Pholema Graham

Hansson, Christer & Shevtsova, Ekaterina, 2012, Revision of the European species of Omphale Haliday (Hymenoptera, Chalcidoidea, Eulophidae), ZooKeys 232, pp. 1-157 : 121-124

Genus Pholema Graham stat. rev.

Remarks.

Graham (1963) described genus Pholema to include the single species microstoma, which was described in the same paper. Graham motivated the new genus because he regarded some morphological features present in Pholema : small clypeus, large malar space, small mouth opening, too discordant for an Omphale species. Schauff (1991) synonymized Pholema with Omphale because he found the characters mentioned by Graham too variable and/or overlapping with some Omphale species.

The type species and the only known species of Pholema , Pholema microstoma , has the following characters important for classification on genus level: clypeus undelimited (Fig. 543), occiput without a groove or fold between occipital margin and occipital foramen (Fig. 541), sensilla ampullacea (peglike sensilla) on flagellomeres short and symmetric (Fig. 542), forewing with postmarginal vein 0.8 × as long as stigmal vein, ovipositor very short - gaster short and rotund and ovipositor only ½ as long as length of gaster, male genitalia with volsellar setae as “normal” thin setae. Some of these characters disagree with a placement of Pholema microstoma in Omphale : undelimited clypeus, antennal sensilla symmetric, and perhaps the most critical - not having enlarged volsellar setae in mal e genitalia, the sole autapomorphy for Omphale . Habitually Pholema microstoma looks like a Neochrysocharis Kurdjumov, mainly because of the distinct and 3-segmented antennal clava and the short postmarginal vein, and some additional characters also agree with a placement in Neochrysocharis (undelimited clypeus, symmetric antennal sensilla). Absence of an occipital groove/fold is very unusual in Neochrysocharis but it is absent in at least one other species, Neochrysocharis albiscapus Erdös. Furthermore, this character state is variable within Neochrysocharis , some species have a complete fold between occipital margin and occipital foramen, while others only have a short fold close to the occipital margin, and as mentioned some species lack it altogether. Therefore the absence of such a fold does not justify a separate genus for Pholema microstoma . The short ovipositor, not present in other Neochrysocharis species (nor in any Omphale species), is probably an adaptation to a close access of the host, and doubtfully of such a value that it justifies a separate genus. Another option is to place Pholema microstoma in Asecodes Förster, but some critical characters disagree with such a placement. Pholema microstoma has symmetrical antennal sensilla, a distinct 3-segmented antennal clava and lacks a fold or groove on occiput; Asecodes species have asymmetric antennal sensilla, a 1-segmented antennal clava and a strong groove between occipital margin and occipital foramen. All things considered Pholema microstoma is a Neochrysocharis and Pholema is thus a synonym of Neochrysocharis .