April 10, 2006

A fishapod called Tiktaalik

The big news these days in evolutionary biology is the discovery of Tiktaalik roseae, a fossil fish dating back to the Late Devonian era, some 375 million years ago. Tiktaalik is particularly exciting because it represents a transitional stage between organisms with distinct attributes of fish and those with distinct attributes of four-legged land animals, or tetrapods. The genus name Tiktaalik was suggested by elders of the Nunavut Territory in the Canadian Arctic, where the fossil was found. According to the Inuktitut Living Dictionary, tiktaalik is the Inuktitut term for the burbot, a large freshwater fish resembling the cod. It's a lovely, evocative name ("music to my ears," in the words of my brother Carl Zimmer, who wrote extensively about the water-to-land evolutionary leap in his book At The Water's Edge). But one of the discoverers, Neil Shubin of the University of Chicago, apparently couldn't leave well enough alone and introduced another less euphonious moniker for Tiktaalik (and creatures like it) when interviewed by the New York Times about the fossil find:

Tiktaalik, Dr. Shubin said, is "both fish and tetrapod, which we sometimes call a fishapod."

In the press release accompanying the discovery's publication in the journal Nature, Shubin says the researchers "jokingly call it a fishapod," but some bloggers didn't seem to appreciate the humor. "Clearly a crap name," fumed Libertaria of The Bewilderness, adding: "Don't make science less interesting by branding good discoveries with a Soviet consumer brand." John Holbo of Crooked Timber wonders why they didn't go for ichthyopod, before deciding that both fishapod and ichthyopod would more accurately denote "an organism with fish for feet."

Holbo's tongue-in-cheek reading of fishapod assumes that the -pod suffix must attach to a form that describes the feet themselves (e.g. arthropod, lit. 'jointed feet') or counts them (e.g., tetrapod, decapod, myriapod, etc.). But the jocular designation offered by Shubin clearly isn't intended to work like these other neo-Latin combinations.  Rather, it's a straightforward blend of the two words fish and tetrapod, iconically representing the neither-here-nor-there transitional nature of Tiktaalik.

I've previously written about political name-blends like Scalito and Camerair (and celebrity name-blends like Bennifer and Brangelina), where the fusing of the two names suggests the creation of a mutant hybrid beast. But the blending or compounding of animal names to indicate hybridity or intermediacy is an old tradition: consider the compound names of such fanciful beasts as the hippogriff ('horse-griffin') or the lycanthrope ('wolf-man'). The giraffe was originally called the camelopard, melding Greek camelos 'camel' and pardalis 'leopard' because it was thought to combine a camel-like head with leopard-like spots. (This was sometimes written as cameleopard, assumed to be a blend of camel and leopard; indeed, giraffes were frequently depicted in early illustrations as if they were camel-leopard amalgams.) In modern times, when new animal hybrids are engineered by interbreeding, they are often given name-blends: the offspring of a male lion and female tiger is a liger, the offspring of a male tiger and female lion is a tigon, the offspring of a male zebra and female donkey is a zedonk or zonkey, and so forth. The earliest such interbred name-blend that I'm aware of is cattalo, a cattle-buffalo hybrid dating to 1888 (now superceded by beefalo).

It's too early to tell whether Shubin's use of the fishapod blend will catch on in popular descriptions of Tiktaalik. Several bloggers (e.g., here, here, here, and here) have independently come up with another name for the fossil: Darwin fish. This refers to a pro-evolution spoof of the "Jesus fish" insignia found on car bumpers across America. Since the discovery of Tiktaalik is already being used as fodder in the battle between evolutionism and creationism, I can see how Darwin fish could spread as a purposefully provocative nickname for the fossil. Tiktaalik has already inspired Darwinian art from Ray Troll with the exhortation to "embrace your inner fish." Troll is also responsible for "The Devonian Blues," a catchy number driving home the evolutionary message that all of us humans are, in a way, fishapods.

Posted by Benjamin Zimmer at April 10, 2006 01:10 AM