Euscyrtus Guerin-Meneville, 1844

Meena, Ashok Kumar, Swaminathan, Rajamani & Swaminathan, Tatiana, 2020, Some lesser known silent crickets (Orthoptera: Gryllidae: Euscyrtinae) from the hilly tracts of India, Zootaxa 4881 (3), pp. 559-572 : 561-565

Subgenus Euscyrtus Guerin-Meneville, 1844

The sub generic name Euscyrtus was established by Guerin-Meneville, 1844 for the first time with Euscyrtus bivittatus Guerin-Meneville, 1844 as the type species by original designation. According to Cigliano et al. (2020), the subgenus at present includes 18 species and 3 subspecies all over the world.

Species included in this subgenus:

Euscyrtus (Euscyrtus) angustifrons Chopard, 1969

E. (E.) bipunctatus Chopard, 1958

E. (E.) bivittatus Guerin-Meneville, 1844

E. (E.) bivittatus abbreviatus Bolivar, 1895

E. (E.) bivittatus bivittatus Guerin-Meneville, 1844

E. (E.) bivittatus fuscinervis Bolivar, 1895

E. (E.) bolivari Chopard, 1969

E. (E.) fuscus Ingrisch, 1987

E. (E.) intermedius Ingrisch, 1987

E. (E.) laminifer Chopard, 1936

E. (E.) lineoculus Ingrisch, 1987

E. (E.) madagascarensis Gorochov, 1988

E. (E.) major Chopard, 1925

E. (E.) mexicanuc Saussure, 1874

E. (E.) necydaloides (Walker, 1869)

E. (E.) nigrifrons Chopard, 1945

E. (E.) pallens Karny, 1907

E. (E.) pallidus Stal, 1877

E. (E.) planiceps Karsch, 1893

E. (E.) quadropunctatus Ingrisch, 1987

E. (E.) sigmoidalis Saussure, 1878

Euscyrtus (Euscyrtus) tubus Meena, Swaminathan & Swaminathan sp. nov. ( Plate I & Fig. 1 )

Material examined: Holotype Ƌ: India (Kerala) Idukki, Wagamon heights, 23.x.2015, 9° 40’ 50’’ N, 76° 52’ 0’’ E, 1200 m.; from grasses; coll. Rajendra Nagar.

Paratype Ƌ(2): India (Kerala) Thiruvananthapuram, Ponmudi , 20.x.2015, 8° 45’ 37’’ N, 77° 07’ 00’’ E, 1100 m.; from tea garden area; coll. T. Swaminathan. Same location, coll. R. Swaminathan . Allotype ♀ (2): Idukki, Wagamon heights, 23.x.2015, 9° 40’ 50’’ N, 76° 52’ 0’’ E, 1200 m.; from grasses; coll. Rajendra Nagar. Same location, coll. T. Swaminathan .

Description: Male. Body elongated with pubescence, black in dorsal view with the exception of forehead. Vertex with 6 to 8 dark bands interspaced with five to seven light brown to yellow stripes; the length and width of head are almost equal. Frontal rostrum is little longer than wide. Second segment of antennae is a dark brown; later, interspaced with dark brown strips on the entire length of the antennae. Apical segments of maxillary palpi are conical in shape and longer than other segments with brown hairs. On each side, a broad longitudinal yellowish band prevails from the back of the eyes to the end of the tegmina, passing through lateral sides of the pronotum. Pronotum significantly wider than long and posterior margin is sinuated with long hairs. Width of anterior margin of pronotum and head is almost equal. Disk almost flat with dark brown/black colour, lateral lobes are yellowish brown and much longer than high. Metanotum without metanotal gland, shape of metanotum in both sexes are same.Tegmina extending to the end of the 4 th abdominal tergite, dorsal and lateral fields are with light brown colour, dorsal field has 3 to 5 long parallel veins with many cross veins and a rather irregular reticulation. Hind wings are longer or equal to the tegmina; if longer than tegmina, it variably reaches up to the 5 th to 7 th abdominal tergite. Abdomen dorsally light brown, but ventral and lateral sides are yellowish brown in colour, including supra anal and sub genital plate. Cerci are light yellowish in colour with long hairs. Legs with hairs, fore and middle legs yellowish, anterior tibiae with tympanum, small and oval; the external in some specimens is hardly visible; the internal tympanum is large and elongated. Hind legs hairy with brown colour, base of hind femora wider. Hind tibiae slightly longer than femora, hind tibiae armed with 5–7 external and 9–11 internal subapical spurs, brownish in colour, and have rather numerous black denticles on external side. Genitalia: subgenital plate of the male is very long, boat shaped and narrowing towards the apex, which is feebly rounded with yellowish brown hairs. Phallus elongated, less sclerotized with long epiphallus and also presenting spermatophore; epiphallus is differently shaped, deeply notched or bifid reaching nearly up to apex of rachis, and is rounded at the apices; dorsally, the epiphallus has two spinulose lobes at its base, apical parts of spinulose lobes facing upwards with three spines; internal side of epiphallus (not ventral side) is modified into a tube like structure, which forms 1/3 rd of epiphallus; apical parts of epiphallus are cup-shaped, laterally membranous almost in middle. Phallus is with well developed ramus, which is closely attached to epiphallus with transparent membranous parts. The basal part of ramus is significantly wider than the apices, length of ramus reaching nearly 1/3 rd of semitubus. Ventral side of epiphallus having transparent paired endoparameral apodemes, semitubus and rachis (= guiding rod) are short with acute apex. Semitubus is an unpaired semimembranous groove between rachis and formula. Ectoparameres are significantly smaller, but hardly separate from epiphallus and rachis. Spermatophore is brownish, pear-shaped, with a thin long tube.

Female: Similar to the male in shape except for the following characters: Body slightly longer than male, abdomen dorsally dark brown in colour. Hind tibiae armed with 6–8 external and 8–12 internal subapical spurs. Ovipositor is brown in colour and S-shaped.

Comparison: The new species differs from the already reported species of subgenus Euscyrtus by the following features: (i) Vertex with 6–8 dark brown bands interspaced with 5–7 light brown to yellow stripes; moreover, according to Chopard (1969), the earlier described species of Euscyrtus have 2 to 4 dark bands except the species, Euscyrtus laminifer Chopard, 1936 that has brown spot in the middle of the vertex in place of bands; similarly, Yang & Yang (2012) have mentioned that Euscyrtus hemelytrus (Haan, 1842) and Euscyrtus japonicus Shiraki, 1930 possess 3 pairs of brown stripes that differ in their degree of darkness; (ii) second segment of antennae dark brown with dark brown strips interspaced along the entire antennal length; (iii) shape of male genitalia differs in having the internal side of epiphallus modified into a tube-like structure that forms 1/3 rd of epiphallic length. Further, the new species is more similar to subspecies E. (E.) bivittatus abbreviatus ; nevertheless, differs in the aforesaid characters (i) to (iii); besides, possessing hind wings that are absent in E. (E.) bivittatus abbreviatus . Morphologically, it is more or less similar to E. (E.) bivittatus , but differs significantly in the structure of the male genitalia. The second segment of antennae is not dark brown in Euscyrtus (Ocus) hemelytrus as in the new species and also does not have such dark brown bands at regular intervals; rather, the antennae and palpi are rufous as described by Chopard (1969). Additionally, the pronotum is wider than long in the new species described, while it is almost a square in E. hemelytrus . Besides, the hind wings of the new species are either equal or significantly longer than the elytra; while in E. hemelytrus , the hind wings and elytra are of equal length ( Chopard, 1969). Another significant difference can be noted in the absence of outer tympanum on the fore tibiae in E. hemelytrus ( Yang & Yang, 2012) ; whereas, in the new species, tympanum on the fore tibiae can be seen on the inner as well as outer side, though in some specimens the outer tympanum is not very conspicuous. In the new species, hind tibiae are armed with 5–7 external and 9–11 internal subapical spurs, but E. hemelytrus has 6 external and 8 internal subapical spurs. The genitalia appear similar in both the species; however, the epiphallus is differently shaped, deeply notched up to nearly the apex of rachis. Dorsally, the epiphallus has two spinulose lobes at its base, the apical part facing upwards with 3 prominent spines in the new species; while, in E. hemelytrus the apical part of epiphallus spinulose lobes are facing sideways, i.e., face laterad ( Gorochov, 1987). When viewed dorsally, the internal side of the epiphallus is modified into a tube-like structure, forming 1/3 rd of epiphallus in the new species, which is not notable in other described species of Euscyrtus .

Etymology: the name of the new species is derived from the Latin word tubus , referring to the modified tubelike structure on the inner side of epiphallus (not on the ventral side), which is 1/3 rd of the epiphallus length.

Figures

FIGURE 1. Euscyrtus (E.) tubus sp. nov. Ƌ Holotype: 1 & 2. Tympanum: 1. Outer side; 2. Inner side; Patiscus quadripunctatus Bolivar Ƌ (3–6): 3. Maxillary palpus; 4. Tegmina, dorsal view; 5&6. Tympanum: 5. Outer side; 6. Inner side.

PLATE I. Euscyrtus (E.) tubus sp. nov. Ƌ Holotype (1–7): 1. Habitus; 2. Head, dorsal view [(a)—antennae close-up]; 3. Tegmi-na, dorsal view; 4–6. View of genitalia: 4. Dorsal [(a)—tube like structure, (b)—spinulose lobes]; 5. Ventral [(a)—guiding rod]; 6. Lateral; 7. Spermatophore; 8. Habitus (Allotype).