Bioacoustics of Ornebius

Ornebius sound recordings taken in Auckland , Coromandel, Waikato and in New Plymouth yield a song with a peak frequency between 4.5 and 5.6 kHz. Chirps are approximately one second apart and consist of three pulses; a single pulse followed by a pause of 0.3 seconds then two more pulses close together ( Fig. 34 ). This song matches that of Ornebius aperta ( Otte & Alexander 1983 : fig. 314; Gwynne et al. 1988 ). As previously observed by Ramsay (1990 , 1991 ), the paraprocts are also a good match for Ornebius aperta , club-like in shape, narrowest at the base and widest one fifth of the length from the apex ( Fig. 33G–I ). Ornebius crickets around Whangārei and Kerikeri in Northland sing at a peak frequency of 4 kHz (T = 23°C). Chirps are approximately two seconds apart and consist of four to five pulses; a single pulse followed by a pause longer than half a second then three to four pulses close together ( Fig. 35 ). This song does not match any known species of Ornebius . The male paraprocts are subtly different from those of O. aperta , with a longer narrow neck at the base, and the widest point one fourth of the length from the apex ( Fig. 33K ). While this shape may resemble more closely the paraprocts of Ornebius wandella Otte & Alexander, 1983 , the latter species has two very prominent hair tufts projecting backwards from the posterior margin of the suranal plate ( Otte & Alexander 1983 : fig. 312y); these are missing in Ornebius aperta and in Ornebius crickets from Northland ( Fig. 33D–E ). Except for the subtle difference in the shape of the male paraprocts, male and female Ornebius crickets from Northland cannot be differentiated from Ornebius aperta by morphology. Based on this information, Ornebius crickets from Northland might be a species other than Ornebius aperta , but I am not confident enough to state that they definitely are, let alone to designate a new species. This really needs to be done in the context of a comprehensive revision of Ornebius from the east coast of Australia and from the wider Pacific region, based on morphology, song and molecular data. I will therefore refer to the Ornebius population in Northland as Ornebius aff. aperta Otte & Alexander, 1983 , where the abbreviation ‘aff.’ is used as suggested by Sigovini et al. (2016) . The boundary between the Auckland and Northland Ornebius populations is unknown.

Description. Male. Body shape typical of the genus ( Fig. 12A ). Head small with a distinct red transverse groove which middle raised and sides sunken in front of pronotum. Rostrum slightly wider than antennal scape, faintly furrowed in the middle; vertex flatten. The apical segment of maxillary palpus distinctly widened; fourth and fifth segments of equal length, and a little shorter than the third one ( Fig. 13A ). Pronotum length nearly three times as head, and longer than width. Pronotal anterior margin straight, posterior margin convex, covering a portion of tegmen and reaching the base of mirror. Fore tibia internal tympanum large and oval, without external tympanum. Tegmen 1.1 times wider than the posterior area of pronotum; apical field convex; mirror roughly triangular, almost as long as width ( Fig. 13B ). Hind femur 1.2 times longer than hind tibia; hind tibia 2.2 times longer than hind metatarsus. Male genitalia visible externally. Abdomen: Supra-anal plate with last abdominal tergite and epiproct distinctly separated by a transverse suture ( Fig. 14B ). Last abdominal tergite transverse, distinctly narrowing posteriorly, rhombic; with dense setae both side of along the apical surface; anterolateral area with a compressed projection ( Fig. 14B ). Epiproct rounded, slightly less wide than posterior margin of last abdominal tergite; setose along posterior margin ( Fig. 14B ). Paraproct process medium-sized, slightly compressed in basal half; external side and apex black, internal side white; apical area styliform, acute ( Figs 14A & C ). Genitalia: Epiphallus membranous; external sclerites elongate, divided at basal and apical part, forming an angle; internal sclerites slightly curved ( Fig. 15F ). Female. Apterous. Pronotum short, little longer than wide, scarcely narrowing in front. Abdomen ornamented with eight lines dorsally ( Fig. 12B ). Legs and cercus distinctly pubescent. Abdomen: Supra-anal plate armed with margins strongly and laterally narrowing; epiproct with apex rounded and setose. Ovipositor straight, apex with sparse hairs ( Fig. 13C ). Colouration. Head reddish-brown; antenna with scapus and pedicellus brown, flagellum light brown; maxillary palps yellowish-brown. Pronotal disc clay bank, with white scales along the apical margin. Tegmen yellowish; in dorsal view, apex with broad black margin; black band not continuing to the lateral field. Femur pale orange. Abdomen with tergite orange, covered by yellow scales, but abdominal apex black. Male paraproct process black. Cerci light orange. Ovipositor yellowish-brown, the base and apical valves reddish-brown. Calling Song. Echeme sequence period 6–14 s, echeme sequence duration continue 2–6 s with 4–8 s echeme sequence interval. Each echeme sequence includes 3–12 echemes. Each echeme period 0.5– 0.65 s , echeme duration 0.2– 0.25 s with 0.3 s echeme interval. Each echeme includes 3 syllables. Echeme sequence rate is about 6 syllables/ s. The dominant harmonic peak observed in the spectrogram is 6.2–6.5 kHz ( Fig. 16 ).