Rhytidaspis arfak, Ingrisch, 2019

Ingrisch, Sigfrid, 2019, Revision of the genus Rhytidaspis Redtenbacher, 1891 including the description of a new genus Haudrhytidaspis gen. nov. (Orthoptera: Tettigoniidae: Conocephalinae), Zootaxa 4661 (2), pp. 343-370: 351-352

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Rhytidaspis arfak

sp. n.

Rhytidaspis arfak   sp. n.

Figs. 1 View FIGURE 1 J–K, 2C–E, 3E–F, 4A, 5B, 6B, 7A–C, 8A–C, 9B, 10K–N, 11A, E, I, M, P, T, W

Holotype (male): Indonesia, Papua Barat: Arfak Mountains (NE Birdshead Peninsula), Kofo ( Anggi ) [Koffo, 1°24’S, 133°55’E], elev. 2000 m, 1–30.vi.1928, leg. E. Mayr (Berlin ZMB). GoogleMaps  

Other specimens studied: same data as holotype— 3 females (paratypes, ZMB); Arfak Mountains , Siwi [Momi Waren, Manokwari Regency, 1°33’S, 134°02’E], 21.iv.–25.v.1928, leg. E. Mayr— 8 females, 12 males (paratypes, ZMB) GoogleMaps   .

Diagnosis. The new species is similar to R. picta   . It differs by the male cerci having the internal proximal angle of the dorsal apical lobe distinctly projecting and twisted instead of not projecting and by the apical tooth of the ventral apical lobe being smaller and inserted in middle of the apical margin instead of at external angle. The titillators have the granular extension on top of the U-shaped curvature followed by a long tubular extension instead of a short conical extension and the apical branch lies in the longitudinal axis of the titillators instead of being twisted against it. From other species of the genus it also differs by the male cerci and the shape of the male titillators as outlined in the key. The apical tooth of the male cerci is inserted in middle of the apical margin and can be seen from above while in the other species except R. picta   it is inserted at the underside of the apical margin and often hidden when seen strictly from above.

Description. Fastigium verticis before eyes 2.0– 2.5 mm; fastigium verticis from base 2.5–2.8 mm; dorsal eye length 1.6 mm; greatest diameter of eye 1.6–1.8 mm; fastigium verticis with a minute tubercle at base; laterally compressed; in lateral view broad, apical area narrowed and faintly curved ( Figs. 10 View FIGURE 10 M–N).

Male. Stridulatory file on underside of left tegmen little curved on both sides, in middle straight; 2.2–2.5 mm long; teeth medium sized, in basal third hyalinous, rather spaced, in apical area narrowed and very small; in middle of file with 25.8–27.6 teeth per mm ( Fig. 4A View FIGURE 4 ). Right tegmen with mirror elevated, transverse ovoid; 1.1–1.3 mm long 1.5–1.9 mm wide; ( Figs. 3 View FIGURE 3 E–F). Titillators elongate, with a huge U-shaped fold in middle; also in basal half curved, giving them an S-shaped appearance; at base with a membranous muscular sac; in U-shaped center with a roughly semi-oval extension that is granular along margin and on internal surface, membranous on external surface; that structure is followed by a rather long granular and tubular, obtuse extension pointing apicad, and then by the longer compressed apical part of the titillators with rather large teeth at tip. This apical area is accompanied by an elongate, little curved and obtuse sclerite at dorso-proximal side; additionally, there is an oval compressed apicolateral sclerite on both sides of the titillators ( Figs. 8 View FIGURE 8 A–C, 9B, 10K). The two titillators are kept together by a strong muscular “band” as a functional unit.

Female. Female subgenital plate with lateral margins of ventral surface approaching from base to tip, with little concave lateral margins; apical lobes rather narrow, distinctly spaced with acute tip ( Figs. 11A, E, I, M, P, T, W View FIGURE 11 ).

Coloration male. Face dark red brown to nearly blackish red, vertex medium reddish brown, ventral area of fastigium verticis black, dorsal area brown; antennal scrobae, scapus and pedicellus black, flagellum yellowish brown; sub-ocular carina of same color as face, genae of lighter color, mandibles and labrum orange brown, upper part of clypeus of same color as face, in few specimens orange or green, lower part of clypeus green, often faded to yellowish in museum specimens; palpi yellowish, last two segments of maxillary palpi infumated with light tips ( Figs. 2 View FIGURE 2 C–E). Pronotum red brown. Abdominal tergites yellow, ochre or brown with narrow black band along hind margin and wide black lateral bands. Meso- and Metasternum black; abdominal sternites brown. Tegmen yellow with few scattered black dots. Legs medium to yellowish brown, tibiae and tarsi of lighter color than femora; coxa and trochanter of all legs black or dark brown, anterior and median femur with black or dark brown transverse strokes, hind femur in more than basal third black or dark brown, in some specimens less darkened, in other specimens the dark spot is dissolved into transverse strokes towards end ( Fig. 1K View FIGURE 1 ). Male tenth abdominal tergite black, in middle and including apical projections brownish yellow; cerci yellow. Male subgenital plate black except at very base; styli black with yellow tip. The intensity and extension of the dark brown to black color pattern varies between specimens.

Coloration female. As in male. Lower part of clypeus green. Abdominal tergites ochre to light brown with narrow black band along hind margin; coxa and trochanter of all legs blackish brown; anterior and median femur with black or dark brown transverse strokes very expressed; the dark spot in basal area of hind femur is rather dark brown or even light to medium brown and towards end dissolved into transverse strokes ( Fig. 1J View FIGURE 1 ). Female tenth abdominal tergite, cerci and epiproct yellowish brown. Subgenital plate black but bend up lateral areas dark brown; base of ovipositor black, remainder medium brown.

Measurements (13 males, 11 females).—Body: male 33–44, female 20.5–41.0; pronotum: male 10.5–12.0, female 9.0–11.5; tegmen: male 6.0–7.5, female 2.5–4.5; hind femur: male 19.5–24.0, female 21.0–27.5; anterior femur: male 10.5–12.5, female 11.5–15.0; antenna: male 115; ovipositor: female 20–25 mm.

Etymology. Named after the type locality; noun in apposition.


Museum für Naturkunde Berlin (Zoological Collections)