"Scorpion Strongmen" - Who's got the strongest grip?

The size of scorpion claws (pincers) vary a lot. Some species has long and slender pedipalps (like Leiurus), while others have broad and powerful claws (like Pandinus). But who's got the strongest pincer force?

A. van der Meijden and co-workers have published a comparison of claw size and pincer force in seven species. Scorpions with the highest claws had the strongest grip. The authors suggest that slender claws may be an adaption to speed (catching quick and elusive prey) rather than maximum force. Large claws may be an adaption to defense against predators, but can also have other functions (like burrowing).

Abstract:
A key feature of the ancient body plan of scorpions is the pincer or chela. These multifunctional structures vary considerably in size and shape between different scorpion species. Here we provide the first comparative data on the pinching performance of the chelae of seven species of scorpions exemplifying the extremes of the shape range from slender to robust; Leiurus quinquestriatus, Androctonus amoreuxi, Androctonus australis, Hadogenes sp., Pandinus imperator, Scorpio maurus and Pandinus cavimanus (in the order of decreasing chela height to width ratio). Size-corrected chela height correlates highly with maximum pinch force. Independent contrasts suggest that the correlation of chela width, height and fixed finger length with maximum pinch force is independent of phylogeny, suggesting an adaptive component to the evolution of chela shape and performance.

Reference:
van der Meijden A, Herrel A, Summers A. Comparison of chela size and pincer force in scorpions; getting a frist grip. J Zool. 2009:1-7. DOI:10.1111/j.1469-7998.2009.00628.x [This is an early view article - Subscription required for fulltext]

Thanks to Dr. van der Meijden for sending me the paper!