Pheidole Working Group - Keys

Key to New World Pheidole
The Lucid software, as detailed below, is no longer accessible for free. You can find a recent update to the Lucid key data/information (a csv file of character data, a document about the characters, lucid files) here: New World Phediole. At present (2021-02-23) it contains 733 species. You should be aware the csv file character measures (head width, for example) include four values: outer minimum, inner minimum, inner maximum, outer maximum.

Launch key: click here

This is a key to the New World Pheidole using Lucid 3.4. The key contains all currently valid New World species. There are no illustrations. At this point it is just a sorting tool that uses a basic set of characters. There is also the option of restriction to one or more geographic regions: U.S.A., Mexico, Central America, Caribbean, South America. The key can be helpful when used in conjunction with Wilson (2003) and/or various websites (e.g., AntWeb, Ants of Costa Rica).

There are some changes from earlier versions. First, I have changed the definition of scape index. It was SL/HL in previous versions, and is now SL/HW. Second, there are two new characters called "minor only" and "major only." Select one of these if you are trying to key a species from a single caste. If you select "minor only," it discards all species known only from majors, and vice versa for "major only."

Notes on 22 August 2009 version: In this new version I incorporated the most recent taxonomic changes, including the new species and synonymies in Longino 2009. I rearranged the order and grouping of characters in a way that I think makes keying a little easier. There are six primary measurements that go a long way toward narrowing the search: head length, head width, and scape length for each caste. These values are measured for almost all species. The other measurements are only available for a subset of the species, mostly those that occur in Central America and southern Mexico. I have moved head length, head width, and scape length (and their respective indices) to the tops of the character lists for each caste.

The key contains 651 valid species from the New World (including the introduced species P. megacephala and P. teneriffana). The following valid taxa are excluded:


 * castanea: old name; type is headless queen from Brazil.
 * detrita: subspecies not treated by Wilson. Venezuela.
 * insipida: species not in Wilson. Mexico.
 * longipes: species not in Wilson. French Guiana.
 * piliventris: species not in Wilson. Type is queen from Brazil.
 * soesilae: a Makhan name, prob. syn. fimbriata.
 * thomensis: subspecies not treated by Wilson. Antilles.

Notes on 8 November 2009 version: There was a major error in the import of minor worker measurement data for the species treated in the Longino 2009 paper. This has been fixed.