Why has Stan Lee not thought of this one!?
Not to worry. The boys over at ScienceDaily.com have not dropped the ball.
The article begins, “Combat-ready spikes which shoot from fingers sounds like the weaponry of a comic book hero, but a Japanese scientist has found exactly this in a rare breed of frog. The discovery, which is published in the Journal of Zoology, reveals how the Otton frog uses spikes which protrude from a false thumb for both combat and mating.”
Yes, my little geeks and nerdlings, male Otton frogs get into vicious cat-fights that leave them scarred and bleeding, thanks to the retractable claws stashed in their “thumbs”.
The study, conducted by Dr Noriko Iwai from the University of Tokyo, focused on the Otton frog (Babina subaspera), whose habitat is the Amami islands of Southern Japan. Unlike most other frogs the Otton has an extra digit-like structure, a trait it shares with the five-fingered Hypsiboas rosenbergi frogs of Latin America.
(The white spike [left side of frog hand] is usually sheathed. Image: N. Iwai)
“Why these ‘fifth fingers’ exist in some species remains an evolutionary mystery, but the extra digit of the Otton is in fact a pseudo-thumb,” said Dr Iwai. “The digit encases a sharp spine which can project out of the skin, which fieldwork demonstrates is used for combat and mating.”
“While the pseudo-thumb may have evolved for mating, it is clear that they’re now used for combat,” said Dr Iwai. “The males demonstrated a jabbing response with the thumb when they were picked up, and the many scars on the male spines provided evidence of fighting.”
“More research is needed to look at how the pseudo-thumb evolved and how it came to be used for fighting,” concluded Dr Iwai. “The thumbs use as a weapon, and the danger of the frogs harming themselves with it, makes the Otton pseudo-thumb an intriguing contribution to the study of hand morphology.”
- N. Iwai. Morphology, function and evolution of the pseudothumb in the Otton frog. Journal of Zoology, 2012; DOI: 10.1111/j.1469-7998.2012.00971.x