Bicknell, Russell D C

Schmidt, Michel

Rahman, Imran A

Edgecombe, Gregory D

Gutarra, Susana

Daley, Allison C

Melzer, Roland R

Wroe, Stephen

Paterson, John R

2023-07-12

<p>The stem-group euarthropod <i>Anomalocaris canadensis</i> is one of the largest Cambrian animals and is often considered the quintessential apex predator of its time. This radiodont is commonly interpreted as a demersal hunter, responsible for inflicting injuries seen in benthic trilobites. However, controversy surrounds the ability of <i>A. canadensis</i> to use its spinose frontal appendages to masticate or even manipulate biomineralized prey. Here, we apply a new integrative computational approach, combining threedimensional digital modelling, kinematics, finite-element analysis (FEA) and computational fluid dynamics (CFD) to rigorously analyse an <i>A. canadensis</i> feeding appendage and test its morphofunctional limits. These models corroborate a raptorial function, but expose inconsistencies with a capacity for durophagy. In particular, FEA results show that certain parts of the appendage would have experienced high degrees of plastic deformation, especially at the endites, the points of impact with prey. The CFD results demonstrate that outstretched appendages produced low drag and hence represented the optimal orientation for speed, permitting acceleration bursts to capture prey. These data, when combined with evidence regarding the functional morphology of its oral cone, eyes, body flaps and tail fan, suggest that <i>A. canadensis</i> was an agile nektonic predator that fed on soft-bodied animals swimming in a well-lit water column above the benthos. The lifestyle of <i>A. canadensis</i> and that of other radiodonts, including plausible durophages, suggests that niche partitioning across this clade influenced the dynamics of Cambrian food webs, impacting on a diverse array of organisms at different sizes, tiers and trophic levels.</p>

Proceedings of the Royal Society B: Biological Sciences, 290(2002), p. 1-19

1471-2954

0962-8452

37403497

https://hdl.handle.net/1959.11/55822

The Royal Society Publishing

Attribution 4.0 International

Raptorial appendages of the Cambrian apex predator Anomalocaris canadensis are built for soft prey and speed

Journal Article

Publication