Promyrmister, a 100 million year old freeloader

[Logo7]

A new genus of clown or hister beetle from the Cretaceous has been described from 100 million year old amber from the amber mines of Myanmar. It has been given the new name Promyrmister kistneri ("Kistner's before ant hister"). The genus name originates from its relationship with stem-ants and its classification as a hister beetle, while the species name originates from Dr. David H. Kitner, an expert on social insect symbionts. This new genus represents the oldest known myrmecophile, suggesting that hister beetles have been living amongst ants since their origin. In the modern day, hister beetles are heavily armored and are able to produce pheromones and chemicals that disguise themselves in an ant colony and pacify the ants within, allowing them to live amongst ant colonies. In fact, hister beetles are so specialized to live amongst ants that they will die if they are seperated from an ant colony. Promyrmister appears to have these same features, suggesting that it led a similar lifestyle. It is believed that Promyrmister went extinct after the extinction of stem-ants, which it relied on for its survival, leading to hister beetles evolving to associate with colonies of modern ants to prevent their own extinction. Here is an image of the specimen in amber as well as a link to the paper that described the new genus.



Paper (open access!): https://elifesciences.org/articles/44985

[Halichoeres]

This is a cool find! I'll add it to the "insects in Burmese amber" thread, if you don't mind.

[Ravonium]

Nice find. I had never heard of this group of beetles prior to reading this thread