Stenopterus rufus is a xerothermic Euro-Turanian species, widespread from Portugal to Turkmenistan, with two "real" subspecies (S. r. transcaspicus Lazarev, 2008 and S. r. syriacus Pic, 1892).
The third one, S. r. geniculatus Kraatz, 1863), is illusory since specimens with the same characters are also frequently collected from Spain to Germany or the Netherlands, where they are even predominant.
Moreover, perfectly typical ones are found in the Balkans, Anatolia and even in the typical series of geniculatus (excerpted from [✧]). Larvae of S. rufus develop in dead branches of many deciduous
trees and shrubs, pupation in pupal cell in the wood during spring. Life-cycle two years. Adults, active from late spring May to August, are diurnal and anthophilous.
Stenopterus rufus transcaspicus, a "dark" subspecies occuring in North Iran and Turkmenistan, has been redescribed by Maxim A. Lazarev in 2008 [✱].
| Body length: | ♂♂ 9 - 13.5 mm / ♀♀ 12 - 14.3 mm |
| Life cycle: | 2 years |
| Adults in: | May - August |
| Host plant: | polyphagous in deciduous trees |
| Distribution: | North Iran, Turkmenistan |
The depicted mounted beetle was collected on flowers in Chālūs environs (Chālūs county, Māzandarān province, Iran) on May 2015.
Collected by Denis G. Kasatkin
[✱]
Lazarev M.A.:
Заметки по спорным вопросам систематики и распространения жуков-усачей (Coleoptera, Cerambycidae) Poccии и coпрeдeльныx cтрaн.
Aктyaльныe пpoблeмы пpиopитeтныx нaпрaвлeний paзвития ecтecтвeнныx нayк, Mocквa, MПГУ, 129-136, 2008.
[download 
]
[✧]
Vitali F.:
Atlas of the Insects of the Grand-Duchy of Luxembourg: Coleoptera, Cerambycidae.
Ferrantia, Musée national d’histoire naturelle, Luxembourg 79: 1-208 [pages 48-49], 2018.
[download ]
