Talk:Florissant Fossil

Colorado Myrmecofauna: Now and Then

Author: Josiah Kilburn

This is a post on my blog some of the terminology is more casual. sections will be confusing without images so checking out the link will help with understanding of the post.

The ant life of Colorado is truly very diverse, and it has been that way for millions of years. This will compare 34 million year old fossil ants to those found today. comparing the desert fauna to fauna of an ancient lake.

The ants of present Colorado

Colorado is a very diverse state for how severely its seasonal temperature changes. With somewhere between 185-225 different species. Many of these species have been adapted to three main habitats; alpine forests, plains, and high desert. Species have also adapted and evolved alongside others forming symbiotic relationships. For example Solenopsis molesta is a species of "thief ant" which have a form cleptobiotic lestobiosis with other species of ants. I have observed this behavior with Solenopsispreying on hosts like Lasius alienus, Lasius neoniger, Lasius claviger, formica podzolica, Crematogaster cf. emeryana, Monomorium minim, and Tetramorium immigrans.Other species of ants in the high desert include generalist species like Dorymyrmex insanus, Formica pallidefulva, Pheidole (in general), and Monomorium minimum. One of the unique generalist species found here in Colorado is Myrmecocystus, or honeypot ants. I only have a few older pictures of these. Colorado may have between 4-7 species of Myrmecocystus. These ants stay in hibernation for a longer periods of time than most, because they collect sugary nectar, and store it in repletes, these repletes give the species their common name. A more specialised species found across Colorado is Pogonomyrmex occidentalis. While in reality this species is likely more generalist than specialist, P. occidentalis obtains All of it's sugar from seeds. and protein from insects and some types of seeds.
A more specialised species found across Colorado is Pogonomyrmex occidentalis. While in reality this species is likely more generalist than specialist, P. occidentalis obtains All of it's sugar from seeds. and protein from insects and some types of seeds.

The ants of Eocene Colorado

The Colorado of the eocene epoch was a vastly different climate than colorado today. Specifically in terms of fauna and flora. During the Eocene epoch, basically everything was a rainforest, either temperate or tropical. Colorado was possibly the latter. as evidenced by this specimen;
Proazteca is is the predecessor to Azteca, which constantly releases alates throughout the year, they can almost always be found at black lights in the tropics. the abundance of proaztecha could suggest two things; [1] the eocene Colorado might have had a similar climate to today's tropics, and [2] that this nuptial flight behavior has been present in ancestors of aztecha for over 35 million years. Some genuses found in eocene colorado have not been found anywhere else. one such example is the genus Miomyrmex. not really anything is known about this genus. Another interesting clue that differentiates eocene colorado from the colorado of today is the overwhelming presence of dolichoderine ants. Almost all of the specimens I found were from dolichoderinae. below are two alates that look to be similar species(or the same species) of what looks like Iridomyrmex. a species that now only resides in australia. The last species of ant I found in florissant shale was unknown. I thought it was Miomyrmex at first but now I have no idea, it appears to be a dealated gyne.