Friday, July 1, 2011

Distribution and Identification of Acanthostichus and Cerapachys

These two genera represent the subfamily Cerapachyinae in North America. These are cryptic ants that not a whole lot is know about. Unfortunately that's about as much as can be said about them. The most wide spread species of the group, Cerapachys davisi, has only ever been collected by it's males. Queens and workers are completely unknown. Other species, though not as spread out, have been collected with better success. 

Acanthostichus arizonensis SW (Arizona)
Acanthostichus punctiscapus SW (Arizona and New Mexico)
Acanthostichus texanus (2) SW (Texas and Mexico)

Cerapachys augustae (2) SW
Cerapachys biroi (2) HA
Cerapachys davisi SW, SC


Key
Acanthostichus and Cerapachys differ by Acanthostichus having 12 antenna segments while Cerapachys only has 11. You may find these hard to count though as Cerapachys tend to be covered in lots of long erect hairs. Acanthostichus tend to have sub-erect hairs with more bare patches revealing their smooth reflective exoskeletons.

With Acanthostichus please note that there are three species found in Mexico and in countries farther south that have not been included in this key due to lack of specimens and research. They are A. emmae, A. quirozi, and A. skwarrae. To read about those and other Acanthostichus species of the new world see MacKay 1996.

Acanthostichus texanus (2) SW (Texas and Mexico) Pubescence is faint almost nonexistent. The eyes in comparison to the head in this species is much larger than other species in this genus. There's also a downward facing tooth under the petiole worth noting but this is consistent with other members of this genus. 

Acanthostichus arizonensis SW (Arizona) Pubescence is moderate. The eyes are small and hard to see. There's also a downward facing tooth under the petiole worth noting but this is consistent with other members of this genus. 

Acanthostichus punctiscapus SW (Arizona and New Mexico) Pubescence is rather thick in comparison to other species. The eyes are small and hard to see. There's also a downward facing tooth under the petiole worth noting but this is consistent with other members of this genus.


Cerapachys augustae (2) SW


Cerapachys davisi SW, SC


Cerapachys biroi (2) HA


Sources
Smith, M. R. 1942. The males of two North American cerapachyine ants. Proceedings of the Entomological Society of Washington 44: 62-64.

Wheeler, W. M. 1902. An American Cerapachys, with remarks on the affinities of the Cerapachyinae. Biological Bulletin 3: 181-191.
MacKay, W. P. 1996. A Revision of the Ant Genus Acanthostichus (Hymenoptera: Formicidae).

No comments:

Post a Comment