Scrobipalpa Janse, 1951

Bidzilya, Oleksiy V., 2021, A review of the genus Scrobipalpa Janse, 1951 (Lepidoptera, Gelechiidae) in the Afrotropical region, Zootaxa 5070 (1), pp. 1-83 : 6-8

Scrobipalpa Janse, 1951

Scrobipalpa Janse, 1951: 199 .

Type species: Gelechia heliopa Lower, 1900: 417 .

Ilseopsis Povolný, 1965: 481 .

Type species: Ilseopsis peterseni Povolný, 1965 . Synonymized by Sattler 1988: 231.

Ergasiola Povolný, 1967: 232 .

Type species: Phthorimaea ergasima Meyrick, 1916 . Synonymized by Huemer & Karsholt 2010: 57.

Euscrobipalpa Povolný, 1967: 212.

Type species: Scrobipalpa grossa Povolný, 1966 . Synonymized by Park & Ponomarenko 2007: 59.

Diagnosis. Species of Scrobipalpa are rather variable and cannot be confidently diagnosed by external characters alone. Most of species have a forewing pattern similar to that of many other Gnorimoschemini , with three dark spots in cell and light costal and tornal spots at 2/3–3/4. However, a wing pattern with white fasciae, dark markings along costal margin and in the fold, or with contrasting veins, is also common among a rather large number of uniformly coloured species. In the Palaearctic region, species of Scrobipalpa may be confused externally with Gnorimoschema Busck, 1900 , Caryocolum Gregor & Povolný, 1964 , Ephysteris Meyrick, 1908 and Vladimirea Povolný, 1967 . However, males of Scrobipalpa usually can be separated from related genera by the characteristic dorsoventrally flattened last segment of the abdomen. In Ephysteris and Vladimirea , sternum VIII is usually more or less gutter-shaped, and tergum VIII is represented by a narrow flap. Males of Gnorimoschema have similarly flattened segment VIII with the tergum and sternum of about same shape, but Gnorimoschema can be separated by apically pointed uncus and distinctly inflated and inward-turned tips of valvae that are usually weakly protruded and can be observed without dissection. Moreover, most of Gnorimoschema species have a narrower and more elongate forewing. Scrobipalpa species can be distinguished by the following suite of male genitalia characters: an elongated uncus, usually apically unmodified; distal sclerite of gnathos short, weakly curved; culcitula well developed; tegumen elongated; valva long, slender; sacculus short; vincular processes short; and phallus inflated at the base with an apical hook. The female genitalia are characterised by the following: unmodified or “foam sculptured” subgenital plates separated by usually foamed or covered with microspines ventromedial depression; straight apophyses anteriores; a membranous ductus bursae with a short colliculum; and the corpus bursae with a distally hook-shaped signum. Turcopalpa Povolný, 1973 and Gobipalpa Povolný, 1973 are most closely related to Scrobipalpa among Palaearctic Gnorimoschemini . Both genera can be separated from Scrobipalpa by short, slender uncus and very broad vinculum in the male genitalia of the latter. The Australian genus Australiopalpa Povolný, 1974 undoubtedly constitutes a branch related to Scrobipalpa , Gobipalpa and Turcopalpa , and it can be distinguished by the presence of an additional lobe on the posterior margin of the vinculum in male genitalia. The taxonomic rank of these three genera will be revised in a separate paper (Bidzilya in prep.). The predominantly Neotropical Scrobipalpopsis Povolný, 1967 is similar to Scrobipalpa in the male genitalia, but differs considerably in the female genitalia. Some members of the genus Scrobipalpomima Povolný, 1985 , e.g., S. neuquenensis Povolný, 1985 (type species of the genus) and S. karsholti Povolný, 1985 , are undoubtedly more closely related to Scrobipalpa , based on male genitalia, than to any other genera of Neotropical Gnorimoschemini . The main differences between the two genera are the shape of the uncus (convex and with tends of forming medial tip), the more apically obtuse gnathos, and the phallus with subterminal modifications in Scrobipalpomima (Povolný 1985: 5) . The female genitalia of Scrobipalpomima are very similar to those of Scrobipalpa as well, but differ in usually sclerotized posterior part of the ductus bursae and the presence of a sclerotized lobe arising from the anterior margin of sternum VIII. A recent phylogenetic study ( Corro Chang 2021) supports previously established relationships of Palaearctic Scrobipalpa (based on S. indignella (Staudinger, 1879) , a member of the genus Euscrobipalpa sensu Povolný), with Gobipalpa and Turcopalpa ( Povolný & Šustek 1988) , whereas the Australian S. aptatella (member of the genus Scrobipalpa sensu Povolný ) is clustered in a separate branch with Australiopalpa . The latter contradicts the current concept of the genus Scrobipalpa ( Bidzilya & Li 2010; Huemer & Karsholt 2010). These results indicate the need for further research using more representative material to clarify the generic concept of Scrobipalpa .

Description. Sexual dimorphism slight; in some species (e.g., S. murinella (Duponchel, 1843) females are slightly smaller and have a more pointed hindwing. Head: Smooth-scaled, frons convex, without modifications, but weakly expanded in S. usingeri Povolný, 1969 or possess irregular frontal process in S. peterseni ( Sattler 1988: 225) , typically concolourous with thorax and tegulae, frons often lighter; labial palpus upcurved, palpomere 2 1.5–3.0 times as broad and 1/2–3/4 length of palpomere 3, outer surface with basal and medial dark belt in most of species, lower surface simple or with bristle of raised scales and more or less distinct medial groove, inner and upper surfaces usually lighter than outer surface, palpomere 3 as palpomere 2 acute, but dark belts usually more diffuse; antennae filiform, scape usually uniformly coloured or dark mixed with light-tipped scales, without pecten, flagellomeres as scape but light ringed as usual.

Thorax: Dorsum and tegulae more or less unicolourous in most species, sometimes with a well-developed contrasting medial line on thorax; wingspan 7–25 mm, forewing moderately elongate to broadly lanceolate, weakly brachypterous in S. peterseni , usually with weakly pointed apex, costal margin gradually convex and weakly arched as usual, covered with smooth scales, several species with tufts of raised scales (e.g., S. admirabilis sp. nov.), pattern rather variable, three dark spots in cell, costal and tornal, light spots at 2/3–3/4, dark oblique basal streak and fuscous dash(es) in fold in most of species; pattern often considerably modified by additional markings, e.g., black, light brown, or fuscous dots, dark irroration along veins, dark patches along costal margin, black suffusion along margins, ochreous irroration and black dash(es) in fold, white subapical fascia, black spots along wing apex, etc.; often more or less unicolourous with reduced markings; rarely with contrasting white fasciae on black ground colour ( S. feralella (Zeller, 1872) ; S. argenteonigra Povolný, 1972 ) or with longitudinal black lines ( S. perinii (Klimesch, 1951) ; S. picta Povolný, 1969 ; S. munita sp. nov.); cilia usually concolorous with ground colour of forewing, darktipped, with or without terminal line; hindwing light grey to dark grey or dark brown, usually with concolorous cilia. Frenulum with a single acanthus in male and three acanthae in female.

Abdomen. Female segment VII as abdominal segments III–VI, but slightly longer, male tergum VIII more or less rounded, sternum VIII elongated, tongue-shaped or subtriangular, with anteromedial emargination, with or without paired coremata; sternum II with distinct venulae and well-developed apodeme. Male genitalia with uncus subrectangular, longer than broad, usually weakly narrowed apically, posterior margin straight or weakly rounded, in some species medially invaginated or pointed, in some species bearing a few short setae; distal sclerite of gnathos moderately elongated, weakly curved or short, axe-shaped, tongue-shaped in S. phagnalella (Constant, 1895) and S. munita sp. nov.; culcitula small to large; tegumen elongated, gradually narrowed distally, usually with indistinct transition to uncus, anterior margin with triangular or broadly rounded medial emargination extending 1/4–1/2 length of tegumen, pedunculi distinct; valva slender, elongated, straight or evenly curved, sometimes slightly sigmoid, apex usually moderately inflated, covered with hairs in distal portion; sacculus maximum 1/2 length of valva, usually about as wide as valva, distinctly or slightly narrowed distally, with inward-curved tips, gap to valva varying form very broad to slender, gap to vincular process usually distinct, sometimes very short and narrow; vinculum longer than wide, with supported system consisting of two slender sclerites extending from anterolateral corners to middle of vinculum, posterior margin with V-, U-, lyre-shaped, or rounded emargination variable in width and length, vincular processes varying from short and slender to long and broad; saccus subtriangular, weakly or distinctly tapered, sometimes truncate, subrectangular, broadly rounded or slender, slightly to conspicuously extending beyond top of pedunculus; phallus stout and moderately long, sometimes slender and elongated, with caecum inflated, distal part straight or weakly sigmoid, rarely with group of short spines (i.e., S. parki ( Povolný, 1993)) , lateral rod(s) along one side ending with triangular tip at apex of phallus, opposite side of apex with perpendicular or down-curved slender beak-, leaf-shaped, or broadly triangular hook, bulbus ejaculatorius sac-shaped, rounded or elongated, ductus ejaculatorius usually with distinct ring- or band-shaped sclerotization (except for S. agassizi sp. nov.). Female genitalia with papillae anales ovate or subtriangular, covered with short setae, membranous; rarely long sensory setae on papillae anales are reduced, replaced with microtrichia (i.e., S. munita sp. nov.); in some species with paired sclerites directed posteriorly from base of papilla analis. Apophyses posteriores slender, usually longer than ductus bursae (except in S. incola and related species), but shorter than combined length of ductus bursae and corpus bursae. Segment VIII subrectangular, tergum unmodified, sternum differentiated into subgenital plates, ventromedial depression, and periostial lobes, subgenital plates 1/4–2/3 with of sternum VIII, narrowed anteriorly in most species, evenly sclerotized and unmodified or partially or entirely covered with foamed sculpture or microspines, wrinkled medially or folded in some species, with distinctly elongated and sclerotized posterolateral corners in S. agassizi sp. nov., posterior margin usually oblique medially, covered with short setae, medial margin straight or weakly undulate, anterior margin straight or convex, sclerotized in some species, with short ( S. ethiopica sp. nov. and S. agassizi sp. nov.) or long ( S. aptatella , S. kasyi Povolný, 1968 ) anteromedial extension, ventromedial depression usually covered with microspines, divided anteromedially into two lobes that differ in shape from slender, digitate, and elongated to broadly rounded, not reaching or extending beyond anterior margin of sternum VIII, subostial sclerites, if present, slender, elongated, extending from base of apophyses anteriores towards ostium; apophyses anteriores usually straight, rod-like, often broadened at base, usually longer than segment VIII, but occasionally very short; ductus bursae membranous, varying in length and width, intersection with corpus bursae gradual or distinct, colliculum usually distinct, belt- or ring-shaped; corpus bursae rounded or weakly elongated, membranous, rarely covered with microtrichia, basal plate of signum variable in shape and size from short and slender to large and subtriangular ( S. caryocoloides Povolný, 1977 ), usually situated on right side on short projection of wall of corpus bursae in its posterior part, distal sclerite predominantly hook-shaped, weakly or strongly curved, acute, sometimes with medial expansion or short tooth, often with group of teeth on posterior margin near basal plate, signum rarely absent (i.e., S. ochrostigma Bidzilya & Li, 2010 ) (needs confirmation).

Biology. Host plants are known for about 90 of the 282 Palaearctic species. The larvae of most species are monophagous or oligophagous on Amaranthaceae , Asteraceae , and Solanaceae ( Sattler 1988: 230; Falkovitsh & Bidzilya 2006). Records of host plants from other families have been reported for S. salicorniae (Hering, 1889) ( Huemer & Karsholt 2010: 21) . Seven of 10 Afrotropical Scrobipalpa for which host plants are known feed on Solanaceae . Larvae are usually foliage feeders that live within a shelter, sometimes gregariously ( S. obsoletella (Fischer von Röslerstamm, 1841) , S. nana caroxyli ( Falkovitsh & Bidzilya, 2006)) , among spun leaves or young shoots. Some species feed on flowers, fruits, or buds ( S. concreta ), others produce stem or twig galls ( S. incola , S. ochroxantha sp. nov., S. gallicola Falkovitsh & Bidzilya, 2003 ) or inhabits galls of Cecidomyiidae ( S. maniaca Povolný, 1969 ; S. pulchra Povolný, 1967 ), and still others bore into shoots ( S. helmins Falkovitsh & Bidzilya, 2009 ), roots ( S. sattleri Lvovsky & Piskunov, 1989 ) or stems ( S. clintoni Povolný, 1968 ). Leaf-mining is common among Scrobipalpa ( S. aptatella , S. acuminatella (Sircom, 1850) , S. chrysanthemella (E. Hofmann, 1867) , S. ceratoides ( Falkovitsh & Bidzilya, 2006) , S. concerna uzbeka ( Falkovitsh & Bidzilya, 2006) and others). True external living larvae are rather rare, as most live within a light silken shelter, leaving it to feed ( S. ebertiana Povolný, 1967 ; S. maniaca Povolný, 1969 ). There are also species whose larvae feed on different parts of the plant during ontogenesis ( S. pulchra ; S. alterna ( Falkovitsh & Bidzilya, 2006) ; S. atriplicella (Fischer von Röslerstamm, 1841) , S. artemisiella (Treitschke, 1833) and others). Pupation usually occurs outside the mine, in the larval habitats, rarely in a cocoon, in plant debris, or underground ( S. nitentella (Fuchs, 1902) , S. alia ( Falkovitsh & Bidzilya, 2006) , S. helmins ).

Scrobipalpa species are most diverse in open arid landscapes of the Palaearctic region. They are the dominant gelechiids in halophytic habitats, dry mountains steppes, deserts, and semideserts. For example, among 143 species of Gelechiidae recorded from several localities in the southwestern part of the Kyzyl-Kum desert ( Uzbekistan), 55 species belong to Scrobipalpa ( Falkovitsh & Bidzilya 2009) . The genus is distributed from the sea level (coastal dunes) to about 3400 m in the mountains of Central Asia. In Africa, the majority of species are known from the arid regions of southern Africa and savannas of eastern Africa up to 3000 m in Kenya ( Kenya Mt.) and 3100 m in Ethiopia (Simien Mts). Scrobipalpa ocellatella (Boyd, 1858) , S. ergasima , S. concreta , and S. aptatella are among regional or worldwide pest of cultivated Amaranthaceae and Solanaceae .

Distribution. Holarctic, Afrotropical, Oriental, and Australian regions.

Notes. Among Scrobipalpa there are both superficially distinct species that can be identified by wing pattern, and uniformly coloured species for which reliable identification is nearly impossible without examining the genitalia. However, even differences in genitalia are very minor in some cases — some characters are variable within a species (length of saccus, length of apophyses, shape of signum and corpus bursae) and others appear to vary depending on the genitalia preparation and pressure of the cover slip. Additional difficulties may arise from comparing the male genitalia fixed using traditional methods and those made using the “unrolling” technique. Regardless, the presence of well-preserved specimens of both sexes are desirable for confident identification. Recent application of DNA study, COI in particular, for separating cryptic species has resulted in the discovery of many undescribed taxa among Palaearctic Gnorimoschemini (Bidzilya et al. 2019) , including European Scrobipalpa ( Huemer & Karsholt 2020) . An integrative approach based on the analyses of morphological and molecular data appears to be promising both for further study of biodiversity of the genus and for systematic arrangement of the species within genus.