“H” is for Haplaletes
Haplaletes is a member of the problematic Order Condylarthra.
Condylarths are a vexing group of mammals as they seem to be ancestral to most modern hoofed mammals. Condylarths are sometimes regarded as a ‘grade’ rather than a clade, meaning that the animals are grouped together because they are at a similar stage of evolution, just beyond the most primitive of mammals, and that makes them look pretty similar. Modern molecular analysis of the groups thought to have evolved from condylarths (including the hoofed mammals, whales, and elephants) aren’t really that closely related.
Haplaletes disceptatrix is represented by only two specimens in The Breaks, both of which are found in the overlap zone. Because the known range of this species extends from the latest Torrejonian into the late Tiffanian, it’s not very useful for biostratigraphy. At least not in The Breaks.

A specimen of Haplaletes pelecatus (a single tooth) is figured in this paper by Benjamin Burger.
Part of the Blogging from A to Z challenge.
4-9-13