Stefaniella skuhravae Elsayed

Elsayed, Ayman Khamis, Skuhravá, Marcela, Karam, Hedaya Hamza, Elminshawy, Abdelaziz & Al-Eryan, Mohamed Awad, 2015, New records and new species of gall midges (Diptera: Cecidomyiidae) developing on Chenopodiaceae in Egypt, Zootaxa 3904 (1), pp. 105-115 : 112-114

Stefaniella skuhravae Elsayed , new species

Adult description. Color of freshly emerged individuals: head black, antennae light brown, thorax brown, wings transparent, legs light brown, upper and lower parts of abdomen light brown, lateral parts orange. Body length. 0.7 mm (n=7) in males and 1.1 mm (n=5) in females.

Head ( Fig. 24 ). Compound eyes with circular facets. Gap between eyes on vertex about 0.5-1.5 times as wide as facet. Palpi 2–segmented, second segment elongated, nearly longer than the first. Antenna 2+9–10 flagellomeres; scape conical, pedicel rounded, flagellomeres barrel-shaped in both sexes; each with two connected rings of circumfila ( Fig. 25 ); the apical two flagellomeres sometimes fused.

Thorax.Wing ( Fig. 26 ) length 0.6 mm (n=7) in males and 1.0 mm (n=5) in females. Vein R5 joining C before its mid-length; C broken beyond the attachment point with R5; M present; CuA simple. Tarsal claws ( Fig. 27 ) toothed. Empodia as long as, or shorter than, claws.

Abdomen, male. Tergites 1–7 rectangular, with a posterior row of strong, hyaline setae; tergites 2–7 with one pair of anterior, small, trichoid sensilla; tergite 8 very narrow, about 0.33 width of tergite 7, with median pair of trichoid sensilla. Sternites 1–7 with scattered setae, in addition to posterior row of strong hyaline setae; sternum 8 undifferentiated from the surrounding membranous tissue. Genitalia ( Fig. 28 ): Gonocoxite slightly elongate, with setulose mediobasal lobe. Gonostylus 0.5 times as long as gonocoxite, arched, ending with a strong tooth. Cerci fused at base, forming one apically notched sclerite, setulose. Hypoproct entire, setulose, shorter than tips of cerci, with rounded tip. Parameres dorsally covered with dense tiny setae, and surrounding aedeagus. Aedeagus cylindrical, straight, slightly longer than parameres, with truncate tip. Female: ( Fig. 29 ): Tergites 1–7 with 1–2 posterior rows of strong, hyaline, setae, and anterior trichoid sensilla; tergite 8 weakly sclerotized, about half width of tergite 7, divided into two sclerites. Sternites 2–7 with 1–2 posterior rows of hyaline setae. Ovipositor: segment 8 with lateral group of strong, curved, internally directed setae; membranous part rugose with papillae surrounded with tiny spines. Segment 9 (ovipositor trunk) with two sclerotized rods that widen posteriorly, forming weakly sclerotized triangular plate covered with tiny spines. Lateral plate bearing about 25 thick and strong setae. Aculeus straight, thick, tapered at apex, with two rows of tiny setae, every row consists of ~22 setae. Apical lamella rectangular and setose.

Holotype. Female, Egypt, El-Amria district (30°59'54.00"N, 29°49'7.00"E), 4. VI.2013, A. K. Elsayed reared from galls on male floral inflorescences of Atriplex halimus .

Paratypes. All material from Egypt, El-Amria district, Alexandria, reared by A. K. Elsayed from galls on male floral inflorescences of A. halimus . 1 males, 12.VI.2013; 1 male, 13.VI.2013; 2 females, 14.VI.2013; 2 females, 3 males, 16.VI.2013; 4 males, 17.VI.2013; 5 males, 2 females, 19.VI.2013; 8 males, 20.VI.2013; 1 female, 22.VI.2013; 2 females, 24.VI.2013.

Distribution. Egypt (El-Amria district).

Etymology. This species is named in honor of Mrs. Marcela Skuhravá, the Czech entomologist and expert on the family Cecidomyiidae (Diptera) .

Biology. Larvae of S. skuhravae induce small, slight swellings ( Fig. 9 and 10 ) on male floral inflorescences of the salt marsh plant Atriplex halimus . The gall consists of a single chamber, and pupation takes place inside it. The pupal exuviae protrude from the emergence hole, and can be distinguished by their hyaline color. The galls were collected and the adults emerged from the end of May to October 2013.

Remarks. The genus Stefaniella contains 9 species ( Gagné & Jaschhof 2014). Dorchin & Freidberg (2008) revised all the species and found no significant differences between them in morphological characters. They concluded that study of the immature stages is needed, and molecular study will be useful to determine relationships between the species. They added that the currently the best characters for distinguishing species of Stefaniella are those of their galls.

There are two known species of Stefaniella that induce galls on A. halimus : S. atriplicis Kieffer, 1898 and S. trinacriae De Stefani, 1900 ( Dorchin & Freidberg 2008, Gagné & Jaschhof 2014). Stefaniella atriplicis induces small stem galls, each gall about 4–5 mm in diameter and multiple chambers ( Skuhravá et al. 2007). Stefaniella trinacriae induces large galls on the stems, each gall about the size of a hazelnut and having multiple chambers. In contrast to the preceding species, S. skuhravae induces small galls on the male floral inflorescence, and each gall consists of only a single chamber. Therefore, we consider it to be a new species.

Figures

FIGURES 24 – 29. Stefaniella skuhravae. 24. Head. 25. The fifth antennal flagellomere. 26. Wing. 27. The distal tarsomere. 28. Genitalia (the mediobasal lobes are shown as would be seen if cerci were removed, setulae are not shown). 29. Female terminal abdominal segments with ovipositor.

FIGURES 5 – 10. Gall midges on host plants. 5. Gall of Asphondylia punica on stems of Atriplex halimus. 6. The pupal exuviae of Houardiella gracilis protruding from the stem of Arthrocnemum macrostachyum. 7. The pupal exuviae (arrow) of Baldratia karamae protruding from a leaf of Suaeda pruinosa. 8. Galls of Primofavilla aegyptiaca on the leaves of A. halimus. 9 – 10. Gall of Stefaniella skuhravae on the male floral inflorescences of A. halimus, and the protruding pupal exuviae (arrow).