Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach

Title
Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach
Publication Date
2022-01
Author(s)
Schmidt, Michel
Melzer, Roland R
Bicknell, Russell D C
( author )
OrcID: https://orcid.org/0000-0001-8541-9035
Email: rbickne2@une.edu.au
UNE Id une-id:rbickne2
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Wiley-Blackwell Publishing Ltd
Place of publication
United Kingdom
DOI
10.1111/1749-4877.12591
UNE publication id
une:1959.11/31703
Abstract
Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial pedipalps for different activities. Although pedipalp use in predation and courtship has been explored in videography in vivo analyses, kinematic ex vivo examination of these appendages has not been conducted. Here, we rectify this lack of data by using micro-CT scans to 3D-kinematically model the appendage morphology and the range of motion (ROM) of the joints for Damon medius and Heterophrynus elaphus. We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint. We also note that, in life, these values would be lower due to motion restricting structures like tendons, arthrodial membranes, and muscles. We further compare our maximum values obtained here with data from video-based motion analyses. The ROM of each joint shows the greatest flexibility in the femur-tibia joint (140–150°), the lowest in the basitarsus-claw joint (35–40°). ROM in the tibia-basitarsus joint is markedly distinct (D. medius: 44°; H. elaphus: 105°). This disparity reflects how H. elaphus uses the joint in the capture basket, while D. medius uses the femur-tibia joint to form the capture basket. We further illustrate notable vertical motion of the H. elaphus pedipalp compared to D. medius. This difference reflects the retro-ventral trochanter apophysis of H. elaphus. Our study opens the possibility to further whip spider kinematic understanding. Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.
Link
Citation
Integrative Zoology, 17(1), p. 156-167
ISSN
1749-4877
1749-4869
Pubmed ID
34532979
Start page
156
End page
167
Rights
Attribution 4.0 International

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