title: Unusual intraosseous fossilized soft tissues from the Middle Triassic Nothosaurus bone.
abstract: 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.
authors.affiliation: Park of Science & Human Evolution, 1 Maja 10, 46-040, Krasiejów, Poland. dawid@surmik.pl.|Faculty of Earth Science, University of Silesia, Będzińska 60, 41-200, Sosnowiec, Poland. dawid@surmik.pl.
authors.forename: Dawid
authors.identifier: http://orcid.org/0000-0003-0121-9592
authors.initials: D
authors.lastname: Surmik
authors.affiliation: Carnegie Museum, 4400 Forbes Ave, Pittsburgh, PA, 15213, USA.|West Virginia University College of Medicine, Morgantown, WV, 26330, USA.
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Rothschild
authors.affiliation: Department of Histology, Jagiellonian University Medical College, Kopernika 7, 31-034, Kraków, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Pawlicki
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology*; D005580:Fossils; D011044:Poland; D012104:Reptiles / Q000033:anatomy & histology*
keywords: Fossilized soft tissues; Intraosseous; Middle Triassic; Nothosaurus; Physiology