(Image: T. ignobilis debilis, Limones, Venezuela © barloventomagico CC BY-NC-ND 2.0 via Flickr)
Latin names can roll beautifully off the tongue (the ant Monomorium minimum) or can celebrate the beauty of the organism named (the bird-of-paradise Paradisaea decora). Or not: consider the unfortunate black-billed thrush, Turdus ignobilis debilis. This is a common songbird of forests and secondary growth in northwestern South America. It may not be particularly showy, and it may not sing the world’s most beautiful song, but surely no creature could deserve the name Turdus ignobilis debilis?*
It took not just one taxonomist but three to heap that much ignomy on the undeserving black-billed thrush.
We begin, as we often do, with Linneaus, who described the genus Turdus in the famous 1758 10th edition of Systema Naturae (page 168, if you’re curious). (We now recognize about 80 species of Turdus, of which the most familiar is the American Robin, Turdus migratorius.) The etymologies of Linnean names can be obscure, but in this case there’s no great mystery: turdus is simply the Latin word for thrush. The birds can take (limited) solace in the fact that Turdus is actually unrelated to the word turd: turd comes from Old English tord, a piece of excrement, which in turn comes from proto-Indo-European drtom, a past participle of der, to split or tear off (thus, a turd is separated from the body, and no, I didn’t make this up, I learned it via the wonderful Online Etymology Dictionary).
It’s bad luck enough to be saddled with the genus name Turdus (even if it doesn’t really come from turd), but our black-billed thrush is Turdus ignobilis – the ignoble Turdus. “Ignoble” can mean of base origin, of obscure origin, or (worst of all) dishonourable or contemptible. Here we can blame Philip Sclater, who described the species in 1857 (Proc Zool Soc London 25:271-277). Sclater doesn’t explain his choice of ignobilis, although it’s possible he considered the bird’s plumage nondescript. It’s true that Sclater’s paper described 11 new bird species, of which Turdus ignobilis is the least visually striking, but this still seems a bit harsh. Perhaps Sclater was just tired; over his career he published over 1,300 papers (granted, some were only notes, but still) and described well over 100 new families and genera and about 1,000 new species and subspecies. He is best known today not for Turdus ignobilis, but for first demarcating and naming six of the eight major zoological provinces we recognize today (Palaearctic, Afrotropics, Indo-Malaya, Australasia, Nearctic and Neotropics). Actually, it’s probably just as well Sclater isn’t remembered for dubbing the black-billed thrush ignobilis.
Now, Turdus ignoblis is bad enough, you’d think, but the subspecies Turdus ignobilis debilis piles insult upon insult: not just a regular Turdus ignobilis, you understand, but one that’s debilis: weak, feeble or infirm. The subspecies was described in 1902 by Hellmayr (J Ornithol 50:44-69), with debilis apparently referring to the “weaker” and lighter-coloured beak (compared to the deep black of the typical subspecies). In the original German, by the way, the beak is “dunkelhornfarbigen”, which sounds a lot cooler than its English translation “dark horn-coloured”. Say it out loud: “dunkelhornfarbigen”. I’ll wait…
So where does that leave us? With Turdus ignobilis debilis, the weaker cousin of the ignoble turd… All right, of the ignoble thrush, but that’s maybe not much better and confusion with turd is inevitable anyway. No bird deserves that, but there’s no provision in the Code of Zoological Nomenclature for changing a Latin name just because it’s kind of insulting. So let’s hope the birds don’t know what we call them, and write this one off as an unfortunately not-so-wonderful Latin name. As we name Earth’s menagerie, we’ll have to come up with names for anywhere from 3 to 300 million species that aren’t yet described**, and I suppose it’s inevitable that a few duds will slip in. If you’re a namer, though, perhaps Turdus ignobilis debilis can stand (or perch) as a cautionary tale – something not (please) to do.
© Stephen Heard (firstname.lastname@example.org) June 22, 2015
I’m grateful to Denis Lepage of Avibase for alerting me to the plight of Turdus ignobilis debilis.
*Conventionally, of course, I’d abbreviate this T. ignobilis debilis after first use. This would, however, deprive me of the opportunity to type “Turdus” over and over again, and given my 12-year-old sense of humour, there’s little chance I’m going to let that go by. Turdus.
**And yes, it’s embarrassing that we don’t know how many species we share our planet with, not even to the closest order of magnitude.