Key to New World Temnothorax species groups

This worker key is based on: MacKay, W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology. 36:265-444.

Temnothorax is a difficult genus of ants to identify to species. Hopefully this additional key will make identification of more of the species possible. It may be easier to use that the key based on morphological characters, or will at least make accurate identifications more certain. Many species remain to be discovered, especially in Mexico. If the two keys lead to different identifications, it is possible that you are dealing with an undescribed species.

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 * Temnothorax
 * New World Temnothorax species groups

1

 * Large ants (total length of worker over 3mm); petiole with long peduncle . . . . . hispidus species complex
 * Smaller (total length less than Smm); petiole with short peduncle . . . . . 2

2
return to couplet #1
 * Propodeum without spines or angles; Mexico . . . . . striatulus species complex


 * Propodeum with spines or at least angles; widely distributed . . . . . 3

3
return to couplet #2
 * Propodeal spines united by carina . . . . . obturatur  species complex


 * Propodeal spines not united by a carina; widely distributed . . . . . 4

4
return to couplet #3
 * Clypeus with 3 well defined carina, one medial and two lateral, in addition to several finer carinae, lateral carinae converging anteriorly. . . . . . tricarinatus species complex


 * Clypeus with medial carina and several lateral carinae that are all more or less equally well defined, and are nearly parallel . . . . . 5

5
return to couplet #4
 * Petiolar node sharp as seen in profile . . . . . nitens species complex


 * Petiolar node blunt (rounded or truncate) in profile . . . . . 6

6
return to couplet #5
 * Petiolar node truncate in profile . . . . . 7


 * Petiolar node round in prolile . . . . . 8

7
return to couplet #6
 * Node of petiole nearly square as seen in profile; concolorous light brown; antenna with 11 or 12 segments . . . . . silvestrii species complex


 * Node of petiole not square as seen in profile; dark brown or bicolored black with red mesosoma; antenna with 11 segments . . . . . longispinosus species complex

8
return to couplet #6
 * Anterior and posterior faces of petiolar node nearly parallel . . . . . andrei species complex


 * Anterior and posterior faces of petiolar node converging dorsally . . . . . 9

9
return to couplet #8
 * Antenna with 11 segments . . . . . 10


 * Antenna with 12 segments . . . . . andersoni species complex

10
return to couplet #9
 * Suprapeduncular process well developed, curved upwards; dorsum of head at least partly smooth and shining . . . . . emmae species complex


 * Suprapeduncular process poorly developed; dorsum of head nearly completely covered with fine striae . . . . . schaumii species complex