On the appendicular anatomy of the xiphosurid Tachypleus syriacus and the evolution of fossil horseshoe crab appendages

Title
On the appendicular anatomy of the xiphosurid Tachypleus syriacus and the evolution of fossil horseshoe crab appendages
Publication Date
2019-08
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
Brougham, Tom
( author )
OrcID: https://orcid.org/0000-0002-2771-536X
Email: tbroughm@une.edu.au
UNE Id une-id:tbroughm
Charbonnier, Sylvain
Sautereau, Frederic
Hitij, Tomaz
Campione, Nicolas E
( author )
OrcID: https://orcid.org/0000-0002-4205-9794
Email: ncampion@une.edu.au
UNE Id une-id:ncampion
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Springer
Place of publication
Germany
DOI
10.1007/s00114-019-1629-6
UNE publication id
une:1959.11/27443
Abstract
Xiphosurida- crown group horseshoe crabs- are a group of morphologically conservative marine chelicerates (at least since the Jurassic). They represent an idealised example of evolutionary stasis. Unfortunately, body fossils of horseshoe crabs seldom preserve appendages and their associated features; thus, an important aspect of their morphology is absent in explorations of their conservative Bauplan. As such, fossil horseshoe crab appendages are rarely considered within a comparative framework: previous comparisons have focussed almost exclusively on extant taxa to the exclusion of extinct taxa. Here, we examine eight specimens of the xiphosurid Tachypleus syriacus (Woodward, 1879) from the Cenomanian (ca 100 Ma) Konservat-Lagerstätten of Lebanon, five of which preserve the cephalothoracic and thoracetronic appendages in exceptional detail. Comparing these appendages of T. syriacus with other fossil xiphosurids highlights the conserved nature of appendage construction across Xiphosurida, including examples of Austrolimulidae, Paleolimulidae, and Limulidae. Conversely, Belinuridae have more elongate cephalothoracic appendages relative to body length. Differences in appendage sizes are likely related to the freshwater and possible subaerial life modes of belinurids, contrasting with the primarily marine habits of other families. The morphological similarity of T. syriacus to extant members of the genus indicates that the conserved nature of the generic lineage can be extended to ecological adaptations, notably burrowing, swimming, possible diet, and sexual dimorphism.
Link
Citation
Naturwissenschaften, v.106, p. 1-18
ISSN
1432-1904
0028-1042
Pubmed ID
31209559
Start page
1
End page
18
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International

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