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Baiano MA, Cerda IA, Bertozzo F, Pol D. New information on paleopathologies in non-avian theropod dinosaurs: a case study on South American abelisaurids. BMC Ecol Evol 2024; 24:6. [PMID: 38291378 PMCID: PMC10829224 DOI: 10.1186/s12862-023-02187-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/06/2023] [Indexed: 02/01/2024] Open
Abstract
Studies on pathological fossil bones have allowed improving the knowledge of physiology and ecology, and consequently the life history of extinct organisms. Among extinct vertebrates, non-avian dinosaurs have drawn attention in terms of pathological evidence, since a wide array of fossilized lesions and diseases were noticed in these ancient organisms. Here, we evaluate the pathological conditions observed in individuals of different brachyrostran (Theropoda, Abelisauridae) taxa, including Aucasaurus garridoi, Elemgasem nubilus, and Quilmesaurus curriei. For this, we use multiple methodological approaches such as histology and computed tomography, in addition to the macroscopic evaluation. The holotype of Aucasaurus shows several pathognomonic traits of a failure of the vertebral segmentation during development, causing the presence of two fused caudal vertebrae. The occurrence of this condition in Aucasaurus is the first case to be documented so far in non-tetanuran theropods. Regarding the holotype of Elemgasem, the histology of two fused vertebrae shows an intervertebral space between the centra, thus the fusion is limited to the distal rim of the articular surfaces. This pathology is here considered as spondyloarthropathy, the first evidence for a non-tetanuran theropod. The microstructural arrangement of the right tibia of Quilmesaurus shows a marked variation in a portion of the outer cortex, probably due to the presence of the radial fibrolamellar bone tissue. Although similar bone tissue is present in other extinct vertebrates and the cause of its formation is still debated, it could be a response to some kind of pathology. Among non-avian theropods, traumatic injuries are better represented than other maladies (e.g., infection, congenital or metabolic diseases, etc.). These pathologies are recovered mainly among large-sized theropods such as Abelisauridae, Allosauridae, Carcharodontosauridae, and Tyrannosauridae, and distributed principally among axial elements. Statistical tests on the distribution of injuries in these theropod clades show a strong association between taxa-pathologies, body regions-pathologies, and taxa-body regions, suggesting different life styles and behaviours may underlie the frequency of different injuries among theropod taxa.
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Affiliation(s)
- Mattia A Baiano
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, 1425, Ciudad Autónoma de Buenos Aires, Argentina.
- Area Laboratorio e Investigación, Museo Municipal 'Ernesto Bachmann', Dr Natali S/N, 8311, Villa El Chocon, Neuquén, Argentina.
- Universidad Nacional de Río Negro (UNRN), Isidro Lobo 516, 8332, General Roca, Río Negro, Argentina.
| | - Ignacio A Cerda
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, 1425, Ciudad Autónoma de Buenos Aires, Argentina
- Universidad Nacional de Río Negro (UNRN), Isidro Lobo 516, 8332, General Roca, Río Negro, Argentina
- Instituto de Investigacion en Paleobiología y Geología (IIPG), Av. Roca 1242, 8332, General Roca, Río Negro, Argentina
- Museo Carlos Ameghino, Belgrano 1700 (Paraje Pichi Ruca, Predio Marabunta), 8324, Cipolletti, Río Negro, Argentina
| | - Filippo Bertozzo
- Operational Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Diego Pol
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, 1425, Ciudad Autónoma de Buenos Aires, Argentina
- Museo Paleontológico Egidio Feruglio, Av. Fontana 140, 9100, Trelew, Chubut, Argentina
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Booth SC, Smith WPJ, Foster KR. The evolution of short- and long-range weapons for bacterial competition. Nat Ecol Evol 2023; 7:2080-2091. [PMID: 38036633 PMCID: PMC10697841 DOI: 10.1038/s41559-023-02234-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 09/22/2023] [Indexed: 12/02/2023]
Abstract
Bacteria possess a diverse range of mechanisms for inhibiting competitors, including bacteriocins, tailocins, type VI secretion systems and contact-dependent inhibition (CDI). Why bacteria have evolved such a wide array of weapon systems remains a mystery. Here we develop an agent-based model to compare short-range weapons that require cell-cell contact, with long-range weapons that rely on diffusion. Our model predicts that contact weapons are useful when an attacking strain is outnumbered, facilitating invasion and establishment. By contrast, ranged weapons tend to be effective only when attackers are abundant. We test our predictions with the opportunistic pathogen Pseudomonas aeruginosa, which naturally carries multiple weapons, including CDI and diffusing tailocins. As predicted, short-range CDI can function at low and high frequencies, while long-range tailocins require high frequency and cell density to function effectively. Head-to-head competition experiments with the two weapon types further support our predictions: a tailocin attacker defeats CDI only when it is numerically dominant, but then we find it can be devastating. Finally, we show that the two weapons work well together when one strain employs both. We conclude that short- and long-range weapons serve different functions and allow bacteria to fight both as individuals and as a group.
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Affiliation(s)
- Sean C Booth
- Department of Biology, University of Oxford, Oxford, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - William P J Smith
- Department of Biology, University of Oxford, Oxford, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
- Division of Evolution, Infection and Genomics, University of Manchester, Manchester, UK
| | - Kevin R Foster
- Department of Biology, University of Oxford, Oxford, UK.
- Department of Biochemistry, University of Oxford, Oxford, UK.
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