"Isthmus" or "isthmus"?

December 5, 2012 5:11 PM

In Chicago style, or barring that, in Generally Accepted Historical Practice, how should one capitalize the following sentence, which discusses the "Isthmus of Panama" (which is undoubtedly capitalized when it appears in full): "The canal crossed the isthmus." or "The canal crossed the Isthmus."? (My CMS subscription has lapsed and I can't afford a re-up, alas.)
posted by flibbertigibbet to Writing & Language (8 answers total)

I would say lower case. It's a description, not a title.
posted by Chocolate Pickle at 5:13 PM on December 5, 2012 [3 favorites]

Either is valid. The two have distinctly, but subtly, different meanings. If you capitalize Isthmus you are shortening "Isthmus of Panama" and referring directly to that isthmus. If you don't cap it, you are talking about some isthmus, which the reader just happens to know is the Isthmus of Panama -- a more indirect reference.
posted by kindall at 5:15 PM on December 5, 2012 [3 favorites]

"The Isthmus of Panama" is the proper name of that isthmus. You capitalize isthmus when referring to that particular strip of land, even if you're not adding the "of Panama" part.
posted by erst at 5:15 PM on December 5, 2012

I believe, in GAHP, that when you are referring back to the proper noun that you have already established as the subject, you'd capitalize the first letter.
posted by PaulaSchultz at 5:16 PM on December 5, 2012

Best answer: Chicago sez (emphasis mine):

§8.53 Generic terms for geographic entities

When a generic term is used descriptively (or in apposition; see 8.20) rather than as part of a name, or when used alone, it is lowercased.

the Amazon basin
along the Pacific coast (but the West Coast; see 8.46)
the California desert
the river Thames
the Hudson River valley

posted by stebulus at 5:21 PM on December 5, 2012 [5 favorites]

(And, for comparison: The Pacific Ocean was settled by Polynesian seafarers. They crossed the ocean using sophisticated navigational techniques...)
posted by stebulus at 5:25 PM on December 5, 2012

Best answer: And, as for accepted practice:

The Pliocene raising of the Isthmus of Panama (IOP) marks the final closure of the tropical seas into two discrete regions. Estimates of the timing of this division vary from 1.8 ... to 3.5 Ma ..., with recent estimates of the first complete closure of the IOP around 3.5–3.1 Ma ... . For fish, the observed impact is predominantly at the species level. There remain about a dozen species of shore fish that span the isthmus with little or no morphological differentiation... [1]

After the rise of the Isthmus of Panama by subduction of the Pacific plate approximately 5 million years ago, the original population was divided. In response to the changing environment, new species evolved on opposite sides of the isthmus. [2]

As the Isthmus of Panama ... formed about 3.5 million years ago, it cut off gene flow among populations of these aquatic shrimp. Individuals from opposite sides of the isthmus are so similar that they might interbreed, but they are now behaviorally isolated: instead of mating when they are brought together, they snap their claws at one another aggressively. [3]

posted by stebulus at 6:17 PM on December 5, 2012 [3 favorites]

Response by poster: Thanks! I was torn as a lot of the historical documents consistently capitalize "Isthmus," even as a stand-alone word, but all is well now!
posted by flibbertigibbet at 6:34 PM on December 5, 2012