Ben Creisler
Some new or recent dino papers:
Highlights
A new workflow for CT-Scan imaging is presented.
Pneumosteum is described in a cervical vertebra of a titanosaur.
We corroborate previous hypotheses on the insertion of bird-like air-sacs system on titanosaurian vertebrae based on external observation and CT-Scans.
It is possible that the camellate architecture is directly influenced by the air-sacs system that surrounds the vertebra.
A good understanding on the diagenesis of a specimen could avoid false negatives of pneumosteum.
Abstract
There is a necessity to systematically sample taxa to enlighten our knowledge on the presence of histological correlates of avian-like air sacs among dinosaurs. This work expands the studies on the occurrence of pneumosteum in sauropods to the Brazilian lithostrotian titanosaur Uberabatitan ribeiroi. This confirms previous hypotheses on the insertion of an air sacs system on titanosaurian vertebrae based on external observation and CT-scans. We also highlight that diagenesis can obliterate traces of pneumosteal bone. Caution is required to have a good understanding of the diagenetic history of the studied specimens. This could avoid false negatives, especially when sampling pneumatic histological traces in stem taxa. Additionally, we describe a new workflow for manipulating CT-scan data using open-source software. The goal is to make this technology more accessible to research groups with limited funding and potentialize the achievement of more paleontological data.
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Free pdf:
Ornithopod dinosaurs were abundant inhabitants of European islands during the Late Cretaceous. The long history of dinosaur research in Europe has led to the establishment of new taxa for numerous ornithopod specimens that received considerable attention in the literature; however, many of these remain essentially unstudied. This explains why little is known of their potential phylogenetic, ecological and biogeographical importance. Here we provide a reassessment of Orthomerus dolloi, an enigmatic ornithopod taxon that was established on the basis of isolated appendicular elements, including a left tibia, a right femur, a left femur and a metatarsal. The material originates from the uppermost Maastrichtian of southern Limburg (the Netherlands) or adjacent Belgian territory. Despite the fact that they have been known for almost 140 years, none of these elements has been evaluated in detail since their original description. Here we redescribe and illustrate the syntypes of O. dolloi, and compare them to corresponding elements in other latest Cretaceous ornithopods from Europe. The character distribution in O. dolloi is further explored by means of phylogenetic analyses, using a revised ornithopod-wide dataset. The material belongs to at least two, probably conspecific, individuals that show clear hadrosauroid affinities, although the exact placement of the taxon within the clade remains contentious, because it is likely that its elements are osteologically immature. Therefore, the common assignment of O. dolloi to hadrosaurid ornithopods is questionable. Nevertheless, our revision of the material has not identified any autapomorphies, nor a combination of characters that would be indisputably unique among Hadrosauroidea.
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Free pdf:
Thiago Vernaschi V. Costa (2019)
Remarks on the name of the hadrosauroid dinosaur Eolambia caroljonesa Kirkland, 1998 (Ornithischia)
Revista Brasileira de Paleontologia 22(2):165â166
doi:10.4072/rbp.2019.2.07
http://www.sbpbrasil.org/assets/uploads/files/rbp2019207.pdfThe large hadrosauroid dinosaur Eolambia caroljonesa was named in honor of Carol Jones, the discoverer of the place where the type specimens were found. However, according to the article 31.1.2 of the ICZN, the form caroljonesae should have been used and, thus, caroljonesa represents an incorrect original spelling subject to a justified emendation. Such emendation is required in cases on which the incorrect original spelling of a species-group name must be corrected, as stated by the article 32.5.1 of the ICZN. Therefore, based on the express application of the nomenclatural rules, the name of the species must be corrected to Eolambia caroljonesae.
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