Zebe tabiwah Mitroiu & Darling

Mitroiu, Mircea-Dan, 2011, New Pireninae (Hymenoptera: Pteromalidae) from South-East Asia, Zootaxa 3065, pp. 1-13 : 8-9

Zebe tabiwah Mitroiu & Darling , sp. nov.

( Fig. 6)

Etymology. In the Berawan language the word “ tabiwah ” means confusing, an allusion to the confusion caused by finding the holotype in association with Z. cornutus .

Diagnosis. Females of this species can be recognized by the following characters: mesoscutum with a small but obvious protuberance that does not extend beyond anterior edge of mesosoma; F5 about 1.4× as long as broad; pecten about 2/3 length of hind tibia; metasoma about 1.3× as long as head plus mesosoma. The fore wing is very different from both known specimens of Z. cornutus ( Fig. 6, cf. Fig. 7 ): the stigmal vein is elongate and angulate (cf. short and straight) and the apical setae are much longer, almost 1/2 the wing width (cf. less than 1/3).

Description. Female. Body length. 0.9 mm

Colour. Body dark brown, without metallic reflections; mandibles light brown; eyes reddish; scape yellowish, flagellum brown; coxae, trochanters and bases of femora whitish; rest of femora brown; fore and mid tibiae yellowish; basal half of hind tibia brown, rest of hind tibia yellowish; tarsi yellowish, last segment brown; tegulae dark brown, wings hyaline, venation light brown.

Head. Eye about 1.4× as high as long. Antenna with scape distinctly shorter than eye height and about equal to eye length. Flagellar segments as in Z. darlingi , but F5 longer, about 1.4× as long as broad; clava length about 3.6× width.

Mesosoma. In profile moderately arched dorsally, length about 1.4× width and about 1.1× as wide as high. Anterior part of mesoscutum with a small but obvious protuberance which does not extend beyond anterior edge of mesosoma. Fore wing similar to that of Z. darlingi ; M:S:P = 24:6.5:9. Pecten about 2/3 length of hind tibia.

Metasoma. Elongated, laterally compressed, length including ovipositor sheaths about 3.5× width, about 1.3× as long as head plus mesosoma. Fifth and sixth metasomal tergites, hypopygium and ovipositor sheaths similar to those of Z. darlingi .

Male. Unknown.

Material examined. Holotype Ƥ: “ MALAYSIA, Sarawak: Borneo Gunung Mulu National Park, 77 m. Long Lansat, in forest, 23 May - 18 Jun 2010, ROM _ OSU 308172”, “ 4°0.099'N, 114°48.899'E, Malaise trap ( SLAM), DC Darling”, “Digital Image Voucher SAR 10-2 Royal Ontario Museum”, “ Holotype Ƥ Zebe tabiwah Mitroiu & Darling ” ( ROM).

Comments. The head of the holotype is slightly collapsed hence some measurements could not be taken. However, other features of the mesosoma, metasoma and fore wings are considered sufficient to differentiate this species from both Z. darlingi and Z. cornutus .

Distribution. Known only from Sarawak.

Hosts. Unknown.

Remarks. Only two specimens of Zebe were collected during an extensive 2-year sampling program at Gunung Mulu National Park, Sarawak, and both of these were found in the same Malaise trap sample (see comments on Z. cornutus below). This seemed like too much of a coincidence and careful consideration was given to the hypothesis that the two specimens were conspecific. Disregarding the mesoscutal horn, the most obvious difference between the two sympatric specimens is body size: Z. cornutus is more than twice as long as the holotype of Z. tabiwah (approx. 2 mm versus 0.9 mm). Both are females, which rules out sexual dimorphism. Consideration was also given to the idea of allometry in the development of the horn because there is a clear indication of a small protuberance in the smaller specimen. Allometric variation in horn size is well documented in dung beetles ( Coleoptera : Scarabaeidae ) and can occur in males and in females although it is much more common in males ( Emlen et al. 2007). However, closer examination of the fore wings (above) and of other characters suggests that the two females from Sarawak are best regarded as separate, sympatric species.

Figures

FIGURE 7. Female of Zebe cornutus La Salle, lateral habitus, with detail of the stigmal vein (ROM _ OSU 308172).