Crystallography of the Calcitic Foliated-Like and Seminacre Microstructures of the Brachiopod <i>Novocrania</i>

Checa, António; Gaspard, Danièle; González-Segura, Alicia; Ramírez‐Rico, J.

doi:10.1021/cg801372j

Cited by 12 publications

(16 citation statements)

References 22 publications

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“…The calcitic brachiopods produce multi‐layered shells that consist of a primary layer with acicular calcite, a secondary layer composed of semi‐nacre in the Craniiformea and calcitic fibres in the Rhynchonelliformea, and sometimes a tertiary prismatic layer (Checa et al . ; Gaspard & Nouet ). Phosphatic brachiopods were more common in the Cambrian than today and exhibited remarkably distinctive and complex shell microstructures, as being columnar (characteristic of acrotretids), bacculate (obolids), or laminar (paterinids) (Williams et al .…”

Section: Discussionmentioning

confidence: 98%

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Homologous shell microstructures in Cambrian hyoliths and molluscs

Zhang

Skovsted

et al. 2018

Palaeontology

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Hyoliths were among the earliest biomineralizing metazoans in Palaeozoic marine environments. They have been known for two centuries and widely assigned to lophotrochozoans. However, their origin and relationships with modern lophotrochozoan clades have been a longstanding palaeontological controversy. Here, we provide broad microstructural data from hyolith conchs and opercula from the lower Cambrian Xinji Formation of North China, including two hyolithid genera and four orthothecid genera as well as unidentified opercula. Results show that most hyolith conchs contain a distinct aragonitic lamellar layer that is composed of foliated aragonite, except in the orthothecid New taxon 1 that has a crossed foliated lamellar microstructure. Opercula are mostly composed of foliated aragonite and occasionally foliated calcite. These blade or lath-like microstructural fabrics coincide well with biomineralization of Cambrian molluscs rather than lophophorates, as exemplified by the Cambrian members of the tommotiid-brachiopod linage. Accordingly, we propose that hyoliths and molluscs might have inherited their biomineralized skeletons from a non-mineralized or weakly mineralized common ancestor rather than as a result of convergence. Consequently, from the view of biomineralization, the homologous shell microstructures in Cambrian hyoliths and molluscs strongly strengthen the phylogenetic links between the two groups.

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Section: Discussionmentioning

confidence: 98%

“…) but, being widely distributed among modern limpets (patellogastropods) and bivalves as well as some calcitic brachiopods (Carter ; Checa et al . , ), the importance of this type of microstructure is difficult to evaluate.…”

Section: Discussionmentioning

confidence: 99%

Homologous shell microstructures in Cambrian hyoliths and molluscs

Zhang

Skovsted

et al. 2018

Palaeontology

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“…In a more recent EBSD study of the calcitic seminacre of the Brachiopod Novocrania, Checa et al (2009) observed sudden changes in the orientation of the c axis within some tablets; they interpreted these sectored tablets as typical examples of (018) and (104) twinning. Considering the mesocrystalline organization of nacre (Mutvei and Dunca 2010;Oaki and Imai 2005;Rousseau et al 2005) and semi-nacre (Checa et al 2009), a re-interpretation in terms of mesotwinning seems appropriate. Concerning artificial mesocrystals, Yuwono et al (2010) synthesized elongated mesocrystals composed of oriented goethite nanocrystals.…”

Section: Interpretation Of the Sectored Sclerites: Twinning Or "Mesotmentioning

confidence: 99%

Mesoscale twinning and crystallographic registers in biominerals

Floquet

Vielzeuf

2011

American Mineralogist

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Mesocrystals attract increasing interest in the fields of physics, chemistry, materials, and Earth sciences. Yet, structural properties of this new class of solid materials are not fully described. Biominerals often display complex hierarchical mesocrystalline organizations. We report on the crystallography of sclerites, which are small (∼80 µm), beautifully shaped calcitic biomineral structures found in the living tissues of octocorals. Despite a layered concentric structure, the submicrometer crystalline units constituting the sclerites display a remarkably simple crystallographic organization of similarly oriented units with only a low degree of misorientation between them. Some sclerites display crystallographic sectors, leading to the concept of "mesotwin." A mesotwin is to a twin what a "mesocrystal" is to a crystal: an analog with defects. On the basis of EBSD data, we propose a simple conceptual crystallographic model that accounts for the observed features. This model involves different rhombohedral unit blocks, with identical shapes and volumes, but different crystallographic faces. EBSD data show that quite unexpectedly slight misorientations of crystallites in the sclerites are not at random but organized around the three equivalent a axes of the hexagonal unit cell of calcite. In a subtle way, the overall organization and morphologies of the red coral sclerites are connected to the calcite crystallography.

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“…Craniids are bivalved, inarticulate brachiopods distinguished by shells in which the calcite is tabulate, with spiral growth (Williams & Wright, ; Checa et al ., ). Although craniiforms comparable to extant forms first appear no earlier than the Ordovician (class Craniata, order Craniida, Bassett, ; Popov, Bassett & Holmer, ), this late appearance may be a taphonomic artefact (Anderson et al ., ) because molecular clock analyses suggest that craniiform and linguliform rDNA lineages diverged not later than the Early Cambrian (Santagata & Cohen, ; Cohen, ; this report).…”

Section: Introductionmentioning

confidence: 60%

Craniid brachiopods: aspects of clade structure and distribution reflect continental drift (Brachiopoda: Craniiformea)

2014

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We present maximum likelihood and Bayesian inference relative time-tree analyses of aligned gene sequences from a worldwide collection of craniiform brachiopods belonging to two genera, Novocrania and Neoancistrocrania. Sequences were obtained from one mitochondrial and three nuclear-encoded ribosomal RNA genes from varying numbers of specimens. Data-exploration by network (splits) analyses indicates that each gene identifies the same divergent clades and (with one minor exception) the same inter-clade relationships. Neoancistrocrania specimens were found only in the Pacific Ocean, near Japan, on the Norfolk and Chesterfield Ridges, and near the Solomon Islands. The Novocrania clades, in approximate order of increasing distance from the root comprise 1. a 'Northern' clade of animals collected in the NE. Atlantic, W. Mediterranean and Adriatic; 2. a 'Tethyan' clade comprising animals from the E. Mediterranean, Cape Verde islands and the Caribbean (Belize and Jamaica); 3. a 'NE. Pacific' clade containing animals from Vancouver Island and from localities near Japan and south of Taiwan; 4. a 'Southern' clade that contains two widely separated subclades, one from New Zealand and the other with an extraordinarily wide distribution, ranging from near Japan in the north to the Chesterfield Ridge and Solomon Islands in the West, and in the East to the Galapagos Islands, the coast of South America (Chile) and Richardson seamount (off South Africa) in the South Atlantic. To the South, members of this clade were found in the Weddell, Scotia and Bellinghausen Antarctic Seas. The root of the extant craniid radiation was previously found (by relaxed-clock analysis) to lie on the branch connecting the two genera so that, in effect, the one clade of Neoancistrocrania serves to polarise evolutionary relationships within the several clades of Novocrania. As previously suggested, all results confirm that Neoancistrocrania is sister to the 'Northern' Novocrania clade, and this leads to a proposal that Neoancistrocrania represents one extreme of a wide range of variation in ancestral ventral valve mineralisation, speciation (∼90 Ma) resulting from competitive exclusion in rapidly-growing reef environments. To the extent possible, the identified molecular clades are correlated with named species of Novocrania.The reproductive and population biology of craniid brachiopods is not well known, but from available evidence they are considered to have low-dispersal potential and, except in enclosed localities such as cold-water fjords, to have small effective population sizes, features which are consistent with the observed divergent populations in well-separated localities. Exceptionally slow craniid molecular (rDNA) evolution is suggested by the short branch of Novocrania where it has been used as an outgroup for large-scale analyses of metazoans. Slow molecular evolution is also indicated by the existence of a distinct Tethyan clade, reflecting restricted dispersal at former times, and by the uniform, short, genetic distances and exception...

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Crystallography of the Calcitic Foliated-Like and Seminacre Microstructures of the Brachiopod Novocrania

Cited by 12 publications

References 22 publications

Homologous shell microstructures in Cambrian hyoliths and molluscs

Homologous shell microstructures in Cambrian hyoliths and molluscs

Mesoscale twinning and crystallographic registers in biominerals

Craniid brachiopods: aspects of clade structure and distribution reflect continental drift (Brachiopoda: Craniiformea)

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