Aneugmenus oertzeni (Konow, 1887)

Liston, Andrew D., Jacobs, Hans-Joachim & Prous, Marko, 2015, The Sawflies of Crete (Hymenoptera, Symphyta), Deutsche Entomologische Zeitschrift 62 (1), pp. 65-79 : 65

Taxon classification Animalia Hymenoptera Tenthredinidae

† Aneugmenus oertzeni (Konow, 1887)

Material.

Crete; 2♀♀, 2♂♂, Marathos, 24.iii.2013. 20♀♀, 23♂♂, Armeni, 25.iii.2013. 2♀♀, Lakki, 21.iv.2013. 7♀♀, 19♂♂, Sempronas, 21.iv.2013. 2♀♀, 5♂♂, Drakona, 22.iv.2013. 5♀♀, 4♂♂, Theriso-Drakona, 22.iv.2013. 7♀♀, 3♂♂, Strovles, 24.iv.2013. 7♀♀, 11♂♂, Agia Irini, 26.iv.2013. 2♀♀, 12♂♂, Topolia, 29.iv.2013. 1♀, 16♂♂, Agia, 29.iv.2013. All swept from, or netted near, Pteridium aquilinum , the only known host ( Schedl 2011).

Barcode data.

The barcodes of four sequenced Cretan specimens (DEIGISHym20637-206340: infraspecific variability about 0.7%) diverge by a minimum of 6.1% from the nearest neighbour Aneugmenus bibolinii Zombori, 1979, represented by one male each from Corsica (first record from France: Ascu, 02.05.2004, leg. Liston, SDEI (DEIGISHym19725) and Sardinia (DEIGISHym19684): infraspecific variability about 0.7%. Minimum divergence of Aneugmenus oertzeni to the next nearest species Aneugmenus padi is 9.2% (many specimens from central and southern Europe, and Iran).

According to Benson (1968), Aneugmenus oertzeni occurs not just in Crete (its type locality), but also in "Turkey and S. E. Europe". However, in the same publication Benson stated that he had never seen specimens of this species. His statement may have been influenced by Konow (1905), who gave the distribution as Crete, Asia Minor and Moscow. The occurrence of Aneugmenus oertzeni outside Crete has not been confirmed.

Niu and Wei (2013) placed Aneugmenus oertzeni in Atoposelandria (type species Selandria fuerstenbergensis Konow, 1885), which they treated as a genus distinct from Aneugmenus (type species Tenthredo coronata Klug, 1818). Aneugmenus fuerstenbergensis is indeed distinguished from the other West Palaearctic Aneugmenus species by several characters: see for example key by Blank (1998). Niu and Wei (2013) stated that " Atoposelandria differs from Aneugmenus in the clypeus roundly and deeply incised; the frontal wall very sharp; claw slender and weakly bent, without basal lobe, and the inner tooth absent". The depth and shape of the excision of the clypeus is by no means so different between Aneugmenus fuerstenbergensis and other Aneugmenus as they suggest, and the development of the frontal wall shows considerable differences between the other W. Palaearctic species. On the other hand, Aneugmenus fuerstenbergensis is unique amongst West Palaearctic species in the claws lacking an inner tooth, the densely transversely striated and matt abdominal terga and the lack of a sinus sexualis in the male. Nevertheless, at present there are no compelling arguments for the recognition of a separate genus, because insufficient phylogenetic evidence is available to support this, and because the practical value of the distinction is low: apart from Aneugmenus fuerstenbergensis and Aneugmenus oertzeni , Niu and Wei (2013) place only two other species, from the Oriental Region, in Atoposelandria . For the present, we point out that according to Niu and Wei’s definition of Atoposelandria , Aneugmenus oertzeni does not belong there, but shares the “generic” characters of other W. Palaearctic Aneugmenus . In particular, its claw has an inner tooth, at least half as long as the outer. The inner one is however easy to overlook, as in all Aneugmenus species, because it arises close to the base of the claw and is obscured by setae and other parts of the apical tarsomere. Schedl (1981), who examined the types of Selandria oertzeni in the SDEI observed that Aneugmenus oertzeni resembles Aneugmenus coronatus (Klug, 1818). This is closer to reality than the comments of Benson (1968), who wrote of Aneugmenus oertzeni : "This species, which I have never seen, is distinguished from Aneugmenus padi by its untoothed tarsal claws. From Aneugmenus fuerstenbergensis it is distinguished in the ♂ by having the 6th tergite emarginate apically and a transverse groove (sinus sexualis) across the 7th tergite (as in Aneugmenus padi ) and the tergites yellow from the 3rd segment; and in both sexes by the shining surface of the tergites which in Aneugmenus fuerstenbergensis are dull with transverse striations." On reading the original description of Selandria oertzeni , one sees how Benson was misled. Konow (1887) wrongly stated that oertzeni has simple claws and accordingly compared the taxon with the only other West Palaearctic Aneugmenus species that does have simple claws, namely Aneugmenus fuerstenbergensis . Our examination of the types of Aneugmenus oertzeni and the recently collected specimens revealed that this species is morphologically similar to Aneugmenus padi . Externally, they can only be distinguished by colour characters and the larger inner tooth of the claw of Aneugmenus padi . However, barcoding suggests a closer relationship of Aneugmenus oertzeni to Aneugmenus bibolinii than to Aneugmenus padi . A revised key to West Palaearctic Aneugmenus species is in preparation.