female male protibial dimorphism - Mycotrupes cartwrighti
Tall Timbers Research Station, Leon County, Florida, USA
March 16, 2006
I have found other dimorphic characters confusing at times for some specimens, but this is pretty definitive to my eye and holds true for the rest of Mycotrupes spp also, with the distal tooth being forked. Olson and Hubbel 1954 state "Sexual dimorphism moderate to pronounced; female having distal tooth of fore tibia of usual Geotrupine form, male having this tooth deeply and broadly divided, the mesal branch forming a slender, elongate, sharp-pointed prong."