# Mechanical Properties, Tissue Structure, and Elemental Composition of the Walking Leg Tips of Coconut Crabs

https://mdr.nims.go.jp/datasets/01159f89-fe74-4977-8ac3-cc21eb8629e9

## Download

- [jmse-12-00639.pdf](https://mdr.nims.go.jp/filesets/45ad9b16-ca72-47fb-8bc9-a1cfd6656eff/download)

## Id

01159f89-fe74-4977-8ac3-cc21eb8629e9

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2024-04-11T04:09:10.499733Z

## Updated at

2024-04-12T03:30:18.876507Z

## Published at

2024-04-12T03:30:19.301105Z

## Doi



## First published url

https://doi.org/10.3390/jmse12040639

## Date published

2024-04-10

## Recorded date published



## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: Mechanical Properties, Tissue Structure, and Elemental Composition of the
    Walking Leg Tips of Coconut Crabs
  title_type: original
  lang: en

## Description

- description: The coconut crab has black protrusions on the tops of its walking legs
    and claw fingers. In addition, there are regularly aligned small black protrusions
    on part of the exoskeleton surface of the claws and leg. The elemental composition,
    crystal structure, tissue structure, and mechanical properties of these protrusions
    were studied using a materials science approach, and the results were compared
    with those of mineralized cuticle. These leg tips were a non-calcified fibrous
    tissue of α-chitin connected to the mineralized cuticle. The tip of the second
    walking leg was elongated and had a pointed shape with an oval cavity at its center
    that was more than 1000 times larger than the pore tubes (100–350 nm) of the mineralized
    cuticle. It was very soft, with a hardness of 0.4 GPa, corresponding to 11–12%
    of the hard exocuticle and 55–57% of the soft endocuticle. The elastic modulus
    of 8.0 GPa obtained by nanoindentation testing was consistent with that of α-chitin
    fibers of shrimp shells obtained by tensile testing. These soft protrusions provide
    a secure grip on the surfaces of trees or rocks and protect the claw fingertips.
    It was concluded that the black protrusions are related to a unique ecological
    aspect of the coconut crab, the largest terrestrial crustacean.
  description_type: abstract
  lang: und

## Creator

- name: Tadanobu Inoue
  role: author
  orcid: https://orcid.org/0000-0002-7366-7688
  organization: National Institute for Materials Science
- name: Shin-ichiro Oka
  role: author
- name: Takanobu Hiroto
  role: author
  orcid: https://orcid.org/0000-0002-6176-5782
  organization: National Institute for Materials Science

## Contact agent



## Publisher

organization: MDPI AG

## Managing organization



## Keyword

- subject: mechanical properties
  schema: not_defined
- subject: nanoindentation
  schema: not_defined
- subject: elemental composition
  schema: not_defined
- subject: tissue structure
  schema: not_defined
- subject: organic matter
  schema: not_defined
- subject: α-chitin
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

## Other identifier(s)



## Data origin

- data_origin_type: other

## Embargo



## Journal

- title: Journal of Marine Science and Engineering
  issn: '20771312'
  volume: '12'
  issue: '4'
  start_page: 639

## Conference



## Related item



## Funding

- identifier: JP21H04537
  funder_name: JSPS KAKENHI

## Instrument



## Instrument operator



## Instrument managing organization



## Measurement method



## Specimen



## Chemical composition



## Structure for specimen



## Structural feature for specimen



## Specific property for specimen



## Process for specimen treatment



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## Fileset

- id: 45ad9b16-ca72-47fb-8bc9-a1cfd6656eff
  filename: jmse-12-00639.pdf
  content_type: application/pdf
  size: 10620268
  md5: 12c963027919bbb4d54cd16eb0b1c21d

## Thumbnail

fileset_id: 45ad9b16-ca72-47fb-8bc9-a1cfd6656eff
filename: jmse-12-00639.pdf