Eurysacca media Povolny 1986
Creators: name: Bidzilya, Oleksiy
name: Chang, Patricia Esther Corro
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Gelechiidae
Eurysacca
Eurysacca media

description: Eurysacca media Povolný, 1986
Figs. 9–17
Eurysacca media Povolný, 1986: 22, figs. 19, 20, 50. TL:
“ ARGENTINA, Neuquen, S.C. de Bariloche, Confluencia ”
Material examined. 1 ♂, 3 ♀♀, Ecuador, Las Pampas, Dez. 1981, leg. Onore (gen. slide 229/19♀; 232/19♂; 264/19♀; 58/22♀, O. Bidzilya) (SMNK).
Notes. The species was described from three males (including holotype) and one female collected in Argentina, and one male collected in Chile. We did not examine the type series. Povolný in the original description provided drawings of the genitalia of a male paratype from Chile and female paratype from Argentina along with a blackand-white photograph of a male paratype from Argentina (dorsal view with head, thorax and right pair of wings). Specimens from Ecuador match the diagnosis of E. media, having similar wing pattern and genitalia in both sexes. However, we discovered several characters that were not mentioned in the original description and may have been overlooked by Povolný. Foremost are prominent patches of black scales on abdominal segment VII in the female (Figs. 11, 13). Additionally, we observed a slight dimorphism in the wing colouration between the male and female, the bulbus ejaculatorius in male genitalia as well as the papillae anales, apophyses posteriores and corpus bursae in the female genitalia, characters that were neither mentioned nor illustrated in the original description.
Additions to original description. Adult (Figs. 9–14). Labial palpus strongly upcurved, far protruded over the head, white to light grey with broad brown basal and subapical rings, diffuse on palpomere 2 and more distinct on palpomere 3 (Fig. 12); forewing (Figs. 9–11) brown mottled with light grey, oblique whitish block from about 1/5 of costa to fold, base of forewing with black spots, diffuse black streak from cell corner towards apex of wing in some individuals, pencil of dark brown scales underside of forewing base (Fig. 14); abdomen dark, blackish-brown on dorsal surface and lighter, grey mottled with black and brown on lower surface, in female segment VII with pair of large ovate lateral patches of black scales extending dorsally and nearly contiguous in middle of tergum VII (Fig. 13).
Male genitalia (Fig. 15). Phallus with bulbus ejaculatorius subovate, about 1/2 length of phallus, with slender, ribbon-shaped, gradually bent lamina.
Female genitalia (Figs 16, 17). Papillae anales subovate, covered with short setae in distal part and long setae in basal part; apophyses posteriores 5–6x as long as apophyses anteriores and 2–3x as long as segment VIII; segment VIII longer than broad, broadest before middle, posterior margin weakly invaginated; tergum VIII membranous, weakly sclerotized in posterior 1/4–1/3; sternum VIII evenly sclerotized except drop-shaped, strongly laterally edged and covered with fine honey-comb sculpturing; subgenital plates subrectangular with distinctly elongated posterolateral corners, surface entirely covered with net of honey-comb sculpturing with large cells; apophyses posteriores 1/3 length of segment VIII, straight; ductus bursae about half length of corpus bursae, well sclerotized and edged along right margin, most anterior part before entrance of corpus bursae membranous, weakly widened and folded, ductus seminalis arising from its most posterior part; gutter-shaped antrum distinctly sclerotized laterally, fused with medial walls of subgenital plates and extending to their posterior margin; corpus bursae elongate, gradually broadened anteriorly, signum small with ovate basal plate and short weakly curved distal process, situated at mid length on right side of corpus bursae.
Distribution. Argentina, Chile (Povolný 1986: 23), Ecuador (new record).
Biology. Quinoa (Chenopodium quinoa Willd.) and Chenopodium album L. Bosc ex Moc. (Amaranthaceae) were recorded as host plants (Lamborot et al. 1999, cit. after Cepeda 2017: 2).
Remarks. Sexual dimorphism in vestiture of abdominal segments VII-VIII in species of Eurysacca has not been clearly described. Povolný (1986: 4, 6) mentioned the presence of a whitish “anal tuft” in the male of some species (e.g., E. atrata Povolný, 1986 and S. danorum Povolný, 1986). Meyrick (1917: 43) described an anal tuft as “ochreous-whitish with a strong black mark on each side above” in the holotype of Phthorimaea urosema Meyrick, 1917 (currently Eurysacca urosema). It is evident that Povolný described “anal tuft” for males only. This structure is represented by caudally directed scales and most likely does not correspond to the patches of black scales described here for the female of E. media. The description by Meyrick of the “anal tuft” in E. urosema also matches what we can see in females of E. media. This suggestion is supported by Clarke (1969: 167) who explained that the tuft described by Meyrick “is only a patch of black scales dorso-laterally placed”. Moreover, Clarke dissected and figured the genitalia, and indicated that the holotype of P. urosema is in fact a female, not a male as stated in the original description. Thus, dorso-lateral patches of black scales on the female abdominal segment VII are known to be present at least in two species of Eurysacca (E. media and E. urosema) and allows for the superficial recognition of the female of these two species. This is worth mentioning in an expanded generic description, although at this point it is not known whether this character is also present in the type species E. melanocampta. Below we provide an improved diagnosis of E. media. Our study of males and females of E. media resulted in the discovery of additional external and genitalia characters of this species, which we add to the generic description as a whole. In the female, the “sclerite arises from the bases of anterior apophyses and shields the posterior part of subgenital plate ventrally” (Povolný 1986: 2) should be treated as a subgenital plate, whereas the weakly sclerotised and more or less foam-like microsculptured sclerite located more dorsally should be treated as a ventromedial depression as described for the Palaearctic Gnorimoschemini (Huemer & Karsholt 2010). The partial separation of these sclerites is unique and putatively autapomorphic for Eurysacca.
The specimens we identify as E. media document the first records of any species from the genus occuring in Ecuador. Povolný (1986: 43, fig. 42) includes “Huigra, Ecuador ” in figure caption of the holotype of Eurysacca urosema. This is an obvious mistake, as Meyrick (1917), Clarke (1969) and Povolný (1967: 117; 1986: 43) himself indicate that holotype is from Matucana, Peru.
Diagnosis. Medium sized with wingspan 14–15 mm. Adults are characterized by a pale oblique basal blotch on brown to blackish-brown forewing with three dark spots in cell. The female can clearly be recognized by dorso-lateral patches of black scales on the female abdominal segment VII. Eurysacca urosema seems to be most externally related to E. media by having the same abdominal colouration in female and somewhat similar wing pattern with a pale basal blotch (Clarke 1969: 166, pl. 83, fig. 3), but differs in the presence of a black irregular patch in the middle of cell. Povolný (1986: 22) indicated a “tuft of brownish hairs arising from base of hindwing costa in male” as an additional diagnostic character of the species. We confirm presence of this structure, which, however, is represented by a brush, rather than a tuft in the examined male. A pencil of dark brown scales on the underside of the forewing discovered for E. media (Fig. 14) can also be used as a potentially important character for identification of this species. However, other species of the genus need to be studied in this respect. The female genitalia of E. media are defined by posterolaterally elongate subgenital plates in combination with short signum. The male genitalia of E. media closely resemble other species of Eurysacca, but differ in an unique combination of certain characters, namely a moderately broad and weakly apically dilated vincular process, a strongly apically broadened sacculus that does not reach the top of vincular process, a moderately elongate saccus and a comparatively wide phallus with a down-curved apical arm. Eurysacca melanocampta has very similar male genitalia but differs in the shorter valva (not extending to posterior margin of uncus), a narrower vincular process and an apical lobe of phallus that is broader and placed nearly perpendicular to the phallus (Povolný 1986: 14, fig. 12; 1990: 200, fig. 63).
description: Published as part of Bidzilya, Oleksiy & Chang, Patricia Esther Corro, 2022, A new species and new records of Gnorimoschemini (Lepidoptera, Gelechiidae) from Ecuador, pp. 388-400 in Zootaxa 5138 (4) on pages 391-395, DOI: 10.11646/zootaxa.5138.4.2, http://zenodo.org/record/6571584