Subgenus Orinodromus Kolbe, 1895
Orinodromus Kolbe, 1895: 57 (type: deckeni Gerstaeker, 1867)
Elgonites Jeannel, 1940: 142 (type: kenyense Breuning, 1928)
According to Jeannel (1940: 64), the African wingless Calosoma, more linked to the mountain habitat of ground and grassland, belong to subgenera (or genera in the opimion of Jeannel): Carabops, Orinodromus and Carabomorphus, and their origin can be traced back to the Castrida - Caminara phyletic line. They differ from the other Calosoma belonging to this line because the lack of serration on the margin of the elytra.
Jeannel, that consideres Orinodromus a genus, divided it into the subgenera Orinodromus, sensu stricto, Elgonites and Carabophanus. In this genus Jeannel had put togheter, because of their morphological characteristics, species more advanced than those in Carabops. In fact they have smoot mandibles, and reduced metaepisterna without punctation, while the inner armature of their penis has a ligule of normal form, as in Carabops although somewhat larger.
While the subgenus Carabophanus belongs to the Ethiopian highland, Elgonites is limited to the mount Elgon and Orinodromus s. str., collects all species of Mount Kilimanjaro and a single species present in some mountain ranges of northern Tanzania. All the species of Orinodromus and Elgonites have a relatively elongated ligule, parallel-sided, and the male's mesotibiae are straight without brush.
We think that the genera of Jeannel should be mantained as subgenera and we consider justified keeping Carabophanus as a subgenus distinct from Orinodromus, also because of its geographical isolation. On the contrary, we do not believe that this distinction is valid for the species of Mount Elgon, which we consider therefore belonging to the subgenus Orinodromus. In fact they differ from the others belonging to the same subgenus only because they lack the setae on the rear lobes of pronotum.
The sculpture of the elytron in Orinodromus varies widely, starting from a model with 16 intervals, all equal, that probably should be regarded as the primitive model, variously modified under the influence of high altitude habitat. Orinodromus neumanni, with intervals that mantain the same width and heigth, occupies three mountain ranges west of Kilimanjaro, widely separated from each other by large tracts of arid savannah, but its populations have only small morphological differences despite the undoubted, and presumably not recent, isolation.
The three species of Orinodromus living on Mount Kilimanjaro, with elytra smooth or with faint streaks, despite the undoubted common characteristics, are well differentiated and are found on high altitude distinct areas.
Orinodromus elgonense and Orinodromus kenyense of Mount Elgon, probably represent a unique lineage that, starting from a type where the sculpture of the elytra has the intervals of the same width and height, gives origin to a series of strikingly different entities that occupy different ecological niches on the same mountain.
In any way, in the following discussion has been widely used the study of Basilewsky (1962) that has critically reviewed the systematic of this subgenus and provided accurate data on the distribution of different species.