Rentziella rufa, Morris & Ingrisch & Willemse & Willemse & De Luca & Klimas, 2025

Morris, Glenn K, Ingrisch, Sigfrid, Willemse, Fer, Willemse, Luc, De Luca, Paul A. & Klimas, Dita, 2025, Stridulation songs of some Tettigoniidae (Ensifera, Orthoptera) from Papua New Guinea, Zootaxa 5600 (1), pp. 1-81 : 38-42

Rentziella rufa sp. nov.

( Figs 35–37 AC, 38, 43)

Specimens studied. Holotype male: 29.x.1963, Aiyura Amomonta, EH PNG 5600 ft J.H. Barrett, ex Pandanus ; separate label: n. 29218; Eastern Highlands District NE New Guinea (Depository NBC Leiden).

Allotype female: 23.viii.1959, Aiyura Akuna, EH PNG 6000 ft, J.H.Barrett, ex Pandanus ; Eastern Highlands District NE New Guinea (Depository NBC Leiden).

Paratypes: (1 male) 28–30.xii.1966, Aseki Bulolo , Morobe District PNG; (1 male) 23.viii.1959, Aiyura (Akuna), 6000 ft; (2 males) 29.x.1963, Aiyura Amomonta 5600 ft J.H. Barrett; MKMM follow: (F. Willemse intended holotype male) “ 19.viii.1981, Mt. Kaindi ‘Gress. Russet’ see file ablat. [file teeth ablated] PNG ”; ( FW intended allotype female) “ 19.viii.1981, Mt. Kaindi PNG ”; (4 males, 2 females) “ 19.viii.1981, Mt. Kaindi PNG ”; (1 male) “ 30. viii.1981, Mt. Kaindi PNG ” . Paratypes (6 males 3 females) from Mt. Kaindi ; ‘ G.K. Morris’ absent from labels .

Description. Male.—As generic description. Elytra remarkably strongly coriaceous, when flexed widely overlapping each other dorsally and even enveloping tip of abdomen on ventral side; R and Sc already separated from each other at base, running parallel at 1 mm distance from each other, M indicated. Stridulatory area wider than pronotal width of 6.5–7 mm; total width of elytron 10–11 mm and stridulatory area 10–12 mm long, being half total length of elytron; stridulatory file of left elytron remarkably long, about 6 mm, in ventral view about straight, strongly widening from proximal end, widest teeth in mid part 0.40–0.45 mm and further distally only slightly tapering again, distal end at posterior margin of elytron and provided with a transversely placed inflated ridge; in profile concave throughout its length, mostly in proximal third; spacing of teeth very narrow proximally (e.g., 25 teeth per 0.25 mm) increasingly wider towards the mid part (4–5 teeth per 0.25 mm) and further distally again slightly closer (5–6 teeth per 0.25 mm); number of teeth in proximal third about 80–100 followed by about 50 more widely set and functional teeth until distal end of file. Mirror of right elytron roughly oval shaped, length about 6 mm, width about 4 mm, deepest point about 2 mm and provided along posterior margin with a strong elongate fold (overmirror fold) of about 2 mm width ( Fig. 37C ).

Legs of normal length, mean ratio length of pronotum to length of hind femur 1:3.6. Fore femur unarmed, mid femur with 2–3 spines on ventro-external keel in distal area, hind femur with 6–9 spines along ventro-external keel.

General coloration reddish brown. Base of pedicel, antennal scrobae, clypeal suture and hind edge of genae black. Lower margin of pronotum black. Some males from Mt. Kaindi have a green pattern as follows: frons, genae, scape and pedicel, distal end of femora and all tibiae dark olive green except very tip of tibiae; first two tarsal segments brown, last one also green, coxae may also be partly green.

Female ( Fig. 38C ).—Slightly larger than male. Elytron less broad but of similar length, reaching almost tip of ovipositor and hind knee. Subgenital plate and ovipositor as described. Coloration as in male but green pattern absent. Clypeal suture, hind edge of genae, lower part of antennal scrobae, articulation between scape and second antennal segment and ventral margin of pronotum blackish. Apical half of ovipositor dark brown.

Measurements. Length in mm (male n = 11, female n = 4): body male 24.5–26.1, female 25.2–30.3; pronotum male 4.7–4.9, female 5.0–5.7; elytron male 19.3–21.1, female 20.1–25.9; hind femur male 16.3–18.5, female 19.2– 21.0; ovipositor 10.5–11.6.

Etymology. Named for its reddish-brown general coloration.

Distribution and Habitat. Known from Mt. Kaindi near Wau and Aseki-Bulolo, both Morobe District and the surroundings of Aiyura, Eastern Highlands District, NE New Guinea.

Comments. Discrimination of this species from other mecopodines, particularly from members of the Mossula group, has already been pointed out above under the discussion of the genus.

Stridulation. Four different males contributed to measurements of song structure and the values given here are averages of a sample of 10 calls from each of these males. The species employs transient stridulation. The song is a sequence of pulse trains ( Fig. 43A ). Each train (apparently a one-way file run) has an average duration of 160 ms and includes>100 transient pulses, which is roughly in accordance with the observed high tooth density of the file (see above). Time-discrete throughout, pulses begin from a remarkably low amplitude becoming more intense very gradually, giving an evenly rising amplitude envelope over the first>2/3 of the train ( Fig. 43 AB). (The train’s stereotyped shape recalls a child’s top.) The pulse train period is 723 ms on average. Each transient pulse starts in a complex wave of higher frequencies ( Fig. 43D ) which ends with a more sinusoid lower frequency wave ( Fig. 43C ); this is unusual for transient stridulators. This sinusoid wave is responsible for the low audio frequency band centred on 6.6 kHz ( Fig. 43 CF) as confirmed by time and spectral domains ( Fig 43 EF). Low ultrasonics extend in a band from the high audio to just beyond 30 kHz ( Fig. 43C ).

In Canada on Dec. 13, 1981, sound levels of a still vigorous male were measured at 20 cm lateral aspect insect body to microphone tip. We used a B&K 2204 sound level meter on impulse mounted with a ¼” microphone. Ten readings on the left and ten on the right gave an average of 94.6 dB on the left and 102.8 on the right, a difference in lateral sound fields of 7.7 dB. This sound level asymmetry is consistent with the open side of the overmirror fold.

Figures

FIGURE 35. Rentziella rufa sp. nov. Habitus, insect on glass.

FIGURE 36. Rentziella. rufa sp. nov. Habitus, insect on fist.

FIGURE 37. A) Rentziella rufa gen. & sp. nov., habitus of male dorsal aspect (Fer Willemse intended male holotype, type of genus); B) Rentziella ‘big blue’ sp. nov. undescribed species, habitus of male (F. Willemse intended male holotype); R. rufa male with extended right male elytron right male elytron showing overmirror fold (paratype).

FIGURE 38. Rentziella rufa sp. nov.: A) male holotype (chosen by F. Willemse) in lateral aspect; B) same specimen viewed dorsally at different magnification; C) Rentziella rufa sp. nov. (F. Willemse intended female allotype).

FIGURE 43. R. rufa acoustic analysis:A) 3 phonatomes (= pulse trains) from call sequence, ~3 calls/s [d 10cm 21.5°C, QMC]; train increments steadily for most of its duration; B) 3rd train in A at higher time resolution indicates transient stridulation; C) Fourier power spectrum of phonatome in B shows low-Q carrier peak centred at 7 kHz; D) high-resolution time sample from the train in B of 2 successive pulses separated by 2.2 ms, complex wave train of each tooth event repeats in high and low frequency wave forms; E) time sample of one pulse’s following waveform; F) spectrum of time sample in E showing 7 kHz peak.