1
|
Surmik D, Słowiak-Morkovina J, Szczygielski T, Kamaszewski M, Kalita S, Teschner EM, Dróżdż D, Duda P, Rothschild BM, Konietzko-Meier D. An insight into cancer palaeobiology: does the Mesozoic neoplasm support tissue organization field theory of tumorigenesis? BMC Ecol Evol 2022; 22:143. [PMID: 36513967 PMCID: PMC9746082 DOI: 10.1186/s12862-022-02098-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Neoplasms are common across the animal kingdom and seem to be a feature plesiomorphic for metazoans, related with an increase in somatic complexity. The fossil record of cancer complements our knowledge of the origin of neoplasms and vulnerability of various vertebrate taxa. Here, we document the first undoubted record of primary malignant bone tumour in a Mesozoic non-amniote. The diagnosed osteosarcoma developed in the vertebral intercentrum of a temnospondyl amphibian, Metoposaurus krasiejowensis from the Krasiejów locality, southern Poland. RESULTS A wide array of data collected from gross anatomy, histology, and microstructure of the affected intercentrum reveals the tumour growth dynamics and pathophysiological aspects of the neoplasm formation on the histological level. The pathological process almost exclusively pertains to the periosteal part of the bone composed from a highly vascularised tissue with lamellar matrix. The unorganised arrangement of osteocyte lacunae observed in the tissue is characteristic for bone tissue types connected with static osteogenesis, and not for lamellar bone. The neoplastic bone mimics on the structural level the fast growing fibrolamellar bone, but on the histological level develops through a novel ossification type. The physiological process of bone remodelling inside the endochondral domain continued uninterrupted across the pathology of the periosteal part. CONCLUSIONS Based on the results, we discuss our case study's consistence with the Tissue Organization Field Theory of tumorigenesis, which locates the causes of neoplastic transformations in disorders of tissue architecture.
Collapse
Affiliation(s)
- Dawid Surmik
- grid.11866.380000 0001 2259 4135Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland
| | - Justyna Słowiak-Morkovina
- grid.413454.30000 0001 1958 0162Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland
| | - Tomasz Szczygielski
- grid.413454.30000 0001 1958 0162Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland
| | - Maciej Kamaszewski
- grid.13276.310000 0001 1955 7966Institute of Animal Sciences, Warsaw University of Life Sciences, Ciszewskiego 8, 02-786 Warsaw, Poland
| | - Sudipta Kalita
- grid.10388.320000 0001 2240 3300Institute of Geosciences, Section Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Elżbieta M. Teschner
- grid.10388.320000 0001 2240 3300Institute of Geosciences, Section Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany ,grid.107891.60000 0001 1010 7301Institute of Biology, University of Opole, Oleska 22, 45-052 Opole, Poland
| | - Dawid Dróżdż
- grid.413454.30000 0001 1958 0162Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland
| | - Piotr Duda
- grid.11866.380000 0001 2259 4135Faculty of Exact and Technical Sciences, University of Silesia, Będzińska 39, 41-200 Sosnowiec, Poland
| | - Bruce M. Rothschild
- grid.420557.10000 0001 2110 2178Carnegie Museum of Natural History, 4400 Forbes Ave, Pittsburgh, PA 15215 USA
| | - Dorota Konietzko-Meier
- grid.10388.320000 0001 2240 3300Institute of Geosciences, Section Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| |
Collapse
|
2
|
Frýdlová P, Mrzílková J, Šeremeta M, Křemen J, Dudák J, Žemlička J, Minnich B, Kverková K, Němec P, Zach P, Frynta D. Determinate growth is predominant and likely ancestral in squamate reptiles. Proc Biol Sci 2020; 287:20202737. [PMID: 33352069 PMCID: PMC7779497 DOI: 10.1098/rspb.2020.2737] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Body growth is typically thought to be indeterminate in ectothermic vertebrates. Indeed, until recently, this growth pattern was considered to be ubiquitous in ectotherms. Our recent observations of a complete growth plate cartilage (GPC) resorption, a reliable indicator of arrested skeletal growth, in many species of lizards clearly reject the ubiquity of indeterminate growth in reptiles and raise the question about the ancestral state of the growth pattern. Using X-ray micro-computed tomography (µCT), here we examined GPCs of long bones in three basally branching clades of squamate reptiles, namely in Gekkota, Scincoidea and Lacertoidea. A complete loss of GPC, indicating skeletal growth arrest, was the predominant finding. Using a dataset of 164 species representing all major clades of lizards and the tuataras, we traced the evolution of determinate growth on the phylogenetic tree of Lepidosauria. The reconstruction of character states suggests that determinate growth is ancestral for the squamate reptiles (Squamata) and remains common in the majority of lizard lineages, while extended (potentially indeterminate) adult growth evolved several times within squamates. Although traditionally associated with endotherms, determinate growth is coupled with ectothermy in this lineage. These findings combined with existing literature suggest that determinate growth predominates in both extant and extinct amniotes.
Collapse
Affiliation(s)
- Petra Frýdlová
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jana Mrzílková
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Martin Šeremeta
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jan Křemen
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Jan Dudák
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Prague 110 00, Czech Republic
| | - Jan Žemlička
- Institute of Experimental and Applied Physics, Czech Technical University in Prague, Prague 110 00, Czech Republic
| | - Bernd Minnich
- Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, Salzburg 5020, Austria
| | - Kristina Kverková
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
| | - Petr Zach
- Specialized Laboratory of Experimental Imaging, Third Faculty of Medicine of Charles University, Institute of Technical and Applied Physics and Faculty of Bioengineering, Prague 100 00, Czech Republic.,Department of Anatomy, Third Faculty of Medicine, Charles University, Prague 100 00, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, Prague 12844, Czech Republic
| |
Collapse
|
3
|
Griffin CT, Stocker MR, Colleary C, Stefanic CM, Lessner EJ, Riegler M, Formoso K, Koeller K, Nesbitt SJ. Assessing ontogenetic maturity in extinct saurian reptiles. Biol Rev Camb Philos Soc 2020; 96:470-525. [PMID: 33289322 DOI: 10.1111/brv.12666] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/09/2020] [Accepted: 10/28/2020] [Indexed: 01/06/2023]
Abstract
Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study the evolution of ontogenetic changes, population structure and palaeoecology, life-history strategies, and heterochrony along evolutionary lineages that would otherwise be lost to time. Saurian reptiles (the least-inclusive clade containing Lepidosauria and Archosauria) have remained an incredibly diverse, numerous, and disparate clade through their ~260-million-year history. Because of the great disparity in this group, assessing maturity of saurian reptiles is difficult, fraught with methodological and terminological ambiguity. We compiled a novel database of literature, assembling >900 individual instances of saurian maturity assessment, to examine critically how saurian maturity has been diagnosed. We review the often inexact and inconsistent terminology used in saurian maturity assessment (e.g. 'juvenile', 'mature') and provide routes for better clarity and cross-study coherence. We describe the various methods that have been used to assess maturity in every major saurian group, integrating data from both extant and extinct taxa to give a full account of the current state of the field and providing method-specific pitfalls, best practices, and fruitful directions for future research. We recommend that a new standard subsection, 'Ontogenetic Assessment', be added to the Systematic Palaeontology portions of descriptive studies to provide explicit ontogenetic diagnoses with clear criteria. Because the utility of different ontogenetic criteria is highly subclade dependent among saurians, even for widely used methods (e.g. neurocentral suture fusion), we recommend that phylogenetic context, preferably in the form of a phylogenetic bracket, be used to justify the use of a maturity assessment method. Different methods should be used in conjunction as independent lines of evidence when assessing maturity, instead of an ontogenetic diagnosis resting entirely on a single criterion, which is common in the literature. Critically, there is a need for data from extant taxa with well-represented growth series to be integrated with the fossil record to ground maturity assessments of extinct taxa in well-constrained, empirically tested methods.
Collapse
Affiliation(s)
- Christopher T Griffin
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Michelle R Stocker
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Caitlin Colleary
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Vertebrate Paleontology, Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, OH, 44106, U.S.A
| | - Candice M Stefanic
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Anatomical Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, NY, 11794, U.S.A
| | - Emily J Lessner
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Pathology and Anatomical Sciences, University of Missouri, 1 Hospital Drive, Columbia, MO, 65212, U.S.A
| | - Mitchell Riegler
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL, 32611, U.S.A
| | - Kiersten Formoso
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy, Los Angeles, CA, 90089, U.S.A
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 W Exposition Boulevard, Los Angeles, CA, 90007, U.S.A
| | - Krista Koeller
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, U.S.A
| | - Sterling J Nesbitt
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| |
Collapse
|
4
|
Klein N, Canoville A, Houssaye A. Microstructure of Vertebrae, Ribs, and Gastralia of Triassic Sauropterygians-New Insights into the Microanatomical Processes Involved in Aquatic Adaptations of Marine Reptiles. Anat Rec (Hoboken) 2019; 302:1770-1791. [PMID: 30989828 DOI: 10.1002/ar.24140] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/07/2018] [Accepted: 12/02/2018] [Indexed: 01/01/2023]
Abstract
Isolated ribs and vertebrae of Middle Triassic sauropterygians are studied. The vertebrae have a well-defined large cavity in their centra, which is a unique feature and is without any modern analogue. The articular facets of vertebrae are made of endochondral bone including calcified as well as uncalcified cartilage. Vertebrae are pachyosteosclerotic in the pachypleurosaurs Neusticosaurus and Serpianosaurus from the Alpine Triassic, and osteosclerotic in the placodont, in the medium-sized Nothosaurus marchicus, and in the pachypleurosaur Anarosaurus. In large Nothosaurus specimens, the vertebrae are cavernous. The ribs of all sampled specimens are osteosclerotic, which resembles the microanatomy of long bones in all studied taxa. The proximal to medial part of ribs mainly consists of a compact periosteal cortex surrounding an inner endosteal territory. Toward the distal end of the ribs, the periosteal thickness decreases whereas the endosteal territory increases. Despite a shift from periosteal versus endosteal tissues, global rib compactness remains relatively constant. Osteosclerosis in ribs and vertebrae is reached by the same processes as in the long bones: by a relative increase in cortex thickness that is coupled by a reduction of the medullary cavity, by the persistence of calcified cartilage, and by an inhibition of remodeling although some resorption may occur but without complete redeposition of bone. Processes differ from those observed in Permian marine reptiles and some mosasaurines, where either extensive remodeling or inhibition of bone resorption leads to osteosclerosis. Besides differences regarding the microanatomy, all studied bones of a taxon are consistent in their bone tissue type. Anat Rec, 302:1770-1791, 2019. © 2019 American Association for Anatomy.
Collapse
Affiliation(s)
- Nicole Klein
- Division of Paleontology, Steinmann Institute, University of Bonn, Bonn, Germany
| | - Aurore Canoville
- Department of Biological Sciences, North Carolina State University and Paleontology, North Carolina Museum of Natural Sciences, Raleigh, North Carolina
| | - Alexandra Houssaye
- UMR 7179 CNRS/Muséum National d'Histoire Naturelle, Département Adaptations du Vivant, Paris, France
| |
Collapse
|
5
|
Griebeler EM, Werner J. Formal comment on: Myhrvold (2016) Dinosaur metabolism and the allometry of maximum growth rate. PLoS ONE; 11(11): e0163205. PLoS One 2018; 13:e0184756. [PMID: 29489816 PMCID: PMC5830040 DOI: 10.1371/journal.pone.0184756] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/08/2017] [Indexed: 11/19/2022] Open
Abstract
In his 2016 paper, Myhrvold criticized ours from 2014 on maximum growth rates (Gmax, maximum gain in body mass observed within a time unit throughout an individual's ontogeny) and thermoregulation strategies (ectothermy, endothermy) of 17 dinosaurs. In our paper, we showed that Gmax values of similar-sized extant ectothermic and endothermic vertebrates overlap. This strongly questions a correct assignment of a thermoregulation strategy to a dinosaur only based on its Gmax and (adult) body mass (M). Contrary, Gmax separated similar-sized extant reptiles and birds (Sauropsida) and Gmax values of our studied dinosaurs were similar to those seen in extant similar-sized (if necessary scaled-up) fast growing ectothermic reptiles. Myhrvold examined two hypotheses (H1 and H2) regarding our study. However, we did neither infer dinosaurian thermoregulation strategies from group-wide averages (H1) nor were our results based on that Gmax and metabolic rate (MR) are related (H2). In order to assess whether single dinosaurian Gmax values fit to those of extant endotherms (birds) or of ectotherms (reptiles), we already used a method suggested by Myhrvold to avoid H1, and we only discussed pros and cons of a relation between Gmax and MR and did not apply it (H2). We appreciate Myhrvold's efforts in eliminating the correlation between Gmax and M in order to statistically improve vertebrate scaling regressions on maximum gain in body mass. However, we show here that his mass-specific maximum growth rate (kC) replacing Gmax (= MkC) does not model the expected higher mass gain in larger than in smaller species for any set of species. We also comment on, why we considered extant reptiles and birds as reference models for extinct dinosaurs and why we used phylogenetically-informed regression analysis throughout our study. Finally, we question several arguments given in Myhrvold in order to support his results.
Collapse
Affiliation(s)
- Eva Maria Griebeler
- Institute of Organismic and Molecular Evolution, Evolutionary Ecology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Jan Werner
- Institute of Organismic and Molecular Evolution, Evolutionary Ecology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| |
Collapse
|
6
|
Neenan JM, Reich T, Evers SW, Druckenmiller PS, Voeten DFAE, Choiniere JN, Barrett PM, Pierce SE, Benson RBJ. Evolution of the Sauropterygian Labyrinth with Increasingly Pelagic Lifestyles. Curr Biol 2017; 27:3852-3858.e3. [PMID: 29225027 DOI: 10.1016/j.cub.2017.10.069] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 11/29/2022]
Abstract
Sauropterygia, a successful clade of marine reptiles abundant in aquatic ecosystems of the Mesozoic, inhabited nearshore to pelagic habitats over >180 million years of evolutionary history [1]. Aquatic vertebrates experience strong buoyancy forces that allow movement in a three-dimensional environment, resulting in structural convergences such as flippers and fish-like bauplans [2, 3], as well as convergences in the sensory systems. We used computed tomographic scans of 19 sauropterygian species to determine how the transition to pelagic lifestyles influenced the evolution of the endosseous labyrinth, which houses the vestibular sensory organ of balance and orientation [4]. Semicircular canal geometries underwent distinct changes during the transition from nearshore Triassic sauropterygians to the later, pelagic plesiosaurs. Triassic sauropterygians have dorsoventrally compact, anteroposteriorly elongate labyrinths, resembling those of crocodylians. In contrast, plesiosaurs have compact, bulbous labyrinths, sharing some features with those of sea turtles. Differences in relative labyrinth size among sauropterygians correspond to locomotory differences: bottom-walking [5, 6] placodonts have proportionally larger labyrinths than actively swimming taxa (i.e., all other sauropterygians). Furthermore, independent evolutionary origins of short-necked, large-headed "pliosauromorph" body proportions among plesiosaurs coincide with reductions of labyrinth size, paralleling the evolutionary history of cetaceans [7]. Sauropterygian labyrinth evolution is therefore correlated closely with both locomotory style and body proportions, and these changes are consistent with isolated observations made previously in other marine tetrapods. Our study presents the first virtual reconstructions of plesiosaur endosseous labyrinths and the first large-scale, quantitative study detailing the effects of increasingly aquatic lifestyles on labyrinth morphology among marine reptiles.
Collapse
Affiliation(s)
- James M Neenan
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK.
| | - Tobias Reich
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Serjoscha W Evers
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Patrick S Druckenmiller
- University of Alaska Museum and Department of Geology and Geophysics, University of Alaska Fairbanks, 907 Yukon Drive, Fairbanks, AK 99775, USA
| | - Dennis F A E Voeten
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France; Department of Zoology and Laboratory of Ornithology, Palacký University, 17 listopadu 50, 771 46 Olomouc, Czech Republic
| | - Jonah N Choiniere
- School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK; School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Roger B J Benson
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK; School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
| |
Collapse
|
7
|
Microanatomy and life history in Palaeopleurosaurus (Rhynchocephalia: Pleurosauridae) from the Early Jurassic of Germany. Naturwissenschaften 2016; 104:4. [PMID: 28005148 DOI: 10.1007/s00114-016-1427-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
The tuatara (Sphenodon punctatus) from New Zealand is often-erroneously-identified as a 'living fossil', although it is the lone survivor of a large, successful radiation of Rhynchocephalia, sister taxon to squamates (lizards and snakes), that thrived through the Mesozoic and Cenozoic and experienced an intricate evolution of life histories and feeding habits. Within Rhynchocephalia, only Pleurosauridae are thought to be marine and piscivorous. Here, we present bone histological data of the Jurassic pleurosaurid Palaeopleurosaurus, showing osteosclerosis (i.e. bone mass increase) in its gastralia, and some osteosclerosis in its rib but no increase in bone mass in the femur, supporting a gradual skeletal specialization for an aquatic way of life. Similar to Sphenodon, the bone tissue deposited in Palaeopleurosaurus is lamellar zonal bone. The femoral growth pattern in Palaeopleurosaurus differs from that of terrestrial Sphenodon in a more irregular spacing of growth marks and deposition of non-annual (i.e. non-continuous) rest lines, indicating strong dependency on exogenous factors. The annual growth mark count in adult but not yet fully grown Palaeopleurosaurus is much lower when compared to adult individuals of Sphenodon, which could indicate a lower lifespan for Palaeopleurosaurus. Whereas the gastral ribs of Palaeopleurosaurus and Sphenodon are similar in composition, the ribs of Sphenodon differ profoundly in being separated into a proximal tubular rib part with a thick cortex, and an elliptical, flared ventral part characterised by extremely thin cortical bone. The latter argues against a previously inferred protective function of the ventral rib parts for the vulnerable viscera in Sphenodon.
Collapse
|
8
|
Klein N, Sander PM, Krahl A, Scheyer TM, Houssaye A. Diverse Aquatic Adaptations in Nothosaurus spp. (Sauropterygia)-Inferences from Humeral Histology and Microanatomy. PLoS One 2016; 11:e0158448. [PMID: 27391607 PMCID: PMC4938232 DOI: 10.1371/journal.pone.0158448] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 06/16/2016] [Indexed: 11/19/2022] Open
Abstract
Mid-diaphyseal cortical bone tissue in humeri of Nothosaurus spp. consists of coarse parallel-fibered bone, finer and higher organized parallel-fibered bone, and lamellar bone. Vascular canals are mainly arranged longitudinally and radially in a dominantly radial system. Blood vessels are represented by simple vascular canals, incompletely lined primary osteons, and fully developed primary osteons. Nothosaurus spp. shows a variety of diaphyseal microanatomical patterns, ranging from thick to very thin-walled cortices. In the early Anisian (Lower Muschelkalk), small- and large-bodied Nothosaurus spp. generally exhibit bone mass increase (BMI). In the middle to late Anisian (Middle Muschelkalk) small-bodied nothosaurs retain BMI whereas larger-bodied forms tend to show a decrease in bone mass (BMD). During the latest Anisian to early Ladinian (Upper Muschelkalk), small- and few large-bodied nothosaurs retain BMI, whereas the majority of large-bodied forms exhibit BMD. The stratigraphically youngest nothosaurs document five microanatomical categories, two of which are unique among marine amniotes: One consists of a very heterogeneously distributed spongy periosteal organization, the other of very thin-walled cortices. The functional significance of the two unique microanatomical specializations seen in large-bodied nothosaurs is the reduction of bone mass, which minimizes inertia of the limbs, and thus saves energy during locomotion. Transitions between the various microanatomical categories are rather gradual. Our results suggest that small-bodied Nothosaurus marchicus and other, not further assignable small-bodied nothosaurs seem to have been bound to near-shore, shallow marine environments throughout their evolution. Some large-bodied Nothosaurus spp. followed the same trend but others became more active swimmers and possibly inhabited open marine environments. The variety of microanatomical patterns may be related to taxonomic differences, developmental plasticity, and possibly sexual dimorphism. Humeral microanatomy documents the diversification of nothosaur species into different environments to avoid intraclade competition as well as competition with other marine reptiles. Nothosaur microanatomy indicates that knowledge of processes involved in secondary aquatic adaptation and their interaction are more complex than previously believed.
Collapse
Affiliation(s)
- Nicole Klein
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
- * E-mail:
| | - P. Martin Sander
- Steinmann-Institute, Division of Paleontology, University of Bonn, Nußallee 8, 53115 Bonn, Germany
| | - Anna Krahl
- Biomechanics Research Group, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland
| | - Alexandra Houssaye
- UMR 7179 CNRS/Muséum National d'Histoire Naturelle, Département Ecologie et Gestion de la Biodiversité, 57 rue Cuvier CP-55, 75000 Paris France
| |
Collapse
|