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Comparative Morphology of Skeletal Development in Homo sapiens and Raja asterias: Divergent Stiffening Patterns Due to Different Matrix Calcification Processes

Authors :
Ugo E. Pazzaglia
Piero A. Zecca
Genciana Terova
Fabrizio Serena
Cecilia Mancusi
Giovanni Raimondi
Guido Zarattini
Mario Raspanti
Marcella Reguzzoni
Source :
Animals, Vol 14, Iss 17, p 2575 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Before calcification begins, the early embryonic and fetal skeletal development of both mammalian Homo sapiens and the chondrichthyan fish Raja asterias consists exclusively of cartilage. This cartilage is formed and shaped through processes involving tissue segmentation and the frequency, distribution, and orientation of chondrocyte mitoses. In the subsequent developmental phase, mineral deposition in the cartilage matrix conditions the development further. The stiffness and structural layout of the mineralized cartilage have a significant impact on the shape of the anlagen (early formative structure of a tissue, a scaffold on which the new bone is formed) and the mechanical properties of the skeletal segments. The fundamental difference between the two studied species lies in how calcified cartilage serves as a scaffold for osteoblasts to deposit bone matrix, which is then remodeled. In contrast, chondrichthyans retain the calcified cartilage as the definitive skeletal structure. This study documents the distinct mineral deposition pattern in the cartilage of the chondrichthyan R. asterias, in which calcification progresses with the formation of focal calcification nuclei or “tesserae”. These are arranged on the flat surface of the endo-skeleton (crustal pattern) or aligned in columns (catenated pattern) in the radials of the appendicular skeleton. This anatomical structure is well adapted to meet the mechanical requirements of locomotion in the water column. Conversely, in terrestrial mammals, endochondral ossification (associated with the remodeling of the calcified matrix) provides limb bones with the necessary stiffness to withstand the strong bending and twisting stresses of terrestrial locomotion. In this study, radiographs of marine mammals (reproduced from previously published studies) document how the endochondral ossification in dolphin flippers adapts to the mechanical demands of aquatic locomotion. This adaptation includes the reduction in the length of the stylopodium and zeugopodium and an increase in the number of elements in the autopodium’s central rays.

Details

Language :
English
ISSN :
20762615
Volume :
14
Issue :
17
Database :
Directory of Open Access Journals
Journal :
Animals
Publication Type :
Academic Journal
Accession number :
edsdoj.1da23b51fbea4af4972db35f6d4367e7
Document Type :
article
Full Text :
https://doi.org/10.3390/ani14172575