Myrmedonota

This is a myrmecophilous genus of Staphylinidae with thirty species.

This genus is characterised and distinguished from the other lomechusine genera by a combination of the following character states: 1) body surface finely punctated; 2) head with occipital suture; 3) pronotum transverse, >1.5 wider than long; 4) setation on abdomen sparse to moderate; 5) cardo of maxilla covers bases of stipes and lacinia (Fig. 3); 6) lacinia extremely narrowed and parallel-sided mentum almost as long as wide apodeme of labium with medial projection 1st segment of labial palpus longer than 2nd segment each lobe of ligula with 2 setulae.

Myrmedonota are predators, and as ant symbionts either predators of ants (Eldredge personal observation, Mathis in preparation) or scavengers ( Kistner 2003 ). In Costa Rica, Eldredge has observed a Myrmedonota species fly into the midst of an agitated Pheidole Westwood, 1839 colony during nest excavation. Mathis (in preparation) has made detailed observations of aggregation and predation behavior of the two new species described below, but these will be presented subsequently.