Apatite varieties in the shell of the Cambrian lingulate brachiopod Obolus apollinis Eichwald

Kallaste, Toivo; Kurvits, T; Nemliher, Jüri; Puura, Ivar

doi:10.3176/geol.2004.4.02

Cited by 13 publications

(4 citation statements)

References 7 publications

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“…Baculate laminae are interpreted as remnants of the organic matrix of brachiopods, while compact laminae are interpreted as densely mineralised apatite structures (Lang (Holmer 1989;Nemliher 2006). The presence of hydroxyapatite and authigenic CAFapatite was reported by Nemliher et al (2004) in Estonian lingulate shells based on X-ray diffraction analyses. The secondarily formed authigenic CAF-apatite is interpreted as the product of post-mortem phosphatisation of organic matter in the shells, combined with a later diagenetic alteration.…”

Section: Resultsmentioning

confidence: 96%

Early diagenetic transformation stages revealed by micro-analytical studies of shelly phosphorites, Rakvere region

Graul¹,

Kallaste²,

Moilanen³

et al. 2023

EJES

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In sedimentary phosphorites, P 2 O 5 can occur in several forms, such as fossilised bones, nodules, or other biochemogenic phosphates (Godet and Föllmi 2021). The precipitation of biochemogenic phosphates in marine sediments is restricted to the transition zone between oxic and suboxic environments close to the sediment-water interface. The most common phosphate encountered belongs to the apatite mineral group, with cryptocrystalline carbonate fluorapatite (CAF-apatite), also referred to as 'francolite', dominating in the occurrence of cryptocrystalline grains (Lécuyer et al. 1998;Ptáček 2016). Francolites are non-stoichiometric minerals with the generalised formula (Ca 10-a-b Na a Mg b (PO 4 ) 6-x(CO 3 ) x-y-z (CO 3 ,F) y (SO 4 ) z F 2 ) and numerous structural and chemical variations. Chemical substitutions can occur in all its lattice sites (the two Ca 2+ sites, PO 4 3− and F − ) (McLennan 2001;Veiderma et al. 2005). Bioapatites, another sedimentary apatite source, originate from phosphate biomineralisation of the hard skeleton of vertebrates and some invertebrates. For the precipitation of vertebrate bones and teeth, the nucleation by proteins and macromolecular matrices provides casts that control crystal growth. Such processes presumably also control the segregation of the skeleton of invertebrates (Trappe 1998). In inarticulate brachiopods, direct biomineralisation occurs as precipitation of phosphate to stabilise the exoskeletons. Their shells are initially composed of hard tissues, amorphous hydrogels, phosphate precipitates, and organic matter (Lowenstam and Weiner 1989). Post-mortem, during the diagenesis, the biogenic phosphatic matter chemically evolves toward CAF-apatite composition through various substitutions, together with an increase in crystallite size and formation of authigenic apatite phases (Trappe 1998). However, such alteration pathways are still only fragmentally understood (Ferretti et al. 2021).The shelly phosphorites found in northern Estonia were deposited during the Cambrian-Ordovician transition in the coastal zone of a shallow, epicontinental sea (Heinsalu and Viira 1997;Nielsen and Schovsbo 2011). They belong to the Kallavere Formation, which spreads over most of northern Estonia and parts of the Leningrad region in northwestern Russia (Fig. 1; Kaljo et al. 1988). The Kallavere Formation in the study area has low thermal maturity. It exhibits no evidence of hydrothermal influence due to overall tectonic stability and shallow burial of the region (Kirsimäe

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Section: Resultsmentioning

confidence: 96%

Early diagenetic transformation stages revealed by micro-analytical studies of shelly phosphorites, Rakvere region

Graul¹,

Kallaste²,

Moilanen³

et al. 2023

EJES

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“…The origin of phosphate biomineralization in the evolutionary distant invertebrate brachiopods and vertebrates is still a big mystery in animal evolution ( Luo et al, 2015 ; Neary et al, 2011 ; Roda and Mar, 2021 ). Thus, more research is needed in order to understand how to relate hierarchical structure to function in the very early examples of calcium phosphate-based biomineralization processes ( Kallaste et al, 2004 ; Weiner, 2008 ). It is noteworthy that South China has been considered as one of centres for the origination and early dispersal of phosphatic-shelled brachiopods ( Zhang et al, 2021a ), and hence, it provides a great opportunity to explore the unique biomineralization process and consequent adaptive evolution of their earliest representatives during the Cambrian radiation.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, more research is needed in order to understand how to relate hierarchical structure to function in the very early examples of calcium phosphate-based biomineralization processes (Kallaste et al, 2004;Weiner, 2008). It is noteworthy that South China has been considered as one of centres for the origination and early dispersal of phosphatic-shelled brachiopods (Zhang et al, 2021a).…”

Section: Introductionmentioning

confidence: 99%

Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods

Zhang,

Holmer

et al. 2024

eLife

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Biologically controlled mineral crystals producing organic-inorganic composites (hard skeletons) by metazoan biomineralizers has been an evolutionary innovation for more than half billion years on Earth. Among them, linguliform brachiopods are the only invertebrates that secrete phosphate to build their skeletons. One of the most distinct shell structures is the organic-phosphatic columns applied exclusively by phosphatic-shelled brachiopods. However, the complexity, diversity and biomineralization process of these microscopic columns are far from clear in brachiopod ancestors. Here, exquisitely well preserved columnar structures are discovered for the first time in the earliest eoobolids. The hierarchical shell architectures, epithelial cell moulds, and the shape and size of cylindrical columns are scrutinised in Latusobolus xiaoyangbaensis gen. et sp. nov. and Eoobolus acutulus sp. nov from the Cambrian Series 2 Shuijingtuo Formation of South China. The secretion and construction of the stacked sandwich model of columnar shell, which played a significant role in the evolution of linguliforms, is highly biologically controlled and organic- matrix mediated. Furthermore, a continuous transformation of anatomic features resulting from the growth of columns is revealed between Eoobolidae, Lingulellotretidae and Acrotretida, shedding new light on the evolutionary growth and adaptive innovation of stacked sandwich columns among early phosphatic-shelled brachiopods during the Cambrian explosion.

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“…The origin of phosphate biomineralization in the evolutionary distant invertebrate brachiopods and vertebrates is still a big mystery in animal evolution (Luo et al, 2015; Neary et al, 2011; Simonet Roda, 2021). Thus, more research is needed in order to understand how to relate hierarchical structure to function in the very early examples of calcium phosphate-based biomineralization processes (Kallaste et al, 2004; Weiner, 2008). It is noteworthy that South China has been considered as one of centres for the origination and early dispersal of phosphatic-shelled brachiopods (Zhang et al, 2021a), and hence, it provides a great opportunity to explore the unique biomineralization process and consequent adaptive evolution of their earliest representatives during the Cambrian radiation.…”

Section: Introductionmentioning

confidence: 99%

Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods

Zhang

Holmer

et al. 2023

Preprint

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Biologically controlled mineral crystals producing organic-inorganic composites (hard skeletons) by metazoan biomineralizers has been an evolutionary innovation for more than half billion years on Earth. Among them, linguliform brachiopods are the only invertebrates that secrete phosphate to build their skeletons. One of the most distinct shell structures is the organic-phosphatic columns applied exclusively by phosphatic-shelled brachiopods. However, the complexity, diversity and biomineralization process of these microscopic columns are far from clear in brachiopod ancestors. Here, exquisitely well preserved columnar structures are discovered for the first time in the earliest eoobolids. The hierarchical shell architectures, epithelial cell moulds, and the shape and size of cylindrical columns are scrutinised in Latusobolus xiaoyangbaensis gen. et sp. nov. and Eoobolus acutulus sp. nov from the Cambrian Series 2 Shuijingtuo Formation of South China. The secretion and construction of the stacked sandwich model of columnar shell, which played a significant role in the evolution of linguliforms, is highly biologically controlled and organic-matrix mediated. Furthermore, a continuous transformation of anatomic features resulting from the growth of columns is revealed between Eoobolidae, Lingulellotretidae and Acrotretida, shedding new light on the evolutionary growth and adaptive innovation of stacked sandwich columns among early phosphatic-shelled brachiopods during the Cambrian explosion.

show abstract

Apatite varieties in the shell of the Cambrian lingulate brachiopod Obolus apollinis Eichwald

Cited by 13 publications

References 7 publications

Early diagenetic transformation stages revealed by micro-analytical studies of shelly phosphorites, Rakvere region

Early diagenetic transformation stages revealed by micro-analytical studies of shelly phosphorites, Rakvere region

Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods

Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods

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