Psilotarsus brachypterus (Gebler, 1830)

Karpinski, Lech, Szczepanski, Wojciech T., lewa, Radoslaw, Walczak, Marcin, Hilszczanski, Jacek, Kruszelnicki, Lech, Los, Krzysztof, Jaworski, Tomasz, Marek Bidas, & Tarwacki, Grzegorz, 2018, New data on the distribution, biology and ecology of the longhorn beetles from the area of South and East Kazakhstan (Coleoptera, Cerambycidae), ZooKeys 805, pp. 59-126 : 62

Psilotarsus brachypterus (Gebler, 1830)

Remarks.

This species is widespread in Central Asia from the southern parts of Russia through most of the territory of Kazakhstan to Uzbekistan, Kyrgyzstan and northwestern China ( Danilevsky 2000). Specimens of this species reach a length of 20-40 mm in the males and 24-45 mm in the females (up to 65 mm when measured to the end of an abdomen filled with eggs). Twelve-segmented antennae occur in both sexes. The females are flightless. The larvae develop on the roots of desert trees and shrubs ( Danilevsky 2014a). Kostin (1973), however, stated that P. brachypterus prefers shrub species, e.g. boyalych Salsola and teresken Krascheninnikovia , in contrast to Mesoprionus angustatus (Jakovlev, 1887) larvae, which feed on saxaul Haloxylon . Our own observations seem to support this thesis since we did not notice any trees or higher ligneous shrubs at the localities of both of the subspecies that were examined. There were the typical habitats of Artemisia - or semi-shrub/dwarf semi-shrub deserts. According to Danilevsky (2014a), the seasonal activity of adults is rather short and only lasts about two weeks; however, based on the data from the labels, it can vary greatly depending on the year - from May to the end of July. On the other hand, the daily activity presumably may differ depending on the particular population or the weather conditions.

Five subspecies are described in this species, four of which are known to occur in Kazakhstan: Psilotarsus brachypterus aralensis (Danilevsky, 2000), P. b. brachypterus (Gebler, 1830), P. b. hemipterus (Motschulsky, 1845) and P. b. pubiventris (Semenov, 1900). The fifth subspecies - P. b. alpherakii (Semenov, 1900) is distributed exclusively in Xinjiang Province of China ( Danilevsky 2018a). A closely related species - Psilotarsus hirticollis Motschulsky, 1860, which is very numerous in Kazakhstan, also consists of several subspecies.

This species is highly variable in many morphological features even within the same population, however, our own observations indicated clear differences between the two taxa collected - P. b. brachypterus and P. b. pubiventris , primarily in the type of pubescence and the sculpture of the pronotum as well as in the size and corpulence of the body. Specimens of the nominotypical subspecies are significantly smaller and slender; even the females are noticeably smaller in size than the males of P. b. pubiventris . The pronotum in the males of the nominative subspecies is almost entirely hairless, smoother and lustrous with a sparse and fine punctuation, while it is definitely hairier and matted with coarse and dense, locally wrinkled punctuation in P. b. pubiventris .