Rhopalina bachma Tan & Storozhenko, 2023

Tan, Ming Kai, Vu, Trung Thanh, Le, Cuong Viet Canh & Pham, Thai Hong, 2023, Pygmy grasshoppers (Orthoptera: Tetrigidae) from B ạch Mã National Park, central Vietnam, Zootaxa 5319 (2), pp. 199-223 : 215-217

Rhopalina bachma Tan & Storozhenko , sp. nov.

( Fig. 17 )

Material examined. VIETNAM, Th ừa Thiên Hu ễ Province, B ạch Mã National Park : • ♀ holotype; Rhododendron Trail, heading to Four Lakes, N16.18950 E107.85360, 1160.0± 7.7 m.a.s.l.; 9 March 2023, 11h02; among leaf litter; coll. M.K. Tan & V. T. Trung; VIET.23.62 ( VNMN) ( Fig. 17 ) .

Remarks. This represents the second species from this little-known genus. The previously monotypic genus consisted of Rhopalina javana Tinkham, 1939 from Java. Here, a second species from this genus was discovered in Indochina (quite far away from Java) and is described.

The fastigium of the holotype has its right margin rounded, but its left margin emarginated in the middle. It is unclear if this asymmetry is due to defects (e.g., damaged during individual development), injuries or genuine character.

Diagnosis. The new species is similar to Rhopalina javana in the general habitus, colouration and the shape of fastigium but differs from latter by the antennal groove inserted at the lower margins of the eyes, the tegmen stouter, 2.4–2.5 times as long as wide, and the pronotum well-surpassing apices of ovipositor (in R. javana , the antennal groove instead of above lower margins of the eyes, the tegmen 2.6–2.7 times as long as wide, and the pronotum slightly surpassing apices of ovipositor).

Etymology. The species is named after the type locality, Bạch Mã National Park; noun in apposition.

Description. Habitus as shown in Figs. 17A, 17B . Different shades of brown, ranging from pale brown, dark brown to red brown, well camouflaged against leaf litter on the ground.

Head: In frontal view ( Fig. 17C ): antennal groove inserted at lower margin of eyes. Fastigium produced into obtuse apex. Face with numerous small nodules and large oval nodules above clypeal triangle; with robust lateral carinae running from ventrad of eyes to labrum, slightly bent in middle. Frontal costa elongated, bifurcation of frontal costa in line with slightly dorsal of middle of eye. Facial carinae straight and slightly diverging ventrally. Compound eyes hemispheric, not exerted above vertex, 1.41 times taller than wide. Lateral ocelli slightly ventral of bifurcation of frontal costa and slightly above antennal groove in line with middle of eye. In dorsal view ( Fig. 17A ): apex of fastigium surpasses frontal margin of eyes; right margin of fastigium rounded, left margin emarginated in the middle. Vertex 1.47 times wider than eye width. Lateral carinae of fastigium not distinct; median carina more distinct, reaching apex of fastigium. In lateral view ( Fig. 17B ): frontal costa well protruding in front of eyes into obtuse apex. Mouthparts with labrum pale coloured. Maxillary palps pale coloured with tint of grey on anterior (or dorsal parts), elongated; with apical (fifth) segment more oval, longest following by third segment and then subapical (fourth) segment.

Pronotum: Pronotum surpassing posterior femur, nearly reaching middle of posterior tibia, 3.26 times longer than wide (pronotal lateral lobe width). In lateral view ( Fig. 17B ): with median, humero-apical and interhumeral carina weakly produced. Infrascapular area broad. Angle of ventral sinus between lateral shoulder and lateral lobe nearly right-angled. In dorsal view ( Fig. 17A ): median carina distinct throughout length of pronotum (except very close to the posterior end). Lateral carinae distinct. Interhumeral carina distinct, diverging posteriorly. Lateral lobe of pronotum slightly produced, and broadly triangular; posterior margin of lateral lobe acute. Apical end of pronotal disc narrow and truncated.

Legs: Fore and middle legs ( Fig. 17A ): femora generally marmoration of pale and dark spots; tibiae with dark and light bands. Hind legs ( Fig. 17B ): hind femur about 4.29 times longer than wide, about 1.09 times longer than hind tibia; with clear carinae along dorsal margin; marmoration of pale and dark spots and ventrad of ventroexternal carina dark coloured. Knee of posterior femur with antegenicular and genicular teeth acute. Hind tibia dark coloured with shades of pale colouration; with six spines on each lateral margin, with numerous spinules between these large dorsal spines. Basal article of hind tarsus generally pale coloured, 1.38 times longer than apical article; middle article dark coloured very short; apical article white, except apex being slightly darker in colouration.

Abdomen: Tergites and sternites typically dark coloured with pale-coloured nodules. Ovipositor ( Fig. 17D ) with pale-coloured spinules with apex red brown; dorsal and ventral valves with sparse hairs along dorsal and ventral margin. Dorsal valve with eight dorsal spines, apex acute; ventral valve with six ventral spines typically smaller than dorsal spines; apical ventral spine of ventral valve more hooked at apex than apical dorsal spine of dorsal valve; spines on valves increasing larger and robust apically. Apices of ovipositor valves red brown. Subgenital plate short in lateral view ( Fig. 17D ), truncated with medial lobule in ventral view ( Fig. 17E ).

Measurements (in mm). PL = 10.34; PW = 3.18; PH = 1.73; HWL = 8.13; HFL = 5.10; HFW = 1.19; TL = 1.20; VW = 0.66; EW = 0.45; SW = 0.19; IAH = 0.22; BL = 8.16; PAW = 1.45; PPW = 1.99; MAL = 0.36; MAW = 0.05; 1 stAW = 0.20; TW = 0.55; FFL = 1.92; FFW = 0.53; MFL = 2.09; MFW = 0.54; HTL = 4.67; 1 st TaL = 0.87; 3 rd TaL = 0.63; SGPL = 0.67; SGPW = 0.54; OVDL = 1.02; OVDW = 0.31; OVVL = 1.01; OVVW = 0.25

Ecology. The leaf litter area at which the specimen was collected was not too far from a forest stream, but the area is clearly elevated and probably not part of the water table.

Distribution. So far known only from type locality.

Type locality. Vietnam, Th ừa Thiên Hu ễ Province, B ạch Mã National Park .

Figures

FIGURE 17. Rhopalina bachma sp. nov. ♀ holotype: dorsal (A) and lateral (B) views of habitus; face in anterior view (C); abdominal apex in lateral (D) and ventral (E) views. Scale bars: 5 mm (A, B), 1 mm (C–E).