Calosoma (Orinodromus) elgonense Burgeon, 1928

Length 10-16 mm. Two species (or perhaps two forms of the same species) are found on Mount Elgon: elgonense and kenyense. Both of them are characterized by well developed rear lobes of pronotum but missing the setae. For them Jeannel (1940) created the subgenus Elgonites.
The populations or individuals inside the populations of this species vary greatly and have been variously named and differently interpreted.
In fact, on Mount Elgon we find individuals where the sculpture of elytra consists of primary intervals raised in continuous ridges and secondary and tertiary ones replaced by disordered punctuation (elgonense s. str). and other smaller size individuals where the sculpture of elytra is affected by more or less deep transverse depressions, which may go to obliterate the primary intervals.
Based on the alleged coexistence of these individuals Jeannel (1940: 147) considered synonymous alinderi and elgonense, but in the same time, further complicating the issue, has distinguished at sub specific level the specimens collected on the western side of the crater in Uganda (malleatus), emphasizing some weak morphological differences (less protruding shoulders, sculpture more accentuated, smaller size).
In the case of elgonense, if really so different individuals coexist in the same population, their morphological differentiation appears to be due to a high degree of individual variability, variously influenced by changes in micro-habitats, rather than due to issues of protracted geographical isolation of populations. Their morphological differentiation could be interpreted not as a starting point of speciation, as has been conjectured by Jeannel (1961: 139) in another case (the case of Elgonotrechus of the same mount Elgon), but instead could be considered as the reversible adaptation of phenotypes extremely sensitive to the changing environmental conditions, typical of the high altitude habitat (Brühl 1977: 239).
For this reason, at the moment and for the purposes of this study, we do not think these populations should be considered as subspecies.
elgonense, interpreted in this way, is found along the slopes all around the crater of Mount Elgon.

Examined specimens and literature’s data
Kenya. Mt Elgon 4000-4200m (SB); Mt Elgon, eastern slopes, 3350-3800m (holotype elgonense, RMCA; AVT, EM, MNHN, SB).
Uganda. Mt Elgon, Mudangi Cliff, 11000 ft (paratype malleatus, RMCA); Mt Elgon, Bulambuli prairies, 3350m (sub malleatus; Jeannel, 1940: 147); Mt. Elgon, on the way to Wagagai peak (SB)

Notes: Wingless. It lives in alpine meadows, from 3300 to 4200m. The adults were found in activity mainly in the wettest period between April and September, and, more rarely, also in December and February.

Calosoma (Orinodromus) elgonense ♂ Burgeon, 1928 British East Africa, Elgon District, IV.V.1914, Dr. Bayer (holotype) (coll. Musée Royal de l'Afrique Central, Tervuren)

Calosoma (Orinodromus) elgonense ♂ Burgeon, 1928 Uganda: Mt. Elgon, on the way to Wagagai peak 28.IV.2009 P. Malec

Calosoma (Orinodromus) elgonense ♀ Burgeon, 1928 Kenya: Mt Elgon vers. Est, 3.000-3.500 m. 7.VII.1991 Casale & Vigna leg. (coll. Vigna Taglianti)

Calosoma (Orinodromus) elgonense ♀ Burgeon, 1928 Uganda: Mt Elgon, Mudangi, 11000 ft, 11.VIII.1934, J. Ford paratype subsp. malleatus Jeannel, (coll. Musée Royal de l'Afrique Central, Tervuren)

Calosoma (Orinodromus) elgonense ♂ Burgeon, 1928 Kenya: Mt Elgon N.P., 4000m, 16.IV.2005

Calosoma (Orinodromus) elgonense ♀ Burgeon 1928 Kenya: Mt Elgon N.P., 4000m, 16.IV.2005