (Poland) are studied for the first time. The growth pattern of Metoposaurus as preserved in a small growth series of femora, shows a regular alternating sequence of fast and slow growth phases, which are interpreted as representing zones and annuli. The slow growth phases (annuli) of the inner and outer cortex as well as those of different specimens are of a regular broad thickness. Such broad annuli are so far unknown for any vertebrate and make the growth pattern for Metoposaurus unique. These slow growth phases always cont…
Unraveling the origin of the Late Triassic multitaxic bone accumulation at Krasiejów (S Poland) by diagenetic analysis
2012
Abstract A study of aquatic and terrestrial vertebrate remains from a bonebed in the Late Triassic continental succession near Krasiejow (S Poland) shows it was deposited by a single catastrophic event, perhaps a flood. Hardparts of Metoposaurus, Paleorhinus, and Stagonolepis show sedimentary infill and geochemical evidence for early diagenesis at different times and in different microenvironments. The infills in the aquatic animal bones (sediment, pyrite and calcite) show deposition in a freshwater environment, while those in the terrestrial Stagonolepis remains (mainly barite) point to an arid terrestial environment. The trace element content of the remains, together with the absence of a…