Eneoptera caliginosa (Walker, 1869) stat. nov.

Figs 1, 2A, 3A, 4A, 5, 6, 9A, 11B

Platydactylus caliginosus Walker, 1869: 79.

Eneoptera surinamensis De Geer, 1838 — Kirby, 1906: 90 (synonym name); Chopard, 1931a: 16; Chopard, 1968: 348; Otte, 1994: 66; Cigliano et al., 2025 (Orthoptera Species File).

Eneoptera caliginosus? (Walker, 1869) — Robillard & Desutter-Grandcolas, 2005: 416 (no type examination).

Eneoptera caliginosa (Walker, 1869) —this study, valid species.

Synonym names

Eneoptera gracilis Robillard, 2005 — syn. nov.

Type material. Holotype (Fig. 1A–D): GUYANA • ♂; #44.85, det. B.C. Townsend, 1975; NHMUK 016032953 [examined]

Additional material examined. GUYANA • 1♂; British Guiana, Kartabo; [6.3446 N, 58.7019W]; ix.1922; leg. Haviland M.D.; identified Eneoptera surinamensis by B. Uvarov Brit Mus 1924-519; NHMUK • 1♀; Kaieteur National Park; 5.273241 –59.391517; on open vegetation; obs. tmurray74; iii.2012; iNaturalist 47297741 • 1♀; Upper Takutu-Upper Essequibo; 2.92395, –58.73736; 24.ii.2022; a1virginia obs.; https://www. inaturalist.org/ observations/138951221 • 1♀; Upper Takutu-Upper Essequibo; 3.75256, –59.30993, 19 m; 07.i.2025; jware42 obs. https://www. inaturalist.org/observations/257743428 • 1♀; Upper Takutu-Upper Essequibo; 3.74749, –59.31245; 03.xi.2025; danbrown_wild-discovery-tours obs.; https://www.inaturalist.org/observations/327023226. BOLIVIA • 1♂; Trinidad; [–14.842134°, –64.888569°]; x.1917; ANSP • 1♀; Cuatro Ojos; [–17.770300° –63.231431°]; ix.1917; ANSP • 1♂; Yung Coroico; Haviland M.D. leg.; ix.1922; identified Eneoptera surinamensis by B. Uvarov; NHMW • 1♂; Prov. Del Sara; 450m; J. Steinbach leg.; ex Carn. Mus. Bruner cln.; ANSP. BRAZIL • 4♂; Chapada, near Cuiabá, Matto Grosso; [–15.555219°, –55.965805°]; previously identified Eneoptera surinamensis, Ex Carn. Mus. Bruner Cln.; ANSP • 5♀, 3♂; Chapada, Chapada; ex Carn. Mus. Bruner cln., identified E. surinamensis; ANSP. • 1♀; Paiva, Cabo de Santo Agostinho, PE; –8.24975, –34.94568, 163 m; negromonte_ion obs.; 08.ii.2024; https://www.inaturalist.org/observations/250498695 • 1♀; Itamarati, Belo Horizonte, MG; –19.86777, –43.98796, 11 m; 31.x.2024; mogweh obs.; https://www.inaturalist.org/observations/249910264 • 1♀; Franco da Rocha, SP; – 23.33620, –46.69940, 201 m; 22.x.2024; https://www. inaturalist.org/observations/249568171 • 1♀; Caeté-Açu, Palmeiras, BA; –12.66526, –41.48652; 08.i.2024; alexandremarx obs.; https://www.inaturalist.org/ observations/196563162 • 1♀; Sorocaba, SP; –23.49166, –47.50692; 1.x.2023; douglasbete obs.; https://www. inaturalist.org/observations/188319466 • 1♀; Brasília, DF; –15.58674, –47.61565, 8 m; 08.x.2023; cdonner obs. https://www.inaturalist.org/observations/186903781 • 1♀; Brasília, DF; –15.76587, –47.85708; 9.x.2023; jeanmartins obs.; https://www.inaturalist.org/observations/186943315 • 1♂; Piedade do Paraopeba, Brumadinho, MG; –20.19529, –43.97886, 206 m; 03.x.2023; colibri82 obs.; https://www.inaturalist.org/observations/186096994 • 1♀; Caucaia, CE; 3.63526, –38.84528, 4 m; 5.xi.2022; ryanvieira obs. https://www.inaturalist.org/ observations/141388138 • 1♂; Parque Estadual do Juquery — R. Miguel Segundo Lerussi, SP; 23.33255, –46.68648, 201 m; 1.v.2023; rick_costa obs; https://www.inaturalist.org/observations/201336366 • 1♀; Mata de São João, BA,; [–12.701943°, –38.342753°], Rafael Salvador obs.; https://www.insetologia.com.br/2018/07/grilo-eneoptera-nabahia.htm • 1♀; Itajá, GO; –19.067471, –51.548837; on vegetation in open area; vii.2019; vinisouza128 obs.; https://www.inaturalist.org/observations/28825474 • 1♀; Itajá, GO; –19.069642, –51.54068; on vegetation in open area; vii.2019; caroline_brasil obs.; https://www.inaturalist.org/observations/29225471 • 1♂; St. Hab Ind Norte, Brasília, Distrito Federal; –15.729445, –47.858891; xii.2019; douglas-u-oliveira obs.; https://www.inaturalist.org/ observations/36297270 • 1♀; ESEC Águas Emendadas, Distrito Federal, Brasília; –15.569503, –47.600444; xii.2019; open area, on sandy soil; ericfischerrempe obs.; https://www.inaturalist.org/observations/36256476 • 1♀; Taguatinga; –15.76587, –48.05934; 16.xi.2021; pedrosisnando obs.; https://www.inaturalist.org/ observations/101278829 • 1♂; Asa Norte; –15.74373, –47.88464; 28.vii.2021; gafischer obs.; https://www. inaturalist.org/observations/88984221 • 1♂; Bela Vista, Rio Claro, SP; –22.40532, –47.54008; 2.xi.2020; gussoni obs; https://www.inaturalist.org/observations/64060473 • 1♀; Cocalzinho de Goiás, GO; –15.71750, –48.33586; 24.x.2020; beatrizventura obs.; https://www.inaturalist.org/observations/63422890 • 1♀; ESEC Águas Emendadas, Distrito Federal; –15.56950, –47.60044; 1.xii.2019; ericfischerrempe obs.; https://www.inaturalist.org/ observations/36256476 • 1♀; Itajá, GO; –19.06747, –51.54883; 13.vii.2019; vinisouza128 obs.; https://www. inaturalist.org/observations/28825474 • 1♂; Panorama, Araçatuba, SP; –21.22139, –50.42832, 362 m; 19.iii.2022; vinisouza128 obs.; https://www.inaturalist.org/observations/109551544 • 1♀; Amajari, RR; 3.77998, –61.73414, 75 m; 20.vi.2025; viniciusviana obs.; https://www.inaturalist.org/observations/292218519 • 1♂; Brasilia, SQDS 403/404; –15.81184, –47.88731, 22 m; 30.ix.2024; mariobarroso obs. https://www.inaturalist.org/ observations/244909592 • 1♂; Brasilia; –15.79876, –47.87254, 25 m; 21.x.2024; andre_ambrozio obs.; https:// www.inaturalist.org/observations/248528622 • 1♀; Lago Sul, Brasília, DF; 15.96301, –47.95599, 461 m; 27.v.2024; kamilly_eduarda_fc obs.; https://www.inaturalist.org/observations/218910985 • 1♀; Brasil, Maceió — AL, 57038- 640; –9.61359, –35.69245, 11 m; 19.i.2025; lucaskaminski obs.; https://www.inaturalist.org/observations/259003262 • 1♀; Rua Brasíliano Ribeiro de Souza; –7.55098, –35.44824, 211 m; 16.i.2025; obs. Renanbryan; https://www. inaturalist.org/observations/258699580 • 1♀; Paiva, Cabo de Santo Agostinho, PE; –8.24975, –34.94568, 163 m; negromonte_ion obs.; 08.ii.2024; https://www.inaturalist.org/observations/250498695 • 1♀; Itamarati, Belo Horizonte, MG; –19.86777, –43.98796, 11 m; 31.x.2024; obs. mogweh; https://www.inaturalist.org/ observations/249910264 • 1♀; Franco da Rocha, SP; –23.33620, –46.69940, 201 m; 22.x.2024; https://www. inaturalist.org/observations/249568171 • 1♀; Caeté-Açu, Palmeiras, BA; –12.66526, –41.48652; 08.i.2024; alexandremarx obs.; https://www.inaturalist.org/observations/196563162 • 1♀; Sorocaba, SP; –23.49166, – 47.50692; 1.x.2023; douglasbete obs.; https://www.inaturalist.org/observations/188319466 • 1♀; Brasília, DF; – 15.58674, –47.61565, 8 m; 08.x.2023; cdonner obs.; https://www.inaturalist.org/observations/186903781 • 1♀; Brasília, DF; –15.76587, –47.85708; 9.x.2023; jeanmartins obs.;https://www.inaturalist.org/observations/186943315 • 1♂; Piedade do Paraopeba, Brumadinho, MG; –20.19529, –43.97886, 206 m; 03.x.2023; colibri82 obs.; https:// www.inaturalist.org/observations/186096994 • 1♀; Caucaia, CE; 3.63526, –38.84528, 4 m; 5.xi.2022; ryanvieira obs. https://www.inaturalist.org/observations/141388138 • 1♂; Parque Estadual do Juquery — R. Miguel Segundo Lerussi, SP; 23.33255, –46.68648, 201 m; 1.v.2023; rick_costa obs; https://www.inaturalist.org/ observations/201336366 • 1♀; Paraná, Tibagi, Parque Estadual do Guartelá; –24.566000 –50.256100; ix.2020; M. Fianco & N. Szinwelski leg.; identified Eneoptera surinamensis; DZUP, Curitiba (http://orthoptera.archive. speciesfile.org/Common/specimen/ShowSpecimen.aspx?SpecimenID=153412). COLOMBIA • 3♂; Dept. Meta, 25 km ENE Pto Lopez on road to El Vento; leg. D.C.F. Rentz, T. Rouse; 9.iii.1971; ANSP • 1♀; Meta, Pto Lopez, Vereda Menegua; 14.iv.1984; R.A. Laguna leg.; identified T. Robillard, 2017; ICN • 1♀; Meta, Pto Lopez, Alto Menegua; 300 m; M. Carvajal leg.; 14.iv.1984; identified T. Robillard 2017; ICN • 1♂; Vichada department 2–3 km S of junction with entrance to Laguna Mozambique hacienda; area of dry moist forest degraded by cattle; N.D. Jago leg.; 17.vii.1981; ANSP • 1♂, 3♀; Menegua, Pto Lopez; N04°05'32.63, W72°48'44.1", 209 m; prairie en bord de forêt, sol sableux [open area near forest, sandy soil]; on low plant; 8–10.xii.2018; T. Robillard & J.L. Benavides-Lopez leg; molecular samples E75, E77 (2♀); ICN • 1♂; Menegua, Pto Lopez; N04°05'32.63, W72°48'44.1", 209 m; prairie en bord de forêt, sol sableux [open area near forest, sandy soil]; on low plant; 8–10.xii.2018; T. Robillard & J.L Benavides-Lopez leg; call recording in captivity, molecular sample E76; MNHN • 1♂, 1♀; Menegua, Pto Lopez; N04°05'32.63, W72°48'44.1", 209 m; prairie en bord de forêt, sol sableux [open area near forest, sandy soil]; on low plant; 8–10.xii.2018; T. Robillard & J.L Benavides-Lopez leg; molecular sample E78 (1♀); MNHN • 1♂; Dept. Vaupés, San-José del Guaviare; M. Descamps leg.; xii.1970, holotype of E. gracilis; MNHN-EO-ENSIF221 • 3♂, 2♀; Dept. Vaupés, San-José del Guaviare; M. Descamps leg.; xii.1970, paratypes of E. gracilis; MNHN-EO-ENSIF223, ENSIF224, ENSIF225, ENSIF229, ENSIF230, ENSIF231 • 1♀; Dept. Vaupés, San-José del Guaviare; M. Descamps leg.; xii.1970, allotype of E. gracilis; MNHN-EO-ENSIF97 • 1♂, 1♀; J. Desplats leg.; paratype of E. gracilis, T. Robillard; MNHN-EO-ENSIF227, ENSIF236 • 1♀; Dept. Vaupés, Bocas del Ariari; M. Descamps leg.; xii.1970, paratypes of E. gracilis; MNHN-EO-ENSIF232 • 1♀; Dept. Amazonas, Rio Igaraparaná, 30 km aval La Chorrera; M. Descamps leg.; xii.1970, paratypes of E. gracilis, molecular sample Egr; MNHN-EO-ENSIF233 • 1♀; Dept. Amazonas, La Sabana; M. Descamps leg.; xii.1970, paratypes of E. gracilis, molecular sample Egr; MNHN-EO-ENSIF235. FRENCH GUIANA • 1♀; Cayenne; M. Klagea; ii.19?7, identified E. surinamensis; AMNH • 4♂, 13♀; Savane Nancibo; 04°38'53.3", 52°25'56.27"W; 14.xii.2018; SEAG leg.; solar pit-fall; MNHN • 1♂, 1♀; Secteur de Mana, Xt RN 1 organado à Mana et RN1 de l’Inini organ. A St Laurent; clairière, forêt, sous litière feuille morte, au sol; 12.i.1968; J. Bonfils leg.; MNHN • 1♀; Carrière de Luz, Kourou; 9.ix.2023; ZNIEF, DEAL Guyane, CNES leg.; malaise trap; MNHN • 1♂; Awala-Yalimapo; 5.73192, –53.92564, 346 m; 29.v.2025; louloubeney obs.; https://www.inaturalist.org/observations/286291979. SURINAME • 1♀; Sud Suriname, Barrage (Bragapuga [?]); identified E. gracilis paratype by T. Robillard, 2005; MNHN-EO-ENSIF237 • 1♂; Sud Suriname, Brarrage (Bragapuga [?]); identified E. gracilis, paratype, by Robillard, 2005; MNHN-EO-ENSIF228 • 1♀; savanne 3e kamp opstrnik; D. C. Geyskes leg.; 15.x.1948; molecular sample E87; RMNH • 1♂, 1♀; savanne; D. C. Geyskes leg.; 12– 15.x.1948; RMNH • 1♀; savanne, Djaikreek km7.5; D. C. Geyskes; 10.X.1948; #1353; RMNH • 1♂; Tibitibos; 7.i.1949; D. C. Geyskes leg.; RMNH • 1♀; 7.i.1949; ex coll. Fruhstorfer, identified Eneoptera surinamensis by Brullé; MHNG. VENEZUELA • 2♀; Guarico, 63 km E. Jct Rts 18 and 8 on Rt 8; [c. 8.741241°, –66.239510°] 18.vii.1981; Otte et al. leg.; ANSP • 2♀; Cojedes Hato Mataclara; 9°S, – 68°30'E; 12.vii.1981; Otte et al. leg.; molecular sample E91; ANSP • 1♂; Caripito; [10.107304°, –63.103077°]; 2.v.1942; gift of New York Zoo. Soc. Dept. Tropical Research; William Beebe Dir. Leg.; AMNH • 1♀; Departamento de Química Facyt, Naguanagua 2005, Carabobo; 10.27749, –68.00145, 6 m; 04.ii.2025; hellviskamacaro obs.; https://www.inaturalist.org/ observations/260626525.

Taxonomic discussion. Chopard (1931a) mentioned that Platydactylus caliginosus differs from E. surinamensis in the study describing the species E. guyanensis. However, in his 1968 catalogue, he considered P. caliginosus as a synonym of E. surinamensis, with no further explanation (Chopard, 1968). The name was later treated by Robillard & Desutter-Grandcolas (2005) as having an unclear status (E. caliginosus?) in their revision of Eneoptera and did not study the type specimen. Here, we compared the type specimens of E. caliginosa and E. gracilis, which revealed that despite minor differences, the two species are very similar in terms of external morphology and male genitalia (Figs 1, 3). Original descriptions by Walker (1869) are very brief, and E. gracilis was described without prior examination of the type of P. caliginosus; in this context, it is likely that E. gracilis, described from Colombia (Fig. 1E–G), could correspond to P. caliginosus, described from Guyana (Fig. 1A–D). Our comparisons of specimens from various localities from French Guiana, Brazil, Colombia, Venezuela, Suriname and Bolivia support this hypothesis, as there are only minor and inconsistent differences among these localities that could be either explained by intraspecific variation within a given series, or by the wide geographic range.

While no detailed molecular data is available yet to test the similarity between the two species, acoustic data are clearly supporting it: the call of E. gracilis has first been described by Zefa et al. (2022) based on the recording of specimens from Brazil. Interestingly, despite the fact that E. gracilis was previously known only from Colombia, Zefa et al. (2022) identified their specimens as E. gracilis, the only species likely matching the morphology and male genitalia of their recorded males. The male that we recorded here from the type locality of E. gracilis in Colombia is similar to the call described by Zefa et al. (2022) (Figs 4A, 5). It supports the hypothesis that the specimens from western (Colombia) and eastern (Brazil) South America belong to one species. Based on these pieces of evidence, and rule of priority, we synonymize E. gracilis Robillard, 2005 under Eneoptera caliginosa (Walker, 1869) stat. nov. as junior synonym (syn. nov.).

Distribution. Guyana (type locality), French Guiana, Brazil (new record), Colombia (type locality of E. gracilis), Venezuela (new record), Suriname, Bolivia (new record).

Differential diagnosis. Eneoptera caliginosa is close to E. surinamensis. While the species ’ general coloration is rather variable, it generally shows a contrast between the lighter dorsum compared to the rest of the body, dark brown. E. surinamensis and E. caliginosa are more similar in this than E. guyanensis and E. nigripedis, which are entirely dark brown (with less contrast between the dorsal part and the rest of the body). Both species also resemble each other for the dull brown male FWs, while E. guyanensis and E. nigripedis showing shiny dark brown FWs (Figs 1, 2). The two species are also more similar in terms of male genitalia, although they differ by shape of pseudepiphallus and endophallus. Morphologically, E. caliginosa can be distinguished from E. surinamensis by its thinner shape, smaller size, hind legs longer proportionally to body, fastigium and head more globular in dorsal view (Fig. 2), and both male and female genitalia. Females are also clearly distinguished by the black triangular area of the lateral field of the FWs with cells underlined with yellow veins in E. caliginosa, while they are entirely black in the other species (Fig. 2).

Redescription

Size average to small for the genus, shape slender (Fig 1), variable in coloration (see below), but dorsum generally lighter than rest of body, dark brown. Fastigium (rostrum) rounded dorsally and apically, giving a more globular aspect to head than in other congeners (Fig. 2A). Vertex rounded, with three wide, well-marked longitudinal black bands. FWs dull brown in both sexes (Fig. 1). Hind legs elongated, FIII with a straight apical part before knee. Coloration variable, encompassing most color patterns documented in congeners, some specimens being light cream, some dark brown, almost black, with or without orange band on hind knee characteristic of E. guyanensis.

Male. Stridulatory file with 51 to 59 simple teeth (mean 55, n=5; Table 2). Harp veins straight, parallel on their whole length (Fig. 11A).

Male genitalia. (Fig. 3A–E) Pseudepiphallic sclerite triangular. Lophi as long as rest of pseudepiphallic sclerite, but shorter and less sclerotised than in E. surinamensis, their membranous part visible both ventrally and dorsally. Pseudepiphallic sclerite setose dorsally. Distal lobe of pseudepiphallic parameres short and rounded; median lobe oriented innerly; basal lobe membranous. Ectophallic fold short, almost triangular.

Female. FW (Figs 1B, 2) with black triangular area of lateral field made of cells slightly wider than long (about 10 cells in the widest part), their delimiting veins underlined with yellow (Fig.2A). Ovipositor shorter than FIII.

Female genitalia. (Fig. 3F) Copulatory papilla well sclerotised, shorter than in E. surinamensis and diamond-shaped; its distal part enlarged, bifid and membranous.

Calling song. (Figs 4A, 5, Table 1) The call has first been described by Zefa et al. (2022) who studied specimens from Brazil.We describe here the call of a specimen from Menegua, Pto Lopez, Colombia (type locality of E.gracilis), which shows similar parameters as reported by Zefa et al. (2022). The calling song is a continuous trill without amplitude modulation as in the other species of the genus. Syllable duration is 8.1±0.9 ms, for a period of 24.7±1.4 ms, which involves a syllable duty cycle of 33.3%. The dominant frequency is 3.58±0.04 kHz and corresponds to the fundamental peak of the spectrum; the calling song of E. caliginosa does not have any particularity in terms of frequency spectrum, except that the harmonics are powerful, as in other non-Lebinthini eneopterines (Fig. 5), but they never co-dominate the spectrum as observed in the “low frequency” part of the calling song of E. guyanensis (Robillard et al., 2015).

Sound-production mechanism. (Fig. 11B, Table 2) Males of Eneoptera caliginosa possess ca. 64 teeth, but only 26 are functional teeth arranged along the straight part of the stridulatory file, as typically observed in crickets. The mean inter-tooth distance of the functional part is 35.66 μm (tooth density = 35.4±1.4 teeth/mm). The global speed of stridulation derived from the syllable duration and file length is ca. 109 mm /s, which matches the tooth strike rate that generates the fundamental peak of the spectrum.

Natural history. (Fig. 6) E. caliginosa lives on low plants, from where the males sing during day time, both in secondary forested areas and in open areas, sometimes with just a few trees. It occurs near forest edges, in crops, in city parks and even in small patches of trees within urban areas. Based on the observed material and citizen science observation pictures, E. caliginosa is cryptic with E. surinamensis on a large part of the wide distribution range of the latter, but the key provided here allows to differentiate the two species with little ambiguity, even on photographs (see Fig. 2).