Pedipalp anatomy of the Australian black rock scorpion, Urodacus manicatus, with implications for functional morphology

Title
Pedipalp anatomy of the Australian black rock scorpion, Urodacus manicatus, with implications for functional morphology
Publication Date
2024-05-13
Author(s)
Bicknell, Russell D C
( author )
OrcID: https://orcid.org/0000-0001-8541-9035
Email: rbickne2@une.edu.au
UNE Id une-id:rbickne2
Edgecombe, Gregory D
Goatley, Christopher H R
( author )
OrcID: https://orcid.org/0000-0002-2930-5591
Email: cgoatley@une.edu.au
UNE Id une-id:cgoatley
Charlton, Glen
Paterson, John R
( author )
OrcID: https://orcid.org/0000-0003-2947-3912
Email: jpater20@une.edu.au
UNE Id une-id:jpater20
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
CSIRO Publishing
Place of publication
Australia
DOI
10.1071/ZO23044
UNE publication id
une:1959.11/59255
Abstract

Pedipalps – chelate 'pincers' as the second pair of prosomal appendages – are a striking feature of scorpions and are employed in varied biological functions. Despite the distinctive morphology and ecological importance of these appendages, their anatomy remains underexplored. To rectify this, we examined the pedipalps of the Australian black rock scorpion, Urodacus manicatus, using a multifaceted approach consisting of microcomputed tomography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and live pinch force measurements. In doing so, we document the following aspects of the pedipalps: (1) the musculature in three dimensions" (2)the cuticular microstructure, focusing on the chelae (tibial and tarsal podomeres)" (3) the elemental construction of the chelae teeth" and (4) the chelae pinch force. We recognize 25 muscle groups in U. manicatus pedipalps, substantially more than previously documented in scorpions. The cuticular microstructure – endo-, meso-, and exocuticle – of U. manicatuspedipalps is shown to be similar to other scorpions and that mesocuticle reinforces the chelae for predation and burrowing. Elemental mapping of the chelae teeth highlights enrichment incalcium, chlorine, nickel, phosphorus, potassium, sodium, vanadium, and zinc, with a marked lack of carbon. These elements reinforce the teeth, increasing robustness to better enable prey capture and incapacitation. Finally, the pinch force data demonstrate that U. manicatus can exert high pinch forces (4.1 N), further highlighting the application of chelae in subduing prey, as opposed to holding prey for envenomation. We demonstrate that U. manicatus has an array of adaptations for functioning as a sit-and-wait predator that primarily uses highly reinforced chelae to process prey.

Link
Citation
Australian Journal of Zoology, 72(2), p. 1-22
ISSN
1446-5698
0004-959X
Start page
1
End page
22
Rights
Attribution 4.0 International

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