Ceratostigma stagona, Jie & Liang & Liu, 2022

Jie, Lulan, Liang, Feiyang & Liu, Xingyue, 2022, Revision of the bark louse genus Ceratostigma Li, 2002 (Psocodea: Psocidae: Psocinae) with description of a new species from China, Zootaxa 5168 (2), pp. 196-206 : 201-204

Ceratostigma stagona sp. n.

( Figs 23–44 )

Diagnosis. Male. Forewing basal one-fifth with a slightly curved grayish white stripe; radial fork with branches diverging at an angle of about 90°. Epiproct pointed at tip, with a nearly U-shaped sclerotized area at base; hypandrium distally with a nearly hat-shaped sclerotized area. Female. Forewing basal one-fifth with a nearly V-shaped grayish white marking. Pigmented area of subgenital plate roughly T-shaped, distally nearly drop-shaped, pointed at tip; dorsal valve of gonapophyses ventro-distally with a slightly sclerotized area.

Description. Male. Coloration (in 95% ethanol). Head ( Figs 25–27 ) pale brown; vertex with two grayish white markings; epicranial suture and inner margin of compound eyes dark brown; postclypeus pale brown with brown stripes; anteclypeus pale brown. Ocelli black, an irregularly shaped brown marking between median ocellus and anteclypeus. Compound eyes black. Antennae dark brown, except scape, pedicel, and first and second flagellomere pale yellow. Maxillary palpus grayish brown, distally brown. Thorax ( Figs 25–27 ) dark brown, median area, scutellum of mesothorax and median area of postnotum pale brown. Legs brown. Forewing ( Fig. 23 ) brown, veins with proximal two-thirds yellow and distal one-third brown; a slightly curved grayish white stripe at proximal one-fifth; pterostigma reddish brown. Hind wing ( Fig. 24 ) brown.

Morphology. Head ( Figs 25–27 ) inverted trapezoidal; compound eyes ovoid. Forewing ( Fig. 23 ) membranous, Sc ending free; Rs and M meet in a point, or fused for a short distance; radial fork with branches diverging at an angle of about 90°; pterostigma subtriangular with apex rounded; discoidal cell nearly rectangular; CuA 1-2 and M+CuA 1 nearly in a line. Genitalia ( Figs 28–33 ): Epiproct ( Figs 28–29 ) nearly semicircular, pointed at apex, with a nearly U-shaped sclerotized area at base, medially with setae. Paraproct distally with a spinous projection slightly curved at apex; sensory field with about 46 trichobothria. Hypandrium ( Figs 30–31 ) of asymmetrical, simple plate, broad median ridge laterally with several creases; a dumbbell-like sclerotized area present at base. Phallosome ( Figs 32–33 ) simple, ring-like.

Measurements. B: 3.31 mm, BW: 4.99 mm. IO: 0.53 mm, d: 0.19 mm, IO/d: 2.9. f1: 1.36 mm. FWL: 4.32 mm, FWW: 1.75 mm, HWL: 3.23 mm, HWW: 1.28 mm. t1: 0.47 mm, t2: 0.22 mm.

Female. Coloration (in 95% ethanol) ( Figs 34–38 ). Same as in male, but marking between median ocellus and anteclypeus paler. Forewing ( Fig. 34 ) separated with numerous irregular pale brown markings and a V-shaped pale brown marking at proximal one-fifth. Morphology. Adult: Generally similar to male except for smaller compound eyes. Genitalia ( Figs 39–44 ): Epiproct ( Figs 39–40 ) subtriangular, with a nearly H-shaped sclerotized area, distally rounded, antero-medially with setae. Paraproct ( Figs 39–40 ) triangular, sensory field with about 38 trichobothria. Subgenital plate ( Figs 43–44 ) with short and distally rounded egg guide, pigmented area slightly sclerotized, roughly T-shaped, apex nearly drop-shaped, pointed at tip, transverse region of pigmented area nearly dumbbelllike with numerous setae. Gonapophyses ( Figs 41–42 ): Ventral valve slender, apex narrowed ventrally with short setae; dorsal valve broad, pointed at tip, with strongly sclerotized area at inner margin, ventro-distally with a slightly sclerotized area; external valve with a triangular posterior lobe.

Measurements. B: 4.16 mm, BW: 6.32 mm. IO: 0.84 mm, d: 0.17 mm, IO/d: 4.94. f1: 1.32 mm; f2: 1.32 mm; f3: 0.50 mm. FWL: 5.36 mm, FWW: 2.21 mm, HWL: 2.26 mm, HWW: 1.37 mm.

Material examined. Holotype female, CHINA: Xizang, Zayu County, Upper Zayu, Cibacun [28°63’N, 97°41’E], 2265 m, 17.VI.2019, Rongrong Shen & Yingnan He ( CAU) . Paratypes: 2 males, 1 female, same as holotype ( CAU) .

Distribution. China (Xizang).

Etymology. The epithet “ stagona ” refers to the drop-shaped apex of the pigmented area of the female subgenital plate.

Remarks. The new species appears to be related to C. gracilis and C. macrostigmatum based on similarity of the following characters: male forewing basal one-fifth with a slightly curved grayish white stripe; epiproct pointed at apex with a nearly U-shaped sclerotized area at base; hypandrium medially with a broad ridge; female forewing radial fork with branches diverging at an angle of about 90°; pigmented area of subgenital plate roughly T-shaped. The new species can be distinguished from them by the male forewing radial fork with branches diverging at an angle of more than 90°, the hypandrium distally with a nearly hat-shaped sclerotized area, the female forewing basal one-fifth with a nearly V-shaped grayish white marking, and the pigmented area of the subgenital distally nearly drop-shaped, pointed at tip.

Figures

FIGURES 23–27. Ceratostigma stagona sp. n., paratype male. 23. Forewing; 24. Hindwing; 25. Head, frontal view; 26. Habitus, lateral view; 27. Habitus, dorsal view.

FIGURES 28–33. Ceratostigma stagona sp. n., paratype male. 28–29. Epiproct and paraproct, dorsal view; 30–31. Hypandrium; 32–33. Phallosome. ep: epiproct; pp: paraproct.

FIGURES 34–38. Ceratostigma stagona sp. n., holotype female. 34. Forewing; 35. Hindwing; 36. Head, frontal view; 37. Habitus, lateral view; 38. Habitus, dorsal view.

FIGURES 39–44. Ceratostigma stagona sp. n., holotype female. 39. Genitalia, dorsal view; 40. Epiproct and paraproct, dorsal view; 41. Genitalia, lateral view; 42. Gonapophyses, ventral view; 43–44. Subgenital plate, ventral view. ep: epiproct; pp: paraproct; vv: ventral valve; dv: dorsal valve; ev: external valve.