The potential relationships between the members of the subgenus Eleodes
The following changes are proposed unofficially, mostly by me (not a scientist (yet)) and likely not how actual taxonomists will arrange these taxa. I do this merely for my own enjoyment and interest.
Using the following papers I created a tree containing every species in the subgenus Eleodes. It's all hypothetical, and I based it on morphology with the help of the trees in one of the papers.
It's doesn't look the best, but it gets the job done. The colored circles (except the orange) are significant clades, the orange circles form a "group" that I believe to be early diverging parts of the major Clade that they are a part of, that clade being named the Armata Clade. The other three clades are the Dentipes Clade, the Spinipes Clade, and the Obscura Clade. Each Clade would be its own subgenus, the Dentipes Clade keeping the name Eleodes as it contains the type species of the subgenus and genus (Eleodes dentipes of which the clade is named after.) I have not given any of the other proposed subgenera names, but the current placeholder clade names are what their type species would be. The branch labeled All other Eleodes (New Sense) is not a monophyletic group, it is a paraphyletic amalgamation of every other subgenus in Eleodes (new sense, https://keep.lib.asu.edu/system/files/c7/205855/Johnston_asu_0010E_18396.pdf)
Most species are in the Armata Clade, 21 total, 5 are in the Spinipes Clade, and 3 in both the Obscura and Dentipes Clade, which is a total of 32 for the now split up subgenus Eleodes.
Taxonomic changes:
I have split Eleodes spinipes into two species due to a fair amount of genetic distinction shown in one of the studies. E. spinipes spinipes is now E. spinipes. The two remaining subspecies are now subspecies of a resurrected species E. ventricosa, the two subspecies being E. ventricosa ventricosa (nominate subspecies), and E. ventricosa macrura.
Eleodes eschscholtzii has also been split for the same reason. I have brought its subspecies back to they were in the past. E. eschscholtzii eschscholtzii is now E. eschscholtzii, and E. lucae has been resurrected in replacement of E. eschscholtzii lucae.
The final taxonomic change proposed is the synonymization of E. samalayucae with E. hispilabris, due to their extreme similarity and for E. samalayucae having a very restricted range. I believe that E. samalayucae is simply a population or "race" of E. hispilabris only found in the Lake Samalayuca region.
New species Eleodes attenuata:
Diagnosis — Body elongate. Pronotum convex, lateral margins evenly arcuate, widest at middle, anterolateral angles dentate; elytral apex attenuate but not caudate; surface wrinkled or densely punctate. Fore femora strongly dentate or not. Estimated length of 25mm.
Distribution — Seemingly found only on the northern parts of the central Mexican Plateau. MEXICO: Jalisco (Yahualica de González Gallo), Guanajuato (Pénjamo, San Felipe)
Remarks — This species is seemingly undescribed as it is not currently placed in the subgenus Eleodes. It could currently be placed in Promus or in incertae sedis but due to appearing more so like a member of the subgenus Eleodes, I believe it has not yet been described, and so, I have unofficially done so myself. I have been forced to describe the species based on images of 4 specimens posted on iNaturalist as I do not have any specimens.
Etymology — Named for its attenuate elytral apex.
Main observation: https://www.inaturalist.org/observations/1968900
Supporting observations 1: https://www.inaturalist.org/observations/16961660
Supporting observations 2: https://www.inaturalist.org/observations/181508119