Kerteszmyia, Woodley, Norman E., 2008

Woodley, Norman E., 2008, Kerteszmyia, a new genus of Pachygastrinae from the Neotropical Region (Diptera: Stratiomyidae), Zootaxa 1746, pp. 39-45 : 39-40

Kerteszmyia gen. nov.

Type species, Kerteszmyia ecuadora sp. nov., by present designation.

Diagnosis. This distinctive genus can be easily separated from other Neotropical pachygastrines that have four scutellar spines by the characteristic antennal flagellum that is kidney-shaped, distinctly higher than long, with a subapical arista-like style that is inserted on the dorsal one-third of the flagellar complex ( Figs. 1–2 ). All other genera with scutellar spines have the antennal flagellar complex as long as high or much longer. Other characters useful in recognition are the densely hairy eyes ( Figs. 1–4 ), the head distinctly higher than long ( Figs. 1–2 ), and the short abdomen that is wider than long.

Description. Male. Head ( Figs. 1, 3 ) with eye very large, occupying most of anterior and lateral head surface, eyes narrowly separated; upper frons reduced to a very narrow strip that is 0.06 width of head at narrowest point ( Fig. 3 ); lower frons gradually diverging toward oral margin; face reduced to an extremely narrow strip below antennae, antennae thus inserted very close to oral margin. Ocellar tubercle slightly prominent. Gena only slightly visible in lateral view, very narrow, about width of two ommatidia; occiput not visible in lateral view. Eye very densely haired, ommatidia uniform in size. Antenna short, scape slightly longer than pedicel, the latter very slightly produced on inner side; flagellum bilaterally flattened, kidney-shaped, about 2.5 times higher than long, last flagellomere an arista-form style that is inserted on the upper third of flagellar complex. Palpus two-segmented, first segment shorter than second, second segment ovoid.

Thorax with scutum convex; scutellum forming angle with scutum (not in same plane), rounded posteriorly with distinct margin, armed with 4 marginal spines, the lateral spines about two-thirds length of medial spines and more slender; subscutellum slightly developed, largely bare, with only very sparse scattered tomentum. Legs unremarkable, without significant modifications. Wing ( Fig. 7 ) with microtrichia present on darkened areas, and scattered on posterior portion; R2+3 originating well beyond crossvein r-m; R4 present.

Abdomen short and convex, wider than thorax, approximately 1.7 times wider than long, posterior half of tergite 4 and all of 5 nearly vertical in lateral view.

Female. Differs from male as follows: Head with eye slightly smaller than in male, upper frons wider, gradually diverging ventrally, 0.14–0.18 width of head.

Abdomen with cercus two-segmented, segments subequal in length and diameter, second segment elongate-ovoid.

Etymology. This genus is named after Kalman Kertész (1867–1922), a Hungarian dipterist who was an excellent taxonomist working on Stratiomyidae among other families. He published several comprehensive and important papers on Pachygastrinae , including a key to world genera.

Remarks. Kerteszmyia has a general appearance that is different from most other Neotropical genera of pachygastrines with scutellar spines due to its smaller size; less elongate thorax; and short, wide abdomen with strongly declivitous apical segments. To the naked eye it is similar to genera such as Popanomyia Kertész and similar medium-sized black taxa, but these lack scutellar spines and do not have darkened wings.

No phylogenetic work has been done on the large, species-rich subfamily Pachygastrinae on a global scale. The character state that unites the genera discussed here, having two or more scutellar spines, is plesiomorphic relative to many genera in the subfamily that have no scutellar spines (see Woodley 2001: 5–6 for a general discussion of this character for the family). Thus, it is possible that the species with scutellar spines form a paraphyletic or polyphyletic assemblage within the pachygastrines depending on how those without spines evolved and how many times loss of scutellar spines occurred.

Due to lack of phylogenetic work, it is not possible to discuss the relationship of Kerteszmyia to other genera with scutellar spines. However, some features that the genus exhibits, such as the short, tall head and small compact body form are similar to those found in some genera that lack scutellar spines. This possibly indicates that Kerteszmyia is more derived among the taxa with scutellar spines, but only a more rigorous study can verify this.

Figures

FIGURES 1 – 7. Kerteszmyia ecuadora, morphological features. 1, male head, lateral view. 2, female head, lateral view. 3, male head anterodorsal view. 4, female head, anterodorsal view. 5, female scutum, dorsal view. 6, female abdomen, posterior view. 7, female right wing, dorsal view.