New Insights in the Ontogeny and Taphonomy of the Devonian Acanthodian Triazeugacanthus affinis From the Miguasha Fossil-Lagerstätte, Eastern Canada

Minerals

Marion Chevrinais³  Etienne Balan²  Richard Cloutier³  Karim Benzerara¹  Jennyfer Miot¹ 

[1] Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, QC G5L 3A1, CanadaInstitut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7590, IRD UMR 206, MNHN, F-75005 Paris, France;Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, QC G5L 3A1, Canada;

关键词: Acanthodii;    biomineralization;    fossilized ontogeny;    paleontology;    Devonian;   

DOI  :  10.3390/min6010001

来源: mdpi

【 摘 要 】

Progressive biomineralization of a skeleton occurs during ontogeny in most animals. In fishes, larvae are poorly mineralized, whereas juveniles and adults display a progressively more biomineralized skeleton. Fossil remains primarily consist of adult specimens because the fossilization of poorly-mineralized larvae and juveniles necessitates exceptional conditions. The Miguasha Fossil-Lagerstätte is renowned for its Late Devonian vertebrate fauna, revealing the exceptional preservation of fossilized ontogenies for 14 of the 20 fish species from this locality. The mineralization of anatomical structures of the acanthodian Triazeugacanthus affinis from Miguasha are compared among larval, juvenile and adult specimens using Energy Dispersive X-ray Spectrometry. Chemical composition of anatomical structures of Triazeugacanthus reveals differences between cartilage and bone. Although the histology and anatomy is well-preserved, Fourier transform infrared spectrometry shows that the original chemical composition of bone is altered by diagenesis; the mineral phase of the bone (i.e., hydroxyapatite) is modified chemically to form more stable carbonate-fluorapatite. Fluorination occurring in mineralized skeletal structures of adult Triazeugacanthus is indicative of exchanges between groundwater and skeleton at burial, whereas the preservation of larval soft tissues is likely owing to a rapid burial under anoxic conditions. The exceptional state of preservation of a fossilized ontogeny allowed us to characterize chemically the progressive mineralization of the skeleton in a Devonian early vertebrate.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.