Xistra nigriabdominis Deng, 2022

Zhang, Rong-Jiao, Deng, Wei-An, Li, Jie-Juan & Lin, Li-Liang, 2022, Pygmy grasshoppers of the genus Xistra Bolívar, 1887 (Orthoptera: Tetrigidae: Metrodorinae), Zootaxa 5162 (2), pp. 183-197 : 190-192

2. Xistra nigriabdominis Deng , sp. nov.

( Figures 4–5 )

Description. Female. Body moderate, slender, body surface smooth and interspersed with granules.

Head. Head and eyes distinctly exserted above pronotal surface ( Fig. 4a ). Vertex narrow, in dorsal view, width of vertex between eyes 0.6 times width of compound eye ( Fig. 4c ); a little narrower in front; anterior margin of fastigium narrowly rounded and not surpassing anterior margin of eye; median carina visible anteriorly; lateral margins turned backward and reaching upper margin of eye; vertex uneven with paired fossulae. In lateral view, frontal costa slightly visible between eyes ( Fig. 4d ), protruded anteriorly and broadly rounded between antennal grooves. In frontal view, vertex with V-shaped concavity, bottom of which reaching one-fourth of upper inner margins of eyes ( Fig 4e ); lateral margins barely reaching the level of upper margin of eyes; frontal costa bifurcated above lateral ocelli, longitudinal furrow divergent between antennae, width of longitudinal furrow of frontal ridge very narrower than antennal groove diameter ( Fig. 4e ). Antennae short, filiform, antennal grooves inserted between inferior margins of compound eyes ( Fig. 4d ), 15-segmented, the 10th and 11th segment are the longest, about 7–8 times longer than its width. Eyes globose, lateral (paired) ocelli located in slightly below the middle of compound eye height.

Thorax. Pronotal surface smooth and interspersed with dense granules ( Fig. 4b ). In dorsal view, anterior margin of pronotum truncate; lateral carinae of prozona parallel; median carina entire; obtuse humeral angles; with a pair of inconspicuous interhumeral carinae; hind pronotal process narrow and long cone-shaped, reaching or approaching apex of hind tibia. In profile, median carina of pronotum slightly undulate before shoulders and straight behind shoulders. Lateral lobes of pronotum turning outwardly, posterior angles directed distinctly transversely, truncate, apex of posterior angles bearing triangular. Posterior margins of lateral lobes of pronotum with ventral sinus and tegminal (upper) sinus. Tegmina long, ovate, apex rounded. Hind wings reaching or slightly surpassing apex of hind pronotal process.

Legs. Fore and middle femora with carinated, margins finely serrated, dorsal and ventral margins of fore femora straight ( Fig. 5a ), dorsal and ventral margins of middle femora slightly undulated ( Fig. 5b ); middle femur narrower than visible part of tegmen in width. Hind femora robust and short, 3.6 times as long as wide; margins finely serrated ( Fig. 5c ); antegenicular denticles right angled and genicular denticles acute. Outer side of hind tibia with 5–6 spines, inner side with 7–8 spines ( Fig. 5d ). First segment of posterior tarsi equal to third in length, three pulvilli of first segment of posterior tarsi equal in length, apices of all pulvilli obtuse ( Fig. 5e ).

Abdomen. Ovipositor narrow and long, length of upper valvulae 4.5 times its width, upper and lower valvulae with slender saw-like teeth. Length of subgenital plate nearly equal to its width, middle of posterior margin of subgenital plate concave and then triangularly projecting ( Fig. 5f ).

Coloration. Body dark brown. Frons dark brown. Hind wings black. Lateral lobes of pronotum and lateral of abdomen with black and white spots. Fore and middle femora brown; fore and middle brown and each with two dark transverse spots. Hind femur brown and outer side with two blackish spots. Hind tibia dark brown, with two light rings in the middle. Sternites of thorax and abdomen black, subgenital plate black.

Male. Similar to female, but smaller and narrower ( Fig. 5g –h ). Width of vertex between eyes 0.5 times width of compound eye ( Fig. 5g ); middle femur nearly equal to visible part of tegmen in width. Subgenital plate short, cone-shaped, apex bifurcated.

Measurements (mm). Length of body: ♂ 10.0–10.5, ♀ 13.0–13.5; length of pronotum: ♂ 12.0–12.5, ♀ 15.0– 15.5; length of hind femur: ♂ 5.4–6.0, ♀ 6.5–7.0.

Type material. Holotype: ♀, China, Sichuan prov., Qingchuan (Maozhai), 32°35ʹ29ʹʹ N, 105°27ʹ29ʹʹ E, 700 m alt., 7 August 2019, collected by Wei-An Deng, CLSGNU . Paratypes. 3♂, 7♀, same data, CLSGNU ; 1♂, 2♀, China, Sichuan prov., Lichuan (Jindong), 32°35ʹ3ʹʹ N, 105°35ʹ55ʹʹ E, 600 m alt., 9 August 2019, collected by Wei- An Deng, CLSGNU .

Diagnosis. This new species is similar to Xistra parvula Liang, 2010 from which it differs in length of body: ♂ 10.0– 10.5 mm, ♀ 13.0– 13.5 mm (Length of body: ♂ 5.9–6.3 mm, ♀ 8.5 mm in X. parvula ); in profile, median carina of pronotum undulate before shoulders and straight behind shoulders (in profile, median carina of pronotum straight in X. parvula ); posterior angles of lateral lobes of pronotum truncate and apex of posterior angles bearing triangular (posterior angles of lateral lobes of pronotum truncate in X. parvula ); middle femur of male equal to visible part of tegmen in width (middle femur of male narrower than visible part of tegmen in width in X. parvula ). It is also similar to Xistra bannaensis Deng et al, 2021 but differs from the latter by length of body in female: 13.0– 13.5 mm (length of body in female: 7.5–7.8 mm in X. bannaensis ); posterior angles of lateral lobes of pronotum truncate and apex of posterior angles bearing triangular (posterior angles of lateral lobes of pronotum truncate in X. bannaensis ); middle femur of male equal to visible part of tegmen in width (middle femur of male 1.3 times as wide as visible part of tegmen in width in X. bannaensis ).

Etymology. The specific epithet is derived from “ nigriabdominis ”, meaning Sternites of abdomen is black. Distribution. P. R. CHINA: Sichuan.

Figures

FIGURE 4A–E. Xistra nigriabdominis Deng, sp. nov., holotype female.A—body, lateral view; B—the same, dorsal view; C— head and anterior part of pronotum, dorsal view; D—head and anterior part of pronotum, lateral view; E—head, frontal view.

FIGURE 5A–H. Xistra nigriabdominis Deng, sp. nov., holotype female: A—left fore femur, lateral view; B—left mid femur, lateral view; C—left hind femur, lateral view; D—left hind tibia, lateral view; E—left posterior tarsus, lateral view; F—subgenital plate of female, ventral view; male, paratype: G—body in dorsal view; H—body in lateral view.