Research Article |
Corresponding author: Pablo M. Dellapé ( pdellape@fcnym.unlp.edu.ar ) Academic editor: Dávid Rédei
© 2022 Pablo M. Dellapé, María C. Melo.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Dellapé PM, Melo MC (2022) Four new species of Ischnodemus (Hemiptera, Heteroptera, Blissidae) and additional records from Argentina. Deutsche Entomologische Zeitschrift 69(2): 283-295. https://doi.org/10.3897/dez.69.94683
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Four new species of the genus Ischnodemus Fieber, 1837 (Hemiptera, Heteroptera, Blissidae) are described from Argentina: I. nigromaculatoides sp. nov., I. formosus sp. nov., I. infernalis sp. nov. and I. correntinus sp. nov. The known distribution is extended for three previously recorded species in the country. The species Ischnodemus brusai Dellapé & Montemayor, 2009 from Peru is transferred to Patritiodemus Slater & Ahmad, 1971. Dorsal habitus photographs and detailed images of the pygophore and right paramere of the new species and a key to the Argentinean species of Ischnodemus are given.
Hemiptera, key to species, Lygaeoidea, Neotropical Region, Patritiodemus
Blissidae (Hemiptera, Heteroptera), commonly referred to as chinch bugs, is a diverse family of worldwide distribution, with 55 genera and 422 currently known species (
The genus Ischnodemus Fieber, 1837, the most diverse genus in the family, includes 96 species (
In this contribution, four new Ischnodemus species are described from Argentina, and the known distribution is extended for three previously recorded species in the country. The species I. brusai Dellapé & Montemayor, 2009 from Peru is transferred to Patritiodemus. Dorsal habitus photographs and images of the pygophore and right paramere of the new species and a key to the Argentinean species of Ischnodemus are given to facilitate identification.
The specimens studied belong to the following institutions: Museo de La Plata, Buenos Aires, Argentina (
Color images were captured using a cellphone Sony Xperia A1 Ultra attached to an Olympus stereomicroscope SZX7 and with a Canon EOS Rebel T7i with a Professional Grade Raynox DCR 150 DSLR Objective Tube Lens and an Objective PLAN Achromatic LWD infinity 5X, mounted on a WeMacro’s automatic focus stacking rail. Multiple focal planes were taken with Helicon Remote software and merged using Helicon Focus software. Plates were created and numbered in Corel Draw 2020.
The genital structures were dissected under a stereomicroscope, cleared in an 85% lactic acid solution for 5 min, washed in distilled water and preserved in vials with glycerol. Measurements were taken under a stereomicroscope and are given in millimeters.
For all species, lsid links to the world catalog Lygaeoidea Species File http://lygaeoidea.speciesfile.org/ (
Taxonomy
1 | Pronotum completely shiny, lacking velvety pruinose areas on dorsal surface | 2 |
– | Pronotum dorsally at least in part pruinose, not completely shiny, usually with shiny glabrous areas on posterior lobe | 4 |
2 | Pedicellus and basiflagellomere pale yellow, strongly contrasting with dark scapus and distiflagellomere; only brachypterous forms known | 3 |
– | Antennal segments uniform in color, either black or light brown, but never with pedicellus and basiflagellomere strongly contrasting with scapus and distiflagellomere; only macropterous forms known | I. grossinigrus Slater & Wilcox, 1969 |
3 | Calli rugose and punctate, not polished and glabrous; 2nd labial segment exceeding base of head by 1/2 length of segment | I. pullus Slater & Wilcox, 1969 |
– | Calli smooth and polished, never conspicuously rugose or punctate; 2nd labial segment only slightly exceeding base of head, never surpassing base of head by 1/2 its length | I. neotropicalis Slater & Wilcox, 1969 |
4 | Hemelytral membrane bearing a central black or very dark brown macula, contrasting strikingly with pale basal and apical areas | 5 |
– | Membrane unicolorous or nearly so, most frequently pale testaceous but sometimes dark smoky grey to nearly black, at most with differentiated spots adjacent to apex of corium, or with only veins contrastingly dark; occasionally strongly micropterous and membrane lacking | 13 |
5 | Posterior pronotal lobe with a complete shiny band and usually nearly of equal width throughout; sometimes entire posterior half of pronotum shiny | 6 |
– | Posterior pronotal lobe pruinose with three distinctly separated shiny areas | 11 |
6 | Tibiae completely dark, concolorous with dark femora | I. gayi (Spinola, 1852) |
– | Tibiae pale, contrasting with darker femora | 7 |
7 | Labium very short, at most slightly exceeding forecoxae | I. tibialis Stål, 1858 |
– | Labium extending to or exceeding anterior margin of prosternum | 8 |
8 | Collar and posterior margin of pronotum pruinose | 9 |
– | Collar shiny mesally, and pruinose area of posterior margin of pronotum restricted to humeral areas, shiny mesally | 10 |
9 | Basal and apical dark areas of clavus connected by a diffuse dark stripe along inner margin, central dark hemelytral macula large, contacting lateral margins of membrane (Fig. |
I. nigromaculatus Slater & Wilcox |
– | Basal and apical dark areas of clavus separated, central dark hemelytral macula small, not contacting lateral margins of membrane (Fig. |
I. formosus sp. nov. |
10 | Head (except clypeus) and anterior lobe of pronotum (except collar) pruinose intermixed with small shiny spots (Fig. |
I. nigromaculatoides sp. nov. |
– | Head and anterior lobe of pronotum mostly shiny with pruinosity restricted to small irregular patches (Fig. |
I. infernalis sp. nov. |
11 | All femora with at least a broad median black band and frequently entirely black, with exception of basal and distal ends; pedicellus less than 1.5 times as long as interocular distance | I. oblongus (Fabricius, 1803) |
– | All femora pale yellow or reddish, concolorous with pale tibiae; if femora appear somewhat infuscate, then pedicellus more than 1.5 times as long as interocular distance | 12 |
12 | Labium relatively short, not exceeding posterior margin of fore coxae and not attaining posterior margin of prosternum; antennae bright orange-yellow, distiflagellomere usually infuscate | I. antennatus Slater & Wilcox, 1969 |
– | Labium usually extending on to anterior portion of mesosternum, always exceeding posterior margin of forecoxae and attaining posterior margin of prosternum; antennae uniformly dark brown | I. formosensis Slater & Wilcox, 1969 |
13 | Pronotum completely pruinose, lacking shiny areas on posterior lobe | I. proprius Slater, 1966 |
– | Pronotum possessing shiny area/s on posterior lobe | 14 |
14 | Posterior lobe of pronotum with a complete shiny band | 15 |
– | Posterior lobe of pronotum with three distinct pruinose areas near humeri as follows: a pair of oval shiny spots on humeri and a transversely elongate median shiny area | 20 |
15 | Pronotal calli bearing large quadrate shiny patches | I. bosqi Slater & Wilcox, 1969 |
– | Pronotal calli pruinose, at most with a series of small shiny spots interspersed with pruinosity | 16 |
16 | Tibiae black, concolorous with dark femora | I. severus Slater & Wilcox, 1969 |
– | Tibiae pale, either strongly contrasting with dark femora, or with both tibiae and femora pale | 17 |
17 | Entire posterior 1/3 to 1/2 of pronotum shiny | I. lactipennis Slater & Wilcox, 1969 |
– | Posterior lobe of pronotum with shiny area consisting of a narrow transverse band | 18 |
18 | Labium very short, extending posteriorly only to the forecoxae | I. paramoides Slater & Wilcox, 1969 |
– | Labium extending posteriorly at least to anterior margin of mesosternum | 19 |
19 | Labium elongate, extending posteriorly to between mesocoxae | I. signoretii Berg, 1883 |
– | Labium at most extending posteriorly on to anterior portion of mesosternum, remote from mesocoxae | I. subflavus Slater & Wilcox, 1969 |
20 | Tibiae and femora uniformly dark chocolate brown to nearly black | I. atricolor Berg, 1883 |
– | Tibiae and femora nearly uniformly pale testaceous | 21 |
21 | Length of pedicellus greater than width of head across eyes; labium attaining or almost attaining mesocoxae; large species, more than 7.5 mm | I. stali (Signoret, 1857) |
– | Length of pedicellus less than width of head across eyes; labium not attaining mesocoxae, extending posteriorly only on to anterior portion of mesosternum; smaller species, less than 6.5 mm | 22 |
22 | Femora and tibiae yellowish, hemelytra without contrasting dark brown veins, connexiva contrasting with rest of abdomen | 23 |
– | Femora and tibiae yellowish brown with anterior femora darker on basal half, hemelytra with contrasting dark brown veins, connexiva concolorous with rest of abdomen | I. spatulatus Slater & Wilcox, 1969 |
23 | Pedicellus longer than distiflagellomere, connexiva uniformly pale ochraceus | I. staliellus Slater & Wilcox, 1969 |
– | Pedicellus subequal to distiflagellomere, connexiva bicolored (Fig. |
I. correntinus sp. nov. |
Labium exceeding base of prosternum. Pronotum in large part pruinose, including collar and posterior margin, and with a complete shiny band on posterior lobe. Basal and apical dark areas of clavus connected by a diffuse dark stripe along inner margin (more evident in recently collected specimens); hemelytral membrane bearing a large central dark macula, contacting lateral margins of membrane and strikingly contrasting with pale basal and apical areas (Fig.
Argentina, Brazil, French Guiana and Trinidad.
We also examined two males from La Paz, Bolivia, deposited in
Ischnodemus lactipennis:
Ischnodemus nigromaculatus:
Ischnodemus nigromaculatus
(misidentification):
Holotype
ARGENTINA • male, Chaco, 3.3 km SW Makallé; 16-XII-2018; -27.1782235, -59.2362379; Dellapé, P.M. col.;
BRAZIL — Pernambuco St. • 2 females; Tupanatinga, Parna do Catimbau, ICMBIO, terra 2; 8°33'54.9"S, 37°14'20.2"W; 730 m; 14-III-2019; Gonçalves, C.C., Takiya, D.M. & Carrenho, R. cols.; Malaise grande;
(male holotype). (Fig.
Head grey-black and pruinose, except irregular areas shiny; clypeus brown apically and shiny; antenniferous tubercles shiny. Head length 0.65, head width 0.88, interocular space 0.55. Vertex flat, eyes ovoid, and set well away from anterolateral pronotal angles. Ocelli relatively large, interocellar space 0.34, closer to anterior margin of pronotum than to the eyes. Labium short attaining anterior margin of mesosternum. Labial segments length: I 0.26, II 0.36, III 0.30, IV 0.32. Antennae dark brown, apex of pedicellus and basiflagellomere paler; with abundant semierect setae; scapus slightly surpassing apex of clypeus, length of segments: scapus 0.20 pedicellus 0.48, basiflagellomere 0.46, distiflagellomere 0.66.
Pronotum
(Fig.
Abdomen
brown, darker from segment VII to apex. Male genitalia: Pygophore (Fig.
The specific epithet refers to the similarity of the species to I. nigromaculatus; the Greek suffix ‘-oides’ means ‘similar to’.
Known from several localities in northern Argentina, Brazil and Paraguay.
(min–max, mean). Males (n = 3): Total length 5.56–6.06, 5.64. Head length 0.68–0.78, 0.70, head width 0.83–0.99, 0.90, interocular space 0.52–0.60, 0.57, interocellar space 0.31–0.34, 0.33. Labial segments length: I 0.26–0.28, 0.27, II 0.32–0.36, 0.35, III 0.30–0.34, 0.31, IV 0.26–0.32, 0.30. Antennal segments length: scapus 0.18–0.22, 0.21 pedicellus 0.54–0.56, 0.53, basiflagellomere 0.48–0.50, 0.48, distiflagellomere 0.64–0.70, 0.67. Pronotum length 0.96–1.14, 1.02, pronotum width 1.04–1.33, 1.13. Hemelytra length 3.20–3.56, 3.31.
Females (n = 5): Total length 6.13–7.44, 6.48. Head length 0.70–0.81, 0.76, head width 0.83–1.01, 0.90, interocular space 0.52–0.62, 0.57, interocellar space 0.36–0.39, 0.37. Labial segments length: I 0.28–0.40, 0.33, II 0.32–0.44, 0.38, III 0.32–0.40, 0.36, IV 0.32–0.40, 0.36. Antennal segments length: scapus 0.18–0.24, 0.21 pedicellus 0.46–0.54, 0.50, basiflagellomere 0.44–0.52, 0.47, distiflagellomere 0.60–0.70, 0.65. Pronotum length 1.01–1.30, 1.08, pronotum width 1.12–1.46, 1.23. Hemelytra length 3.12–3.92, 3.48.
This new species corresponds to the variety “a” of I. nigromaculatus mentioned by
Holotype
ARGENTINA • male; Formosa, ruta 14, 12 km NW Colonia Pastoril; 25.571°S, 58.322°W; 11-XII-2018; Dellapé & Melo cols.;
(male holotype). (Fig.
Head grey-black, pruinose dorsally except shiny clypeus and antenniferous tubercles. Head length 0.70, head width 0.88, interocular space 0.55. Vertex flat, eyes ovoid, and set well away from anterolateral pronotal angles. Ocelli relatively large, interocellar space 0.34, closer to anterior margin of pronotum than to the eyes. Labium short attaining anterior margin of mesosternum. Labial segments length: I 0.30, II 0.40, III 0.36, IV 0.40. Antennae dark brown, apex of pedicellus and basiflagellomere, and distiflagellomere distally paler; with abundant decumbent and sparse semierect setae; scapus slightly surpassing apex of clypeus, antennal segments length: scapus 0.23, pedicellus 0.64, basiflagellomere 0.58, distiflagellomere 0.72.
Pronotum
(Fig.
Abdomen
brown to dark brown, connexiva paler. Male genitalia: Pygophore (Fig.
The epithet is the Latin adjective formosus, -a, -um, meaning ‘beautiful’, also referring to Formosa, the Argentinean province where the type material was collected.
Only known from Formosa Province, Argentina.
(min–max, mean). Males (n = 4): Total length 5.50–5.81, 5.65. Head length 0.73–0.81, 0.75, head width 0.88–0.96, 0.91, interocular space 0.55–0.60, 0.57, interocellar space 0.31–0.36, 0.33. Labial segments length: I 0.32–0.34, 0.32, II 0.38–0.40, 0.39, III 0.30–0.40, 0.35, IV 0.38–0.40, 0.39. Antennal segments length: scapus 0.20–0.22, 0.22 pedicellus 0.60–0.70, 0.64, basiflagellomere 0.50–0.62, 0.55, distiflagellomere 0.74–0.78, 0.75. Pronotum length 1.04–1.12, 1.08, pronotum width 1.17–1.25, 1.21. Hemelytra length 2.96–3.28, 3.07.
Females (n = 5): Total length 6.56–7.72, 7.10. Head length 0.83–0.88, 0.85, head width 0.96–1.07, 1.01, interocular space 0.60–0.68, 0.63, interocellar space 0.36–0.42, 0.40. Labial segments length: I 0.34–0.42, 0.38, II 0.42–0.50, 0.45, III 0.40–0.46, 0.42, IV 0.42–0.52, 0.47. Antennal segments length: scapus 0.22–0.26, 0.24 pedicellus 0.60–0.70, 0.65, basiflagellomere 0.54–0.64, 0.59, distiflagellomere 0.76–0.88, 0.78. Pronotum length 1.07–1.33, 1.21, pronotum width 1.33–1.53, 1.42. Hemelytra length 3.36–3.92, 3.68.
Holotype
ARGENTINA • male; Chaco, 2.3 km S Pampa del Infierno; 26.529°S, 61.185°W; 18-XII-2018; Dellapé, P.M. col.;
(male holotype). (Fig.
Head black, clypeus paler, shagreened and shiny dorsally. Head length 0.73, head width 0.88, interocular space 0.52. Vertex flat, eyes ovoid, and set well away from anterolateral pronotal angles. Ocelli relatively large, interocellar space 0.34, closer to anterior margin of pronotum than to the eyes. Labium short attaining anterior margin of mesosternum. Labial segments length: I 0.40, II 0.34, III 0.32, IV 0.26. Antennae brown, apex of pedicellus and basiflagellomere and distiflagellomere paler; with abundant semierect setae; scapus slightly surpassing apex of clypeus, antennal segments length: scapus 0.20, pedicellus 0.42, basiflagellomere 0.46, distiflagellomere 0.66.
Pronotum
(Fig.
Abdomen
brown irregularly pigmented. Male genitalia: Pygophore (Fig.
The antenna varies from uniformly dark brown to brown with the distiflagellomere darker. The anterior pronotal lobe shows a median shallow longitudinal sulcus. Femora of some specimens less pigmented, and tibiae somewhat darker, not strongly contrasting with femora. Some specimens show the median macula of the membrane darker and well defined; the brown pattern of corium is restricted to the distal area adjacent to the orange area or can extend anteriorly to the apex of clavus.
The specific epithet is the Latin adjective infernalis, -is, -e, meaning ‘infernal’, referring to the locality ‘Pampa del Infierno’ where the holotype and most of the paratypes were collected.
Only known from Chaco Province, Argentina.
(min–max, mean). Males (n = 4): Total length 5.56–5.94, 5.71. Head length 0.68–0.75, 0.71, head width 0.83–0.94, 0.88, interocular space 0.55–0.62, 0.56, interocellar space 0.31–0.36, 0.34. Labial segments length: I 0.32–0.40, 0.38, II 0.32–0.40, 0.36, III 0.32–0.38, 0.34, IV 0.28–0.40, 0.32. Antennal segments length: scapus 0.18–0.20, 0.20 pedicellus 0.50–0.56, 0.50, basiflagellomere 0.42–0.46, 0.45, distiflagellomere 0.62–0.64, 0.64. Pronotum length 1.07–1.17, 1.13, pronotum width 1.01–1.09, 1.04. Hemelytra length 2.92–3.20, 3.07.
Females (n = 5): Total length 7.12–7.68, 7.41. Head length 0.81–0.83, 0.83, head width 0.96–1.01, 0.99, interocular space 0.62–0.65, 0.64, interocellar space 0.36–0.42, 0.39. Labial segments length: I 0.36–0.40, 0.40, II 0.40–0.48, 0.44, III 0.34–0.40, 0.44, IV 0.36–0.40, 0.38. Antennal segments length: scapus 0.20–0.26, 0.24 pedicellus 0.56–0.60, 0.59, basiflagellomere 0.50–0.56, 0.54, distiflagellomere 0.64–0.76, 0.71. Pronotum length 1.12–1.20, 1.19, pronotum width 1.30–1.40, 1.34. Hemelytra length 3.00–3.76, 3.49.
Ischnodemus stalii
(misidentification):
Holotype
ARGENTINA • male; Corrientes, Col. Pellegrini; 27-IX-2002; Malaise trap;
(Fig.
Head grey-black, pruinose dorsally except shiny clypeus and antenniferous tubercles. Head length 0.65, head width 1.01, interocular space 0.62. Vertex slightly convex, eyes ovoid, and set well away from anterolateral pronotal angles. Ocelli much closer to anterior margin of pronotum than to the eyes, interocellar space 0.34. Labium short, not attaining anterior margin of mesosternum. Labial segments length: I 0.34, II 0.34, III 0.30, IV 0.26. Antennae brown, distiflagellomere paler medially; with abundant decumbent and sparse erect setae; scapus surpassing apex of clypeus by half its length, antennal segments length: scapus 0.26, pedicellus 0.78, basiflagellomere 0.58, distiflagellomere 0.80.
Pronotum slightly sinuate laterad, narrowing gradually from mid-length of anterior lobe to collar; transverse impression shallow, nearly obsolete; posterior margin concave. Pronotum length 1.04, pronotum width 1.43. Anterior pronotal lobe grey-black, pruinose with intermixed small shiny spots, collar entirely pruinose; posterior pronotal lobe brown with three distinct shiny areas (pair of oval spots on humeri and a transversely elongate median band). Metathoracic scent gland auricle slightly produced anteriorly, orange brown dorsally. Scutellum grey-black, pruinose, with a longitudinal median fringe without punctures. All femora moderately incrassate, mutic. Coxae brown, rest of legs light brown. All legs with abundant decumbent short setae. Hemelytra attaining half the length of 7th abdominal tergum, length 3.84. Hemelytra yellowish brown, with base of clavus and apical region of corium darker; membrane smoky brown, veins concolorous. Sterna pruinose, except a two quadrangular shiny areas on mesosternum, densely clothed with short decumbent setae.
Abdomen
dark brown, connexiva contrastingly paler, with the anterior outer region yellowish. Male genitalia: Pygophore (Fig.
The specific epithet is a Latinized word created from the Spanish adjective correntino, -a, meaning “related to the Corrientes”, in reference to Corrientes Province (Argentina) where the holotype was collected. To be treated as an adjective (correntinus, -a, -um).
Only known from the type locality Col. Pellegrini, Corrientes Province, Argentina.
This specimen was mentioned in the inventory from Colonia Carlos Pellegrini (Esteros de Iberá, Corrientes, Argentina) as Ischnodemus stalii (
ARGENTINA — Buenos Aires Prov. • 1 male; Magdalena, Reserva Natural Privada El Destino; 35.135°S, 57.391°W; 14-II-2018; Montemayor, S. col.;
Argentina. Brazil.
Buenos Aires, Chaco, Corrientes, Jujuy, and Misiones provinces (
ARGENTINA — Santa Fe Prov. • 1 female; Piquete; 16-I-[19]28; M.N.;
Argentina.
Buenos Aires, Entre Rios, and Formosa provinces (
ARGENTINA — Formosa Prov. • 1 female; P.N. Rio Pilcomayo, mirador del Rio; 25.015°S, 58.130°W; 24-II-2022; Dellapé, P.M. col.;
Argentina and Paraguay.
Chaco, Santa Fe and Misiones (see remarks) provinces (
Additional phylogenetic studies will be necessary to better define the generic limits. The presence of pedunculate eyes, a short labium not attaining forecoxae, an entirely dull pronotum, and the color pattern of hemelytra with a dark suffusion along the central area in Patritiodemus brusai comb. nov. indicate that the genus Patritiodemus is the best placement for this species.
More than a half of the Neotropical species of Ischnodemus are recorded from central and northeastern Argentina, mostly distributed in the Chaco and Pampa ecoregions where grasslands are abundant. A recent study on mitogenomes of 10 species in eight genera of Blissidae (
The new species described in this work, I. nigromaculatoides sp. nov., I. formosus sp. nov., and I. infernalis sp. nov., are quite similar to I. nigromaculatus in general color pattern, with only subtle differences. However, these species can be easily discriminated by the texture of head and pronotum and hemelytral color pattern. In I. nigromaculatus and I. formosus sp. nov. the head, collar and the posterior margin of pronotum are pruinose, whereas in I. nigromaculatoides sp. nov. the head is pruinose, but the collar is shiny mesally, and the pruinosity on the posterior margin of pronotum is restricted to the humeral areas, being only shiny mesally. In I. infernalis sp. nov. the head and the anterior pronotal lobe are shiny, with the pruinosity restricted to small irregular patches. The pruinosity pattern was considered a fundamental character by
The additional material (varieties ‘a’ and ‘b’) mentioned by
The fourth new species described in the present paper, Ischnodemus correntinus sp. nov., can be easily separated from the other seven Neotropical species with three shiny spots on posterior lobe of pronotum by the yellowish femora and tibiae, the concolorous veins on the hemelytra, and the pale color of the connexiva contrasting with the rest of the abdomen.
We are grateful to Anna Ágnes Somogyi (
Field trips were partially funded by Fondo para la Investigación Científica y Tecnológica (FONCYT) PICT 2018-0771, and the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PIP 1505.
Data occurrences of studied material
Data type: occurences