Rentziella, 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 : 42-44

Rentziella ‘big blue’ undescribed species

( Figs 37B , 40–42 , 44 )

Specimen studied. Fer Willemse intended holotype male: Papua New Guinea, Mt. Kaindi: 19 viii 1981, Coll. Glenn Morris ( NBC Leiden, MKMM). Specimen discovered missing from NBC Leiden 2024 .

Description. Male ( Fig. 37B ).—Differing from genus type-species as follows. Size larger. Surface of pronotum less coarsely rugose, fore margin convex. Meso- and metasternal lobes more pointed. Elytra less coriaceous, relatively less broad, not extending so far ventrally as in type-species, tapering apically, tip narrowly rounded, main veins more recognizable; stridulatory area as wide as pronotal width (about 5 mm) and slightly longer than third of elytron length (11 mm); file of left elytron less concave ventrally, shortest distance between proximal and distal end 4.4 mm, widest in mid and distal parts, 0.25 mm, distal end provided with transverse raised ridge, total number of teeth about 100, in proximal fourth very closely set, in remainder more widely and almost evenly distributed, 6 teeth per 0.25 mm; mirror of right elytron elongate, length 5.2 mm, width 3.4 mm, with 1.5 mm wide fold (OMF) covering mirror from above. Legs comparatively slender, ratio pronotal length to length of hind femur 1:5. Fore coxa with a strong spine. Ventro-external keel of fore femora with 3, of mid femur with 2, of hind femur with 8 and ventro-internal keel of hind femur with 5 spines. General coloration pale brown. Head from above reddish brown; scape, ventral part of scrobae, clypeal suture and ventral margin of pronotum blackish as in type-species. Left posterior angle of pronotal dorsum with green flush. Venation of elytra, including archedictyon, dark brown dorsally, pale brown laterally.

Female.—Unknown.

Measurements. Length in mm (male n = 1): body 32; pronotum 5.6; elytron 29; hind femur 28.

Distribution and habitat. Known only from one male specimen taken on Mt. Kaindi near Wau, Morobe District, NE New Guinea. It was found perching on Pandanus in earshot of the type species of the new genus Rentziella rufa .

Searching at night up and across Mt. Kaindi’s eastern face we discovered a narrow path. It wound generally higher diagonally across the mountain, emerging onto the access road to the summit about 600 paces below the microwave repeater station. This trail was very steep in some places “with ‘steps’ of barefoot-pounded mud between tree roots; it took us the whole way through undisturbed montane forest. Over several hours we stopped frequently to capture accessible Paraphyllomimus spp. At one point the trail sloped a little downward and passed by huge Pandanus plants. Specimens of Rentziella both rufa and ‘big blue’ were perched in amongst the edge-serrated Pandanus leaves, detected by the slow agitation of their very long antennae ( Fig. 42 ) waving in the light beam. We were able to effect capture by gingerly pulling down the appropriate Pandanus leaf and encouraging the insect into the mouth of a net held below. Initially we also took a (large colourful) female of R. ‘big blue’, but it escaped during transfer to a vial. My expletives did not preclude the taking of a male that had orginally been perched quite near this female. He emitted a loud protest sound on being trapped within the net. The moon, past full but still more than half, emerged from clouds giving the forest a silvery white appearance. It was quite bright, at times penetrating down to the trail. Once out on the road under a clear sky we no longer needed our flashlights. The summit and the walk down the road to the station was bathed in moonlight and banks of white cloud lay between the folds of the hills and out in the valley of Eadie Creek. (excerpted from the daily journal of Aug. 19).

Comments. Specific distinction from type-species R. rufa as given in the description: bigger size, proportions and texture of the male elytra and its slenderer legs are obvious. We are not fully convinced of its congeneric state.

Stridulation. This insect called with a period of about 1 sec. One such call is shown in Fig. 44A, a train of>60 irregularly time-separated pulses, creating overall a ‘time symmetric’ amplitude envelope rising (first half) then falling (second half). The pulses of the train, as shown in higher time resolution ( Fig. 44C ) also build and decay symmetrically, rather than having the exponential decay of its congener R. rufa . The dominant carrier near 7 kHz ( Fig 44B ) is almost the same as R. rufa . Spectral frequencies are all in the audio with an intense peak centred on 6.7 kHz. Perhaps more than one tooth contributes to each sinusoid making up the pulse. Scraper velocity is presumably below that necessary to sustain a many-waved prolonged ‘resonant’ pulse.

Figures

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 40. Rentziella ‘big blue’ sp. nov. undescribed species, frontal aspect with white-rimmed oval tympanal openings on foretibiae.

FIGURE 41. Rentziella ‘big blue’ habitus in more lateral aspect.

FIGURE 42. Rentziella ‘big blue’ on entomologist shows long antennae to advantage.

FIGURE 44. Rentziella ‘big blue’ acoustic analysis: A) one phonatome (= pulse train); B) Fast Fourier transform of power spectrum showing most intense carrier a low-Q peak near 6.7 kHz, ultrasonics absent; C,D) at higher time resolution pulse waveforms appear as variable-amplitude sinusoids suggesting multiple tooth events per pulse.