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Climatic influence on the growth pattern ofPanthasaurus maleriensisfrom the Late Triassic of India deduced from paleohistology
- Source :
- PeerJ, PeerJ, Vol 8, p e9868 (2020)
- Publication Year :
- 2020
- Publisher :
- PeerJ, 2020.
-
Abstract
- Metoposaurids are representatives of the extinct amphibian clade Temnospondyli, found on almost every continent exclusively in the Late Triassic deposits. Osteohistologically, it is one of the best-known temnospondyl groups, analyzed with a wide spectrum of methods, such as morphology, morphometry, bone histology or computed modelling. The least known member of Metoposauridae isPanthasaurus maleriensisfrom the Pranhita-Godavari basin in Central India, being geographically the most southern record of this family. For the first time the bone histology of this taxon was studied with a focus on the intraspecific variability of the histological framework and the relationship between the observed growth pattern and climatic and/or environmental conditions. The studied material includes thin-sections of five long bones, a rib, an ilium and an intercentrum belonging most likely to eight individuals ranging from different ontogenetic stages. All bones have a large medullary region with progressively increasing remodeling, surrounded by a lamellar-zonal tissue type. The primary cortex consists of parallel-fibered matrix showing various degrees of organization, less organized collagen fibers in the zones and higher organized in the annuli. Growth marks occur in the form of alternating zones and annuli in every bone except the ilium and the intercentrum. The vascularity becomes less dense towards the outermost cortex in all sampled limb bones. Towards the outermost cortex the zone thickness is decreasing, in contrast to the avascular annuli, that become thicker or are of the same thickness. The growth pattern ofP. maleriensisis uniform and represents changes in ontogenetic development. Multiple resting lines are prominent in the outer annuli of the limb bones and the rib and they presumably indicate climatic and environmental influence on the growth pattern. Therefore, a prolonged phase of slowed-down growth occurred during the unfavorable phase, but a complete cessation of growth indicated by Lines of Arrested Growth (LAGs) is not recorded in the studied samples. Based on the histological framework we conclude that the climate had an impact on the growth pattern. As we do not see any LAGs in the Indian metoposaurid, we assume that the local climate was relatively mild in India during the Late Triassic. A similar prolonged phase of slowed down growth without the occurrence of LAGs was observed inMetoposaurus krasiejowensisfrom the Late Triassic of Krasiejów (Poland). This is in contrast to Moroccan metoposauridDutuitosaurus ouazzouifrom the Late Triassic of Argana Basin, where LAGs are regularly deposited throughout ontogeny indicating most likely harsher climatic conditions.
- Subjects :
- 0106 biological sciences
Amphibian
010506 paleontology
Histology
Ontogeny
lcsh:Medicine
Metoposaurus
010603 evolutionary biology
01 natural sciences
General Biochemistry, Genetics and Molecular Biology
Intraspecific competition
Paleontology
Temnospondyli
Metoposauridae
biology.animal
Cortex (anatomy)
medicine
0105 earth and related environmental sciences
Panthasaurus maleriensis
Histovariability
biology
Late triassic
General Neuroscience
lcsh:R
Paleohistology
Climatic influence
General Medicine
biology.organism_classification
Taxon
medicine.anatomical_structure
General Agricultural and Biological Sciences
Zoology
Subjects
Details
- ISSN :
- 21678359
- Volume :
- 8
- Database :
- OpenAIRE
- Journal :
- PeerJ
- Accession number :
- edsair.doi.dedup.....e71cdb401f188fe82268e893c843ab49