Xenogryllus transversus (Walker, 1869)

(Figs 2 E–H, 3O–P, 4E, 5G, 7O–P, 8I, 9G, 11M–O, 12D, 17)

Platydactylus transversus Walker, 1869: 88. Cardiodactylus? transversus — Saussure 1878: 665. Madasumma transversa — Kirby 1906: 94; Chopard 1968: 350. Xenogryllus transversus — Chopard 1969: 310; Bhowmik 1976: 46; 1985: 67; Saeed et al. 1990: 309 (redescription); Yin & Liu

1995: 96; Nattier et al. 2011: 2199 (molecular phylogeny); Vicente et al. 2017: 2203 (historical biogeography); He 2018:

516; Cigliano et al. 2018 (Orthoptera Species File Online) Jing et al. 2018: 274.

Synonym names:

Dionymus calcaratus Brunner von Wattenwyl, 1893: 213 — Chopard 1968: 350.

Calyptotrypus roonwali Bhowmik, 1977: 35 — Vasanth 1993: 131.

Type material. Holotype, ♂, Bangladesh: Silhat [= Silhet / Sylhet] (NHMUK010362937) [examined].

Additional examined material. India: Meghalaya, Jaintia Hills, 1♀, Narpuh R.F. Umpyrsung—off R. Lubha Sunapor Town, N25°06.683’ E92°21.559’, 149 ft. N25°06.983' E92°21,559', Elev. 149ft, 19.x.2004, molecular sample Xtr-X2, Svenson (MNHN-EO-ENSIF87). India, 1♀, #6752 (MNHN). Sikkim, 1♂, identified Dionymus calcaratus Br. by L. Chopard (MNHN-EO-ENSIF1516). Lebong, 3000 ft, IX.1908, 1 ♀, H.M. L., identified Dionymus calcaratus Br. (NHMUK010362936). Manipur, Imphal Valley, alt 715 m., 11.x.1945, 1♂, HT of Calyptotrypus roonwali Bhowmik (ZSI). Jammu, Tawi river, 32.715736° 74.860403°, secondary area, 30.VII, 11 pm, 1♂, chorus, molecular sample X26 (MNHN-EOENSIF4395), 1♂ (MNHN). Punjab, IISER Mohali, 30.663169° 76.724212°, 5♂ (MJO_765, 766, 411, 715, 413), 2 ♀ (MJO_36, MJO_726), molecular sample Xtr- 715, 765, 766, R. Jaiswara (IISER Mohali). Myanmar: Bhamo, Birmania, Fea ix.1886, Museo Civ. Genova,

Type locality. Bangladesh, Silhet.

Distribution. Myanmar, India (North and East), Bangladesh, Pakistan.

Emended diagnosis. Species of large size, similar in size, venation and coloration to X. maichauensis, from which it differs by male genitalia, with long sclerotized pseudepiphallic lophi ended by a sharp apex with a dorsal preapical pointed expansion (Fig. 8I); from X. ululiu, X. transversus differs by its larger size and by larger pseudepiphallic sclerite in male genitalia, with lophi proportionally smaller, separated by a deep indentation (lophi basally fused in X. ululiu).

Redescription. In addition to the characters of the genus, X. transversus has a large size and a golden coloration (Fig. 2 E–H). Fastigium 1.5 times wider than scape, slightly widened apically as in X. ululiu and X. maichauensis. Eyes rather small, located on face, restricted to the dorsal third of head in lateral view (Fig. 3 O–P). Lateral angle of dorsal disc of pronotum not carinated, as in X. maichauensis and X. ululiu, with a thin yellow band underlined by a black line anteriorly. Hind wings tail gray brown, nearly as long as pronotum.

Male. Pronotum dorsal disc forming a wide trapezoid, with a wide median black longitudinal band pronlonging vertex coloration; posterior margin slightly bisinuate. FW venation (Fig. 5G): 1A forming a 90° angle, with 265 stridulatory teeth (n=1) on transverse part of 1A. Dark coloration anterior to 1A including angle of file. Harp wide. Mirror large, well-rounded, its inner limit forming a wide curve. Apical field forming a triangle longer than wide, with six cell alignments.

Male genitalia (Fig. 7 O–P): Pseudepiphallic sclerite elongate, with a wide basis; lophi separated by a large indentation (Fig. 8I), similar to that of X. ululiu, with a sharp apex and a strong dorsal preapical expansion. Rami strong, convergent apically. Ectophallic apodemes strong, lamellate apically. Ectophallic fold and endophallic sclerite almost fused, forming a long ventral gutter, wider than in X. ululiu, trifurcate posteriorly. Endophallic apodemes made of lateral lamellas.

Female (Fig. 2 G–H). Head slightly wider than pronotum. Dorsal disc of pronotum almost rectangular, its posterior margin slightly bisinuate. FWs slightly longer than abdomen, light brown, with anterior dark spot very small; dorsal field with 10–11 (n=3) strong longitudinal veins. Subgenital plate with a deep V-shaped apical indentation with sharp edges (Fig. 9G). Ovipositor as long as FIII.

Female genitalia: Copulatory papilla conical (Fig. 11 M–O), wider than in X. maichauensis, its apex rounded and sclerotized.

Life history traits. X. transversus lives in open secondary habitats, where males usually call in chorus from 120–180 cm height dense shrubs. In IISER Mohali (Northern India), two males were seen calling from a bamboo plantation on one occasion, from a height of 60 cm, where one male was probably trying to mount the other (RJ personal obs.). In Jammu (Northern India), males were found calling from cannabis plant. Calling activity starts late in the evening, almost around 22:00 hrs and continues until 03:00 hrs in the morning. Spacing between calling males of this species is quite variable, the closest males being spaced by approximately one meter horizontally.

Calling song. (Figs 12D, 17) The calling songs of three males were recorded from IISER Mohali campus. At 25–27 °C, the calling song of X. transversus is made of short echemes quickly repeated and lasting for 197 ± 4 ms (echeme period = 873 ± 13 ms), and composed of 4–5 long syllables (m = 4.5 ± 0.5). Within echemes, the syllables usually show increasing amplitudes. Syllables are rather long (duration = 31 ± 4 ms) with a syllable period of 46 ± 3 ms (syllable duty cycle = 71%). The frequency spectrum shows a pure-tone dominant frequency at 4.5 ± 0.5 kHz followed by two powerful harmonics.

Measurements. See Table 8.

Taxonomic discussion. We confirm the status of junior synonyms of Calyptotrypus roonwali and Dionymus calcaratus according to re-examination of type specimens (HT of C. roonwali and one male ST of D. calcaratus).