Metoisops Popov & Herczek, 1992

Herczek, Aleksander & Popov, Yuri A., 2014, Revision of the genus Metoisops (Hemiptera: Heteroptera, Miridae, Isometopinae) from late Eocene European amber, Zootaxa 3887 (3), pp. 401-421 : 402-403

Metoisops Popov & Herczek, 1992

Metoisops Popov & Herczek, 1992: 251 (n. gen.) Metoisops: Popov & Herczek, 1993: 25

Metoisops: Popov & Herczek, 1993: 10 , 51

Metoisops: Schuh, 1995: 12

Metoisops: Herczek & Popov, 1997: 190

Metoisops: Weitschat & Wichard, 2002: 120

Metoisops: Popov & Herczek, 2008: 66

Metoisops: Popov, Kosmowska-Ceranowicz, Herczek & Kupryjanowicz, 2011: 707 , 717

Type species: Metoisops kerzhneri Popov & Herczek, 1992

Redescription. Macropterous. Body size small, ranging in total length 2.4–3.0 mm, head strongly vertical with vertex broadly visible from above; reddish-brown, green-bluish, brown or yellowish uniform coloration, dorsum somewhat rugulose (especially pronotum and hemelytra), usually with deep and dense punctuation (except M. punctatodiffusus and M. intergerivus ), with dense hairs (setae) arising from articulate punctures ( Figs. 1, 2 ); relatively broad head, distinctly wider than anterior margin of pronotum, not less than twice as wide as long and not more than 2.6x as wide as long (except M. akingbohungbei ); clypeus weakly differentiated, rather short and wide, base ventral to level of eyes wide, elongate frontal-clypeal area not developed laterally or dorso-ventrally; prominent globular or semi-globular eyes; ocelli large and located at base of vertex; vertex varies in width from less than twice (e.g. M. punctatus , M. variabilis , M. intergerivus , M. punctatodiffusus and M. grabenhorsti ) to more than twice (e.g. M. kerzhneri , M. akingbohungbei , M. groehni , and M. consimilis ) width than dorsal width of eye; antennae cylindrical, inserted ventral to ventral margin of eye, 1st antennal segment long and visible dorsally; 1st and 2nd segments thickened in males, 1st antennal segment shortest, 2nd segment longest, 4th segment sometimes divided into 2 parts ( Fig. 3 ); rostrum long, apex always passed hind coxae; relative length of rostral segments varies; 2nd rostral segment usually longest, sometime 4rd segment longest (e.g. M. kerzhneri ) or even shortest (e.g. M. akingbohungbei ), or 1st, 2nd and 4th of equal length (e.g. M. punctatus ); pronotum broad, with some species twice as broad than long (e.g. M. akingbohungbei and M. groehni ) as wide as long; posterior angles angulated; anterior of pronotum polished, posterior disc weakly rugulose or punctate; narrow depressed collar prominent, calli weakly developed and confluent, median pit (incision) present, posterior margin usually weakly convex or straight (e.g. M. akingbohungbei and M. kerzhneri ); visible portion of mesoscutum narrowly exposed, not less than 3x shorter in length than scutellum (except M. punctatodiffusus ); scutellum nearly reaching median length of clavus, radial vein of hemelytra nearly reaching apex of clavus; outer margin of hemelytra distinctly polished and inpunctate; claval commissure length variable, ranging from longer, almost equal length (e.g. M. kerzhneri ) or even shorter (e.g. M. akingbohungbei ) than length of mesoscutum and scutellum combined; hemelytral membrane usually crumpled, with two different size of cells, the last of which is very variable in size; cuneus corial length 3x shorter or more than length of corium; hind tibia length longer than femur (except M. akingbohungbei ;); 1st tarsal segment always shorter than 2nd; claws with very small subapical tooth.

Species composition. Eight species: M. kerzhneri Popov & Herczek , M. akingbohungbei sp. nov., M. groehni sp. nov., M. intergerivus sp. nov., M. punctatodiffusus sp. nov., M. variabilis sp. nov., and M. consimilis sp. nov. from Baltic amber, M. punctatus Popov & Herczek from Baltic and Ukrainian (Rovno) amber, and M. grabenhorsti sp. nov. from Saxonian (Bitterfeld) amber.

Comments. This genus was placed to the separate tribe Electromyiommini Herczek, 1993 due to a mistake in the taxonomical check-list where all the genera from the Baltic amber were placed in Isometopini Fieber 1860 (Popov & Herczek, 2008). This tribe is characterized by the following features: front-clypeal part not expanded dorso-ventrally or laterally; clypeus well-marked, not shifted from frons; ocelli placed at some distance from the posterior head margin; claval commissure longer (eexcept M. akingbohungbei ) than mesoscutum and scutellum taken together (like Myiommini). Now just five extinct genera of this tribe are recognized: Electromyomma, Metoisops , Clavimyiomma , Electroisops , and Hoffeinsoria. It is also possible that the subbrachypterous Clavimyiomma henryi Popov & Herczek belongs to the genus Metoisops as well. Among these genera, only the Metoisops and Electromyiomma are not monotypic, the most specious genus being Metoisops . Moreover, representatives of Metoisops are found not only in Baltic amber, but also in the Eocene Ukrainian (Rovno) and Saxonian amber. Our analysis (see Table 1 ) of all obtained specimens of the genus Metoisops from different Eocene European ambers clearly demonstrate the variability of their features. This unfortunately made it practically impossible to reliably separate species since we cannot, for instance, prepare genital segments of males from amber to compare. We found only continuous characters for length ratios among different studied specimens. Metoisops akingbohungbei was the only species with characters we deemed significant enough to be its own genus, and therefore we made a preliminary decision to separate it out. The ratios of measurements for the 9 total specimens studied are in ( Table 1 ). The most variable characters in their ratio are the width/length head (2.2–2.6) or width eye/vertex (1.4–2.1) ratios. Other characters with less are the ratios of total width/length pronotum (1.72–1.82), ratio length scutellum/mesoscutum (3.2–4.25), and mesoscutum + scutellum/claval commissure ratio (1.1–1.27).

A key to all of the currently know species of Metoisops is given below.

Figures

FIGURES 1 – 3. Metoisops kerzhneri— dorsal vievs, antennal segments.