Sathrophylliopsis mentham, Tan & Wahab, 2020

Tan, Ming Kai & Wahab, Rodzay Bin Haji Abdul, 2020, New taxa and notes on palm and false-leaf katydids (Orthoptera: Tettigoniidae: Mecopodinae, Sexavaini; Pseudophyllinae, Cymatomerini) from Brunei Darussalam, Zootaxa 4808 (2), pp. 301-316 : 307-310

Sathrophylliopsis mentham sp. n.

( Figs. 4–6 )

Material examined. Holotype, 1 male (KB.19.18), Brunei Darussalam, Temburong District, Kuala Belalong Field Studies Centre, along Ashton Trail , N4.54555, E115.15691, 176.0±6.0 m.a.s.l., 2018 hours, on rattan leaf feeding on dead leaf, 14 July 2019, coll. M. K. Tan & H. Yeo ( UBDM).

Genus status. Our specimen belongs to Sathrophylliopsis for the striking characters of this genus: femora with margins smooth and carinate, not lobate or dentate; pronotum nearly smooth; radial vein of tegmen forms two deep angular curves towards the radial branch vein in its apical half; fully developed hind wings (de Jong, 1939).

Diagnosis. This new species differs from congeners by the body being not covered with dense long hairs, and the anterior margin of tegmen not undulated and anterior and posterior margins are not diverging apically.

Comparison with congeners. In addition to the diagnostic differences, this species differs from S. longepilosa ( Brunner von Wattenwyl, 1895) by the male epiproct being triangular instead of tongue-shaped and the subgenital plate has the apical lobes much shorter than the stylus instead of the lobes longer than the stylus; from S. truncatipennis Beier, 1944 it differs by the tegmen distinctly tapering apically instead of widening apically, and the stridulatory area on left tegmen is more elongated.

Description. Habitus typical for the genus, albeit lacking dense long hairs around body, as shown in Figs. 4 , 5A .

Fastigium of vertex stout, triangular; tapering into an acute apex; not surpassing antennal scapus ( Fig. 6A ). Frons oblique, smooth; without lateral carinae. Maxillary palps elongated and slender; apical segment almost twice the length of subapical and third segments; apical segment with apex slightly swollen and faintly bent. Eyes protruding, rounded to slightly oval ( Figs. 6B ); median and lateral ocelli absent.

Pronotum weakly rugose, 2.06 times as long as head; disc 1.06 times as wide as long, anterior part broadly rounded into paranota, apical area not raised but shouldered ( Fig. 6A ); anterior margin nearly straight; posterior margin broadly curved, straight in middle ( Fig. 6A ). Lateral lobe about 1.95 times as long as high; lower margin straight; marginal fold of pronotum very narrow, smooth ( Fig. 6B ). Thoracic auditory spiracle very small, rounded, not covered by paranota ( Fig. 6B ). Prosternum without spine. Mesosternal lobe broad and metasternal lobes narrow, apices obliquely truncated.

Anterior coxa without spine. Anterior tibia with both tympana conchate, very swollen, opening oval, very similar in size. Femora with following number of robust spines on ventral margins: anterior femur without ventral spines; middle femur with 3 to 4 external spines at apical half, 0 internal spine; posterior femur with 5 to 6 external spines at apical half, 0 internal spine. All knee lobes lobular, without spine externally and internally. Tibiae with following number of spines on ventral margins: anterior tibia 3 external, 4 very small internal; middle tibia 3 external, 3 slightly larger internal. Middle tibia with 3 to 5 nodule-like dorsal spines on internal and external margins.

Male. Tegmen macropterous, surpassing abdominal apex, anterior and posterior margins of tegmen not diverging apically, anterior margin very faintly undulating, apex obliquely truncated ( Fig. 5B ). Stridulatory file on CuPb underside of left tegmen crescent-shaped, basal end more strongly curved than anal end; circa 6.8 mm long; with many teeth densely and evenly distributed ( Fig. 6C ). Mirror areas on tegmina asymmetrical. Mirror on left tegmen 1.17 as long as wide, with posterior end rounded ( Fig. 6D ). Mirror on right tegmen more developed, rectangular, with anterior margin more rounded, 1.50 times longer than wide, area net-like especially at distal end ( Fig. 6E ). Hind wings completely concealed under tegmina.

Tenth abdominal tergite strongly and angularly excised in middle, lateral lobe with apex rounded ( Fig. 6G ). Epiproct triangular, wider than long, apex obtuse; furrowed longitudinally in middle. Cercus conical, stout, tapering to a subacute apex bearing a small tooth pointing internally ( Fig. 6F ). Subgenital plate elongated, shaft-like, lateral margins narrow in basal half, widens a little then tapers towards posterior end; posterior margin narrowly excised in middle, lateral lobes short with truncated apex; styli long, circa 2.3 longer than lateral lobe of subgenital plate, oblong to pyriform, posterior end with apex rounded ( Fig. 6H ).

Female. Unknown.

Colouration. Generally pale brown with white and darker brown patterns, with tint of greyish-green; somewhat mimicking lichens when alive; brown when dry-pinned ( Figs. 4 , 5A ). Face white, with a dark curved stripe extending from beneath of scapus; genae pale brown. Mouthparts pale brown. Fastigium verticis with apex brown. Scapus brown, antennae yellow brown. Dorsum of head generally brown ( Fig. 6A ). Pronotum with dorsal disc and lateral lobe generally pale brown with tint of greyish-green; dorsal disc with a faint dark longitudinal stripe in anterior half; posterior margin darker brown ( Fig. 5A ). Tegmen mottled red brown, pale brown and grey; radial field distinctly pale mint green with oblique white stripe ( Figs. 4 , 5 ). Coxae dirty green dorsally and pale ventrally. Anterior and middle femora and tibiae pale brown with tint of green and yellow, with carinae pale ( Fig. 4 ). Posterior femur and tibia pale, with dorsal part brown. Thoracic and abdominal tergites pink brown dorsally, pale brown laterally; thoracic sternites pale brown, mesosternite and metasternite at posterior end with a dark transverse stripe, lobes darkened; abdominal sternites pink.

Measurements (in mm). BL = 28.1, PL = 7.4, PW = 7.0, TL = 31.7, HFL = 15.2, HTL = 14.0.

Etymology. The species name refers to the characteristics pale mint green colouration on the radial field (mentham = mint in Latin).

Figures

FIGURE 4. Sathrophylliopsis mentham sp. n. male holotype in its natural environment.

FIGURE 5. Sathrophylliopsis mentham sp. n. male holotype dry-pinned in dorsal view (A); left tegmen in dorsal view (B). Scale bars: 10 mm.

FIGURE 6. Sathrophylliopsis mentham sp. n. male holotype: head and pronotum in dorsal (A) and lateral (B) views; stridulatory file on the left tegmen in ventral view (C); stridulatory area on left (D) and right (E) tegmina in dorsal view; abdominal apex in lateral (F), dorsal (G) and ventral (H) views. Scale bars: 5 mm (A, B, D, E); 2 mm (C, F–H).