Some recent (mainly) non-dino papers:
The link between claw morphology and function has been historically difficult to quantify, analyze and interpret. In this study, the functional morphology of vertebrate claws is analyzed using measurements taken from 80 modern claw specimens spanning birds, mammals, and one reptile. Claw measurements were chosen for their potential biomechanical significance and a revised, expanded categorization of claw function is defined and used. This categorization scheme is the result of an extensive literature review and is based on the observed mechanics of claw function rather than the animal's overall ecology, an important departure from the norm followed in previous studies. A principal component analysis of the claw measurements reveals that some of the morphological disparity is related to functional differences; however, different functional categories are not clearly separated based solely on morphology. A linear discriminant analysis successfully classifies 81.25% of the claw specimens to their documented functional categories. When the posterior probabilities of each classification are examined, and the next highest probabilities are considered, the analysis is able to successfully classify 96.25% of the claw specimens. Expressing angle measurements in terms of lengths prior to analysis and incorporating crossâsectional shape data both serve to reduce the misclassification rate. The use of biomechanically meaningful claw measurements and categories based on function (rather than ecology) improves confidence in the ability to infer claw function based on morphology using discriminant analysis methods. While overall claw morphology is most certainly the result of multiple factors (e.g., growth, size, etc.), this study establishes that it reflects mechanical function more than previously demonstrated.
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Evolution of the terrestrial egg of amniotes (reptiles, birds, and mammals) is often considered to be one of the most significant events in vertebrate history. Presence of an eggshell, fetal membranes, and a sizeable yolk allowed this egg to develop on land and hatch out wellâdeveloped, terrestrial offspring. For centuries, morphologicallyâbased studies have provided valuable information about the eggs of amniotes and the embryos that develop from them. This review explores the history of such investigations, as a contribution to this special issue of Journal of Morphology, titled Developmental Morphology and Evolution of Amniote Eggs and Embryos. Anatomicallyâbased investigations are surveyed from the ancient Greeks through the Scientific Revolution, followed by the 19th and early 20th centuries, with a focus on major findings of historical figures who have contributed significantly to our knowledge. Recent research on various aspects of amniote eggs is summarized, including gastrulation, egg shape and eggshell morphology, eggs of Mesozoic dinosaurs, sauropsid yolk sacs, squamate placentation, embryogenesis, and the phylotypic phase of embryonic development. As documented in this review, studies on amniote eggs and embryos have relied heavily on morphological approaches in order to answer functional and evolutionary questions.
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Free pdf:
Kazuhiko Kawasaki, Joseph N. Keating, Mitsushiro Nakatomi, Monique Welten, Masato Mikami, Ichiro Sasagawa, Mark N. Puttick, Philip C.J. Donoghue & Mikio Ishiyama (2020)
Coevolution of enamel, ganoin, enameloid, and their matrix SCPP genes in osteichthyans.
iScience 102023
doi:
https://doi.org/10.1016/j.isci.2020.102023https://www.sciencedirect.com/science/article/pii/S2589004220312207Highlights
Ganoin emerged in actinopterygian scales; true enamel arose in sarcopterygian teeth.
Dental enamel, acrodin, and enameloid in actinopterygians are related to ganoin.
SCPP5 evolved in association with ganoin, while AMEL evolved with true enamel.
Shifts in SCPP gene _expression_ explain the evolution of hypermineralized tissues.
SUMMARY
We resolve debate over the evolution of vertebrate hypermineralized tissues through analyses of matrix protein-encoding secretory calcium-binding phosphoprotein (SCPP) genes and phylogenetic inference of hypermineralized tissues. Among these genes, AMBN and ENAM are found in both sarcopterygians and actinopterygians, while AMEL and SCPP5 are found only in sarcopterygians and actinopterygians, respectively. Actinopterygian AMBN, ENAM, and SCPP5 are expressed during formation of hypermineralized tissues on scales and teeth: ganoin, acrodin, and collar enamel in gar, and acrodin and collar enameloid in zebrafish. Our phylogenetic analyses indicate emergence of an ancestral enamel in stem-osteichthyans, while ganoin emerged in stem-actinopterygians, and true enamel in stem-sarcopterygians. Thus, AMBN and ENAM originated in concert with ancestral enamel, SCPP5 evolved in association with ganoin, while AMEL evolved with true enamel. Shifts in gene _expression_ domain and timing explain the evolution of different hypermineralized tissues. We propose that hypermineralized tissues in osteichthyans coevolved with matrix SCPP genes.
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Free pdf:
John R. Wood, Michael A. Bozek, Andrew R.C. Milner, Alison L. Mims, Forest Frost, and Vincent L. Santucci (2021)
Structure from motion photogrammetry enhances paleontological resource documentation, research, preservation and education efforts for National Park Service areas.
In: Lucas, S. G., Hunt, A. P. & Lichtig, A. J., 2021, Fossil Record 7. New Mexico Museum of Natural History and Science Bulletin 82: 513-523
Âand
https://www.researchgate.net/publication/348008430_STRUCTURE_FROM_MOTION_PHOTOGRAMMETRY_ENHANCES_PALEONTOLOGICAL_RESOURCE_DOCUMENTATION_RESEARCH_PRESERVATION_AND_EDUCATION_EFFORTS_FOR_NATIONAL_PARK_SERVICE_AREASStructure-from-motion (SfM) photogrammetry is an increasingly common component of paleontological research and fossil resources management. The three-dimensional (3D) data and the derived products allow for novel and useful avenues to engage and problem-solve with park resource managers and stakeholders. The National Park Service (NPS) is developing a robust SfM program to support park units with resource documentation and monitoring efforts, training for staff, and building capacity for 3D data processing. We report on three case studies as examples where SfM techniques have been applied: 1) monitoring of paleontological localities; 2) documenting in situ fossil discoveries; and 3) digitization of fossil specimens in museum collections. The capacity within the NPS for photogrammetry to support paleontological research is also enhancing collaborative efforts resulting in new fossil discoveries in NPS areas. The case study for Curecanti National Recreation Area (CURE) is the design and testing of monitoring methods for paleontological resources subject to accelerated erosion due to reservoir management. The fossil locations at CURE are inundated by reservoir pool level changes, with loss of paleontological resources to erosion, burial and permanent submersion as the beach is reworked by wave energy due to fluctuating water level elevations. At Glen Canyon National Recreation Area a recently discovered track block with numerous vertebrate trace fossils was documented. The fossil tracks on the block appear on a bedding surface of a large vertically oriented fallen slab of Wingate Sandstone. Photogrammetry has enabled detailed 3D mapping and surface topology analysis of the slab, revealing in more detail the abundant theropod tracks and trackways. The digital nature of photogrammetric data also opens new avenues for engaging with scientists and the public. These data can be grouped into digital collections for showcasing a park's paleontological resources and are easily adapted for producing 3D replicas. Use of such models allows outreach to current and new park audiences and others who benefit from interaction with tactile elements. Rapid prototyping technology (e.g., 3D printing) employs newer materials and comes with lower costs when compared to traditional fossil replication methods. New applications for 3D data and SfM photogrammetry methods will continue to expand within paleontological research. The NPS continues to take positive strides to be at the forefront of developing SfM methods for paleontology.
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Some dinosaur-related items...
Free pdf:
Brianna A. Santucci, ÂCarol A. Moneymaker, ÂJohn F. Lisco Âand Vincent L. Santucci (2021)
An overview of paleontological resources preserved within prehistoric and historic structures.
In: Lucas, S. G., Hunt, A. P. & Lichtig, A. J., 2021, Fossil Record 7. New Mexico Museum of Natural History and Science Bulletin 82: 347-356
https://irma.nps.gov/DataStore/DownloadFile/654713
The occurrence of fossils and fossiliferous stone within historic and prehistoric structures is relatively widespread and presents some unique insights into the human dimensions of paleontological resources. Fossil invertebrates, vertebrates, plants, and trace fossils are all known to occur within building stones incorporated into a wide variety of structures. The presence of fossils within structures can be either intentional or unintentional actions by individuals involved with the design and construction of these man-made features. This overview of fossils within historic and prehistoric structures enables a greater understanding of the scope, significance, distribution, and management issues associated with the preservation, conservation, and protection of these fossiliferous cultural resources.