Rhogogaster chlorosoma ( Benson, 1943 )

Taeger, Andreas & Viitasaari, Matti, 2015, European Rhogogaster s. str., with notes on several Asian species (Hymenoptera: Tenthredinidae), Zootaxa 4013 (3), pp. 369-398 : 375-376

Rhogogaster chlorosoma ( Benson, 1943)

( Figs 3c, d , h, i, s, 4b, c, 6c, k, compare 5a, b, j, l)

Tenthredo chlorosoma Benson, 1943: 139 , 142–143. Holotype ♂, not examined (BMNH). Type locality: Czech Republic: Chodau (Chodov). 1♂ 1♀ paratype from the type locality (SDEI, both damaged, ♀ see http://dx.doi.org/10.6084/m9.figshare.1378995).

Rhogogaster scalaris sensu Thomson (1871) and Zhelochovtsev & Zinovjev (1988)

Discussion. In the original description Benson (1943) listed Tenthredo chloros Rudow, 1871 , Rhogogaster viridis var. sibirica Enslin, 1912 , and R. viridis forma montana Betrem, 1933 as questionable synonyms. In the course of this study these taxa were excluded from synonymy of chlorosoma . Rhogogaster chlorosoma podkumokensis Muche, 1973 is a synonym of R. scalaris (see below).

The species is very similar to R. scalaris , the COI barcodes of R. chlorosoma and R. scalaris fall in the same cluster and do not allow the separation of the taxa. The males are well characterized by the large plantar lobes and the shape of the penis valves. The females also have large plantar lobes, but the range of their size overlaps with scalaris . The saw does not differ from that of scalaris . Usually the color characters given in the key may help to identify the females. The coloration of chlorosoma and scalaris is variable. However, the coloration pattern may be comparatively stable in restricted areas, and the identification of the species based on color characters may be fairly reliable in such areas.

Benson (1965) distinguished the coloration of chlorosoma and scalaris (“ viridis ”) as follows:

( chlorosoma ) “Very pale. Abdomen in male may be entirely pale but usually with a narrow black medial line; female with at most a medial vitta of separated black spots.”

( scalaris ) “Very variable in colour but often much darker than chlorosoma (male with at least black vitta on abdomen, and both male and female may be entirely black above).”

Though chlorosoma tends on average to be paler than scalaris , the latter may be nearly completely pale, and thus clearly paler than dark specimens of chlorosoma . Consequently, identifications of females remain uncertain, if the usual local color pattern of the species is unknown, and the size of the plantar lobes falls in the overlapping range (length between the 1st and 2nd lobes about 0.9–1.1 × their own length). The examination of nuclear genes might help to separate the taxa in the future.

Rhogogaster naias Benson, 1965 and R. auctor Weiffenbach, 1967 are known only from Turkey. Both are similar to chlorosoma , but the male genitalia are very different ( Figs 6d, i ). At present, we are unable to separate their females from chlorosoma .

Figures

FIGURE 3. a – f: color pattern in dorsal view— a Rhogogaster punctulata ♂, b R. punctulata ♀, c – d R. chlorosoma ♂, e R. polaris ♂, f R. scalaris ♀. g – n: 1 st and 2 nd plantar lobe of hind tarsus— g R. punctulata ♂, h R. chlorosoma ♂, i R. chlorosoma ♀, j R. sibirica ♀ (lectotype), k R. scalaris ♀ (lectotype), l R. scalaris ♂, m R. scalaris ♀, n R. scalaris ♂ (lectotype R. chlorosoma podkumokensis). o – r: mesoscutellum and appendage in dorsolateral view— o – p R. viridis, q – r R. polaris. s – t: thorax in dorsal view— s R. chlorosoma, t R. scalaris. u – y: figures of R. gayuboi (from Llorente Vigil, 1988) — u face, v head dorsal, w penis valve, x mesoscutellum and appendage dorsal, y abdomen.

FIGURE 6. a – j: penis valves— a – b Rhogogaster scalaris, c R. chlorosoma, d R. auctor (holotype), e R. punctulata, f R. polaris, g R. sibirica (paralectotype), h R. viridis, i R. naias (paratype). j – n: drawings of penis valves by Benson (1943, 1952, 1965) and Ross (1943) — j R. scalaris (as R. viridis), k R. chlorosoma, l R. punctulata, m R. californica, n R. viridis (as R. dryas). o: variability of penis valves in R. polaris (all from Sweden, Abisko area). p: records of R. magniserrula (displayed with Map data, © Basarsoft, Google).