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Trilobite tridents demonstrate sexual combat at 400 Mya
Alan D Gishlick1, Richard A Fortey2
1Department of Environmental, Geographical and Geological Sciences, Bloomsburg University of Pennsylvania, Bloomsburg, PA 17815.
Summary
The Devonian trilobite Walliserops had a unique head trident. A four-tined specimen suggests this structure was used for sexual combat, not feeding, indicating potential sexual dimorphism in trilobites.
Area of Science:
- Paleontology
- Evolutionary Biology
- Trilobite Research
Background:
- The Devonian trilobite genus *Walliserops* is known for its distinctive anterior cephalic trident.
- The function of this trident has been a subject of debate among paleontologists.
Purpose of the Study:
- To investigate the functional interpretation of the *Walliserops* cephalic trident.
- To explore hypotheses regarding the trident's role in feeding versus sexual selection.
Main Methods:
- Analysis of a unique teratological specimen of *Walliserops trifurcatus* with four tines.
- Comparison of trident morphology with structures used in sexual combat in extant organisms (dynastine beetles).
Main Results:
- A four-tined specimen contradicts feeding-related hypotheses for the trident.
- Morphometric analysis supports the hypothesis of the trident as a sexual combat weapon.
- This represents the oldest known example of such a structure used for sexual combat.
Conclusions:
- The *Walliserops* trident likely served a role in sexual selection and intraspecific combat.
- The findings lend support to the theory of significant sexual dimorphism in some trilobite species.
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