Hypermineralized whale rostrum as the exemplar for bone mineral

Area of Science:

• Biomineralization research
• Skeletal biology
• Paleoproteomics

Background:

• Bone is a complex nanocomposite material primarily composed of collagen and mineral.
• Studying the mineral component of bone has been challenging due to its intricate structure and processing.
• A standardized bone mineral sample is crucial for accurate analysis and comparative studies.

Purpose of the Study:

• To identify and characterize a natural, minimally processed bone mineral standard.
• To investigate the rostrum of the Mesoplodon densirostris, known for its exceptionally dense bone.
• To confirm that this dense bone exhibits bone-like properties aside from its high mineral content.

Main Methods:

• Analysis of Mesoplodon densirostris rostrum using transmitted-light microscopy and FE-SEM.
• Raman spectroscopy to determine chemical-structural features and mineral composition.
• Assessment of collagen fiber density and distribution.
• Quantification of organic content and carbonate substitution in the apatite mineral.

Main Results:

• The whale rostrum displays normal bone morphology, including osteon geometry and vasculature.
• Rostral bone consists predominantly of dense mineral prisms with minimal collagen.
• Raman spectroscopy confirmed the mineral is primarily apatite with high carbonate substitution (∼8.5 wt.%).
• The organic content is remarkably low (∼4 wt.%), indicating a highly mineralized structure.

Conclusions:

• The Mesoplodon densirostris rostrum, despite extreme mineralization, is structurally and chemically bone-like.
• This rostrum provides an uncontaminated and unaltered exemplar of bone mineral.
• The findings establish a new standard for bone mineral research, facilitating further studies on bone composition and properties.