Ducetia assamica Tiwari and Diwakar, 2023

Tiwari, Chandranshu & Diwakar, Swati, 2023, Description of two new species of the Genus Ducetia Stål 1874 (Orthoptera: Tettigoniidae: Phaneropterinae) from India, Zootaxa 5296 (2), pp. 292-300 : 294-296

Ducetia assamica Tiwari and Diwakar sp. n.

( Fig. 2–3 , Table 2 )

Material examined. Holotype: Male. INDIA: Assam, Hollangapar Gibbon Wildlife Sanctuary , Jorhat ~ 120 m a.s.l. 2015, Coll. Chandranshu Tiwari, Department of Environmental Studies, University of Delhi, 110007 (Delhi), India . Paratype: Assam, Hollangapar Gibbon Wildlife Sanctuary, Jorhat ~ 120 m a.s.l., 2021 Coll. Chandranshu Tiwari (2 ♁).

Type locality. Hollangapar Gibbon Wildlife Sanctuary , Jorhat , Assam, India.

Measurements (length in mm): Body 16.99 (1.34); tegmen 22.98 (0.69), pronotum 3.82 (0.57); pro-femur 6.55 (0.35); meso-femur 7.84 (0.46); post-femur 18.85 (0.57); pro-tibia 6.97 (0.58); meso-tibia 7.87 (1.03); post-tibia 20.67 (0.93); file 1.52 (0.13).

Distribution. Crepescular - Nocturnal. Bushes and shrubs, fallow land, gardens on the forest edge. In addition to type locality, the new species was also recorded by the collector in ONGC colony, Cinnamara in Jorhat. The collector also heard the same call type in Namdapha Tiger Reserve, Arunachal Pradesh. The species is likely to be distributed in North-East Himalayas.

Seasonal occurrence: The species was observed perennially at the type locality.

Etymology. The species is named after Assam where the species was first discovered and recorded from. The species epithet refer to the location of the type locality. Adjective following Ducetia in gender.

Differential diagnosis. The new species is allied to Ducetia japonica ( Thunberg, 1815) but differs in following characters: significantly smaller size, hind lobes of subgenital plate narrowing from the base towards the tip. The call pattern of D. assamica matches with the calling song of northern type D. japonica but differs in significantly longer call duration and composition of concluding trill segment ( Heller et al. 2017; Tiwari and Diwakar 2023).

Description:

Male: Body small and slender. Head. Fastigium verticis narrow conical, dorsally furrowed, apex subacute, separated from fastigium frontis by a rectangular step. Eye ovoid, slightly bulging. Pronotum with disc rounded into paranota, only apical area flat and shouldered. Legs. Anterior coxa with a small spine. Anterior femur slightly compressed. Genicular lobes of all legs bispinose. Tibial tympana open on both sides. Femora with following number of spines on ventral margins: femur 6–7 external, 5–6 internal; mesofemur 10–12 external, no internal; postfemur 9–10 external, no internal. Pro- and mesotibiae each with 4 apical spurs and following number of spines: protibia 11–12 ventro-internal, 9–10 ventro external, 6–7 dorso-external, 5–6 dorso-interal; mesotibia 1–2 ventro-internal, 7–8 ventro-external, 6–7 dorso-internal, 4–5 dorso-external, posterior tibia with 6 apical spurs possessed 18–20 ventro-internal, 29–31 ventro-external, 33–34 dorso-internal and 30–32 dorso-external spines. Spines on ventral margins scarce near base, close towards apex. Wings. Tegmina surpassing hind knee; Radius sector branching pectinately before middle of tegmina. Hind wings caudate. Stridulatory file. with 121±3 teeth (n=3), which are large and spaced in basal half, gradually becoming narrower and denser towards the apex.

Male. genitalia. Subgenital plate without apical teeth, divided from apex for almost half of its length, dorsad and covered on internal surface with small spinules with a medial furrow continuing to the base. Distal lobes contiguous. Cerci long, slender, feebly directed upwards with interno-ventral ridge.

Female: Unknown. Supposed to be similar to that of D. japonica .

Coloration: Green and brown color morphs. Males with a narrow brown medial band starting from head continuing to disc of pronotum and dorsal margin of tegmen. Tegmen with little conspicuous black dots in cells. Antennae pale brown, annulated. Pro- and mid femora brown; posterior femora green with dark dots on dorsal areas, anterior tibia tympanum yellowish brown. Tibial segments dark brown-black. Tegmen appears green/yellow when live, but is hyaline with veins and veinlets brown. Stridulatory vein brown with brownish-black file, cerci darkened towards tip.

Depositories: The specimen are deposited in the Department of Environmental Studies, Faculty of Science , University of Delhi.

Figures

FIGURE 2. Ducetia assamica sp. nov. Habitus (a) male, (b) female and Call pattern (c) spectrogram, (d) oscillogram.

FIGURE 3. D. assamica sp. nov. (a) pronotum depicting Plectrum (P) and Mirror (M); (b) stridulatory file; (c) lateral view of cercus; (d) ventral view of subgenital plate; (e) scanning electron microscope image of stridulatory file.

Tables

TABLE 2. Comparison of morphometric details for genus Ducetia from India. Values in parentheses indicate s.e. *Fa- rooqi et al. 2021; #Nagar et al. 2015: ǂShishodia and Ingrisch 1998.

Species	D. assamica (n=3)	D. rohinii (n=3)	D. inerma * (n=2)	D.serrata # (n=5)	D.japonica # (n=30)	D. dichotoma ǂ (n=1)
Body	16.99 (1.34)	19.6 (2.3)	26.83-27.05	15.28	18.06	19
Tegmen	22.98 (0.69)	28.24 (2.07)	28.56-28.63	19.85	25.87	26.5
Pronotum	3.82 (0.57)	4.55 (0.49)	4.1-4.13	3.75	4.26	4.3
Fore Femur	6.55 (0.35)	7.17 (0.32)	7.85-7.93	6.93	6.79	8
Mid Femur	7.84 (0.46)	10.32 (0.82)		8.16	9.14
Hind Femur	18.85 (0.57)	22.43 (1.22)	24.97-25.09	19.24	21.74	23
Fore Tibia	6.97 (0.58)	7.33 (1.28)	4.79-4.83	12.09	10.2
Mid Tibia	7.87 (1.03)	10.09 (0.7)		14.96	13.78
Hind Tibia	20.67 (0.93)	24.66 (1.01)	27.20-27.28	25.22	26.91	25
File	1.52 (0.13)	1.42 (0.10)
Teeth	121 (3)	138 (2)		80	150
Teeth Density	80 (7)	97 (8)