Stenus medus Puthz, 1981 : 702

Serri, Sayeh & Frisch, Johannes, 2016, The Steninae MacLeay, 1825 (Coleoptera: Staphylinidae) of Iran: identification key, checklist of species and a new synonymy, Zootaxa 4168 (3), pp. 453-480 : 476

Stenus medus Puthz, 1981: 702

Stenus alanorum Ryvkin, 1990: 211 ; syn. n.

Type material examined. Stenus alanorum : Holotype: Russia, North Ossetia, Kabardino-Sunzha Mts, 3.5 km NW Kardzhin, slope beems 45°, 500 m, steppe meadow with clumps of almonds, 16.11.1985, leg. C. Alekseev (Zoological Museum of the Moscow Lomonosov State University). Stenus medus : Paratype: Iran, Gilan: S Astara (38°24'N 48°26'E), 1200 m, 26.6.1973, leg. Senglet (Collection Volker Puthz, Schlitz).

Additional specimens examined (Hayk Mirzayans Insect Museum Tehran, Museum für Naturkunde Berlin) . Ardabil: Nir - Shahneshin (38°05'37''N 47°57'21''E), 1830 m, 6.8.2005, leg. Serri & Frisch . East Azarbaijan: Tabriz, Osku , Amghan (37°49'35''N 46°16'15''E), 2100 m, 8.8.2005, leg. Serri & Frisch ; Zijenab ( Mt Sahand ) (37°52'09''N 46°18'45''E), 2150 m, 8.8.2005, leg. Serri & Frisch . Ghazvin : 25 km NE Ghazvin (36°21'N 50°12'E), 13.7.2008, leg. Serri . Gilan: Barresar, Damash road, Sebostaneh (36°47'08''N 49°48'19''E), 1400 m, 31.7.2005, leg. Serri & Frisch ; Barresar , 5 km W Kelishom (36°46'51''N 49°47'39''E), 1320 m, 30.7.2005, leg. Serri & Frisch . Golestan: S Gorgan, Shahkuh-e Paieen [36°34'N 54°26'E], 10.8.2009, leg. Serri & Nasserzadeh . Mazandaran: Baladeh , Nesen, E pass (36°14'37''N 51°27'17''E), 2960 m, 10.6.2008, leg. Serri, Nasserzadeh & Pütz ; Kelardasht, N Mt Alamkuh, Sardabrud River (36°26'18''N 51°03'38''E), 1800–1950 m, 26.7.2005, leg. Serri & Frisch ; 6 km SE Kiasar (36°12'00''N 53°35'05''E), 1340 m, 9.6.2006, leg. Serri & Frisch ; Rineh, S Mt Damavand (35°53'56''N 52°06'29''E), 2960 m, 3.8.2009, leg Serri & Nasserzadeh. Semnan: Shahmirzad, NE Chashm, Hikuh, Sheil , Parvar NR (36°0'54''N 53°23'07''E), 1900 m, 7.8.2009, leg. Serri & Nasserzadeh . Tehran: Fasham, Dizin (36°01'53''N 51°28'52''E), 2810 m, 10.6.2008, leg. Serri, Nasserzadeh & Pütz . West Azarbaijan : Orumieh, S Silvaneh, 10 km S Ziveh (37°10'37''N 44°52'58''E), 1750 m, 1.9.2008, leg. Serri & Frisch ; W Salmas, 10 km W Kuzerash (38°11'40''N 44°33'04''E), 1960 m, 31.8.2008, leg. Serri & Frisch ; NE Takab, 13 km E (36°36'06''N 47°19'42''E), 2 km N (36°38'05''N 47°14'07''E), 15 km E (36°36'21''N 47°21'16''E), 8 km E Takht-e Soleiman (36°36'02''N 47°17'36''E), 2210–2420 m, 7.- 8.9.2008, leg. Serri & Frisch .

Discussion. Stenus alanorum Ryvkin is proposed as junior synonym of S. medus Puthz based on the comparison of the holotype of S. alanorum Ryvkin with the paratype of S. medus and recent samples from Iran, which revealed that they represent one species with a variable length of the elytra and somewhat variable antennomere proportions. Ryvkin (1990: 211) distinguished S. alanorum from S. medus mainly by the antennomere 8 being three times longer than wide and the elytra being almost 1.5 times longer than the pronotum. He argued that S. medus would have thicker antennae with antennomere 8 not longer than twice as long as wide. Comparison of the above listed type specimens clearly showed, however, that in both specimens the 8th antennomere is three times longer than wide. The recently collected specimens of S. medus in Iran revealed that different populations show variation in some characters including elytral length, depth of the frontal furrows, punctation and the length of antennomere 8. There is also no difference in the primary genital characters of the examined type specimens. Both the external shape and the endophallic structures of the median lobes of the examined type specimens show no difference. Most examined specimens of S. medus have, however, a slightly broader apex of the parameres compared to the holotype of S. alanorum . There is moreover biogeographical evidence for the conspecificity. According to Schülke & Smetana (2015: 828), S. medus is recorded from Azerbaijan, Armenia, Georgia, Iran and Turkey. Stenus alanorum was described from North-Ossetia, which borders on Georgia to the north. Thus, both nominal species are distributed in the Caucasus. Based on the above-mentioned morphological and distributional data, we propose S. alanorum Ryvkin as a junior synonym of S. medus Puthz.